Małgorzata Kalisz

Plasma leptin levels and free leptin index in women with Alzheimer's disease.

Alzheimers disease (AD) is a neurodegenerative disorder characterized by irreversible and progressive loss of memory and other cognitive functions. Controversies still exist on the precise mechanisms contributing to neurodegeneration. Obesity and disturbances in metabolic homeostasis are thought to be AD risk factors. Adipokine leptin has receptors in the brain, also in the regions related to AD. Leptin may protect against AD. The aim was to assess leptin and soluble leptin receptor levels in plasma as well as free leptin index (FLI) in correlation with metabolic status of women diagnosed with Alzheimers disease. Eighteen women with moderate to severe stage of AD, 40 women with AD at early stage, and 42 female controls, matched for age and body mass index, participated in the study. Leptin and soluble leptin receptor levels were measured with RIA and IRMA, respectively. Then, FLI was calculated. In addition, metabolic parameters (lipid profile, glucose and insulin concentrations, HOMA-IR) were estimated. Clinical and anthropometric data were collected. The Mini-Mental State Examination (MMSE) as a cognitive impairment measurement was performed. Correlations with both leptin and FLI, and MMSE, clinical and biochemical parameters were evaluated. Leptin levels and FLI were significantly lower and leptin receptor concentrations were higher in AD subjects when compared with the controls. In AD group leptin, soluble leptin receptor and FLI correlated with selected metabolic parameters but not with MMSE. We conclude that alterations in leptin, leptin receptor, and FLI were the most intensified in advanced AD. However, these results did not correlate with dementia stage measured with MMSE. Therefore, further intensive research is needed to explain the mechanisms involved in this phenomenon.

Assessment of adiponectin and its isoforms in Polish centenarians

BACKGROUND The physiological mechanisms that promote longevity remain unclear. It has been suggested that insulin sensitivity is preserved in centenarians, whereas typical aging is accompanied by increasing insulin resistance. The oldest-old individuals display raised total adiponectin levels, despite the potential correlation between enhanced adiponectin and all-cause and cardiovascular mortality. AIM To evaluate the level of adiponectin and its isoforms in sera of centenarians and to assess associations between adiponectin and metabolic parameters. PARTICIPANTS A group of 58 Polish centenarians (50 women and 8 men, mean age 101±1.34 years) and 68 elderly persons (55 women and 13 men, mean age 70±5.69 years) as controls. MEASUREMENTS Serum samples were analyzed to evaluate the following parameters: adiponectin array (total adiponectin, HWM-, MMW- and LMW-adiponectin; all by ELISA methods), insulin (by IRMA methods), glucose and lipid profiles. HOMA-IR was calculated. Clinical data were collected. Statistical analyses were performed. RESULTS The concentrations of all adiponectin isoforms were significantly higher in the oldest-old participants. In the centenarian group, total adiponectin positively correlated with age and HDL-cholesterol, and HMW-adiponectin was negatively associated with insulin and triglycerides. The long-lived participants had a lower incidence of hypertension, type 2 diabetes, overweight and obesity, with lower concentrations of serum glucose and insulin, and reduced HOMA-IR. CONCLUSION Our findings support the thesis that centenarians possess a different adiponectin isoform pattern and have a favorable metabolic phenotype in comparison with elderly individuals. However, additional work is necessary to understand the relevance of these findings to longevity.

Effects of chymostatin, a chymase inhibitor, on blood pressure, plasma and tissue angiotensin II, renal haemodynamics and renal excretion in two models of hypertension in the rat.

What is the central question of this study? We examined, in hypertensive rats, whether the angiotensin‐converting enzyme‐independent enzymes generating angiotensin II in the tissues modulate blood pressure, peripheral circulation and renal function. What is the main finding and its importance? The results suggest that chymostatin‐sensitive enzymes diminish vascular tone in renal and extrarenal vascular beds. Chymase or similar chymostatin‐sensitive enzymes have a significant role in the synthesis of angiotensin II in different tissues but do not control blood pressure in the short term, similarly in salt‐dependent or Goldblatt‐type rat hypertension. In salt‐dependent hypertension, chymase blockade protected renal outer medullary perfusion, probably by reducing the angiotensin II content in the kidney.

Effect of orexin A on the release of GnRH-stimulated gonadotrophins from cultured pituitary cells of immature and mature female rats

Orexin A (OxA), also known as hypocretin 1, is a regulatory neuropeptide involved in the control of various autonomic and neuroendocrine functions. It appears to have a significant impact on the regulation of trophic hormones secretion by influencing the hypothalamus and the pituitary. Orexin A acts through two types of receptor found in the pituitary. This suggests the possibility of direct action of OxA at the adenohypophysis level. The aim of this study was to investigate the direct effect of OxA on GnRH (gonadotrophin-releasing hormone)-stimulated LH and FSH secretion from cultured pituitary cells of sexually immature and mature female rats. Anterior pituitary cells obtained from immature and mature female rats (ovariectomized, and ovariectomized and treated with estradiol) were incubated with 10(-10)M or 10(-7)M orexin A for 1 hour and 4h and the effect on GnRH-stimulated (10(-9)M or 10(-6)M) LH and FSH release was examined. The concentrations of secreted gonadotrophins in the culture media were determined by RIA methods. Orexin A significantly inhibited GnRH-stimulated FSH release from pituitary cells isolated from immature female rats, whereas in cells of mature ovariectomized animals, the effect of OxA was dependent on the stimulatory dose of GnRH. When the cells were stimulated with a low dose of GnRH, orexin A inhibited the secretion of gonadotrophins, but when a high dose of GnRH was used, orexin A increased mainly the release of LH. In cultured pituitary cells from ovariectomized, estrogenized mature rats, orexin A inhibited the secretion of LH if the cells were stimulated with a high dose of GnRH. In conclusion, the results of this study revealed that orexin A may modify the sensitivity of gonadotrophic cells to GnRH, and its effect depends on the maturity and estrogen status of the rats from which the cells are isolated.

