Positive Response of Isolated Rat Pancreatic Islets to IMOD; Hopes for Better Transplant Outcome and Graft Function

Immunomodulator Drug (IMODTM) and Exercise Improve Cardiac Oxidative Stress and Antioxidant Balance in Diabetic Rats

: Diabetes is a common metabolic disease that increases the risk of cardiovascular disease. It seems that the reduction of oxidative stress or increasing antioxidant levels improves diabetic cardiomyopathy. Antioxidant effects of immunomodulatory drug (IMODTM) and also beneficial influences of exercise on diabetic complications have been shown. The present study examined the effects of IMODTM and exercise on cardiac oxidative stress and antioxidants in diabetes. For this purpose, 64 rats were divided into 8 groups: control (C), exercise (E), IMODTM (20 mg/kg) (I), exercise plus IMODTM (E + I), diabetes (D), diabetic rats treated with exercise (D + E), diabetic rats treated with IMODTM (D + I), and diabetic rats treated with exercise plus IMODTM (D + E + I). Treatments with exercise and/or IMODTM were performed for 8 weeks. Type 1 diabetes was induced by intraperitoneal injection of 60 mg/kg streptozotocin. After the treatment period, all rats were anesthetized, and blood and heart samples were gathered for measurement of malondialdehyde (MDA) as an oxidative stress marker, lactate dehydrogenase (LDH) as a cardiac injury marker, total antioxidant capacity (TAC), and superoxide dismutase (SOD) as well as glutathione peroxidase (GPx) as antioxidant enzymes. The present study, for the first time, showed that IMODTM alone or in combination with exercise had positive effects on alleviating hyperglycemia, MDA, and LDH along with elevation of antioxidant enzymes activities in type 1 diabetic rats.

Cerium and Yttrium Oxide Nanoparticles and Nano-selenium Produce Protective Effects Against H2O2-induced Oxidative Stress in Pancreatic Beta Cells by Modulating Mitochondrial Dysfunction

BACKGROUND

Type 1 diabetes mellitus is characterized by the destruction of insulin- producing Beta cells in the pancreas. Researchers hope that islet transplantation will help to patients with insulin-dependent diabetes mellitus (IDDM). Oxidative stress is the most important challenge that beta cells face to it after isolation, and mitochondrial dysfunction is a crucial mediator in beta cells death. Hence, therapeutic approaches can shift to antioxidants through the application of nanoparticles such as cerium and yttrium oxide nanoparticles (Cer and Ytt Ox NPs) and nano-selenium (Nan Se).

OBJECTIVE

This study evaluates the effects of Cer and Ytt Ox NPs and Nan Se on H2O2- induced oxidative stress in pancreatic beta cells with focus on mitochondrial dysfunction pathway.

METHODS

CRI-D2 beta-cell line were pretreated with Cer Ox NPs (200 µM) + Ytt Ox NPs (0.5 µg/mL) for 3 days and/or Nan Se (0.01 µM) for 1 day. Then markers of oxidative stress, mitochondrial dysfunction, insulin and glucagon secretion were measured.

RESULTS

We reported a decrease in H2O2-induced reactive oxygen species (ROS) level and glucagon secretion, and an increase in H2O2-reduced ATP/ADP ratio, MMP, as well as UCP2 protein expression, and insulin secretion by pretreatment of CRI-D2 cells with Cer and Ytt Ox NPs and/or Nan Se.

CONCLUSION

We found maximum protective effect with Cer and Ytt Ox NPs on CRI-D2 beta-cell line exposed by H2O2 for keeping beta cells alive until transplant whereas combination of Cer and Ytt Ox NPs and Nan Se had very little protective effect in this condition.

Can highly cited herbs in ancient Traditional Chinese medicine formulas and modern publications predict therapeutic targets for diabetes mellitus?

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of diabetes among all age groups worldwide was estimated to be more than 382 million in 2013. Traditional Chinese medicine (TCM) has been practiced for thousands of years, and substantial valuable experience and prescriptions have been accumulated in the TCM system for the treatment of diabetes. In recent decades, a large amount of experimental and clinical data has been published on the use of herbal medicines related to these ancient TCM prescriptions.

AIM OF THE STUDY

This study aimed to discover a method for the investigation of potential antidiabetic herbs from the large amount of data in ancient TCM formulas and modern publications and to verify this method through an in vitro bioactivity study.

MATERIALS AND METHODS

In our review, the most frequently cited TCM herbs were selected as potential antidiabetic herb candidates on the basis of TCM philosophical theory (ancient TCM formulas) and Western medicine philosophical theory (modern publications). The ethanol and aqueous extracts of the selected herbs were screened for their α-glucosidase inhibitory, glucose-stimulated insulin secretion (GSIS), and intestinal glucose transport inhibitory effects.

