Life Extension Magazine®

Issue: Feb 2012


Alzheimer’s disease.

An estimated 24 million people worldwide have dementia, the majority of whom are thought to have Alzheimer’s disease. Thus, Alzheimer’s disease represents a major public health concern and has been identified as a research priority. Although there are licensed treatments that can alleviate symptoms of Alzheimer’s disease, there is a pressing need to improve our understanding of pathogenesis to enable development of disease-modifying treatments. Methods for improving diagnosis are also moving forward, but a better consensus is needed for development of a panel of biological and neuroimaging biomarkers that support clinical diagnosis. There is now strong evidence of potential risk and protective factors for Alzheimer’s disease, dementia, and cognitive decline, but further work is needed to understand these better and to establish whether interventions can substantially lower these risks. In this seminar, we provide an overview of recent evidence regarding the epidemiology, pathogenesis, diagnosis, and treatment of Alzheimer’s disease, and discuss potential ways to reduce the risk of developing the disease.

Lancet. 2011 Mar 19;377(9770):1019-31

Enhancement of learning and memory by elevating brain magnesium.

Learning and memory are fundamental brain functions affected by dietary and environmental factors. Here, we show that increasing brain magnesium using a newly developed magnesium compound (magnesium-L-threonate, MgT) leads to the enhancement of learning abilities, working memory, and short- and long-term memory in rats. The pattern completion ability was also improved in aged rats. MgT-treated rats had higher density of synaptophysin-/synaptobrevin-positive puncta in DG and CA1 subregions of hippocampus that were correlated with memory improvement. Functionally, magnesium increased the number of functional presynaptic release sites, while it reduced their release probability. The resultant synaptic reconfiguration enabled selective enhancement of synaptic transmission for burst inputs. Coupled with concurrent upregulation of NR2B-containing NMDA receptors and its downstream signaling, synaptic plasticity induced by correlated inputs was enhanced. Our findings suggest that an increase in brain magnesium enhances both short-term synaptic facilitation and long-term potentiation and improves learning and memory functions.

Neuron. 2010 Jan 28;65(2):165-77

Magnesium homeostasis and aging.

Aging is very often associated with magnesium (Mg) deficit. Total plasma magnesium concentrations are remarkably constant in healthy subjects throughout life, while total body Mg and Mg in the intracellular compartment tend to decrease with age. Dietary Mg deficiencies are common in the elderly population. Other frequent causes of Mg deficits in the elderly include reduced Mg intestinal absorption, reduced Mg bone stores, and excess urinary loss. Secondary Mg deficit in aging may result from different conditions and diseases often observed in the elderly (i.e. insulin resistance and/or type 2 diabetes mellitus) and drugs (i.e. use of hypermagnesuric diuretics). Chronic Mg deficits have been linked to an increased risk of numerous preclinical and clinical outcomes, mostly observed in the elderly population, including hypertension, stroke, atherosclerosis, ischemic heart disease, cardiac arrhythmias, glucose intolerance, insulin resistance, type 2 diabetes mellitus, endothelial dysfunction, vascular remodeling, alterations in lipid metabolism, platelet aggregation/thrombosis, inflammation, oxidative stress, cardiovascular mortality, asthma, chronic fatigue, as well as depression and other neuropsychiatric disorders. Both aging and Mg deficiency have been associated to excessive production of oxygen-derived free radicals and low-grade inflammation. Chronic inflammation and oxidative stress are also present in several age-related diseases, such as many vascular and metabolic conditions, as well as frailty, muscle loss and sarcopenia, and altered immune responses, among others. Mg deficit associated to aging may be at least one of the pathophysiological links that may help to explain the interactions between inflammation and oxidative stress with the aging process and many age-related diseases.

Magnes Res. 2009 Dec;22(4):235-46

Magnesium and aging.

Over the past decades, the clinical relevance and biological significance of magnesium (Mg) have been documented. Deficiency in Mg, aside from having a negative impact on the energy production pathway required by mitochondria to generate ATP, also reduces the threshold antioxidant capacity of the aging organism and its resistance to free-radical damage. Mg also acts as an antioxidant against free radical damage of the mitochondria. Chronic inflammation and oxidative stress have both been identified as pathogenic factors in aging and in several age-related diseases. Chronic Mg deficiency results in excessive production of oxygen-derived free radicals and low grade inflammation. Aging is very often associated with Mg inadequacy and with increased incidence of many chronic diseases, with muscle loss and sarcopenia, altered immune responses, and vascular and metabolic conditions, such as atherosclerosis, diabetes and the cardiometabolic syndrome. The most common cause of Mg deficit in the elderly population is dietary Mg deficiency, although secondary Mg deficit in aging may also results from many different mechanisms. The aim of the present manuscript is to discuss the mechanisms and consequences of the modifications of Mg metabolism with age, the difficulties in the measurement of Mg status, and to review the current evidences suggesting that age-related chronic Mg deficits may be proposed as one of the physiopathological links that may help to explain the interactions between inflammation, oxidative stress with the aging process and many age-related diseases.

Curr Pharm Des. 2010;16(7):832-9

Skeletal and hormonal effects of magnesium deficiency.

Magnesium (Mg) is the second most abundant intracellular cation where it plays an important role in enzyme function and trans-membrane ion transport. Mg deficiency has been associated with a number of clinical disorders including osteoporosis. Osteoporosis is common problem accounting for 2 million fractures per year in the United States at a cost of over $17 billion dollars. The average dietary Mg intake in women is 68% of the RDA, indicating that a large proportion of our population has substantial dietary Mg deficits. The objective of this paper is to review the evidence for Mg deficiency-induced osteoporosis and potential reasons why this occurs, including a cumulative review of work in our laboratories and well as a review of other published studies linking Mg deficiency to osteoporosis. Epidemiological studies have linked dietary Mg deficiency to osteoporosis. As diets deficient in Mg are also deficient in other nutrients that may affect bone, studies have been carried out with select dietary Mg depletion in animal models. Severe Mg deficiency in the rat (Mg at <0.0002% of total diet; normal = 0.05%) causes impaired bone growth, osteopenia and skeletal fragility. This degree of Mg deficiency probably does not commonly exist in the human population. We have therefore induced dietary Mg deprivation in the rat at 10%, 25% and 50% of recommended nutrient requirement. We observed bone loss, decrease in osteoblasts, and an increase in osteoclasts by histomorphometry. Such reduced Mg intake levels are present in our population. We also investigated potential mechanisms for bone loss in Mg deficiency. Studies in humans and and our rat model demonstrated low serum parathyroid hormone (PTH) and 1,25(OH)(2)-vitamin D levels, which may contribute to reduced bone formation. It is known that cytokines can increase osteoclastic bone resorption. Mg deficiency in the rat and/or mouse results in increased skeletal substance P, which in turn stimulates production of cytokines. With the use of immunohistocytochemistry, we found that Mg deficiency resulted in an increase in substance P, TNFalpha and IL1beta. Additional studies assessing the relative presence of receptor activator of nuclear factor kB ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG), found a decrease in OPG and an increase in RANKL favoring an increase in bone resorption. These data support the notion at dietary Mg intake at levels not uncommon in humans may perturb bone and mineral metabolism and be a risk factor for osteoporosis.

J Am Coll Nutr. 2009 Apr;28(2):131-41

Depression and magnesium deficiency.

The psychiatric symptoms of magnesium deficiency are unspecific, ranging from apathy to psychosis, and may be attributed to other disease processes associated with poor intake, defect absorption, or excretion of magnesium. Serum magnesium should be determined when there are symptoms consistent with magnesium deficiency and/or in conditions which can lead to a deficiency, e.g., malabsorption, malnutrition, alcoholism and diuretic treatment. A low serum value suggests magnesium deficiency, but the diagnosis is reinforced with analyses of magnesium in the urine and a loading test with magnesium. Magnesium can be given orally or intramuscular/intravenously.