Adipokine profile in patients with anorexia nervosa

INTRODUCTION Anorexia nervosa (AN) is an eating disorder characterised with extremely low weight. Adipokines are adipose tissue-derived substances that show a wide spectrum of biological activities. We aimed to assess selected adipokine levels in women with AN before and after nutritional intervention. We also sought to examine whether BMI is the only confounding factor influencing adipokine assessment in AN. MATERIAL AND METHODS Sixty-five women participated in the study: 20 individuals with AN before any treatment, 18 AN patients after nutritional intervention lasting for at least six months, and 27 women as controls. In all participants blood collection and anthropometric measurements were performed. ELISA was used for evaluation of leptin receptor, adiponectin and its isoforms, and resistin. Leptin was assessed with RIA, and visfatin was measured with EIA assay. RESULTS Leptin and free leptin index (FLI) were lowest in treatment-naïve AN women. HMW-adiponectin and visfatin were enhanced in AN. Other adipokine levels showed no significant differences. When two subsets of anorexia nervosa were compared, only leptin, leptin receptor, and FLI were markedly different. When data were adjusted to BMI, leptin and FLI remained significantly different in the pre-treated AN subgroup when compared with the control group. CONCLUSIONS Our results suggest that leptin is the most important adipokine in AN. It is also important that in our AN population leptin and FLI are the only factors that are influenced not only by the fat content.

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase activating polypeptide (PACAP) in humans with multiple sclerosis.

Multiple sclerosis (MS) is a chronic neuroinflammatory disease of the central nervous system that leads to demyelination and neurodegeneration. VIP and PACAP are structurally related neuropeptides with neuroprotective and anti-inflammatory activities. To evaluate VIP and PACAP-38 in plasma and CSF in humans in correlation with IL-6, IL-10 and TNFα, we compared 20 MS individuals with 27 healthy controls. In MS, a decrease in PACAP-38 in CSF and a decrease in plasma IL-6 concentration were seen. A positive correlation between plasma VIP and plasma IL-6 was identified. We conclude that VIP and PACAP may influence the course of MS.

Plasma adiponectin array in women with Alzheimer’s disease

Introduction Alzheimers disease (AD) is a progressive and irreversible neurodegenerative disease. Typical features of AD include memory loss, social dysfunction and physical impairment. Although the pathological findings in the central nervous system are well established, the etiological factors are poorly known. Recent studies suggested the role of metabolic disturbances in the development of AD neurodegeneration. Adiponectin, an anti-inflammatory and metabolism regulating factor, was linked to AD. Aim The aim was to examine whether adiponectin fractions combined with insulin/insulin resistance-associated metabolic parameters correlate with AD progression. Material and methods The study comprised 98 women: 27 with moderate to severe AD, 31 with AD at early stage and 40 healthy controls, matched for age and BMI. To evaluate memory impairment, the MMSE was performed. Plasma total adiponectin and its high-, medium- and low molecular weights were measured with ELISA. Anthropometric, clinical and metabolic parameters were assessed. Correlations between adiponectin array and measured parameters were evaluated. Results In comparison to the controls, enhanced levels of total and medium molecular weight adiponectin characterized AD individuals. In AD, we found correlations between adiponectin array, and anthropometric and biochemical parameters. After adjustment to BMI, a significant increase of the total adiponectin and high- and medium molecular weight fractions was observed. A negative correlation between low molecular weight adiponectin and MMSE was found. Conclusions Our results indicate a possible link between adiponectin variations and AD. We hypothesize that changes in adiponectin profile observed in AD result from compensatory mechanism against neuropathological processes, as well as from adiponectin homeostasis impairment.

Vitamin D deficiency in obesity and its relationship to insulin resistance and plasma leptin levels – preliminary study**

Introduction. Obesity is a risk factor for vitamin D deficiency and there is some evidence that vitamin D may be involved in the pathogenesis of insulin resistance. Aim. The aim of the study was to evaluate whether vitamin D deficiency is associated with insulin resistance and leptin level in obese subjects. Material and methods. 43 obese (body mass index (BMI) ≥ 35 kg/m2) individuals before bariatric surgery and 16 healthy volunteers with normal body weight were enrolled in this study. In all subjects serum level of glucose, 25-hydroxyvitamin D (25(OH)D), calcium, insulin, leptin, leptin soluble receptor were evaluated, insulin resistance was estimated by the homeostasis model assessment (HOMA-IR), free leptin index was calculated. Results. In the obese group 90% of patients had lower than recommended level of 25(OH)D, in the control group – 75%. In all investigated groups significant negative correlations between 25(OH)D and insulin, HOMA-IR, leptin, and free leptin index were found but in obese subjects this correlations were not observed. There were significant negative correlations between serum calcium and BMI, insulin, HOMA-IR, leptin, and free leptin index and a significant positive correlation between serum calcium and leptin receptor in all investigated groups. In obese subjects there were correlations between calcium levels and soluble leptin receptor as well as free leptin index. Conclusions. Vitamin D deficiency and insufficiency are common in obese and normal weight subjects. There is a lack of correlation between 25(OH)D concentration and insulin resistance parameters and leptin in obese subjects. Vitamin D may impact leptin activity through calcium concentration.