Histological parameters of the adrenal cortex after testosterone application in a rat model of the andropause.

Histological analysis of the adrenal cortex, after testosterone application in a rat model of the andropause, was the main subject of the present study. Middle-aged Wistar rats were divided into sham-operated (SO; n=8), orchidectomized (Orx; n=8) and testosterone treated orchidectomized (Orx+T; n=8) groups. Testosterone propionate (5 mg/kg b.w. /day) was administered for three weeks, while SO and Orx groups received the vehicle alone. Histological objectives were achieved using stereology, histochemistry and steroid receptor immunostaining. The concentrations of testosterone, aldosterone, corticosterone and DHEA were determined by immunoassays. Expectedly, increased (p<0.05) serum concentration of testosterone was observed in Orx+T group. The volume of ZG cells and nuclei increased in Orx+T animals by 50% and 25% (p<0.05) respectively, but the serum concentrations of aldosterone decreased (p<0.05) by 60%, all compared to the same parameters in Orx group. The immunostaining for androgen receptors (ARs) suggested their cytoplasmic localization in ZG cells of Orx+T rats. Volume of the ZF cell nuclei in Orx+T group decreased (p<0.05) by 17%, which was followed by the significant (p<0.05) fall in corticosterone production and secretion, all in comparison with Orx animals. Also, nuclear immunolocalization of ARs of high optical density was observed through the ZF of Orx+T group. In Orx+T rats volume of ZR cells and nuclei, and circulating DHEA concentration increased (p<0.05) by 68%, 22% and about 6.6 times respectively, compared to Orx animals. Besides the extra-receptor actions in adrenal cortex, testosterone supposedly affects some steroidogenesis-related gene expression, as indicated by centripetal rise in the number of nuclear ARs.

Effects of soy phytoestrogens on pituitary-ovarian function in middle-aged female rats.

The aim of this study was to assess the effects of genistein (G) and daidzein (D) on the histological, hormonal, and functional parameters of the pituitary-ovarian axis in middle-aged female rats, and to compare these effects with the effects of estradiol (E), commonly used in the prevention and treatment of menopausal symptoms. Middle-aged (12 month old) Wistar female rats subcutaneously received 35 mg/kg of G, or 35 mg/kg of D, or 0.625 mg/kg of E every day for 4 weeks. Each of the treated groups had a corresponding control group. An intact control group was also established. G and D did not change the intracellular protein content within gonadotropic and lactotropic cells, but vacuolization was observed in all the cell types. In contrast, E caused an inhibition of gonadotropic and stimulation of lactotropic cells. Also, ovaries of middle-aged female rats exposed to G or D have more healthy primordial and primary follicles and less atretic follicles. E treatment in the ovaries had a mostly negative effect, which is reflected by the increased number of atretic follicles in all tested classes. G and D provoked decrease in CuZnSOD and CAT activity, while E treatment increased MnSOD and decreased CuZnSOD and GSHPx activity. All the treatments increased serum estradiol and decreased testosterone levels, while D and E increased the serum progesterone level. In conclusion, soy phytoestrogens exhibited beneficial effects on pituitary-ovarian function in middle-aged female rats, as compared to estradiol.

Age-dependent modulation of central ghrelin effects on food intake and lipid metabolism in rats.

Ghrelin is an endogenous peptide potentially useful in therapy of anorexia and other age-related metabolic disturbances. We evaluated the influence of age on the orexigenic and lipid metabolism-altering effects of ghrelin. Peripubertal, young, adult and middle-aged rats (1, 2, 7 and 12 months old, respectively) were treated with 5 daily intracerebroventricular injections of ghrelin (0.15 nmol) or saline (control). The food intake was measured daily before treatment, while white adipose tissue and serum/plasma samples for detection of lipid metabolites/hormones were collected at the end of the experiment. The values of cumulative food intake and body weight gain declined, while the white adipose tissue deposits and blood concentrations of triglycerides, cholesterol and free fatty acids all increased with age. Ghrelin significantly increased all parameters, but the stimulatory effects on body weight gain and food intake were more pronounced in peripubertal/young rats, while the increase in white adipose mass, triglyceride and low-density lipoprotein cholesterol levels was more noticeable in adult/middle-aged animals. The decrease in sensitivity to ghrelin-mediated stimulation of food intake in older animals could not be explained by alterations in ghrelin's ability to reduce anorexigenic hormones insulin and leptin. However, the higher responsiveness of aged rats to ghrelin-mediated increase in lipid metabolites was accompanied by an increase in adrenocorticotropic hormone and corticosterone levels. These results indicate that aging, while reducing sensitivity to ghrelin-mediated increase in body weight gain and food intake, might enhance the responsiveness to the stimulatory effects of ghrelin on lipid metabolites and hypothalamic-pituitary-adrenal axis activity.

