No abstract

Stress causes a major effect on several systems of the body, including cardiovascular, digestive and immune systems. Behavioral signs also reflect stressful condition. Exercise and a good social network are believed to lower stress. We used dogs kenneled in a humane society as a model to study the effect of exercise and socialization on stress‐related symptoms. We measured behavioral signs of stress including but not limited to scratching, distress whining and exaggerated grooming Research shows a relationship between stress and elevated cortisol levels. We measured salivary cortisol as a biochemical measure of stress. Dogs were allowed to acclimatize to shelter conditions. The experiment was conducted over four days with 40 dogs. The experimental group consisting of 20 dogs, were allowed to play and socialize for 30 minutes, whereas control dogs stayed in their kennels. Salivary cortisol and behavioral indices were measured before and after exercise play session. Dogs that played and had social contact showed less stressful behaviors as well as lower cortisol levels. Our studies suggest that physical activity and social contact alleviates stress.

A major complication in diabetes is loss of peripheral nerve function, termed as diabetic neuropathy. Glycation of cellular proteins by reducing sugars contributes to neuronal death and loss of nerve function. Hyperglycemia present in diabetes leads to increased production of methylglyoxal (MG), a strong glycating agent, forming advanced glycation end products (AGEs). The accumulation of AGEs has been implicated in several long‐term diabetic complications. One of the mechanisms involved is oxidative stress. We used PC12 cells treated with MG to determine the mechanism(s) involved in apoptosis of cells under glycating conditions. MG at 0.8 mM caused 70% cell death. The effect was observed as early as 6 hours of treatment. Caspase activity was increased in treated cells, indicating that MG caused apoptosis of cells. Treatment with curcumin, a compound from turmeric known for its antioxidant properties, inhibited the effect of MG and 80% of treated cells remained viable. Treatment with glutathione showed a similar, although less effective protection (60% survival). These results suggested that MG may cause oxidative stress to cells. We are currently studying the expression of iNOS and glutathione metabolizing enzymes. Our studies suggest that restoring redox balance in the cell may be an effective way of reducing cell death observed under glycating conditions.

Diabetes mellitus is a metabolic disease characterized by high level of blood sugar. In a healthy person, the hormone insulin from β‐cells of pancreatic islets regulates blood sugar level. In diabetic patients, there is a continuous loss of pancreatic β‐cells mass, dysfunction of β‐cells that result in deficiency of insulin. Methylglyoxal (MG), a normal by product of glycolysis, is in high in a diabetic person. MG causes oxidative stress to β‐cells leading to cell death. A linear pentadecapeptide segment of Islet Neogenesis Associated Protein ‐ Peptide (INGAP‐P), Ac‐IGLHDPSHGTLPNGS‐NH2, has been shown to induce proliferation of β‐cells through transdifferentiation of matured ductal cells. The goal of this research was to determine whether INGAP‐P protects RINm5F cells, an islet β‐cell line, from the detrimental effects of MG. Cells were treated with different concentrations of MG in the absence or presence of INGAP‐P. Cell viability of RINm5F cells after treatment was measured by MTT, [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide], assay at 570 nm. MG at 40μM caused 53% cell death in 24 hours. When treated with INGAP‐P at 1μM for 24 hours cell viability increased by 20%. When cells were treated with MG and INGAP‐P together, RINm5F cells showed no cell death suggesting that INGAP‐P protects the cells from MG. We are currently determining whether the cell death is due to apoptosis and how INGAP‐P protects RINm5F cells from the effect of MG. We will study the expression of Bax and Bcl2 in RINm5F cells treated with MG and INGAP‐P. The findings from this research will provide insights into the mode of action of INGAP‐P and guide the design of new synthetic drug molecules for diabetes that act in a similar mechanism.Support or Funding InformationUS Department of Education Title III GrantThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Hyperglycemia, a condition in which blood glucose level exceeds the normal level, is often observed in diabetes mellitus. Normally, the hormone insulin, secreted by β‐cells of the pancreas, regulates blood glucose level. However, in patients with diabetes type 2, hyperglycemia decreases beta cell mass, resulting in a deficiency of insulin. Methylglyoxal (MG), a carbonyl derivative of glucose, is believed to cause the deleterious effects observed in type‐2 diabetes, such as neuropathy. MG is known to cause oxidative stress in neural cells, leading to apoptosis. It was of interest to see whether MG showed a similar effect on pancreatic β‐cells. Also, curcumin, a compound present in turmeric is known to have anti‐oxidative and anti‐inflammatory properties. In this study, we determined the effect of MG and curcumin on the viability of RINm5F cells (rat pancreatic β‐cells). Cells were treated in the presence of 20μM and 40μM MG, with different concentrations of curcumin (2μM to 10μM). Preliminary results showed that MG treatment at 40 μM causes 50% cell death in 24 hours, due to apoptosis of cells. Curcumin alone induced cell proliferation. When curcumin was added along with MG, the effect of MG was alleviated. Similar results were observed earlier with neuronal PC12 cells. In addition, various spices such as cinnamon, black pepper and saffron were also tested and found to alleviate the effect of MG. We are currently studying the expression of Bax and Bcl2 in both RINm5F and PC12 cells in the presence of MG and curcumin. This study will help determine whether the loss of β‐cells seen in diabetes, could be prevented using natural products.Support or Funding InformationMcNair Scholars ProgramThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.