Copper addition prevents the inhibitory effects of interleukin 1-beta on rat pancreatic islets

Carnosine, Zinc and Copper: A Menage a Trois in Bone and Cartilage Protection

Dysregulated metal homeostasis is associated with many pathological conditions, including arthritic diseases. Osteoarthritis and rheumatoid arthritis are the two most prevalent disorders that damage the joints and lead to cartilage and bone destruction. Recent studies show that the levels of zinc (Zn) and copper (Cu) are generally altered in the serum of arthritis patients. Therefore, metal dyshomeostasis may reflect the contribution of these trace elements to the disease's pathogenesis and manifestations, suggesting their potential for prognosis and treatment. Carnosine (Car) also emerged as a biomarker in arthritis and exerts protective and osteogenic effects in arthritic joints. Notably, its zinc(II) complex, polaprezinc, has been recently proposed as a drug-repurposing candidate for bone fracture healing. On these bases, this review article aims to provide an overview of the beneficial roles of Cu and Zn in bone and cartilage health and their potential application in tissue engineering. The effects of Car and polaprezinc in promoting cartilage and bone regeneration are also discussed. We hypothesize that polaprezinc could exchange Zn for Cu, present in the culture media, due to its higher sequestering ability towards Cu. However, future studies should unveil the potential contribution of Cu in the beneficial effects of polaprezinc.

Efficacy of Postbiotics in a PRP-Like Cosmetic Product for the Treatment of Alopecia Area Celsi: A Randomized Double-Blinded Parallel-Group Study

INTRODUCTION

Alopecia areata (AA), also known as 'area Celsi', is the second most common form of hair loss affecting the scalp. Newly proposed treatments for AA include low-level light therapy, biologics such as Janus kinase inhibitors and autologous platelet-rich plasma (PRP), which is a well-known "elixir" for hair growth. Bioactive peptides developed through biotechnological applications have been used to overcome the limitations of PRP. More recently, the involvement of microbiota in hair growth disorders, in AA in particular, has been reported, and the usefulness of microbial metabolites, i.e. postbiotics, has been suggested.

METHODS

This study was a randomized double-blinded parallel-group study in which 160 persons of both sexes affected by AA and aged between 18 and 60 years were enrolled. The subjects were randomly assigned to a treatment group (group 1), receiving the TR-PRP plus-Celsi cosmetic product, and a placebo group (group 2). The SALT (Severity of Alopecia Tool) score was determined in both groups at baseline and after 2 and 3 months of treatment, and the results compared between groups.

RESULTS

The subjects in group 1 showed a significant change from baseline in SALT score at 2 months of treatment (61.04% ± 3.45%; p < 0.0001), with a further improvement at the end of treatment (3 months) (69.56% ± 4.32%; p < 0.0001). No significant changes from baseline were reported for the subjects in group 2 (T1: 26.45% ± 3.64%; T3: 27.63% ± 7.61%).

CONCLUSIONS

The results of this study provide further proof of the efficacy of bioactive peptides that mimick the growth factors present in PRP in subjects affected by AA. They also add to our knowledge of the link between microbiota and hair growth disorders, emphasizing the importance of studies on the microbial community and microbial metabolites as a novel therapeutic approach.

Randomized controlled trial on a PRP-like cosmetic, biomimetic peptides based, for the treatment of alopecia areata

Background: Alopecia areata (AA) is a non-scarring auto-immune hair disorder. Recent researches explained the role of growth factors (GFs) in hair follicle cycling. The main reservoir of GFs are alpha-granules of platelets and novel procedures have been implemented aimed at collecting platelet-rich plasma (PRP). PRP has been safely implemented in many medical applications and has also been successfully used as alternative cell-based therapy for the treatment of hair growth disorders, among which also AA. Objectives: By means of a randomized double-blinded, placebo and active-controlled, parallel group study we have studied the efficacy of a cosmetic product (named TR-M-PRP plus) comprising biomimetic peptides specific for hair growth, mimicking PRP composition for the treatment of AA. Subjects were treated for three months and evaluated, at the end of the study and after one month of follow-up, as regards hair growth using SALT score. Results: TR-M-PRP plus-like topic produced a statistically significant (p < .001) clinical improvement in SALT score after 3 months of therapy, compared to baseline. Hair growth results further improved after 1 month of follow-up. Conclusions: This clinical investigation suggests that the biotechnological designed PRP-like cosmetic could represent a valid and safer alternative to autologous PRP for the treatment of AA.