The long-term risk of stroke in patients with acute myocardial infarction complicated with new-onset atrial fibrillation.

BACKGROUND: The long-term risk of stroke after acute myocardial infarction (AMI) complicated with new-onset atrial fibrillation (AF) remains unclear. The aim of this study was to determine the long-term risk of AF and stroke in patients with AMI complicated with new-onset AF. METHODS: Patients with AMI complicated with new-onset AF (n = 260) and those without new-onset AF (n = 292) were followed for a mean of 7 years. All patients had sinus rhythm at hospital discharge. RESULTS: During the follow-up, AMI patients with new-onset AF had more frequent AF than those without new-onset AF (10.4% vs 2.7%, respectively; P < 0.0001). New-onset AF during AMI was a significant predictor of subsequent AF occurrence (the time elapsing between 2 consecutive R waves [RR] = 3.15, P = 0.004); but AF recurrence in follow-up (RR = 5.08, P = 0.001) and non-anticoagulation at discharge (RR = 0.29, P = 0.008) were independent predictors of stroke (Cox regression analysis). A period of 3.5 hours of AF within the first 48 hours of AMI was the high sensitivity cut-off level for the prediction of low long-term risk of stroke obtained by receiver operating characteristic analysis. Among patients who did not receive anticoagulants at discharge, the patients with short AF did not experience stroke and AF recurrence during follow-up, while those in the other group developed it (10.8%, P = 0.038 and 13.5%, P = 0.019, respectively). CONCLUSION: New-onset AF during AMI identifies the patients at long-term risk for stroke who may potentially benefit from anticoagulant therapy. Atrial fibrillation recurrence in follow-up was independently related to the development of stroke. However, for low-risk patients with AF (those with short AF occurring early in AMI) long-term anticoagulants might not be required.

[Inflammatory markers, nutritional parameters and polyunsaturated fatty acids in hemodialysis patients].

INTRODUCTION: Malnutrition and inflammation are associated with end-stage renal disease. Inflammation leads to reduced synthesis of albumin, transferin, and other negative acute-phase proteins and increases their catabolic rates. The causes of inflammation are multifactorial, including oxidative modification of plasma proteins, interaction of blood with nonbiocompatible membranes, and other infectious processes. Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) powerfully predict death from cardiovascular disease in dialysis patients as well as progression of vascular injury. The aim of our study was to establish a correlation between markers of inflammation and parameters of malnutrition in hemodialysis patients. MATERIAL AND METHODS: We examined 42 hemodialysis patients at the mean age of 55+/-8 with dialysis duration 52.6+/-42. For nutritional assessment subjective global assessment (SGA), anthropometric parameters, bio-electric impedance (BIA), and biochemical nutritional parameters were used. We measured their plasma levels of inflammatory markers: C-reactive protein, IL-6 and TNF-alpha. Patients with severe malnutrition had higher level of IL-6 and TNF-alpha. RESULTS AND DISCUSSION: The following correlations between measured parameters emerged. There was a negative correlations between serum albumin concentration and inflammatory markers (r=-0.31; p=0.05). Anthropometric parameters in hemodialysis patients were lower when inflammatory markers were higher and correlation was significant (p=0.05). A statistically significant negative correlation between TNF-alpha and EPA (r=-0.497; p<0.05) and IL-6 and EPA (r=-468; p=0.03) was found in hemodialysis patients. CONCLUSION: The main findings of this study were that the decrease of nutritional parameters in hemodialysis patients were related to the degree of inflammation. Nutritional factors, as essential fatty acids, could lead to permanent changes in the inflammatory process.