Int J Psychiatry Med. 1989;19(1):57-63

Magnesium dietary manipulation and recovery of function following controlled cortical damage in the rat.

Previous research has shown that dietary magnesium (Mg2+) deficiency prior to injury worsens recovery of function and that systemic administration of Mg2+ pre or post-injury significantly improves functional recovery. The purpose of the present study was to determine if manipulations in dietary Mg2+ would alter functional recovery following unilateral cortical injuries. Two weeks prior to injury, rats were placed on a customized diet enriched with Mg2+, deficient in Mg2+, or on a standard Mg2+ diet. Rats were then prepared with unilateral cortical contusion injuries (CCI) of the sensorimotor cortex. Two days following CCI, rats were tested on a battery of sensorimotor (vibrissae-forelimb placing and bilateral tactile adhesive removal tests), as well as the acquisition of reference memory in the Morris water maze. Serum analysis for Mg2+ prior to injury showed a diet-dependent modulation in levels. The Mg(2+)-enriched diet showed significantly higher levels of serum Mg2+ compared to the normal diet and the Mg(2+)-deficient diet showed significantly lower levels compared to the Mg(2+)-normal diet. On the placing and tactile removal tests Mg2+ deficiency significantly worsened recovery compared to the Mg(2+)-enriched and Mg(2+-)normal diet conditions. There were no statistically significant differences between the Mg(2+)-normal and Mg(2+)-enriched diets on the sensorimotor tests. On the acquisition of reference memory there were no significant difference between diet conditions; however, the Mg(2+)-deficient diet showed a trend toward impaired performance compared to the other diet conditions. The Mg(2+)-deficient diet resulted in a larger lesion cavity compared to the other diet conditions. These findings suggest that dietary Mg2+ modulates recovery of function.

Magnes Res. 2008 Mar;21(1):29-37

Magnesium deficiency accelerates cellular senescence in cultured human fibroblasts.

Magnesium inadequacy affects more than half of the U.S. population and is associated with increased risk for many age-related diseases, yet the underlying mechanisms are unknown. Altered cellular physiology has been demonstrated after acute exposure to severe magnesium deficiency, but few reports have addressed the consequences of long-term exposure to moderate magnesium deficiency in human cells. Therefore, IMR-90 human fibroblasts were continuously cultured in magnesium-deficient conditions to determine the long-term effects on the cells. These fibroblasts did not demonstrate differences in cellular viability or plating efficiency but did exhibit a decreased replicative lifespan in populations cultured in magnesium-deficient compared with standard media conditions, both at ambient (20% O(2)) and physiological (5% O(2)) oxygen tension. The growth rates for immortalized IMR-90 fibroblasts were not affected under the same conditions. IMR-90 fibroblast populations cultured in magnesium-deficient conditions had increased senescence-associated beta-galactosidase activity and increased p16(INK4a) and p21(WAF1) protein expression compared with cultures from standard media conditions. Telomere attrition was also accelerated in cell populations from magnesium-deficient cultures. Thus, the long-term consequence of inadequate magnesium availability in human fibroblast cultures was accelerated cellular senescence, which may be a mechanism through which chronic magnesium inadequacy could promote or exacerbate age-related disease.

Proc Natl Acad Sci U S A. 2008 Apr 15;105(15):5768-73

Analysis of the brain bioavailability of peripherally administered magnesium sulfate: A study in humans with acute brain injury undergoing prolonged induced hypermagnesemia.

OBJECTIVE: Based on preclinical investigations, magnesium sulfate (MgSO4) has gained interest as a neuroprotective agent. However, the ability of peripherally administered MgSO4 to penetrate the blood-brain barrier is limited in normal brain. The current study measured the passage of intravenously administered Mg into cerebrospinal fluid in patients with brain injury requiring ventricular drainage. DESIGN: A prospective evaluation of the cerebrospinal fluid total and ionized magnesium concentration, [Mg], during sustained hypermagnesemia was performed. SETTING: Neuro-sciences intensive care unit at a major teaching institution. PATIENTS: Thirty patients with acute brain injury secondary to subarachnoid hemorrhage, traumatic brain injury, primary intracerebral hemorrhage, subdural hematoma, brain tumor, central nervous system infection, or ischemic stroke were studied. INTERVENTIONS: Patients underwent 24 hrs of induced hypermagnesemia during which total and ionized cerebrospinal fluid [Mg] was measured. Serum [Mg] was adjusted to 2.1-2.5 mmol/L. Cerebrospinal fluid [Mg] was measured at baseline, at 12 and 24 hrs after onset of infusion, and at 12 hrs following infusion termination. MEASUREMENTS AND MAIN RESULTS: At baseline, total (1.25 +/- 0.14 mmol/L) and ionized (0.80 +/- 0.10 mmol/L) cerebrospinal fluid [Mg] was greater than serum total (0.92 +/- 0.18 mmol/L) and ionized (0.63 +/- 0.07 mmol/L) [Mg] (p < .05). Total (1.43 +/- 0.13 mmol/L) and ionized (0.89 +/- 0.12 mmol/L) cerebrospinal fluid [Mg] was maximally increased by 15% and 11% relative to baseline, respectively, during induced hypermagnesemia (p < .05). CONCLUSIONS: Hypermagnesemia produced only marginal increases in total and ionized cerebrospinal fluid [Mg]. Regulation of cerebrospinal fluid [Mg] is largely maintained following acute brain injury and limits the brain bioavailability of MgSO4.

Crit Care Med. 2005 Mar;33(3):661-6

Hypomagnesemia: an evidence-based approach to clinical cases.

Hypomagnesemia is defined as a serum magnesium level less than 1.8 mg/dL (< 0.74 mmol/L). Hypomagnesemia may result from inadequate magnesium intake, increased gastrointestinal or renal losses, or redistribution from extracellular to intracellular space. Increased renal magnesium loss can result from genetic or acquired renal disorders. Most patients with hypomagnesemia are asymptomatic and symptoms usually do not arise until the serum magnesium concentration falls below 1.2 mg/dL. One of the most life-threatening effects of hypomagnesemia is ventricular arrhythmia. The first step to determine the likely cause of the hypomagnesemia is to measure fractional excretion of magnesium and urinary calcium-creatinine ratio. The renal response to magnesium deficiency due to increased gastrointestinal loss is to lower fractional excretion of magnesium to less than 2%. A fractional excretion above 2% in a subject with normal kidney function indicates renal magnesium wasting. Barter syndrome and loop diuretics which inhibit sodium chloride transport in the ascending loop of Henle are associated with hypokalemia, metabolic alkalosis, renal magnesium wasting, hypomagnesemia, and hypercalciuria. Gitelman syndrome and thiazide diuretics which inhibit sodium chloride cotransporter in the distal convoluted tubule are associated with hypokalemia, metabolic alkalosis, renal magnesium wasting, hypomagnesemia, and hypocalciuria. Familial renal magnesium wasting is associated with hypercalciuria, nephrocalcinosis, and nephrolithiasis. Asymptomatic patients should be treated with oral magnesium supplements. Parenteral magnesium should be reserved for symptomatic patients with severe magnesium deficiency (< 1.2 mg/dL). Establishment of adequate renal function is required before administering any magnesium supplementation.

Iran J Kidney Dis. 2010 Jan;4(1):13-9

Therapeutic efficacy of undenatured type-II collagen (UC-II) in comparison to glucosamine and chondroitin in arthritic horses.