GHK and DNA: resetting the human genome to health

During human aging there is an increase in the activity of inflammatory, cancer promoting, and tissue destructive genes plus a decrease in the activity of regenerative and reparative genes. The human blood tripeptide GHK possesses many positive effects but declines with age. It improves wound healing and tissue regeneration (skin, hair follicles, stomach and intestinal linings, and boney tissue), increases collagen and glycosaminoglycans, stimulates synthesis of decorin, increases angiogenesis, and nerve outgrowth, possesses antioxidant and anti-inflammatory effects, and increases cellular stemness and the secretion of trophic factors by mesenchymal stem cells. Recently, GHK has been found to reset genes of diseased cells from patients with cancer or COPD to a more healthy state. Cancer cells reset their programmed cell death system while COPD patients' cells shut down tissue destructive genes and stimulate repair and remodeling activities. In this paper, we discuss GHK's effect on genes that suppress fibrinogen synthesis, the insulin/insulin-like system, and cancer growth plus activation of genes that increase the ubiquitin-proteasome system, DNA repair, antioxidant systems, and healing by the TGF beta superfamily. A variety of methods and dosages to effectively use GHK to reset genes to a healthier state are also discussed.

IL-1β hampers glucose-stimulated insulin secretion in Cohen diabetic rat islets through mitochondrial cytochrome c oxidase inhibition by nitric oxide

A high-sucrose, low-copper-diet (HSD) induces inhibition of glucose-sensitive rats (CDs) but not Cohen diabetes-resistant rats (CDr). Copper-supplemented HSD increased activity of the copper-dependent mitochondrial respiratory chain enzyme cytochrome c oxidase (COX) and reversed hyperglycemia. This study examined the mechanism by which interleukin-1β modulates GSIS and the role of COX in this process. We measured COX activity, ATP content, GSIS, iNOS expression, and nitrite production with and without IL-1β, N(ω)-nitro-l-arginine, copper, or potassium cyanide in isolated islets of CDs and CDr fed different diets. We found reduced COX activity, ATP content, and GSIS in isolated islets of CDs rats fed a regular diet. These were severely reduced following HSD and were restored to regular diet levels on copper-supplemented HSD (P < 0.01 vs. CDr islets). Potassium cyanide chemically reduced COX activity, decreasing GSIS and thus reinforcing the link between islet COX activity and GSIS. Interleukin-1β (2.5 U/ml) reduced GSIS and COX activity in CDs islets. Exposure to 10 U/ml interleukin-1β decreased GSIS and COX activity in both CDs and CDr islets, inducing a similar nitrite production. Nevertheless, the effect on GSIS was more marked in CDs islets. A significant iNOS expression was detected in CDs on the HSD diet, which was reduced by copper supplementation. N(ω)-nitro-l-arginine and copper prevented the deleterious effect of interleukin-1β on COX activity and GSIS. We conclude that reduced islet COX activity renders vulnerability to GSIS inhibition on low-copper HSD through two interrelated pathways: 1) by further reducing the activity of COX that is essential for β-cell ATP-production and insulin secretion and 2) by inducing the expression of iNOS and nitric oxide-mediated COX inhibition. We suggest that islet COX activity must be maintained above a critical threshold to sustain adequate GSIS with exposure to low-copper HSD.

