Prior Chronic in Vivo Glucocorticoid Excess Leads to an Anabolic Phenotype and an Extension of Cellular Life Span of Skin Fibroblasts in Vitro

Carnosine research in relation to aging brain and neurodegeneration: A blessing for geriatrics and their neuronal disorders

Carnosine, an endogenous dipeptide (β-Ala-l-His), is enriched in prefrontal cortex and olfactory bulb of the brain, blood and also in muscle. It has mainly antioxidant and antiglycating properties which makes this molecule unique. Its content reduces during aging and aging-induced neurodegenerative diseases. Aging is a progressive biological process that leads to develop the risk factors of diseases and death. During aging the morphological, biochemical, cellular and molecular changes occur in brain and blood including other tissues. The objective of this review is to combine the updated information from the existing literature about the aging-induced neurodegeneration and carnosine research to meet the lacuna of mechanism of carnosine. The grey matter and white matter loses its normal ratio in aging, and hence the brain volume and weight. Different aging related neurodegenerative disorders arise due to loss of neurons, and synapses as a result of proteinopathies in some cases. Carnosine, being an endogenous biomolecule and having antioxidant, antiglycating properties has shown its potency to counteract erroneous protein biosynthesis, stress, activated microglial and astrocyte activity, and different neurodegenerative disorders. It (carnosine) can also inhibit the metal ion-induced degeneration by acting as a metal chelator. In this review the trends in carnosine research in relation to aging brain and neurodegeneration have been discussed with a view to its (carnosine) eligibility (including its mechanism of action) to be used as a promising neurotherapeutic for the betterment of elderly populations of our society at the national and international levels in near future.

Biphasic Dose-Response and Hormetic Effects of Stress Hormone Hydrocortisone on Telomerase-Immortalized Human Bone Marrow Stem Cells In Vitro

Although high levels of stress hormones are associated with well-known negative health outcomes, their low levels can have health-promoting effects by virtue of the phenomenon of mild stress-induced hormesis. We have studied the effects of a wide range (between 100 nmol/L and 150 μmol/L) of hydrocortisone (HC) on human bone marrow stem cells in vitro. Telomerase-immortalized human mesenchymal stem cells (hTERT-MSCs) were exposed to various doses of HC for different durations (1-6 days) and analyzed for survival and metabolic activity by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, for cell migratory ability by a wound-healing assay and for osteoblastic and adipogenic differentiation abilities in vitro. Our findings indicate that hTERT-MSCs exposed to HC resulted in a biphasic hormetic dose–response in some measures but not all. Although the mitochondrial and metabolic MTT activity assay clearly showed low-level stimulatory (between 0.1 and 1 µmol/L) and high-level inhibitory effects (from about 10 µmol/L onward), the cytostatic and differentiation-inducing effects were mostly linear at concentrations between 1 and 100 µmol/L. Further long-term studies will elucidate whether chronic or intermittent exposure of human cells to stress hormones has physiologically beneficial hormetic effects.

Influence of local or systemic corticosteroids on skin wound healing resistance

PURPOSE: To compare the resistance of skin wound healing of mice submitted to local or systemic hydrocortisone administration, in different postoperative periods. METHODS: An incision and suture was performed on the thoracic skin of 130 male mice: Group 1 (n = 10) resistance of the integer skin; Group 2 (n = 30) submitted only to skin incision and suture; Group 3 (n = 30) skin incision and suture followed by administration of saline fluid; Group 4 (n = 30) skin incision and suture followed by administration of local hydrocortisone; Group 5 (n = 30) skin incision and suture followed by administration of systemic hydrocortisone. The resistance of the wound healing and the weight of the animals were studied on the seventh, 14th and 21st postoperative days. Histological examination was also performed. RESULTS: The mice that received corticoid (groups 4 and 5) presented significant decreasing on their weight (p = 0.02). The Groups 3, 4 and 5 showed lower scar resistance than Group 2 on the seventh postoperative day (p < 0.05). On the 14th and 21st days, there was no difference on the skin would healing resistance (p > 0.05). CONCLUSION: Administration of hydrocortisone in mice is responsible for weight decreasing and reduction of the skin wound healing resistance during the first postoperative week.