The present investigation evaluated arthritic pain in horses receiving daily placebo, undenatured type II collagen (UC-II) at 320, 480, or 640 mg (providing 80, 120, and 160 mg active UC-II, respectively), and glucosamine and chondroitin (5.4 and 1.8 g, respectively, bid for the first month, and thereafter once daily) for 150 days. Horses were evaluated for overall pain, pain upon limb manipulation, physical examination, and liver and kidney functions. Evaluation of overall pain was based upon a consistent observation of all subjects during a walk and a trot in the same pattern on the same surface. Pain upon limb manipulation was conducted after the walk and trot. It consisted of placing the affected joint in severe flexion for a period of 60 sec. The limb was then placed to the ground and the animal trotted off. The response to the flexion test was then noted with the first couple of strides the animal took. Flexion test was consistent with determining clinically the degree of osteoarthritis in a joint. Horses receiving placebo showed no change in arthritic condition, while those receiving 320 or 480 or 640 mg UC-II exhibited significant reduction in arthritic pain (P < 0.05). UC-II at 480 or 640 mg dose provided equal effects, and therefore, 480 mg dose was considered optimal. With this dose, reduction in overall pain was from 5.7 +/- 0.42 (100%) to 0.7 +/- 0.42 (12%); and in pain upon limb manipulation from 2.35 +/- 0.37 (100%) to 0.52 +/- 0.18 (22%). Although glucosamine and chondroitin treated group showed significant (P < 0.05) reduction in pain compared with pretreated values, the efficacy was less compared with that observed with UC-II. In fact, UC-II at 480 or 640 mg dose was found to be more effective than glucosamine and chondroitin in arthritic horses. Clinical condition (body weight, body temperature, respiration rate, and pulse rate), and liver (bilirubin, GGT, and ALP) and kidney (BUN and creatinine) functions remained unchanged, suggesting that these supplements were well tolerated.

J Vet Pharmacol Ther. 2009 Dec;32(6):577-84

Treatment of rheumatoid arthritis with oral type II collagen. Results of a multicenter, double-blind, placebo-controlled trial.

OBJECTIVE: Oral administration of cartilage-derived type II collagen (CII) has been shown to ameliorate arthritis in animal models of joint inflammation, and preliminary studies have suggested that this novel therapy is clinically beneficial and safe in patients with rheumatoid arthritis (RA). The present study was undertaken to test the safety and efficacy of 4 different dosages of orally administered CII in patients with RA. METHODS: Two hundred seventy-four patients with active RA were enrolled at 6 different sites and randomized to receive placebo or 1 of 4 dosages (20, 100, 500, or 2,500 microg/day) of oral CII for 24 weeks. Efficacy parameters were assessed monthly. Cumulative response rates (percentage of patients meeting the criteria for response at any time during the study) were analyzed utilizing 3 sets of composite criteria: the Paulus criteria, the American College of Rheumatology criteria for improvement in RA, and a requirement for > or = 30% reduction in both swollen and tender joint counts. RESULTS: Eighty-three percent of patients completed 24 weeks of treatment. Numeric trends in favor of the 20 microg/day treatment group were seen with all 3 cumulative composite measures. However, a statistically significant increase (P = 0.035) in response rate for the 20 microg/day group versus placebo was detected using only the Paulus criteria. The presence of serum antibodies to CII at baseline was significantly associated with an increased likelihood of responding to treatment. No treatment-related adverse events were detected. The efficacy seen with the lowest dosage is consistent with the findings of animal studies and with known mechanisms of oral tolerance in which lower doses of orally administered autoantigens preferentially induce disease-suppressing regulatory cells. CONCLUSION: Positive effects were observed with CII at the lowest dosage tested, and the presence of serum antibodies to CII at baseline may predict response to therapy. No side effects were associated with this novel therapeutic agent. Further controlled studies are required to assess the efficacy of this treatment approach.

Arthritis Rheum. 1998 Feb;41(2):290-7

Comparative therapeutic efficacy and safety of type-II collagen (uc-II), glucosamine and chondroitin in arthritic dogs: pain evaluation by ground force plate.

The investigation was conducted on client-owned moderately arthritic dogs with two objectives: (i) to evaluate therapeutic efficacy of type-II collagen (UC-II) alone or in combination with glucosamine hydrochloride (GLU) and chondroitin sulphate (CHO), and (ii) to determine their tolerability and safety. Dogs in four groups (n = 7-10), were treated daily for a period of 150 days with placebo (Group-I), 10 mg active UC-II (Group-II), 2000 mg GLU + 1600 mg CHO (Group-III), and UC-II + GLU + CHO (Group-IV). On a monthly basis, dogs were evaluated for observational pain (overall pain, pain upon limb manipulation, and pain after physical exertion) using different numeric scales. Pain level was also measured objectively using piezoelectric sensor-based GFP for peak vertical force and impulse area. Dogs were also examined every month for physical, hepatic (ALP, ALT and bilirubin) and renal (BUN and creatinine) functions. Based on observations, significant (p < 0.05) reduction in pain was noted in Group-II, III, and IV dogs. Using GFP, significant increases in peak vertical force (N/kg body wt) and impulse area (N s/kg body wt), indicative of a decrease in arthritis associated pain, were observed in Group-II dogs only. None of the dogs in any group showed changes in physical, hepatic or renal functions. In conclusion, based on GFP data, moderately arthritic dogs treated with UC-II (10 mg) showed a marked reduction in arthritic pain with maximum improvement by day 150. UC-II, GLU and CHO operate through different mechanisms of action, and were well tolerated over a period of 150 days.

J Anim Physiol Anim Nutr (Berl). 2011 May 30

Efficacy and tolerability of Boswellia serrata extract in treatment of osteoarthritis of knee—a randomized double blind placebo controlled trial.

Osteoarthritis is a common, chronic, progressive, skeletal, degenerative disorder, which commonly affects the knee joint. Boswellia serrata tree is commonly found in India. The therapeutic value of its gum (guggulu) has been known. It posses good anti-inflammatory, anti-arthritic and analgesic activity. A randomized double blind placebo controlled crossover study was conducted to assess the efficacy, safety and tolerability of Boswellia serrata Extract (BSE) in 30 patients of osteoarthritis of knee, 15 each receiving active drug or placebo for eight weeks. After the first intervention, washout was given and then the groups were crossed over to receive the opposite intervention for eight weeks. All patients receiving drug treatment reported decrease in knee pain, increased knee flexion and increased walking distance. The frequency of swelling in the knee joint was decreased. Radiologically there was no change. The observed differences between drug treated and placebo being statistically significant, are clinically relevant. BSE was well tolerated by the subjects except for minor gastrointestinal ADRs. BSE is recommended in the patients of osteoarthritis of the knee with possible therapeutic use in other arthritis.

Phytomedicine. 2003 Jan;10(1):3-7

Inhibition by boswellic acids of human leukocyte elastase.

Frankincense extracts and boswellic acids, biologically active pentacyclic triterpenes of frankincense, block leukotriene biosynthesis and exert potent anti-inflammatory effects. Screening for additional effects of boswellic acids on further proinflammatory pathways, we observed that acetyl-11-keto-beta-boswellic acid, an established direct, nonredox and noncompetitive 5-lipoxygenase inhibitor, decreased the activity of human leukocyte elastase (HLE) in vitro with an IC50 value of about 15 microM. Among the pentacyclic triterpenes tested in concentrations up to 20 microM, we also observed substantial inhibtion by beta-boswellic acid, amyrin and ursolic acid, but not by 18beta-glycyrrhetinic acid. The data show that the dual inhibition of 5-lipoxygenase and HLE is unique to boswellic acids: other pentacyclic triterpenes with HLE inhibitory activities (e.g., ursolic acid and amyrin) do not inhibit 5-lipoxygenase, and leukotriene biosynthesis inhibitors from different chemical classes (e.g., NDGA, MK-886 and ZM-230,487) do not impair HLE activity. Because leukotriene formation and HLE release are increased simultaneously by neutrophil stimulation in a variety of inflammation- and hypersensitivity-based human diseases, the reported blockade of two proinflammatory enzymes by boswellic acids might be the rationale for the putative antiphlogistic activity of acetyl-11-keto-beta-boswellic acid and derivatives.