Dietary copper supplementation restores β-cell function of Cohen diabetic rats: a link between mitochondrial function and glucose-stimulated insulin secretion

β-Cell mitochondrial dysfunction as well as proinflammatory cytokines have been suggested to contribute to reduced glucose-stimulated insulin secretion (GSIS) in type 2 diabetes. We recently demonstrated that Cohen diabetic sensitive (CDs) rats fed a high-sucrose, low-copper diet (HSD) developed hyperglycemia and reduced GSIS in association with peri-islet infiltration of fat and interleukin (IL)-1β-expressing macrophages, whereas CD resistant (CDr) rats remained normoglycemic on HSD. We examined: 1) the correlation between copper concentration in the HSD and progression, prevention, and reversion of hyperglycemia in CDs rats, 2) the relationship between activity of the copper-dependent, respiratory-chain enzyme cytochrome c oxidase (COX), infiltration of fat, IL-1β-expressing macrophages, and defective GSIS in hyperglycemic CDs rats. CDs and CDr rats were fed HSD or copper-supplemented HSD before and during hyperglycemia development. Blood glucose and insulin concentrations were measured during glucose tolerance tests. Macrophage infiltration and IL-1β expression were evaluated in pancreatic sections by electron-microscopy and immunostaining. COX activity was measured in pancreatic sections and isolated islets. In CDs rats fed HSD, GSIS and islet COX activity decreased, while blood glucose and infiltration of fat and IL-1β-expressing macrophages increased with time on HSD (P < 0.01 vs. CDr-HSD rats, all parameters, respectively). CDs rats maintained on copper-supplemented HSD did not develop hyperglycemia, and in hyperglycemic CDs rats, copper supplementation restored GSIS and COX activity, reversed hyperglycemia and infiltration of fat and IL-1β-expressing macrophages (P < 0.01 vs. hyperglycemic CDs-HSD rats, all parameters, respectively). We provide novel evidence for a critical role of low dietary copper in diminished GSIS of susceptible CDs rats involving the combined consequence of reduced islet COX activity and pancreatic low-grade inflammation.

Effects of copper and zinc on proteoglycan metabolism in articular cartilage

Co-Cultures of porcine articular cartilage and synovium or synovial conditioned medium were used as an in vitro model to mimic inflammatory events at the cartilage/synovial junction in degenerative joint disease. This model provides a useful tool to assess the anti-inflammatory and antiarthritic properties of pharmacological agents. In this study the effects of copper and zinc on (i) PG synthesis by cartilage and (ii) synovial-induced PG depletion have been investigated. Copper sulphate at a concentration of 0.01 mM did not stimulate PG synthesis significantly in cultured cartilage explants but completely abrogated the inhibitory effects of synovial tissue in co-culture experiments. This finding was supported by the histological demonstration of copper-dependent reversal of the PG depletion in cartilage exposed to synovial conditioned medium. Zinc sulphate at 0.01 mM had no effect on PG synthesis and was unable to protect cartilage against synovialinduced PG depletion. These results reveal possible mechanisms by which copper exerts its anti-inflammatory and anti-arthritic actions.

Effects of metformin on oxidative stress, adenine nucleotides balance, and glucose-induced insulin release impaired by chronic free fatty acids exposure in rat pancreatic islets

BACKGROUND

In rat pancreatic islets, chronic exposure to high free fatty acid (FFA) levels impairs insulin secretion and β cell mass. The mechanisms underlying this defect are not completely understood. Since islets have intrinsically low anti-oxidant enzyme defense, oxidative stress might be responsible for β cell damage.

AIM

In this study, we investigated if FFA could induce oxidative stress in rat pancreatic islets and if metformin might reverse adverse effects.

MATERIAL AND METHODS

We cultured rat pancreatic islets in the presence or absence of FFA (oleate/palmitate 2:1, 2 mM) for 72 h. In some experiments, we used metformin (2.5 μg/ml) during the last 24 h.

