Katherine Forman

Beneficial effects of melatonin on cardiological alterations in a murine model of accelerated aging.

Abstract:  This study investigated the effect of aging‐related parameters such as inflammation, oxidative stress and cell death in the heart in an animal model of accelerated senescence and analyzed the effects of chronic administration of melatonin on these markers. Thirty male mice of senescence‐accelerated prone (SAMP8) and 30 senescence‐accelerated‐resistant mice (SAMR1) at 2 and 10 months of age were used . Animals were divided into eight experimental groups, four from each strain: two young control groups, two old untreated control groups, and four melatonin‐treated groups. Melatonin was provided at two different dosages (1 and 10 mg/kg/day) in the drinking water. After 30 days of treatment, the expression of inflammatory mediators (tumor necrosis factor‐alpha, interleukin 1 and 10, NFkBp50 and NFkBp52), apoptosis markers (BAD, BAX and Bcl2) and parameters related to oxidative stress (heme oxygenases 1 and 2, endothelial and inducible nitric oxide synthases) were determined in the heart by real‐time reverse transcription polymerase chain reaction (RT‐PCR). Inflammation, as well as, oxidative stress and apoptosis markers was increased in old SAMP8 males, when compared to its young controls. SAMR1 mice showed significantly lower basal levels of the measured parameters and smaller increases with age or no increases at all. After treatment with melatonin, these age‐altered parameters were partially reversed, especially in SAMP8 mice. The results suggest that oxidative stress and inflammation increase with aging and that chronic treatment with melatonin, a potent antioxidant, reduces these parameters. The effects were more marked in the SAMP8 animals.

Beneficial effect of melatonin treatment on inflammation, apoptosis and oxidative stress on pancreas of a senescence accelerated mice model

This study has investigated the effect of aging on parameters of inflammation, oxidative stress and apoptosis in pancreas obtained from two types of male mice models: senescence-accelerated prone (SAMP8) and resistant mice (SAMR1). Animals of 2 (young) and 10 months of age (old) were used (n = 64). The influence of the administration of melatonin in the drinking water for one month at two different dosages (1 and 10mg/(kg day) on old SAMP8 mice on these parameters was also studied. SAMP8 mice showed with age a significant increase in the relative expression of pancreatic genes involved in inflammation, oxidative stress and apoptosis. Furthermore the protein expression of several NFκB subunits was also enhanced. On the contrary aged SAMR1 mice did not show significant increases in these parameters. Melatonin administration to SAMP8 mice was able to reduce these age related alterations at the two used dosages.

Effect of a Combined Treatment With Growth Hormone and Melatonin in the Cardiological Aging on Male SAMP8 Mice

The effect of a chronic combined treatment with growth hormone (GH) plus melatonin (Mel) on different age-related processes in cytosolic and nuclear fractions of hearts from SAMP8 mice (2 and 10 months) has been investigated. The parameters studied have been messenger RNA expressions of IL-1, IL-10, NFkBp50, NFkBp52, TNFα, eNOS, iNOS, HO-1, HO-2, BAD, BAX, and Bcl2 and protein expressions of iNOS, eNOS, TNFα, IL-1, IL-10, NFkBp50, NFKbp52, and caspase activity (3 and 9). Our results supported the existence of a proapoptotic and oxidative status together with inflammatory processes in the heart of old mice, with increases of inflammatory cytokines, caspase activity, HO-1, BAX, NFkBp50, and NFkBp52 and decreases of eNOS and Bcl2. Also, we were able to observe the translocation of NFkB to nuclei. The combined treatment was able to partially reduce the incidence of these deleterious changes, showing differences with the separated treatments with GH and Mel as were investigated in previous articles from our group.

Protective actions of melatonin and growth hormone on the aged cardiovascular system.