J Pharmacol Exp Ther. 1997 Apr;281(1):460-3

Mechanism of 5-lipoxygenase inhibition by acetyl-11-keto-beta-boswellic acid.

The formation of 5-lipoxygenase (EC products from endogenous substrate by intact rat neutrophilic granulocytes and from exogenous arachidonic acid by rat granulocyte 105,000 x g supernatants and affinity chromatography-purified human leukocyte 5-lipoxygenase was inhibited by acetyl-11-keto-beta-boswellic acid (IC50 values of 1.5 microM, 8 microM, and 16 microM, respectively). With other pentacyclic triterpenes lacking the 11-keto function and/or the carboxyl function on ring A (e.g., amyrin and ursolic acid), no 5-lipoxygenase inhibition was observed. The presence of the noninhibitory pentacyclic triterpenes both in intact cells and in the cell-free system caused a concentration-dependent reversal of the 5-lipoxygenase inhibition by acetyl-11-keto-beta-boswellic acid, whereas the inhibitory actions of 5-lipoxygenase inhibitors from different chemical classes (MK-886, L-739,010, ZM-230,487, and nordihydroguaiaretic acid) were not modified. The inhibition by acetyl-11-keto-beta-boswellic acid and the antagonism by noninhibitory pentacyclic triterpenes were not due to nonspecific lipophilic interactions, because lipophilic four-ring compounds (cholesterol, cortisone, and testosterone) neither inhibited the activity of the 5-lipoxygenase nor antagonized the inhibitory action of acetyl-11-keto-beta-boswellic acid. Therefore, we conclude that acetyl-11-keto-beta-boswellic acid acts directly on the 5-lipoxygenase enzyme at a selective site for pentacyclic triterpenes that is different from the arachidonate substrate binding site.

Mol Pharmacol. 1995 Jun;47(6):1212-6

Comparative efficacy and tolerability of 5-Loxin and Aflapin against osteoarthritis of the knee: a double blind, randomized, placebo controlled clinical study.

Aflapin® is a novel synergistic composition derived from Boswellia serrata gum resin (Indian Patent Application No. 2229/CHE/2008). Aflapin is significantly better as an anti-inflammatory agent compared to the Boswellia extracts presently available in the market. A 90-day, double-blind, randomized, placebo-controlled study was conducted to evaluate the comparative efficacy and tolerability of 5-Loxin® and Aflapin® in the treatment of osteoarthritis (OA) of the knee (Clinical trial registration number: ISRCTN80793440). Sixty OA subjects were included in the study. The subjects received either 100 mg (n=20) of 5-Loxin® or 100 mg (n=20) of Aflapin® or a placebo (n=20) daily for 90 days. Each patient was evaluated for pain and physical functions by using the standard tools (visual analog scale, Lequesne›s Functional Index, and Western Ontario and McMaster Universities Osteoarthritis Index) at the baseline (day 0), and at days 7, 30, 60 and 90. A battery of biochemical parameters in serum, urine and hematological parameters in citrated whole blood were performed to assess the safety of 5-Loxin® and Aflapin® in OA subjects. Fifty seven subjects completed the study. At the end of the study, both 5-Loxin® and Aflapin conferred clinically and statistically significant improvements in pain scores and physical function scores in OA subjects. Interestingly, significant improvements in pain score and functional ability were recorded as early as 7 days after initiation of the study in the treatment group supplemented with 100 mg Aflapin. Corroborating the improvements in pain scores in treatment groups, our in vitro studies provide evidences that Aflapin® is capable of inhibiting cartilage degrading enzyme MMP-3 and has the potential to regulate the inflammatory response by inhibiting ICAM-1. Aflapin® and 5-Loxin® reduce pain and improve physical functions significantly in OA subjects. Aflapin exhibited better efficacy compared to 5-Loxin®. In comparison with placebo, the safety parameters were almost unchanged in the treatment groups. Hence both 5-Loxin® and Aflapin® are safe for human consumption.

Int J Med Sci. 2010 Nov 1;7(6):366-77

Effects of glucosamine administration on patients with rheumatoid arthritis.

The purpose of this study was to examine whether glucosamine has an antirheumatic effect in a randomized placebo-controlled study. The subjects were 51 rheumatoid arthritis (RA) patients: 25 patients in the glucosamine group and 26 patients in the placebo group. Glucosamine hydrochloride at a daily dose of 1,500 mg and placebo, respectively, were administered for 12 weeks along with conventional medication. While significant improvement was not found in joint counts and in the rate of ACR20 responders, the face scale and a visual analogue scale pain were significantly in favor of the glucosamine group. ESR and CRP levels did not change, but serum MMP-3 levels decreased in the glucosamine group. Results of the patients’ self-evaluations and the physicians’ global evaluations indicated that the glucosamine treatment produced noticeable improvements in symptoms. Although glucosamine administration had no antirheumatic effect evaluated by conventional measures, it seemed to have some symptomatic effects on RA.

Rheumatol Int. 2007 Jan;27(3):213-8

The epigenetic effect of glucosamine and a nuclear factor-kappa B (NF-kB) inhibitor on primary human chondrocytes—implications for osteoarthritis.

OBJECTIVE: Idiopathic osteoarthritis is the most common form of osteoarthritis (OA) world-wide and remains the leading cause of disability and the associated socio-economic burden in an increasing aging population. Traditionally, OA has been viewed as a degenerative joint disease characterized by progressive destruction of the articular cartilage and changes in the subchondral bone culminating in joint failure. However, the etiology of OA is multifactorial involving genetic, mechanical and environmental factors. Treatment modalities include analgesia, joint injection with steroids or hyaluronic acid, oral supplements including glucosamine and chondroitin sulfate, as well as physiotherapy. Thus, there is significant interest in the discovery of disease modifying agents. One such agent, glucosamine (GlcN) is commonly prescribed even though the therapeutic efficacy and mechanism of action remain controversial. Inflammatory cytokines, including IL-1b, and proteinases such as MMP-13 have been implicated in the pathogenesis and progression of OA together with an associated CpG demethylation in their promoters. We have investigated the potential of GlcN to modulate NF-kB activity and cytokine-induced abnormal gene expression in articular chondrocytes and, critically, whether this is associated with an epigenetic process. METHOD: Human chondrocytes were isolated from the articular cartilage of femoral heads, obtained with ethical permission, following fractured neck of femur surgery. Chondrocytes were cultured for 5 weeks in six separate groups; (i) control culture, (ii) cultured with a mixture of 2.5 ng/ml IL-1b and 2.5 ng/ml oncostatin M (OSM), (iii) cultured with 2mM N-acetyl GlcN (Sigma-Aldrich), (iv) cultured with a mixture of 2.5 ng/ml IL-1b, 2.5 ng/ml OSM and 2mM GlcN, (v) cultured with 1.0 μM BAY 11-7082 (BAY; NF-kB inhibitor: Calbiochem, Darmstadt, Germany) and, (vi) cultured with a mixture of 2.5 ng/ml IL-1b, 2.5 ng/ml OSM and 1.0 μM BAY. The levels of IL1B and MMP13 mRNA were examined using qRT-PCR. The percentage DNA methylation in the CpG sites of the IL-1b and MMP13 proximal promoter were quantified by pyrosequencing. RESULT: IL1b expression was enhanced over 580-fold in articular chondrocytes treated with IL-1b and OSM. GlcN dramatically ameliorated the cytokine-induced expression by 4-fold. BAY alone increased IL1b expression by 3-fold. In the presence of BAY, IL-1binduced IL1B mRNA levels were decreased by 6-fold. The observed average percentage methylation of the -256 CpG site in the IL1b promoter was 65% in control cultures and decreased to 36% in the presence of IL-1b/OSM. GlcN and BAY alone had a negligible effect on the methylation status of the IL1B promoter. The cytokine-induced loss of methylation status in the IL1B promoter was ameliorated by both GlcN and BAY to 44% and 53%, respectively. IL-1b/OSM treatment increased MMP13 mRNA levels independently of either GlcN or BAY and no change in the methylation status of the MMP13 promoter was observed. CONCLUSION: We demonstrate for the first time that GlcN and BAY can prevent cytokine-induced demethylation of a specific CpG site in the IL1b promoter and this was associated with decreased expression of IL1b. These studies provide a potential mechanism of action for OA disease modifying agents via NF-kB and, critically, demonstrate the need for further studies to elucidate the role that NF-kB may play in DNA demethylation in human chondrocytes.

