M. Cacchio

A review of specific dietary antioxidants and the effects on biochemical mechanisms related to neurodegenerative processes

Aging is a major risk factor for neurodegenerative diseases including Alzheimers disease (AD), Parkinsons disease (PD), and amyotrophic lateral sclerosis (ALS). An unbalanced overproduction of reactive oxygen species (ROS) may give rise to oxidative stress which can induce neuronal damage, ultimately leading to neuronal death by apoptosis or necrosis. A large body of evidence indicates that oxidative stress is involved in the pathogenesis of AD, PD, and ALS. An increasing number of studies show that nutritional antioxidants (especially Vitamin E and polyphenols) can block neuronal death in vitro, and may have therapeutic properties in animal models of neurodegenerative diseases including AD, PD, and ALS. Moreover, clinical data suggest that nutritional antioxidants might exert some protective effect against AD, PD, and ALS. In this paper, the biochemical mechanisms by which nutritional antioxidants can reduce or block neuronal death occurring in neurodegenerative disorders are reviewed. Particular emphasis will be given to the role played by the nuclear transcription factor-kappaB (NF-kappaB) in apoptosis, and in the pathogenesis of neurodegenerative disorders, such as AD, PD, and ALS. The effects of ROS and antioxidants on NF-kappaB function and their relevance in the pathophysiology of neurodegenerative diseases will also be examined.

Role of serotonin2C receptors in the control of brain dopaminergic function

There is substantial evidence that the functional status of mesocorticolimbic dopaminergic (DA) system originating in the ventral tegmental area (VTA) is under a phasic and tonic inhibitory control by the serotonergic system, which acts by stimulating serotonin(2C) (5-HT(2C)) receptor subtypes. This assertion is based upon a number of electrophysiological and biochemical data showing that 5-HT(2C) receptor agonists decrease, while 5-HT(2C) receptor antagonists enhance mesocorticolimbic DA function. On the other hand, it does not seem that 5-HT(2C) receptors play a relevant role in the control of nigrostriatal DA system originating in the substantia nigra pars compacta (SNc). The authors of this article review the most relevant data regarding the role of 5-HT(2C) receptors in the control of brain DA function and underline the importance of this subject in the search of new therapies for neuropsychiatric disorders such as depression, schizophrenia, drug addiction, and Parkinsons disease.

Biochemical evidence that the atypical antipsychotic drugs clozapine and risperidone block 5-HT2C receptors in vivo

Clozapine and risperidone are two atypical antipsychotic drugs which bind, among other receptors, to 5-HT(2C) receptor subtypes. They inhibit the basal inositol phosphate production in mammalian cells expressing rat or human 5-HT(2C) receptors. This biochemical effect is indicative of inverse agonist activity at these receptors. There is evidence that 5-HT(2C) receptors are involved in the control of the activity of central dopaminergic system. Therefore, the effects of clozapine (5 mg/kg ip), risperidone (0.08 mg/kg ip) and of the typical antipsychotic haloperidol (0.1 mg/kg ip) were studied on the extracellular concentration of dopamine (DA) in the nucleus accumbens of chloral hydrate-anesthetized rats, using intracerebral microdialysis. When injected alone, clozapine, risperidone and haloperidol caused only small variations in DA efflux. However, clozapine and risperidone completely prevented the inhibitory action of RO 60-0175 (1 mg/kg ip), a 5-HT(2C) receptor agonist, on DA release. On the other hand, haloperidol did not affect RO 60-0175-induced decrease in DA release. Taken together, these data indicate that clozapine and risperidone, unlike haloperidol, are capable of blocking 5-HT(2C) receptors in the nucleus accumbens. It is concluded that the experimental model presented in this study might represent a simple and useful in vivo biochemical method to test the effect of putative atypical antipsychotic drugs on 5-HT(2C) receptors.

Caffeic acid phenethyl ester blocks apoptosis induced by low potassium in cerebellar granule cells

Primary cultures of cerebellar granule neurons (CGNs) were prepared from 8‐day‐old Wistar rats, and maintained in an appropriate medium containing a high (25 mM) concentration of KCl. To induce apoptosis, culture medium was replaced with serum‐free medium (containing 5 mM KCl) 8 days after plating. Apoptosis was measured by the terminal deoxynucleotidyl transferase‐mediated dUTP‐fluorescein nick end‐labeling (TUNEL) method, and by flow cytometry. Since there is evidence that an increased formation of reactive oxygen species (ROS) is involved in the apoptosis induced by low K+ (5 mM) concentrations, the potential anti‐apoptotic effect of caffeic acid phenethyl ester (CAPE), a potent flavonoid antioxidant, was tested in this experimental model. It was found that CAPE (10 μg/ml) promoted cell survival and was capable of blocking the apoptotic process as assayed by both TUNEL and flow cytometric methods. The same concentration of CAPE prevented the formation of ROS induced by low K+. Since there is evidence that low K+‐induced apoptosis in CGNs is associated with a drop in intracellular Ca2+ concentration ([Ca2+]i), activation of the cell death effector proteases caspase‐3 and caspase‐9, and of the transcription factor nuclear factor kappa B (NF‐κB), the interference of CAPE with these purported mediators of apoptosis was also evaluated. It was found that CAPE did not interfere with the marked decrease in [Ca2+]i induced by low K+, whereas it completely blocked caspase‐3, caspase‐9, and NF‐κB activation. It is concluded that CAPE could exert its anti‐apoptotic effect in CGNs by blocking ROS formation and by inhibiting caspase activity.