Abstract Epidemiological studies indicate that certain aspects of lifestyle and genetics act as risk factors for a variety of cardiovascular disorders, including coronary disease, hypertension, heart failure and stroke. Aging, however, appears to be the major contributor for morbidity and mortality of the impaired cardiovascular system. Growth hormone (GH) and melatonin seem to prevent cardiac aging, as they contribute to the recovery of several physiological parameters affected by age. These hormones exhibit antioxidant properties and decrease oxidative stress and apoptosis. This paper summarizes a set of studies related to the potential role that therapy with GH and melatonin may play in the protection of the altered cardiac function due to aging, with a focus on experiments performed in our laboratory using the senescence-accelerated mouse as an aging model. In general, we observed significantly increased inflammation, oxidative stress and apoptosis markers in hearts from senescence-accelerated prone 10-month-old animals compared to 2-month-old controls, while anti-inflammatory and antiapoptotic markers as well as endothelial nitric oxide synthase were decreased. Senescence-accelerated resistant animals showed no significant changes with age. GH or melatonin treatment prevented the age-dependent cardiac alterations observed in the senescence-accelerated prone group. Combined administration of GH plus melatonin reduced the age-related changes in senescence-accelerated prone hearts in an additive fashion that was different to that displayed when administered alone. GH and melatonin may be potential agents for counteracting oxidative stress, apoptosis and inflammation in the aging heart.

Effect of Chronic Melatonin Administration on Several Physiological Parameters from Old Wistar Rats and Samp8 Mice

UNLABELLED The effect of melatonin administration on age-induced alterations in hepatocytes, central nervous system, immune system, and skin are reviewed. Twenty-two-month-old Wistar rats and SAMP8 (senescence prone) mice of 10 months of age were used as experimental models. Wistar rats were analyzed untreated or after the chronic administration of melatonin at a dose of 1 mg/kg/day in the drinking water for 10 weeks. At the end of the treatment period, the various parameters were investigated. Results were compared with those of 2-month-old controls. In hepatocytes, aging induced a significant increase in oxidative stress, inflammation, and apoptosis when compared to young animals. Melatonin administration significantly ameliorated all these age-related changes. The impairment of the cardiovascular system with aging appears to contribute to the increased morbidity and mortality of the aged subjects. The process was investigated in SAMP8 mice of 10 months of age. Melatonin was provided for 30 days at two different dosages (1 mg/kg/day and 10 mg/kg/day), also in the drinking water. After treatment, the expression of inflammatory mediators (tumor necrosis factor-α, interleukin 1 and 10, NFκBp50 and NFκBp52), apoptosis markers (BAD, BAX, and Bcl2), and parameters related to oxidative stress (heme oxygenases 1 and 2, endothelial and inducible nitric oxide synthases) were determined in the heart. Inflammation as well as oxidative stress and apoptosis markers were increased in old SAMP8 males, as compared to young controls. After treatment with melatonin, these age-altered parameters were partially reversed. The results suggest that oxidative stress and inflammation increase with aging and that chronic treatment with melatonin is able to reduce these parameters. In the skin, a reduction of epidermal thickness together with a marked increase of the hypodermis with great fat accumulation was observed in old rats, together with an increase in caspase 3, 8 of nucleosomes and LPO and a reduction in Bcl2 levels in the cultured keratinocytes. Melatonin treatment was able to reduce the fat content of the hypodermis and to increase Bcl2 and reduce nucleosomes, caspases, and LPO in keratinocytes. CONCLUSION Melatonin administration exerts a beneficial effect against age-induced changes in several physiological parameters in Wistar rats and SAMP 8 mice.

Effect of Growth Hormone Treatment on Pancreatic Inflammation, Oxidative Stress, and Apoptosis Related to Aging in SAMP8 Mice

Aging is associated with an increase in inflammation, oxidative stress, and apoptosis. Furthermore, aging is accompanied by an alteration of the growth hormone (GH) -insulin-like growth factor-1 (IGF-1) axis. The aim of this study was to examine the regulation of these parameters in the pancreas of old mice and how GH treatment could affect this process. Male senescence-accelerated prone mice (SAMP8) and male senescence-accelerated resistant mice (SAMR1) 2 (young) and 10 months old were used (n = 40). Animals were divided into five experimental groups: 1 and 2, SAMP8/R1 young control; 3 and 4, SAMP8/R1 old control (untreated); and 5, SAMP8 old treated with GH. Physiologically equivalent doses of GH were administered for 1 month (2 mg subcutaneously [s.c.]/kg/day) and several parameters were analyzed. Aging was associated with increased inflammation, oxidative stress, and apoptosis (increased tumor necrosis factor-α [TNF-α], interleukin-β [IL-β], IL-6, monocyte chemoattractant protein-1 [MCP1], IL-2, heme oxygenase [HO-1], inducible nitric oxide synthase [iNOS], and nitric oxide metabolites [NOx]). The ratio of anti/pro apoptotic mRNA expression-B cell lymphoma 2 (Bcl-2) Bcl-2-associated X protein (BAX) + Bcl-xL/Bcl-2-associated death promoter (BAD)-was decreased during aging in SAMP8 mice. X-inhibitor of apoptosis (XIAP) was decreased during the aging process. Furthermore, no changes were observed in protein expression of nuclear factor-κB (NF-κB p65 and NF-κBp50-105. However, the protein expression of NF-κB p52-100 and inhibitor kappa B (IκB) alpha was increased with age in the pancreas of SAMP8 mice. On the other hand, the expression of IκB beta was decreased with aging. These results indicate that aging is associated with significant alterations in the relative expression of pancreatic genes involved in inflammation, oxidative stress, and apoptosis. According to our results, GH administration to old SAMP8 mice was able to improve pancreas from this parameters.