RESULTS

Twelve herbs [Terminalia chebula Retz., fructus immaturus, dried; Poria cocos (Schw) Wolf., sclerotium, dried; Zea mays L., stigma, dried; Pueraria lobata (Willd.) Ohwi, radix, dried; Cucurbita moschata (Duch. ex Lam.) Duch. ex Poiret, fructus, dried; Lycium barbarum L., fructus, dried; Glycine max (L.) Merr., semen, fermented; Glycyrrhiza uralensis Fisch., radix and rhizoma, dried; Dioscorea opposita Thunb., rhizoma, dried; Morus alba L., folium, dried, Morus alba L., fructus, dried; and Polygonatum odoratum (Mill.) Druce, rhizoma, dried] were finally selected as candidates with potential glucose-lowering effects after a review was performed of herbs that are frequently cited in ancient TCM formulas and modern publications. The bioactive study results demonstrated that both the ethanol extracts and crude polysaccharides of M. alba L., fructus, dried, and M. alba L., folium, dried, and the crude polysaccharides of T. chebula Retz., fructus immaturus, dried, exhibited α-glucosidase inhibitory effects. Moreover, the crude polysaccharides of P. cocos (Schw) Wolf., sclerotium, dried; Z. mays L., stigma, dried; and T. chebula Retz., fructus immaturus, dried, exhibited favorable GSIS effects, and the ethanol extracts of P. odoratum (Mill.) Druce, rhizoma, dried; T. chebula Retz., fructus immaturus, dried; and G. uralensis Fisch., radix and rhizoma, dried, significantly decreased glucose transport across the cell monolayer.

CONCLUSIONS

Our review and the preliminary bioactive study revealed that 10 of the 12 recommended edible TCM herbs had favorable antidiabetic effects, demonstrating that TCM herbs with a high prescription and publication frequency may provide insights into the potential therapeutic targets of diabetes mellitus and may aid in the discovery of effective compounds complementary to currently used medicines. Such a literature and medicine review is a useful method of exploring potential antidiabetic herbs by using the wealth of information in ancient TCM formulas and modern publications.

Zinc oxide nanoparticles reduce apoptosis and oxidative stress values in isolated rat pancreatic islets

Although toxic effects of zinc oxide nanoparticles (ZnO NPs) have been previously studied, there are still controversies in terms of dose, size, shape, and affecting cells. By such a perspective, in this study, small size of ZnO NPs with a diameter of 10 nm at low concentrations was studied for any effect on the viability and function of isolated rat pancreatic islets. Islets of Langerhans were isolated and assessed for viability, functionality (insulin secretion), cytosolic reactive oxygen species (ROS), and apoptosis by flow cytometry. The LC50 of ZnO NPs was found at 1,400 ng/mL at the first phase of the study. A meaningful increase in viability of islets and insulin secretion in basal and even stimulated concentrations of glucose was found by ZnO NPs (70 ng/mL) with p < 0.001 and p < 0.05, respectively. Likewise, ZnO NPs in 70 ng/mL concentration decreased cytosolic ROS generation (p < 0.05). In the meantime, the percentage of early stage of apoptotic cells dropped down to 17 % (from 29 % of control). These results for the first time confirm that ZnO NPs are not only safe when used at dose of 70 ng/mL but also improve viability and function of pancreatic islets and meanwhile reduce oxidative stress and prevent cells from entering the apoptotic phase.

Toxicological and pharmacological concerns on oxidative stress and related diseases

Although reactive oxygen species (ROS) such as superoxide, hydrogen peroxide and hydroxyl radical are generated as the natural byproduct of normal oxygen metabolism, they can create oxidative damage via interaction with bio-molecules. The role of oxidative stress as a remarkable upstream part is frequently reported in the signaling cascade of inflammation as well as chemo attractant production. Even though hydrogen peroxide can control cell signaling and stimulate cell proliferation at low levels, in higher concentrations it can initiate apoptosis and in very high levels may create necrosis. So far, the role of ROS in cellular damage and death is well documented with implicating in a broad range of degenerative alterations e.g. carcinogenesis, aging and other oxidative stress related diseases (OSRDs). Reversely, it is cleared that antioxidants are potentially able to suppress (at least in part) the immune system and to enhance the normal cellular protective responses to tissue damage. In this review, we aimed to provide insights on diverse OSRDs, which are correlated with the concept of oxidative stress as well as its cellular effects that can be inhibited by antioxidants. Resveratrol, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, statins, nebivolol and carvedilol, pentaerythritol tetranitrate, mitochondria-targeted antioxidants, and plant-derived drugs (alone or combined) are the potential medicines that can be used to control OSRD.

Antiapoptotic effects of cerium oxide and yttrium oxide nanoparticles in isolated rat pancreatic islets

Type I diabetes mellitus is a metabolic disease caused by the impairment of pancreatic β-cells mainly mediated through oxidative stress and related apoptosis. Islets transplantation seems a promising treatment for these patients, but during islets transplant, various types of stresses related to the isolation and transplantation procedure compromise the function and viability of islets. We recently hypothesized that the combination of cerium oxide (CeO2) and yttrium oxide (Y2O3) nanoparticles with a potential free radical scavenger behavior should be useful to make isolated islets survive until transplanted. In the present study, oxidative stress-induced apoptosis in isolated rat pancreatic islets exposed to hydrogen peroxide (H2O2) and the protective effects of CeO2 and Y2O3 nanoparticles were investigated. Exposure of islets to H2O2 (50 µm, 2 h) increased intracellular oxidant formation such as reactive oxygen species and subsequently apoptosis and decreased viability, glucose-induced adenosine triphosphate (ATP) production and glucose-stimulated insulin secretion. Pretreatment with CeO2 and/or Y2O3 nanoparticles reduced the oxidant formation and apoptosis and increased viability, glucose-induced ATP production and glucose-stimulated insulin secretion. These results suggest that this combination may protect β-cell apoptosis by improving the oxidative stress-mediated apoptotic pathway.