HIF-1alpha cytoplasmic accumulation is associated with cell death in old rat cerebral cortex exposed to intermittent hypoxia.

Intermittent hypoxia, followed by reoxygenation, determines the production of reactive oxygen species (ROS), which may lead to accelerated aging and to the appearance of age‐related diseases. The rise in ROS levels might constitute a stress‐stimulus activating specific redox–sensitive signalling pathways, so inducing either damaging or protective functions. Here, we report that in old rat cerebral cortex exposed to hypoxia, the accumulation in the cytoplasm of hypoxic inducible factor 1α (HIF‐1α) – the master regulator of oxygen homeostasis – concomitant with p66Shc activation and reduced IkBα phosphorylation is associated with tissue apoptosis or necrosis. In young cerebral cortex, we hypothesize that the hypoxic damage may be reversible, based on our demonstration of elevated HIF‐1α levels, combined with a low level of IkBα phosphorylation, a decrease in IAP‐1 and a lack of major change in Bcl2 family proteins. These observations are associated with a low level of cell death induced by hypoxia, suggesting that HIF‐1α activation in cortical neurons may produce rescue proteins in response to intermittent hypoxia.

Treatment of osteoarthritis with Pycnogenol®. The SVOS (San Valentino osteo‐arthrosis study). evaluation of signs, symptoms, physical performance and vascular aspects

The aim of this double‐blind, placebo‐controlled study was to evaluate the efficacy of 100 mg Pycnogenol® daily (oral capsules) in a 3 month study in patients with osteoarthritis (OA). OA symptoms were evaluated by WOMAC scores, mobility by recording their walking performance (treadmill). Treatment (77 patients) and placebo group (79) were comparable for age, sex distribution, WOMAC scores, walking distances and use of antiinflammatory drugs. The global WOMAC score decreased by 56% (p < 0.05) in the treatment group versus 9.6% in the placebo group. Walking distance in the treadmill test was prolonged from 68 m at the start to 198 m after 3 months treatment (p < 0.05), under placebo, from 65 m to 88 m (NS). The use of drugs decreased by 58% in the treatment group (p < 0.05) versus 1% under placebo. Gastrointestinal complications decreased by 63% in the treatment group, but only 3% under placebo. Overall, treatment costs were reduced significantly compared with placebo. Foot edema was present in 76% of the patients of the treatment group at inclusion and in 79% of the controls. After 3 months edema decreased in 79% of Pycnogenol patients (p < 0.05) vs 1% in controls. In conclusion, Pycnogenol offers an option for reduction of treatment costs and side effects by sparing antiinflammatory drugs. Copyright

Venoruton® vs Daflon®: Evaluation of Effects on Quality of Life in Chronic Venous Insufficiency:

The aim of this independent study was to investigate differences in efficacy between oxerutins (Venoruton) and 500 mg micronized diosmin + hesperidin (D+H) (Daflon) in patients with chronic venous insufficiency (CVI), evaluating venous-related quality of life (Ve-QOL). A first group of 90 patients with severe venous hypertension (CVI, ankle swelling) was randomized to treatment with oxerutins or D+H. The oxerutins group received oral oxerutins (2 g/day); the D+H group received 3 (500 mg) tablets daily every 8 hours for 8 weeks. A second group of 122 comparable patients was included in a registry following the same study format. The 2 treatments were administered with the same methods and procedures. Clinical conditions were comparable. All patients completing 8 weeks of treatment were included in a registry. Specialists or general practitioners included patients when they considered that clinical conditions were compatible with treatment indications using 1 of the 2 treatments on the basis of their evaluation and experience. When cases were compatible with the registry, the prescribing physician communicated the case to our monitoring center. Patients were evaluated without interfering with their treatment. The main target of evaluation for this study was the change in Ve-QOL (range, 0-100) induced by treatment. A specific Ve-QOL questionnaire was used for this study. Ve-QOL score is a specific expression of the changes in QOL induced by CVI in patients between 35 and 75 years old (defined in our population studies) in which no other significant clinical disease is present (as a confounding factor affecting QOL). Two hundred twelve patients completed the 2 parts of the study. The 2 treatment groups were comparable for age and gender distribution. The mean age was 42 years (SD ±5.5) in the oxerutins group and 41.5 (SD ±6) in the D+H group. There were no differences in the severity of CVI between the treatment groups at inclusion. A significant decrease (46.8%, p<0.05) in Ve-QOL score; that is, improvement, was observed in the oxerutins group. The change in Ve-QOL was significantly less in the D+H group (15.5%). In conclusion, CVI, venous microangiopathy, and edema were significantly improved by the treatment with oxerutins; the improvement in QOL was significantly greater in the oxerutins group. The comparison with D+H indicates that oxerutins is comparatively more effective on Ve-QOL and on signs/symptoms of CVI