Growth hormone can improve insulin resistance and differentiation in pancreas of senescence accelerated prone male mice (SAMP8)

OBJECTIVE The aim of the present study was to investigate the effect of aging on several parameters related to glucose metabolism, proliferation and differentiation in the pancreas and how GH administration to old SAMP8 mice could affect these parameters. MATERIALS AND METHODS Pancreas samples were obtained from two types of male mice models: senescence-accelerated prone (SAMP8) and senescence-accelerated-resistant (SAMR1) mice SAMP8 and SAMR1 mice and the influence of exogenous administration of GH (2mgs.c./kg/day) on SAMP8 mice. RNA was isolated from pancreas samples of male mice using the kit RNeasy total RNA kit Ref. 50974104 (Qiagen). Insulin was measured in plasma by RIA kit and glucose was measured in plasma by an assay kit. RESULTS Aging decreases the expression of differentiation in the pancreas of Pdx-1, FoxO 1 and FoxO 3A but not of Sirt 1 or of the expression of the proliferative genes PCNA and Sei1. The expression of glucagon and GLUT2 were increased with aging and no differences were observed in somatostatin and insulin expressions. Insulin levels in plasma were increased with aging in SAMP8 mice. IGF-1 expression was reduced with aging. The treatment with GH was able to increase the expression of Sirt 1, Pdx-1, FoxO 3A and IGF-1. On the other hand, the treatment decreased the expression of glucagon, GLUT2, somatostatin and insulin, furthermore GH was able to decrease the plasma levels of insulin in old male SAMP8 mice (p<0.0004). CONCLUSION The present study has shown that aging is associated with significant alterations in the relative expression of pancreatic genes involved in insulin secretion as well as in the differentiation and in the intra islet glucose metabolism. According to our results, GH administration to old SAMP8 mice was able to improve the pancreatic function of the old SAMP8 mice and to decrease insulin and glucagon expressions in the pancreas improving instead insulin levels and glucose metabolism.

Influence of aging and growth hormone on different members of the NFkB family and IkB expression in the heart from a murine model of senescence-accelerated aging.

Inflammation is related to several pathological processes. The aim of this study was to investigate the protein expression of the different subunits of the nuclear factor Kappa b (NFkBp65, p50, p105, p52, p100) and the protein expressions of IkB beta and alpha in the hearts from a murine model of accelerated aging (SAM model) by Western blot. In addition, the translocation of some isoforms of NFkB from cytosol to nuclei (NFkBp65, p50, p52) and ATP level content was studied. In addition we investigated the effect of the chronic administration of growth hormone (GH) on these age-related parameters. SAMP8 and SAMR1 mice of 2 and 10 months of age were used (n = 30). Animals were divided into five experimental groups: 2 old untreated (SAMP8/SAMR1), 2 young control (SAMP8/SAMR1) and one GH treated-old groups (SAMP8). Age-related changes were found in the studied parameters. We were able to see decreases of ATP level contents and the translocation of the nuclear factor kappa B p50, p52 and p65 from cytosol to nuclei in old SAMP8 mice together with a decrease of IKB proteins. However p100 and p105 did not show differences with aging. No significant changes were recorded in SAMR1 animals. GH treatment showed beneficial effects in old SAMP8 mice inducing an increase in ATP levels and inhibiting the translocation of some NFkB subunits such as p52. Our results supported the relation of NFkB activation with enhanced apoptosis and pro-inflammatory status in old SAMP8 mice and suggested a selective beneficial effect of the GH treatment, which was able to partially reduce the incidence of some deleterious changes in the heart of those mice.