RESULTS

In our model, glucosestimu lated insulin release was markedly reduced (p<0.005) after chronic FFA exposure, and the ATP/ADP ratio was altered (p<0.05). We observed a significant increase of reactive oxygen species (ROS) (p<0.001), malondialdehyde a lipid peroxidation product (p<0.01) and nitric oxide (NO) levels in the culture media (p<0.001). Inducible NO synthase (iNOS) and heat shock protein-70 (HSP-70) protein expression were also increased (p<0.001 and p<0.01, respectively). When metformin was present during the last 24 h of culture, insulin secretion was restored, and the ATP/ADP ratio was normalized. ROS production, NO production, lipid peroxidation, iNOS and HSP-70 protein expression levels had decreased.

CONCLUSIONS

These data indicate that, in rat pancreatic islets, chronic exposure to high FFA induces oxidative stress and that metformin, by reducing this effect, may have a direct beneficial effect on insulin secretion impaired by lipotoxicity.

Metallothionein as an adaptive protein prevents diabetes and its toxicity

Metallothioneins (MTs) are a group of intracellular metal-binding and cysteine-enriched proteins and are highly inducible in many tissues in response to various types of stress. Although it mainly acts as a regulator of metal homeostasis such as zinc and copper in tissues, MT also acts as a potent antioxidant and adaptive (or stress) protein to protect cells and tissues from oxidative stress. Diabetes affects many Americans and other populations, and its development and toxic effect on various organs have been attributed to increased oxidative stress. Studies showed that zinc-induced or genetically enhanced pancreatic MT synthesis prevented diabetes induced by chemicals such as streptozotocin and alloxan, and zinc pretreatment also prevented spontaneously developed diabetes. Since diabetic complications are the consequences of organ damage caused by diabetic hyperglycemia and hyperlipidemia through oxidative stress, whether MT in nonpancreatic organs also provides a preventive effect on diabetic toxicity has been recently investigated. We demonstrated that overexpression of cardiac MT significantly prevented diabetes-induced cardiomyopathy. Likewise, overexpression of renal MT also prevented diabetes-induced renal toxicity. In addition, we also found that MT as an adaptive protein is overexpressed in several organs in response to diabetes. Therefore, the biological importance of diabetes-induced MT in diabetic complications and subsequent other pathogenesis was further explored. We found that diabetes-induced hepatic and renal MT synthesis was accompanied by a significant prevention of endotoxin-induced hepatic toxicity and cisplatin-induced renal toxicity. These studies suggest that MT as an adaptive protein can prevent both diabetes development and its complications or subsequent suffered other pathogenic injury.

Nitric oxide and neuronal and pancreatic beta cell death

Neural cells are found in all organs of the body and play an important role in the maintenance of the internal milieu. The pancreatic beta cell is the most numerous cell types in the endocrine pancreas. It is particularly important because of its role in insulin secretion, a crucial hormone in glucose metabolism. In view of this, the significance of the survival of neural and pancreatic beta cell cannot be over emphasised. Neural and pancreatic beta cell death occurs in a variety of ways. The destruction of neural cells can be induced with (1) free radicals (H(2)O(2), O(2)(-)(,) HO(-)) and nitric oxide; (2) Cytokines (tumour necrosis factor, interleukin-1 beta, interferon-gamma); (3) Glutamate; (4) Amphetamine analog (Ecstasy); (5) S100 protein; (6) Ammonia; (7) Iron ions; (8) Resins, e.g. methylmethycrylate. Pancreatic beta cell can be destroyed by (1) free radicals (H(2)O(2), O(2)(-)(,) HO(-)) and nitric oxide; (2) Cytokines (tumour necrosis factor, interleukin-1 beta, interferon-gamma); (3) alkylating agents (streptozotocin, alloxan, N-methyl-nitrosourea N-ethyl-N-nitrosourea, Methylmethanesulphonate and ethylmethanesulphonate); (4) hyperglycaemia; (5) islet amyloid poplypeptide; and (6) Inositol Monophosphate dehydrogenase inhibitors. There is enough evidence that most of these agents involved in neural and pancreatic beta cell death exert their toxic effects through the nitric oxide pathway. Neuroprotective agents include vitamin B12 analogs and alpha-tocopherol, NOS inhibitors, antioxidants (e.g. glutathione, superoxide dismutase), metals like cobalt, neurotrophic receptors (Akt kinase) and growth factors. The pancreatic beta cell death induced by these toxic agents can be prevented and or delayed by nicotinamide (vitamin B3), heat shock, copper, alpha-tocopherol (vitamin E), succinic acid, dihydroxylipoic acid, fusidic acid, glucocorticoids, cyclosporin A, growth factors and gene therapy.