Biochem Biophys Res Commun. 2011 Feb 18;405(3):362-7

Glucosamine inhibits IL-1beta-induced NFkappaB activation in human osteoarthritic chondrocytes.

OBJECTIVE: Glucosamine sulfate (GS) is a commonly used drug for the treatment of osteoarthritis. The mechanism of the action of this drug does, however, remain to be elucidated. In human osteoarthritic chondrocytes (HOC) stimulated with a proinflammatory cytokine, we studied whether GS could modify the NFkappaB activity and the expression of COX-2, a NFkappaB-dependent gene. METHODS: Using HOC in culture stimulated with interleukin-1 beta (IL-1beta), the effects of GS on NFkappaB activation, nuclear translocation of NFkappaB/Rel family members, COX-1 and COX-2 expressions and syntheses and prostaglandin E2 (PGE2) concentration were studied. RESULTS: GS significantly inhibited NFkappaB activity in a dose-dependent manner, as well as the nuclear translocation of p50 and p65 proteins. Furthermore, GS-preincubated IL-1beta-stimulated HOC showed an increase in IkappaBalpha in the cell cytoplasm in comparison with HOC incubated with IL-1beta alone. GS also inhibited the gene expression and the protein synthesis of COX-2 induced by IL-1beta, while no effect on COX-1 synthesis was seen. GS also inhibited the release of PGE2 to conditioned media of HOC stimulated with IL-1beta. CONCLUSIONS: GS inhibits the synthesis of proinflammatory mediators in HOC stimulated with IL-1beta through a NFkappaB-dependent mechanism. Our study further supports the role of GS as a symptom- and structure-modifying drug in the treatment of OA.

Osteoarthritis Cartilage. 2003 Apr;11(4):290-8

Metformin: taking away the candy for cancer?

Metformin is widely used in the treatment of diabetes mellitus type 2 where it reduces insulin resistance and diabetes-related morbidity and mortality. Population-based studies show that metformin treatment is associated with a dose-dependent reduction in cancer risk. The metformin treatment also increases complete pathological tumour response rates following neoadjuvant chemotherapy for breast cancer, suggesting a potential role as an anti-cancer drug. Diabetes mellitus type 2 is associated with insulin resistance, elevated insulin levels and an increased risk of cancer and cancer-related mortality. This increased risk may be explained by activation of the insulin- and insulin-like growth factor (IGF) signalling pathways and increased signalling through the oestrogen receptor. Reversal of these processes through reduction of insulin resistance by the oral anti-diabetic drug metformin is an attractive anti-cancer strategy. Metformin is an activator of AMP-activated protein kinase (AMPK) which inhibits protein synthesis and gluconeogenesis during cellular stress. The main downstream effect of AMPK activation is the inhibition of mammalian target of rapamycin (mTOR), a downstream effector of growth factor signalling. mTOR is frequently activated in malignant cells and is associated with resistance to anticancer drugs. Furthermore, metformin can induce cell cycle arrest and apoptosis and can reduce growth factor signalling. This review discusses the role of diabetes mellitus type 2 and insulin resistance in carcinogenesis, the preclinical rationale and potential mechanisms of metformin’s anti-cancer effect and the current and future clinical developments of metformin as a novel anti-cancer drug.

Eur J Cancer. 2010 Sep;46(13):2369-80

Is it time to test metformin in breast cancer clinical trials?

Several studies have identified an increased risk of cancer in type 2 diabetic patients and this is in accordance with the hypothesis that increased insulin levels might promote cancer. Thus, there is a great interest in exploring the possibility that antidiabetic therapies lowering insulin levels could decrease cancer incidence or cancer-related mortality. Recent observational studies have shown that metformin, an oral safe and well-tolerated insulin-sensitizer antidiabetic drug, has been associated with reduced cancer risk. Recently, several preclinical studies have evaluated the effect of metformin in vivo on nude mice and showed a significant reduction of both breast epithelial cell proliferation and protein synthesis. Further investigations in the clinical setting are well-supported by the promising results obtained thus far. At the European Institute of Oncology, the Division of Cancer Prevention and Genetics is planning to conduct a clinical trial to evaluate the activity of metformin on tumor cell proliferation in breast cancer patients undergoing surgery. It will be a presurgical randomized, double blind, placebo-controlled phase II biomarker trial: 100 histologically confirmed breast cancer patients will be randomly assigned to metformin (850 mg twice/daily) or placebo for 28+7 days till surgery to assess drug activity on tumor proliferation, as measured by Ki-67. The confirmation of the efficacy of metformin on cancer cell proliferation may lead the way to larger chemoprevention clinical trials.

Cancer Epidemiol Biomarkers Prev. 2009 Mar;18(3):701-5

Repositioning chloroquine and metformin to eliminate cancer stem cell traits in pre-malignant lesions.

Ideal oncology drugs would be curative after a short treatment course if they could eliminate epithelium-originated carcinomas at their non-invasive, pre-malignant stages. Such ideal molecules, which are expected to molecularly abrogate all the instrumental mechanisms acquired by migrating cancer stem cells (CSCs) to by-pass tumour suppressor barriers, might already exist. We here illustrate how system biology strategies for repositioning existing FDA-approved drugs may accelerate our therapeutic capacity to eliminate CSC traits in pre-invasive intraepithelial neoplasias. First, we describe a signalling network signature that overrides bioenergetics stress- and oncogene-induced senescence (OIS) phenomena in CSCs residing at pre-invasive lesions. Second, we functionally map the anti-malarial chloroquine and the anti-diabetic metformin (“old drugs”) to their recently recognized CSC targets (“new uses”) within the network. By discussing the preclinical efficacy of chloroquine and metformin to inhibiting the genesis and self-renewal of CSCs we finally underscore the expected translational impact of the “old drugs-new uses” repurposing strategy to open a new CSC-targeted chemoprevention era.

Drug Resist Updat. 2011 Aug-Oct;14(4-5): 212-23

Targeting cancer cell metabolism: the combination of metformin and 2-deoxyglucose induces p53-dependent apoptosis in prostate cancer cells.

Targeting cancer cell metabolism is a new promising strategy to fight cancer. Metformin, a widely used antidiabetic agent, exerts antitumoral and antiproliferative action. In this study, the addition of metformin to 2-deoxyglucose (2DG) inhibited mitochondrial respiration and glycolysis in prostate cancer cells leading to a severe depletion in ATP. The combination of the two drugs was much more harmful for cancer cells than the treatment with metformin or 2DG alone, leading to 96% inhibition of cell viability in LNCaP prostate cancer cells. In contrast, a moderate effect on cell viability was observed in normal prostate epithelial cells. At the cellular level, the combination of metformin and 2DG induced p53-dependent apoptosis via the energy sensor pathway AMP kinase, and the reexpression of a functional p53 in p53-deficient prostate cancer cells restored caspase-3 activity. In addition to apoptosis, the combination of metformin and 2DG arrested prostate cancer cells in G(2)-M. This G(2)-M arrest was independent of p53 and correlated with a stronger decrease in cell viability than obtained with either drug. Finally, metformin inhibited 2DG-induced autophagy, decreased beclin 1 expression, and triggered a switch from a survival process to cell death. Our study reinforces the growing interest of metabolic perturbators in cancer therapy and highlights the potential use of the combination of metformin and 2DG as an anticancerous treatment.