Interactive association of heat shock protein 70 genes variants with natural longevity in Xinjiang Hetian Uygur ethnicity

Mounting evidence suggests that all organisms at the cellular level respond to stress by synthesizing heat shock proteins at the expense of other proteins, and the ability of human cells to respond to heat stress decreases with aging. We thus investigate the association of 3 variants (A1267G in HSPA1B, G190C in HSPA1A, and T2437C in HSPA1L) in the heat shock protein 70 (Hsp70) family with natural longevity in a Xinjiang Hetian Uygur population. A case-control study was conducted in 191 healthy individuals greater than 90 years of age, and 53 naturally died persons 65-70 years of age. Promoter activity was evaluated by luciferase reporter assays. The data were analyzed using an EH/EH+ program for haplotype prediction and MDR software for gene-gene interaction. All studied variants satisfied the Hardy-Weinberg equilibrium in each group. In single-locus analysis, no significant differences were found between long-lived people and short-lived people in the genotype/allele distributions of all variants. In contrast, haplotype analysis indicated that haplotypes A-G-C and A-C-T were more prevalent in long-lived people than short-lived people (P=0.026 and 0.017), and the analysis conferred a 3.46- and 4.51-fold increased tendency for longevity, respectively (P=0.025 and 0.016). The haplotype results were strengthened by interaction analysis, which suggests an optimal model in which G190C and T2437C exert an interacting effect on longevity. No functional significance was observed between 190G and 190C alleles in both control and heat-inducible A549 cells (P>0.05). Taken together, our findings suggested that common genetic variants in Hsp70 family might contribute interactively to longevity the Xinjiang Hetian Uygur population.

Carnosine and its possible roles in nutrition and health

The dipeptide carnosine has been observed to exert antiaging activity at cellular and whole animal levels. This review discusses the possible mechanisms by which carnosine may exert antiaging action and considers whether the dipeptide could be beneficial to humans. Carnosine's possible biological activities include scavenger of reactive oxygen species (ROS) and reactive nitrogen species (RNS), chelator of zinc and copper ions, and antiglycating and anticross-linking activities. Carnosine's ability to react with deleterious aldehydes such as malondialdehyde, methylglyoxal, hydroxynonenal, and acetaldehyde may also contribute to its protective functions. Physiologically carnosine may help to suppress some secondary complications of diabetes, and the deleterious consequences of ischemic-reperfusion injury, most likely due to antioxidation and carbonyl-scavenging functions. Other, and much more speculative, possible functions of carnosine considered include transglutaminase inhibition, stimulation of proteolysis mediated via effects on proteasome activity or induction of protease and stress-protein gene expression, upregulation of corticosteroid synthesis, stimulation of protein repair, and effects on ADP-ribose metabolism associated with sirtuin and poly-ADP-ribose polymerase (PARP) activities. Evidence for carnosine's possible protective action against secondary diabetic complications, neurodegeneration, cancer, and other age-related pathologies is briefly discussed.

The pituitary-adrenal axis and body composition

The activity of the pituitary-adrenal axis can profoundly impact on body composition. This is dramatically seen in Cushing's syndrome (CS) but changes in body composition are also implicated in depression and alcoholic pseudocushing's. The pathophysiological mechanisms underlying these changes remain poorly understood. Changes to body composition in CS include increased fat mass, decreased bone mass, thinning of the skin and reduced lean mass. Why these tissues are affected so dramatically is unclear. Additionally, the change in body composition between individuals varies considerably for reasons which are only now becoming evident. This paper reviews the phenotypic changes with altered pituitary-adrenal axis activity and discusses the mechanisms involved. The primary focus is on adipose, bone, muscle and skin since the most dramatic changes are seen in these tissues.