Dietary copper supplementation reduces atherosclerosis in the cholesterol-fed rabbit

There has been considerable debate about how copper status may affect the biochemical and cellular processes associated with atherogenesis. In the present study we have attempted to address this issue directly by investigating the effects of dietary copper supplementation on processes likely to contribute to atherogenesis, using the cholesterol-fed New Zealand White rabbit model. Age matched rabbits (n = 16) were fed a 0.25-1% cholesterol diet to maintain plasma cholesterol concentrations at approximately 30 mmol/l. Eight of these animals also received 0.2% copper acetate. Control animals (n = 8) received rabbit chow without supplements. After 13 weeks on the experimental diets the animals were killed. Integrated cholesterol levels were similar for the cholesterol-fed animals (31.1+/-2.5 vs. 29.9+/-1.9 mmol/l weeks; P>0.05). Although integrated plasma copper levels were higher in the animals receiving the copper supplements, these did not differ significantly (19.0+/-4.8 vs. 15.1+/-2.9 micromol/l weeks; P>0.05). Tissue concentrations of copper were higher in the copper fed animals compared to those on cholesterol alone in aortic 14.0+/-0.75 vs. 1.8+/-0.2 microg/g wet tissue; P<0.05), carotid artery (11.4+/-3.5 vs. 4.9+/-0.9 microg/g wet tissue; P<0.05), and hepatic (332.5+/-28.6 vs. 3.3+/-1.1 microg/g wet tissue; P<0.0001) samples. The concentration of copper within the carotid artery was also significantly higher than that within the aorta (7.5+/-1.8 vs. 2.4+/-0.4 microg/g wet tissue; P<0.05). In animals fed a normal rabbit chow aortic, carotid and hepatic copper concentrations were 3.7+/-0.8, 9.4+/-3.4, and 5.0+/-1.6 microg/g, respectively. These values did not differ significantly from the cholesterol-fed animals (P>0.05). Plasma concentrations of caeruloplasmin, the major copper carrying protein, were estimated as plasma ferroxidase activity and were similar for the groups (P>0.05), as were aortic superoxide dismutase activity levels (P>0.05). Copper supplementation was associated with increased mononuclear cell adhesion to the endothelium of the carotid endothelium, with 2.6+/-0.3 adherent monocytes/1000 endothelial cells in the cholesterol plus copper-fed animals compared to 1.3+/-0.3 in the cholesterol-fed group (P = 0.0006), and 0.1+/-0.1 in the control animals (P<0.002). This may reflect the higher concentrations of copper found within the carotid artery. Histology of the thoracic aorta at the level of the third and sixth intercostal arteries, showed that copper supplementation was associated with significantly smaller intimal lesions (P<0.05 and P<0.01, respectively). These data suggest that copper supplements possibly inhibit the progression of atherogenesis.

Glucose induces an acute increase of superoxide dismutase activity in incubated rat pancreatic islets

The activity of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSP) in isolated rat pancreatic islets exposed to high glucose concentration for a short period of time (60 min) was determined. High glucose concentration (16.7 mM) did not significantly alter catalase activity. GSP activity was increased by glucose at 5.6 mM, remaining elevated at higher concentrations up to 16.7 mM. However, the activity of SOD increased with glucose concentration, and this increment was closely correlated with the rate of insulin secretion (r = 0.96). High potassium (30 mM) did not increase SOD activity, suggesting that the increase in intracellular ionic calcium concentration does not stimulate this enzyme activity. alpha-Ketoisocaproic acid and pyruvate, which are metabolized through the TCA cycle, did not increase SOD activity, indicating that the stimulation of SOD activity might be triggered by a factor produced through glycolysis or the pentose phosphate pathway.