Comparison of Pycnogenol® and Daflon® in Treating Chronic Venous Insufficiency: A Prospective, Controlled Study

The aim of this study was to investigate the clinical efficacy of oral Pycnogenol® (Horphag Research Ltd., UK) in patients with severe chronic venous insufficiency (CVI) in comparison to the combination of diosmin and hesperidin (Daflon®, Servier, France). A group of 86 patients with severe chronic venous insufficiency (CVI), venous hypertension, ankle swelling) and previous history of venous ulcerations received either oral Pycnogenol (capsules) 150 mg or 300 mg daily for 8 weeks or Daflon, 1000 mg/day. All patients completed the study without dropouts. At the end of the study, microcirculatory results indicated: a progressive decrease of skin flux at rest (RF); a significant decrease in capillary filtration (RAS); an improvement in the symptomatic venous score (ASLS); a reduction in edema; a significant improvement (increase) in pO2 and a decrease in pCO2 in the Pycnogenol group. A significant level of improvement was reached after 4 weeks of treatment in most patients (p < .05) of the Pycnogenol group while clinical improvement was significant only in 6 subjects in the Daflon group. The positive effects of treatment with Pycnogenol after 8 weeks were significantly larger in comparison with the Daflon group. In conclusion, this study confirms the fast clinical efficacy of Pycnogenol in patients with chronic venous insufficiency and venous microangiopathy and its superiority—considering the evaluated parameters—to the combination of diosmin and hesperidin.

Improvement of diabetic microangiopathy with pycnogenol® : A prospective, controlled study

The aim of this study was to investigate the clinical efficacy of oral Pycnogenol® (Horphag Research Ltd, United Kingdom) in patients with diabetic microangiopathy. Patients without a history of diabetic ulcerations were treated with Pycnogenol. Patients received oral Pycnogenol (50 mg capsules, 3 times daily for a total of 150 mg daily for 4 weeks). A group of 30 patients was included (severe microangiopathy); 30 comparable patients were observed as controls (no treatment during the observation period). All patients (age, 59 years; range, 55-68 years; male:female = 18:12) included in the treatment group completed the 4-week study. Also, all controls completed the follow-up period. There were no drop-outs. All included subjects had signs and symptoms of diabetic microangiopathy. The duration of diabetes—from the first signs/symptoms—was on average 7.5 years (SD = 3). After 4 weeks, microcirculatory and clinical evaluations showed a progressive decrease in skin flux at rest in the foot (indicating an improvement in the level of microangiopathy), a significant decrease in capillary filtration, and a significant improvement in the venoarteriolar response in all treated subjects. There were no visible effects in controls except a slight reduction in skin flux at rest in the foot. Treatment was well tolerated in both groups. In conclusion, this study confirms the clinical efficacy of Pycnogenol in patients with diabetic microangiopathy. The study indicates the clinical role of Pycnogenol in the management, treatment, and control of this common clinical problem. The treatment may be also useful to prevent diabetic ulcerations by controlling the level of microangiopathy.

Venous ulcers : Microcirculatory improvement and faster healing with local use of pycnogenol®

Chronic venous insufficiency (CVI) causes a well-defined microangiopathy described as venous hypertensive microangiopathy (VHM) leading to venous ulcerations. VHM is mainly observed in the distal part of the leg, in the perimalleolar region. In VHM edema is the consequence of increased capillary pressure and reduced local clearance, and this affects local perfusion. The healing of venous ulcers is usually very slow. Many treatments are available, but there is still no standard. Oral Pycnogenol® is effective in venous disease and particularly in controlling edema. The aim of this study was the evaluation of the local effects of Pycnogenol on ulcers healing associated with venous hypertension. The study lasted 6 weeks including 18 patients (16 completed the study) with venous ulcerations. The oral treatment with Pycnogenol was compared with a combination treatment including oral and local treatment. In subjects treated with the combination treatment (oral and local), venous ulcers healed better (there was a faster reduction in ulcerated area) in comparison with oral treatment only. According to this pilot study Pycnogenol appears to have an important role in local treatment of venous ulcers improving healing and signs/symptoms.