Your Trusted Brand for Over 35 Years

Life Extension Magazine

<< Back to April 2016

PQQ, Fiber, Astaxanthin, and Blueberry

April 2016

By Life Extension

PQQ

Pyrroloquinoline quinone-conferred neuroprotection in rotenone models of Parkinson’s disease.

Pyrroloquinoline quinone (PQQ), a redox cofactor in the mitochondrial respiratory chain, has proven to protect neurons against glutamate-induced damage both in vitro and in vivo. This study was aimed to investigate the possible neuroprotective effects of PQQ in rotenone-induced Parkinson’s disease (PD) model. Pre-treatment with PQQ prevented cultured SH-SY5Y cells from rotenone-induced apoptosis, accompanied by modulation of apoptosis-related proteins (Bcl-2, Bax and Smac), restoration of the mitochondrial membrane potential, inhibition of intracellular reactive oxygen species (ROS) production, suppression of tyrosine residues nitration, and dopamine redistribution. PQQ also exerted protective effects in an in vivo PD model, which was created by rotenone injection into the medial forebrain bundle of rats. Co-injection with PQQ and rotenone improved the apomorphine-evoked rotation, decreased neuronal loss, increased the ROS-scavenging ability, regulated intracellular expressions of mitochondrial complex subunits (Ndufs1-4), tyrosine hydroxylase, and vesicular monoamine transporter 2. Taken together, our results collectively suggest that PQQ confers neuroprotection in rotenone-induced PD model probably through complex and multifaceted mechanisms, at least involving oxidative stress, mitochondrial integrity, and dopamine functions.

Toxicol Lett. 2015 Nov 4;238(3):70-82

Involvement of ERK1/2 pathway in neuroprotective effects of pyrroloquinoline quinine against rotenone-induced SH-SY5Y cell injury.

Pyrroloquinoline quinone (PQQ), a redox cofactor in the mitochondrial respiratory chain, has been shown to protect neurons against glutamate-induced damage both in vitro and in vivo. In this study, specific inhibitors to each of the mitochondrial complexes were used to find out which reactive oxygen species (ROS)-generating sites could be affected by PQQ. Then we established an in vitro model of Parkinson’s disease (PD) by exposing cultured SH-SY5Y dopaminergic cells to rotenone, a complex I inhibitor. The neuroprotective effects of PQQ were observed by pretreatment of SH-SY5Y cells with PQQ before rotenone injury, and the possible involvement of certain signaling pathways were investigated. PQQ pretreatment prevented SH-SY5Y cells from rotenone-induced apoptosis in a concentration-dependent manner. PQQ neuroprotection was associated with inhibition of intracellular ROS production, modulation of the expression of apoptosis-related Bcl-2 and Bax, and regulation of the level of superoxide dismutase, glutathione, and malondialdehyde. Meanwhile, PQQ up-regulated the gene expression of Ndufs 1, 2, and 4 (complex I subunits), and increased mitochondrial viability and mitochondrial DNA content. Furthermore, PQQ pretreatment activated ERK1/2 phosphorylation in rotenone-injured SH-SY5Y cells, while ERK1/2 inhibition suppressed PQQ neuroprotection. All the results suggested that PQQ could protect SH-SY5Y cells against rotenone injury by reducing ROS production and maintaining mitochondrial functions through activation of ERK1/2 pathway.

Neuroscience. 2014 Jun 13;270:183-91

Dietary pyrroloquinoline quinone (PQQ) alters indicators of inflammation and mitochondrial-related metabolism in human subjects.

Pyrroloquinoline quinone (PQQ) influences energy-related metabolism and neurologic functions in animals. The mechanism of action involves interactions with cell signaling pathways and mitochondrial function. However, little is known about the response to PQQ in humans. Using a crossover study design, 10 subjects (5 females, 5 males) ingested PQQ added to a fruit-flavored drink in two separate studies. In study 1, PQQ was given in a single dose (0.2 mg PQQ/kg). Multiple measurements of plasma and urine PQQ levels and changes in antioxidant potential [based on total peroxyl radical-trapping potential and thiobarbituric acid reactive product (TBAR) assays] were made throughout the period of 48 h. In study 2, PQQ was administered as a daily dose (0.3 mg PQQ/kg). After 76 h, measurements included indices of inflammation [plasma C-reactive protein, interleukin (IL)-6 levels], standard clinical indices (e.g., cholesterol, glucose, high-density lipoprotein, low-density lipoprotein, triglycerides, etc.) and (1)H-nuclear magnetic resonance estimates of urinary metabolites related in part to oxidative metabolism. The standard clinical indices were normal and not altered by PQQ supplementation. However, dietary PQQ exposure (Study 1) resulted in apparent changes in antioxidant potential based on malonaldehyde-related TBAR assessments. In Study 2, PQQ supplementation resulted in significant decreases in the levels of plasma C-reactive protein, IL-6 and urinary methylated amines such as trimethylamine N-oxide, and changes in urinary metabolites consistent with enhanced mitochondria-related functions. The data are among the first to link systemic effects of PQQ in animals to corresponding effects in humans.

J Nutr Biochem. 2013 Dec;24(12):2076-84

Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect.

Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide conduits in the field of nerve tissue engineering.

Biochem Biophys Res Commun. 2015 Feb 20;457(4):507-13

Improvement of functional recovery of transected peripheral nerve by means of chitosan grafts filled with vitamin E, pyrroloquinoline quinone and their combination.