Cancer Res. 2010 Mar 15;70(6):2465-75

Dual antiglioma action of metformin: cell cycle arrest and mitochondria-dependent apoptosis.

The present study reports for the first time a dual antiglioma effect of the well-known antidiabetic drug metformin. In low-density cultures of the C6 rat glioma cell line, metformin blocked the cell cycle progression in G(0)/G(1) phase without inducing significant cell death. In confluent C6 cultures, on the other hand, metformin caused massive induction of caspase-dependent apoptosis associated with c-Jun N-terminal kinase (JNK) activation, mitochondrial depolarization and oxidative stress. Metformin-triggered apoptosis was completely prevented by agents that block mitochondrial permeability transition (cyclosporin A) and oxygen radical production (N-acetylcisteine), while the inhibitors of JNK activation (SP600125) or glycolysis (sodium fluoride, iodoacetate) provided partial protection. The antiglioma effect of metformin was reduced by compound C, an inhibitor of AMP-activated protein kinase (AMPK), and was mimicked by the AMPK agonist AICAR. Similar effects were observed in the human glioma cell line U251, while rat primary astrocytes were completely resistant to the antiproliferative and proapoptotic action of metformin.

Cell Mol Life Sci. 2007 May;64(10):1290-302

The antidiabetic drug metformin exerts an antitumoral effect in vitro and in vivo through a decrease of cyclin D1 level.

Metformin is a widely used antidiabetic agent, which regulates glucose homeostasis through inhibition of liver glucose production and an increase in muscle glucose uptake. Recent studies suggest that metformin may reduce the risk of cancer, but its mode of action in cancer remains not elucidated. We investigated the effect of metformin on human prostate cancer cell proliferation in vitro and in vivo. Metformin inhibited the proliferation of DU145, PC-3 and LNCaP cancer cells with a 50% decrease of cell viability and had a modest effect on normal prostate epithelial cell line P69. Metformin did not induce apoptosis but blocked cell cycle in G(0)/G(1). This blockade was accompanied by a strong decrease of cyclin D1 protein level, pRb phosphorylation and an increase in p27(kip) protein expression. Metformin activated the AMP kinase pathway, a fuel sensor signaling pathway. However, inhibition of the AMPK pathway using siRNA against the two catalytic subunits of AMPK did not prevent the antiproliferative effect of metformin in prostate cancer cells. Importantly, oral and intraperitoneal treatment with metformin led to a 50 and 35% reduction of tumor growth, respectively, in mice bearing xenografts of LNCaP. Similar, to the in vitro study, metformin led to a strong reduction of cyclin D1 protein level in tumors providing evidence for a mechanism that may contribute to the antineoplastic effects of metformin suggested by recent epidemiological studies.

Oncogene. 2008 Jun 5;27(25):3576-86

Metformin attenuates ovarian cancer cell growth in an AMP-kinase dispensable manner.

Metformin, the most widely used drug for type 2 diabetes activates 59 adenosine monophosphate (AMP)-activated protein kinase (AMPK), which regulates cellular energy metabolism. Here, we report that ovarian cell lines VOSE, A2780, CP70, C200, OV202, OVCAR3, SKOV3ip, PE01 and PE04 predominantly express -a(1), -b(1), -g(1) and -g(2) isoforms of AMPK subunits. Our studies show that metformin treatment (1) significantly inhibited proliferation of diverse chemo-responsive and -resistant ovarian cancer cell lines (A2780, CP70, C200, OV202, OVCAR3, SKVO3ip, PE01 and PE04), (2) caused cell cycle arrest accompanied by decreased cyclin D1 and increased p21 protein expression, (3) activated AMPK in various ovarian cancer cell lines as evident from increased phosphorylation of AMPKa and its downstream substrate; acetyl co-carboxylase (ACC) and enhanced b-oxidation of fatty acid and (4) attenuated mTOR-S6RP phosphorylation, inhibited protein translational and lipid biosynthetic pathways, thus implicating metformin as a growth inhibitor of ovarian cancer cells. We also show that metformin-mediated effect on AMPK is dependent on liver kinase B1 (LKB1) as it failed to activate AMPK-ACC pathway and cell cycle arrest in LKB1 null mouse embryo fibroblasts (mefs). This observation was further supported by using siRNA approach to down-regulate LKB1 in ovarian cancer cells. In contrast, met formin inhibited cell proliferation in both wild-type and AMPKa(1/2) null mefs as well as in AMPK silenced ovarian cancer cells. Collectively, these results provide evidence on the role of metformin as an anti-proliferative therapeutic that can act through both AMPK-dependent as well as AMPK-independent pathways.

J Cell Mol Med. 2011 Jan;15(1):166-78

Metformin inhibits melanoma development through autophagy and apoptosis mechanisms.

Metformin is the most widely used antidiabetic drug because of its proven efficacy and limited secondary effects. Interestingly, recent studies have reported that metformin can block the growth of different tumor types. Here, we show that metformin exerts antiproliferative effects on melanoma cells, whereas normal human melanocytes are resistant to these metformin-induced effects. To better understand the basis of this antiproliferative effect of metformin in melanoma, we characterized the sequence of events underlying metformin action. We showed that 24 h metformin treatment induced a cell cycle arrest in G0/G1 phases, while after 72 h, melanoma cells underwent autophagy as demonstrated by electron microscopy, immunochemistry, and by quantification of the autolysosome-associated LC3 and Beclin1 proteins. In addition, 96 h post metformin treatment we observed robust apoptosis of melanoma cells. Interestingly, inhibition of autophagy by knocking down LC3 or ATG5 decreased the extent of apoptosis, and suppressed the antiproliferative effect of metformin on melanoma cells, suggesting that apoptosis is a consequence of autophagy. The relevance of these observations were confirmed in vivo, as we showed that metformin treatment impaired the melanoma tumor growth in mice, and induced autophagy and apoptosis markers. Taken together, our data suggest that metformin has an important impact on melanoma growth, and may therefore be beneficial in patients with melanoma.

Cell Death Dis. 2011 Sep 1;2:e199

Metformin promotes progesterone receptor expression via inhibition of mammalian target of rapamycin (mTOR) in endometrial cancer cells.

Progesterone has been used in the hormonal treatment of endometrial cancer (EC) for many years, but the response rates are unsatisfying. The down-regulated progesterone receptor (PR) is the main reason for treatment failure. The insulin-like growth factor (IGF) system is related to EC risk, and IGF-I can inhibit PR transcription in breast cancer. Recent evidence suggests that metformin-combined oral contraceptives may reverse progesterone-resistant atypical endometrial hyperplasia, but the mechanism is unclear. We attempt to investigate the interaction of metformin, PR and IGF-II expression, and identify whether metformin can enhance the antitumor effect of medroxyprogesterone acetate (MPA) using Ishikawa and HEC-1B EC cell lines. We found that both IGF-I and IGF-II inhibit PR A/B mRNA and protein expression, whereas metformin markedly promotes PR expression. In parallel, IGF-II increases phosphorylation of AKT and p70S6K, while metformin increases AMPK phosphorylation and decreases p70S6K phosphorylation. The effects of metformin on PR A/B and p70S6K are partially reversed by an AMPK inhibitor. Furthermore, metformin synergistically antiproliferates MPA in two cell lines, with the peak synergy occurring with 10μM metformin combined with 1μM MPA (CI=0.20448 for Ishikawa, CI=0.12801 for HEC-1B). Our results demonstrate that metformin promotes PR expression, which can be inhibited by overexpressed IGF-II in EC. This effect is partially mediated through activating AMPK followed by inhibiting the overactivated mTOR pathway.