Extent of Intramolecular Aromatic-Ring Stacking in Ternary Cu(2+) Complexes Formed by 2,2'-Bipyridyl or 1,10-Phenanthroline and Flavin Mononucleotide (FMN(2)(-))(1)(,)(2)

The stability constants of the 1:1 complexes formed between Cu(Arm)(2+), where Arm = 2,2'-bipyridyl or 1,10-phenanthroline, and flavin mononucleotide (= FMN(2)(-) = riboflavin 5'-phosphate) were determined by potentiometric pH titrations in aqueous solution at 25 degrees C and I = 0.1 M (NaNO(3)). The experimental conditions were carefully selected such that only the monomeric complex species formed. On the basis of previously established log K versus pK(a) straight-line plots (Chen, D.; et al. J. Chem. Soc., Dalton Trans. 1993, 1537-1546) for the corresponding ternary complexes of simple phosphate monoesters and phosphonate derivatives, R-PO(3)(2)(-), where R is a noncoordinating residue, it is shown that the stability of the ternary Cu(Bpy)(FMN) and Cu(Phen)(FMN) complexes is considerably higher than is expected on the basis of the basicity of the phosphate group of FMN(2)(-). By comparison with the stability of the ternary Cu(Arm)(G1P) complexes, where G1P = glycerol 1-phosphate, which had previously been studied (Liang, G.; et al. J. Am. Chem. Soc.1992, 114, 7780-7785) and in which the coordination sphere of Cu(2+) is identical with the one in Cu(Arm)(FMN), it can unequivocally be shown that the mentioned enhanced stability of the Cu(Arm)(FMN) complexes is solely due to the formation of intramolecular stacks; their formation degree reaches for Cu(Bpy)(FMN) and Cu(Phen)(FMN) about 80 and 90%, respectively. These, as well as recent results regarding the self-stacking of FMN(2)(-) (Bastian, M.; Sigel, H. Biophys. Chem. in press) show that the flavin moiety is ideally suited for stacking and charge-transfer interactions, which are so important for the flavin coenzymes in nature.

Enteroglucagon

The gene encoding proglucagon, the biosynthetic precursor of glucagon, is expressed not only in the pancreatic islets but also in endocrine cells of the gastrointestinal mucosa. The proglucagon (PG)-derived peptides from the gut include glicentin (corresponding to PG 1-69); smaller amounts of oxyntomodulin (PG 33-69) and glicentin-related pancreatic polypeptide (GRPP, PG 1-30); glucagon-like peptide-1 (GLP-1, PG 78-107 amide); intervening peptide-2 (IP-2, PG 111-122 amide); and glucagon-like peptide-2 (GLP-2, PG 126-158). All are secreted into the blood in response to ingestion of carbohydrates and lipids. Only oxyntomodulin and GLP-1 have proven biological activity; oxyntomodulin possibly because it interacts (but with lower potency) with GLP-1 and glucagon receptors. GLP-1 is the most potent insulinotropic hormone known and functions as an incretin hormone. It also inhibits glucagon secretion and, therefore, lowers blood glucose. This effect is preserved in patients with non-insulin-dependent diabetes mellitus, in whom infusions of GLP-1 may completely normalize blood glucose. However, GLP-1 also potently inhibits gastrointestinal secretion and motility, and its physiological functions include mediation of the "ileal-brake" effect, i.e. the inhibition of upper gastrointestinal functions elicited by the presence of unabsorbed nutrients in the ileum. As such it may serve to regulate food intake.