Diabetic neuropathy and oxidative stress: therapeutic perspectives

Diabetic neuropathy (DN) is a widespread disabling disorder comprising peripheral nerves' damage. DN develops on a background of hyperglycemia and an entangled metabolic imbalance, mainly oxidative stress. The majority of related pathways like polyol, advanced glycation end products, poly-ADP-ribose polymerase, hexosamine, and protein kinase c all originated from initial oxidative stress. To date, no absolute cure for DN has been defined; although some drugs are conventionally used, much more can be found if all pathophysiological links with oxidative stress would be taken into account. In this paper, although current therapies for DN have been reviewed, we have mainly focused on the links between DN and oxidative stress and therapies on the horizon, such as inhibitors of protein kinase C, aldose reductase, and advanced glycation. With reference to oxidative stress and the related pathways, the following new drugs are under study such as taurine, acetyl-L-carnitine, alpha lipoic acid, protein kinase C inhibitor (ruboxistaurin), aldose reductase inhibitors (fidarestat, epalrestat, ranirestat), advanced glycation end product inhibitors (benfotiamine, aspirin, aminoguanidine), the hexosamine pathway inhibitor (benfotiamine), inhibitor of poly ADP-ribose polymerase (nicotinamide), and angiotensin-converting enzyme inhibitor (trandolapril). The development of modern drugs to treat DN is a real challenge and needs intensive long-term comparative trials.

Effects of IMOD™ and Angipars™ on mouse D-galactose-induced model of aging

The aim of this study was to evaluate the effects of two registered herbal drugs called IMOD and Angipars on mouse model. Aging was induced by D-galactose (500 mg/kg) administered to animals for 6 weeks through drinking water. Male BALB/c mice were randomly divided into 5 groups receiving D-galactose (D-galactose, 500 mg/kg) for 6 weeks; positive control (D-galactose [500 mg/kg] for 6 weeks + Vitamin E [200 mg/kg/day] intraperitoneally for 4 weeks); IMOD (D-galactose [500 mg/kg] for 6 weeks + IMOD [20 mg/kg/day] intraperitoneally for 4 weeks), Angipars (D-galactose [500 mg/kg] for 6 weeks + Angipars [2.1 mg/kg/day] by gavage for 4 weeks); and the fifth group that was sham and not given D-galactose. At the end of treatment, pro-inflammatory markers including tumor necrosis factor-α (TNF-α), interlukine-1β (IL-β), interlukine-6 (IL-6), Nuclear Factor-kappaB (NF-κb), total antioxidant power (TAP), lipid peroxides (LPO) and male sex hormones i.e. testosterone and dehydroepiandrosterone-sulfate (DHEA-S) were measured in the blood.

Results showed that D-Galactose induces a significant oxidative stress and proinflammatory cascade of aging while both IMOD and Angipars recovered all of them. Interestingly, IMOD and Angipars were better than Vitamin E in improving male sex hormones in aged mice. This effect is so important and should be considered as an advantage although it cannot be explained with current knowledge. The conclusion is that IMOD and Angipars have marked anti-aging effect on D-galactose-induced model of aging.

Improvement of isolated rat pancreatic islets function by combination of cerium oxide nanoparticles/sodium selenite through reduction of oxidative stress

Insulin Dependent Diabetes Mellitus (IDDM) is a disease with high incidence with no pure cure therapy yet. In most of cases, these patients need pancreatic islets transplantation that is not completely successful because of oxidative stress happening during isolation and transplantation procedures. In the present study, effective factors in transplantation procedure such as viability, insulin secretion, production of reactive oxygen molecules (ROM), and mitochondrial energy as ATP/ADP ratio were examined in the isolated islets exposed to sodium selenite (Na₂SeO₃; 0 30 nmol/L), metal form of cerium oxide (100 nm), cerium oxide nanoparticles (100 nm) and combination of Na₂SeO₃ (30 nmol/L)/cerium oxide nanoparticles (100 nm) in a time course (1, 2, 4 and 6 days posttreatment) manner. The results showed a significant increase of cells viability, secretion of insulin, and ATP/ADP ratio and a reduction in ROM by use of sodium selenite, cerium oxide nanoparticles, and especially combination of cerium oxide nanoparticles/sodium selenite. Interestingly, not only no improvement was found with metal form of cerium oxide but also deterioration occurred in tested markers. Results suggest that pretreatment with combination of cerium oxide nanoparticles/sodium selenite can improve transplantation outcome and graft function by control of oxidative stress damage.