J Steroid Biochem Mol Biol. 2011 Sep;126


Metformin, independent of AMPK, induces mTOR inhibition and cell-cycle arrest through REDD1.

Metformin is a widely prescribed antidiabetic drug associated with a reduced risk of cancer. Many studies show that metformin inhibits cancer cell viability through the inhibition of mTOR. We recently showed that antiproliferative action of metformin in prostate cancer cell lines is not mediated by AMP-activated protein kinase (AMPK). We identified REDD1 (also known as DDIT4 and RTP801), a negative regulator of mTOR, as a new molecular target of metformin. We show that metformin increases REDD1 expression in a p53-dependent manner. REDD1 invalidation, using siRNA or REDD1(-/-) cells, abrogates metformin inhibition of mTOR. Importantly, inhibition of REDD1 reverses metformin-induced cell-cycle arrest and significantly protects from the deleterious effects of metformin on cell transformation. Finally, we show the contribution of p53 in mediating metformin action in prostate cancer cells. These results highlight the p53/REDD1 axis as a new molecular target in anticancer therapy in response to metformin treatment.

Cancer Res. 2011 Jul 1;71(13):4366-72

The effect of chlorogenic acid enriched coffee on glucose absorption in healthy volunteers and its effect on body mass when used long-term in overweight and obese people.

The results from a clinical study performed in 12 healthy volunteers with different coffee products containing glucose show that instant coffee enriched with chlorogenic acid induced a reduction in the absorption of glucose of 6.9% compared with the control. No such effects were seen with normal or decaffeinated instant coffee. In a second, comparative, randomized, double-blind, 12-week study we investigated the effect on the body mass of 30 overweight people, compared with normal instant coffee. The average losses in mass in the chlorogenic acid enriched and normal instant coffee groups were 5.4 and 1.7 kg, respectively. We conclude that chlorogenic acid enriched instant coffee appears to have a significant effect on the absorption and utilization of glucose from the diet. This effect, if the coffee is used for an extended time, may result in reduced body mass and body fat when compared with the use of normal instant coffee.

J Int Med Res. 2007 Nov-Dec;35(6):900-8

Acute effects of decaffeinated coffee and the major coffee components chlorogenic acid and trigonelline on glucose tolerance.

OBJECTIVE: Coffee consumption has been associated with lower risk of type 2 diabetes. We evaluated the acute effects of decaffeinated coffee and the major coffee components chlorogenic acid and trigonelline on glucose tolerance. RESEARCH DESIGN AND METHODS: We conducted a randomized crossover trial of the effects of 12 g decaffeinated coffee, 1 g chlorogenic acid, 500 mg trigonelline, and placebo (1 g mannitol) on glucose and insulin concentrations during a 2-h oral glucose tolerance test (OGTT) in 15 overweight men. RESULTS: Chlorogenic acid and trigonelline ingestion significantly reduced glucose (-0.7 mmol/l, P = 0.007, and -0.5 mmol/l, P = 0.024, respectively) and insulin (-73 pmol/l, P = 0.038, and -117 pmol/l, P = 0.007) concentrations 15 min following an OGTT compared with placebo. None of the treatments affected insulin or glucose area under the curve values during the OGTT compared with placebo. CONCLUSIONS: Chlorogenic acid and trigonelline reduced early glucose and insulin responses during an OGTT.

Diabetes Care. 2009 Jun;32(6):1023-5

Inhibitory effect of green coffee bean extract on fat accumulation and body weight gain in mice.

BACKGROUND: An epidemiological study conducted in Italy indicated that coffee has the greatest antioxidant capacity among the commonly consumed beverages. Green coffee bean is rich in chlorogenic acid and its related compounds. The effect of green coffee bean extract (GCBE) on fat accumulation and body weight in mice was assessed with the objective of investigating the effect of GCBE on mild obesity. METHODS: Male ddy mice were fed a standard diet containing GCBE and its principal constituents, namely, caffeine and chlorogenic acid, for 14 days. Further, hepatic triglyceride (TG) level was also investigated after consecutive administration (13 days) of GCBE and its constituents. To examine the effect of GCBE and its constituents on fat absorption, serum TG changes were evaluated in olive oil-loaded mice. In addition, to investigate the effect on hepatic TG metabolism, carnitine palmitoyltransferase (CPT) activity in mice was evaluated after consecutive ingestion (6 days) of GCBE and its constituents (caffeine, chlorogenic acid, neochlorogenic acid and feruloylquinic acid mixture). RESULTS: It was found that 0.5% and 1% GCBE reduced visceral fat content and body weight. Caffeine and chlorogenic acid showed a tendency to reduce visceral fat and body weight. Oral administration of GCBE (100 and 200 mg/kg. day) for 13 days showed a tendency to reduce hepatic TG in mice. In the same model, chlorogenic acid (60 mg/kg. day) reduced hepatic TG level. In mice loaded with olive oil (5 mL/kg), GCBE (200 and 400 mg/kg) and caffeine (20 and 40 mg/kg) reduced serum TG level. GCBE (1%), neochlorogenic acid (0.028% and 0.055%) and feruloylquinic acid mixture (0.081%) significantly enhanced hepatic CPT activity in mice. However, neither caffeine nor chlorogenic acid alone was found to enhance CPT activity. CONCLUSION: These results suggest that GCBE is possibly effective against weight gain and fat accumulation by inhibition of fat absorption and activation of fat metabolism in the liver. Caffeine was found to be a suppressor of fat absorption, while chlorogenic acid was found to be partially involved in the suppressive effect of GCBE that resulted in the reduction of hepatic TG level. Phenolic compounds such as neochlorogenic acid and feruloylquinic acid mixture, except chlorogenic acid, can enhance hepatic CPT activity.

BMC Complement Altern Med. 2006 Mar 17;6:9

Coffee polyphenols suppress diet-induced body fat accumulation by downregulating SREBP-1c and related molecules in C57BL/6J mice.

The prevalence of obesity is increasing globally, and obesity is a major risk factor for type 2 diabetes and cardiovascular disease. We investigated the effects of coffee polyphenols (CPP), which are abundant in coffee and consumed worldwide, on diet-induced body fat accumulation. C57BL/6J mice were fed either a control diet, a high-fat diet, or a high-fat diet supplemented with 0.5 to 1.0% CPP for 2-15 wk. Supplementation with CPP significantly reduced body weight gain, abdominal and liver fat accumulation, and infiltration of macrophages into adipose tissues. Energy expenditure evaluated by indirect calorimetry was significantly increased in CPP-fed mice. The mRNA levels of sterol regulatory element-binding protein (SREBP)-1c, acetyl-CoA carboxylase-1 and -2, stearoyl-CoA desaturase-1, and pyruvate dehydrogenase kinase-4 in the liver were significantly lower in CPP-fed mice than in high-fat control mice. Similarly, CPP suppressed the expression of these molecules in Hepa 1-6 cells, concomitant with an increase in microRNA-122. Structure-activity relationship studies of nine quinic acid derivatives isolated from CPP in Hepa 1-6 cells suggested that mono- or di-caffeoyl quinic acids (CQA) are active substances in the beneficial effects of CPP. Furthermore, CPP and 5-CQA decreased the nuclear active form of SREBP-1, acetyl-CoA carboxylase activity, and cellular malonyl-CoA levels. These findings indicate that CPP enhances energy metabolism and reduces lipogenesis by downregulating SREBP-1c and related molecules, which leads to the suppression of body fat accumulation.

Am J Physiol Endocrinol Metab. 2011 Jan;300(1):E122-33

National, regional, and global trends in fasting plasma glucose and diabetes prevalence since 1980: systematic analysis of health examination surveys and epidemiological studies with 370 country-years and 2•7 million participants.