Effects of vitamin E and pyrroloquinoline quinone on peripheral nerve regeneration were studied using a rat sciatic nerve transection model. Ninety male healthy White Wistar rats were divided into three experimental groups (n = 15), randomly: Sham-operation (SHAM), transected control (TC), chitosan conduit (Chit) and three treatment groups (Vit E, PQQ and PQQ + Vit E). In SHAM group after anesthesia, left sciatic nerve was exposed through a gluteal muscle incision and after homeostasis muscle was sutured. In Chit group left sciatic nerve was exposed the same way and transected proximal to tibio-peroneal bifurcation leaving a 10-mm gap. Proximal and distal stumps were each inserted into a chitosan tube. In treatment groups the tube was implanted the same way and filled with Vit E, PQQ and PQQ + Vit E. Each group was subdivided into three subgroups of six animals each and were studied 4, 8, 12 weeks after surgery. Functional and electrophysiological studies, and gastrocnemius muscle mass measurement confirmed faster and better recovery of regenerated axons in Vit E + PQQ combination compared to Vit E or PQQ solely (P < 0.05). Morphometric indices of regenerated fibers showed number and diameter of the myelinated fibers in PQQ + Vit E was significantly higher than in other treatment groups. In immunohistochemistry, location of reactions to S-100 in PQQ + Vit E was clearly more positive than in other treatment groups. Response to PQQ + Vit E treatment demonstrates that it influences and improves functional recovery of peripheral nerve regeneration.

Int J Surg. 2014;12(5):76-82

Pyrroloquinoline quinone (PQQ) prevents cognitive deficit caused by oxidative stress in rats.

The effects of pyrroloquinoline quinone (PQQ) and coenzyme Q(10) (Co Q(10)), either alone or together, on the learning ability and memory function of rats were investigated. Rats fed a PQQ-supplemented diet showed better learning ability than rats fed a CoQ(10)-supplemented diet at the early stage of the Morris water maze test. The combination of both compounds resulted in no significant improvement in the learning ability compared with the supplementation of PQQ alone. At the late stage of the test, rats fed PQQ-, CoQ(10)- and PQQ + CoQ(10)-supplemented diets showed similar improved learning abilities. When all the groups were subjected to hyperoxia as oxidative stress for 48 h, rats fed the PQQ- and CoQ(10) supplemented diets showed better memory function than the control rats. The concurrent diet markedly improved the memory deficit of the rats caused by oxidative stress. Although the vitamin E-deficient rats fed PQQ or CoQ(10) improved their learning function even when subjected to hyperoxia, their memory function was maintained by PQQ rather than by CoQ(10) after the stress. These results suggest that PQQ is potentially effective for preventing neurodegeneration caused by oxidative stress, and that its effect is independent of either antioxidant’s interaction with vitamin E.

J Clin Biochem Nutr. 2008 Jan;42:29-34

Pyrroloquinoline quinone is a potent neuroprotective nutrient against 6-hydroxydopamine-induced neurotoxicity.

Pyrroloquinoline quinone (PQQ), which is an essential nutrient, has been shown to act as an antioxidant. Reactive oxygen species (ROS) are thought to be responsible for neurotoxicity caused by the neurotoxin 6-hydroxydopamine (6-OHDA). In this study, we investigated the ability of PQQ to protect against 6-OHDA-induced neurotoxicity using human neuroblastoma SH-SY5Y. When SH-SY5Y cells were exposed to 6-OHDA in the presence of PQQ, PQQ prevented 6-OHDA-induced cell death and DNA fragmentation. Flow cytometry analysis using the ROS-sensitive fluorescence probe, dihydroethidium, revealed that PQQ reduced elevation of 6-OHDA-induced intracellular ROS. In contrast to PQQ, antioxidant vitamins, ascorbic acid and alpha-tocopherol, had no protective effect. Moreover, we showed that PQQ effectively scavenged superoxide, compared to the antioxidant vitamins. Therefore, our results suggest the protective effect of PQQ on 6-OHDA-induced neurotoxicity is involved, at least in part, in its function as a scavenger of ROS, especially superoxide.

Neurochem Res. 2007 Mar;32(3):489-95

The putative essential nutrient pyrroloquinoline quinone is neuroprotective in a rodent model of hypoxic/ischemic brain injury.

Pyrroloquinoline quinone is a ubiquitous redox cofactor and putative essential nutrient in mammals. Pyrroloquinoline quinone has recently been demonstrated to depress N-methyl-D-asparate induced electrical responses and is neuroprotective in vitro. In addition, pyrroloquinoline quinone has been demonstrated to act as a free radical scavenger in mammalian tissues. In this study, we demonstrate a neuroprotective effect of pyrroloquinoline quinone in an in vivo cerebral hypoxia/ischemia model in the rodent. Significant reduction in infarct size resulted from pyrroloquinoline quinone pretreatment and also when pyrroloquinoline quinone was administered following induction of hypoxia/ischemia. The neuroprotective effect was not dependent on change in core or cranial temperatures, as there was no difference between temperature measurements in pyrroloquinoline quinone-treated and vehicle-treated controls. No changes in electroencephalographic activity were observed at neuroprotective doses. These findings suggest that pyrroloquinoline quinone may represent a novel class of quinoid reagents of potential use in the treatment of neurological disorders that involve excitotoxicity. This study demonstrates a protective effect of the novel essential nutrient pyrroloquinoline quinone on brain injury in a rodent model of cerebral hypoxia/ischemia. Pyrroloquinoline quinone was neuroprotective when administered before and even after the insult, and did not appear to have significant neurobehavioral side effects. Pyrroloquinoline quinone represents a new class of agents with potential use in the therapy of stroke.

Neuroscience. 1994 Sep;62(2):399-406