BACKGROUND: Data for trends in glycaemia and diabetes prevalence are needed to understand the effects of diet and lifestyle within populations, assess the performance of interventions, and plan health services. No consistent and comparable global analysis of trends has been done. We estimated trends and their uncertainties in mean fasting plasma glucose (FPG) and diabetes prevalence for adults aged 25 years and older in 199 countries and territories. METHODS: We obtained data from health examination surveys and epidemiological studies (370 country-years and 2•7 million participants). We converted systematically between different glycaemic metrics. For each sex, we used a Bayesian hierarchical model to estimate mean FPG and its uncertainty by age, country, and year, accounting for whether a study was nationally, subnationally, or community representative. FINDINGS: In 2008, global age-standardised mean FPG was 5•50 mmol/L (95% uncertainty interval 5•37-5•63) for men and 5•42 mmol/L (5•29-5•54) for women, having risen by 0•07 mmol/L and 0•09 mmol/L per decade, respectively. Age-standardised adult diabetes prevalence was 9•8% (8•6-11•2) in men and 9•2% (8•0-10•5) in women in 2008, up from 8•3% (6•5-10•4) and 7•5% (5•8-9•6) in 1980. The number of people with diabetes increased from 153 (127-182) million in 1980, to 347 (314-382) million in 2008. We recorded almost no change in mean FPG in east and southeast Asia and central and eastern Europe. Oceania had the largest rise, and the highest mean FPG (6•09 mmol/L, 5•73-6•49 for men; 6•08 mmol/L, 5•72-6•46 for women) and diabetes prevalence (15•5%, 11•6-20•1 for men; and 15•9%, 12•1-20•5 for women) in 2008. Mean FPG and diabetes prevalence in 2008 were also high in south Asia, Latin America and the Caribbean, and central Asia, north Africa, and the Middle East. Mean FPG in 2008 was lowest in sub-Saharan Africa, east and southeast Asia, and high-income Asia-Pacific. In high-income subregions, western Europe had the smallest rise, 0•07 mmol/L per decade for men and 0•03 mmol/L per decade for women; North America had the largest rise, 0•18 mmol/L per decade for men and 0•14 mmol/L per decade for women. INTERPRETATION: Glycaemia and diabetes are rising globally, driven both by population growth and ageing and by increasing age-specific prevalences. Effective preventive interventions are needed, and health systems should prepare to detect and manage diabetes and its sequelae.

Lancet. 2011 Jul 2;378(9785):31-40

A large proportion of prediabetes and diabetes goes undiagnosed when only fasting plasma glucose and/or HbA1c are measured in overweight or obese patients.

AIMS: The purposes of the study were to determine the prevalence of unrecognized dysglycaemia in overweight (body mass index [BMI] 25-29.9 kg/m(2)) and obese (BMI ≥30 kg/m(2)) patients, to assess the extent to which measures of fasting plasma glucose (FPG) and/or HbA(1c), compared with oral glucose tolerance tests (OGTTs), misdiagnose dysglycaemia, and to determine the factors associated with an isolated abnormal post-OGTT glucose value. METHODS: OGTT was performed and HbA(1c) was measured in 1283 inpatients with BMI scores ≥ 25 kg/m(2) and no history of dysglycaemia. RESULTS: Prediabetes was found in 257 (20.0%) subjects (197 with impaired glucose tolerance, 29 with impaired fasting glucose, 31 with both) and diabetes in 77 (6.0%), including 22 with FPG ≥ 7 mmol/L (WHO definition). The sensitivity of FPG >6 mmol/L, FPG >5.5 mmol/L, HbA(1c) ≥ 6% and the recommendations of the French National Agency of Accreditation and Evaluation in Health Care (ANAES) to identify patients with abnormal OGTTs was 29.9, 41.3, 36.8 and 15.6%, respectively. The factors that were independently associated with diabetes in obese women with FPG <7 mmol/L were age (per 10 years: OR 1.54 [1.00-2.11]; P=0.049) and FPG (OR 6.1 [1.4-30.0]; P=0.014), whereas age (OR 1.26 [1.09-1.44]; P<0.01) and waist circumference (per 10 cm: OR 1.17 [1.01-1.33]; P<0.05) were independently associated with dysglycaemia in obese women with FPG <6.1 mmol/L. CONCLUSION: In overweight and obese patients: dysglycaemia is commonly seen; FPG alone, compared with OGTT, failed to diagnose 70% of dysglycaemia cases; FPG >5.5 mmol/L and HbA(1c) ≥ 6.0% are not necessarily substitutes for OGTT; and older age and larger waist circumference should be used to select those obese women with normal FPG who might further benefit from OGTTs to diagnose dysglycaemia.

Diabetes Metab. 2010 Sep;36(4):312-8

Chlorogenic acid reduces the plasma glucose peak in the oral glucose tolerance test: effects on hepatic glucose release and glycaemia.

The effects of chlorogenic acid (CA) on hepatic glucose output, blood glucose levels and on glucose tolerance were analysed. Hepatic uptake of CA and its effects on hepatic catabolism of L-alanine and glucose-6-phosphatase (G-6-Pase) activity were also evaluated. CA (1 mM) inhibited about 40% of G-6-Pase activity (p < 0.05) in the microsomal fraction of hepatocytes, but no effect was observed on production of glucose from gluconeogenesis or on L-alanine catabolism, at various concentrations of CA (0.33, 0.5 and 1 mM), in liver perfusion experiments. Since there were indications of a lack of uptake of CA by the liver, it is possible that this compound did not reach sufficiently high intracellular levels to inhibit the target enzyme. Accordingly, intravenous administration of CA also failed to provoke a reduction in blood glucose levels. However, CA did promote a significant reduction (p < 0.05) in the plasma glucose peak at 10 and 15 min during the oral glucose tolerance test, probably by attenuating intestinal glucose absorption, suggesting a possible role for it as a glycaemic index lowering agent and highlighting it as a compound of interest for reducing the risk of developing type 2 diabetes.

Cell Biochem Funct. 2008 Apr;26(3):320-8

Characterization of inhibitors of postprandial hyperglycemia from the leaves of Nerium indicum.

Nerium indicum is an India-Pakistan-originated shrub belonging to the oleander family. The ingestion of leaves of N. indicum before a meal is known to effect the lowering of postprandial glucose levels in type II diabetic patients and this plant is now used as a folk remedy for type II diabetes in some regions of Pakistan. In the present study, the hot-water extract of N. indicum leaves was found to reduce the postprandial rise in the blood glucose when maltose or sucrose was loaded in rats. It was also found that the extract strongly inhibited alpha-glucosidase, suggesting that the suppression of the postprandial rise in the blood glucose is due to the occurrence of some inhibitors of alpha-glucosidase in the leaves. We, therefore, tried to isolate the active principles from the leaf extract, using alpha-glucosidase-inhibitory activity as the index. Employing Sephadex G-15, silica gel and reversed-phase HPLC, we isolated two active compounds. The UV, mass and NMR spectrometric analyses established that the chemical structures of these compounds are 3-O-caffeoylquinic acid (chlorogenic acid) and its structural isomer, 5-O-caffeoylquinic acid. Both compounds were shown to inhibit alpha-glucosidases in a non-competitive manner. The authentic chlorogenic acid was found to suppress the postprandial rise in the blood glucose in rats and also inhibited the absorption of the glucose moiety from maltose and glucose in the everted gut sac system prepared from rat intestine. These results demonstrate that chlorogenic acid is one of the major anti-hyperglycemic principles present in the leaves of N. indicum. Furthermore, among polyphenol compounds tested, quercetin and catechins were shown to have strong inhibitory activity against alpha-glucosidase.

J Nutr Sci Vitaminol (Tokyo).2007 Apr;53(2):166-73