Comparison of vasopressin and oxytocin expressions in the hypothalamo-neurohypophysial system of patients with chronic heart failure.

The hypothalamic nonapeptide vasopressin is a known player in the pathogenesis of chronic heart failure. According to the large body of clinical evidence, vasopressin has an impact on salt and water imbalance, hyponatremia, and subsequent renal insufficiency - the most common and destructive co-morbidity of patients afflicted with chronic heart failure. Despite the well-documented elevated levels of vasopressin in the blood of such patients, its expression in the magnocellular hypothalamic nuclei and transport to the posterior pituitary has not yet been investigated. In addition, the literature almost lacks the information on the contribution of another member of nonapeptide family, oxytocin, in the pathogenesis of this disease. Here we present a postmortem analysis of vasopressin and oxytocin-immunoreactive neurons and their terminals in the posterior pituitary of 8 male patients (53.8+/-9.3 years) who had died from CHF and 9 male controls (54.6+/-11.8 years). In line with previous clinical reports, our study on hypothalami of chronic heart failure patients revealed a significant increase in the relative profile density (+29%) of vasopressin-positive neurons in the hypothalamic supraoptic nucleus. Consistently we found a significant increase in the relative optic density of vasopressin-immunoreactivity in the posterior pituitary (+33%) of these patients. In contrast, the similar analysis applied for oxytocin neurons revealed no statistically significant differences to controls. In conclusion, our study provides the morphological evidence for activation of vasopressin (but not oxytocin) expression and vasopressin transport to the posterior pituitary in patients with chronic heart failure.

[Supraoptic nucleus of hypothalamus in subjects with chronic heart failure].

Postmortem paraffin hypothalamic blocks from male subjects with chronic heart failure (CHF) were used for morphometric and immunohistochemical studies of the supraoptical nucleus (SON). Morphometric analysis revealed a significant enlargement of pericarya and nuclei in SON of CHF subjects compared with controls. In addition, eccentrically positioned nucleoli were more frequently found in SON of the subjects with CHF. Moreover, a significant rise in relative entropy of all studied parameters of SON was documented in CHF subjects. The immunohistochemical study revealed a substantial increase of vasopressin immunoreactivity in SON neurons of the CHF subjects in comparison with control ones. Taken together, these results suggest considerable enhancement of synthetic activity of SON neurons in patients with CHF consistent with clinical observations that demonstrate significant elevation of blood vasopressin levels in patients with chronic cardiac insufficiency.

Altered hypothalamic-pituitary-adrenal axis activity in patients with chronic heart failure.

Neuroendocrine factors play an important role in the pathogenesis of chronic heart failure. Despite numerous clinical and experimental studies, the role of the hypothalamic-pituitary-adrenal axis and glucocorticoid hormones is not fully characterised. Here we present a study of plasma cortisol concentration in 74 chronic heart failure patients, divided into four groups based on NYHA functional classes I-IV, and in 17 control subjects. In parallel, we performed morphological analysis of the hypothalamic-pituitary-adrenal axis components from 8 male patients who had died from chronic heart failure, and 9 male controls. In our study we applied immunohistochemical method and quantitative analysis to investigate an expression of hypothalamic neurohormones (corticotropin-releasing hormone, vasopressin) and adrenocorticotropin hormone in the pituitary, as well as performed general histological examination of the adrenal cortex. Measurement of morning cortisol concentration in plasma of chronic heart failure patients revealed neither difference compared to controls nor with the severity of the disease. Despite this, a two-fold increase in the density of corticotropin-releasing hormone-immunoreactive neurons as well as a two-fold increase in the number of corticotropin-releasing hormone neurons co-expressing vasopressin in the hypothalamic paraventricular nucleus were found. In the anterior pituitary the density of adrenocorticotropin hormone-immunoreactive cells was significantly increased. General histological analysis of the adrenal cortex revealed a drastic thinning of the zona fasciculata and dystrophic changes in corticocytes. Structural changes, observed in the adrenal cortex, suggest a relative glucocorticoid deficiency, which may contribute to corticotropin-releasing hormone and adrenocorticotropin hormone upregulation in hypothalamus and pituitary of chronic heart failure patients.

Effects of chronic alcoholic disease on magnocellular and parvocellular hypothalamic neurons in men.

Although numerous data showing severe morphological impairment of magnocellular and parvocellular hypothalamic neurons due to chronic alcoholic consumption have been gathered from animal experiments, only one study (Harding et al., 1996) was performed on POST MORTEM human brain. This study showed a reduction in the number of vasopressin (VP)-immunoreactive neurons in the supraoptic (SON) and paraventricular (PVN) nuclei, but did not provide any data regarding the effect of chronic alcohol intake on human parvocellular neurons. In order to assess whether the changes observed in the animal model also occur in humans and provide a structural basis for the results of clinical tests, we performed immunohistochemical and morphometric analysis of magnocellular (VP and oxytocin, OT) and parvocellular (corticotropin-releasing hormone, CRH) neurons in post-mortem brains of patients afflicted with chronic alcoholic disease. We analyzed 26-male alcoholics and 22 age-matched controls divided into two age groups--"young" (< 40 yr) and "old" (> 40 yr). Hypothalamic sections were stained for OT, VP, and CRH. The analysis revealed: 1) decrease in VP-immunoreactivity in the SON and PVN as well as OT-immunoreactivity in the SON in alcoholic patients; 2) increase in OT-immunoreactivity in the PVN; 3) increase in CRH-immunoreactivity in parvocellular neurons in the PVN. Furthermore, the proportion of cells containing CRH and VP was increased in alcoholics. These findings indicate that chronic alcohol consumption does indeed impair the morphology of magnocellular neurons. The enhancement of CRH-immunoreactivity and increased co-production of CRH and VP in parvocellular neurons may be due to a decline in glucocorticoid production, implied by the hypoplasic impairment of adrenal cortex we observed in alcoholics during the course of this study.

Expression of corticosteroid-binding protein in the human hypothalamus, co-localization with oxytocin and vasopressin.

Corticosteroid-binding globulin, a specific steroid carrier in serum with high binding affinity for glucocorticoids, is expressed in various tissues. In the present study, we describe the immunocytochemical distribution of this protein in neurons and nerve fibers in the human hypothalamus. CBG immunoreactive perikarya and fibers were observed in the paraventricular, supraoptic, and sexual dimorphic nuclei in the perifornical region, as well as in the lateral hypothalamic and medial preoptic areas, the region of the diagonal band, suprachiasmatic and ventromedial nuclei, bed nucleus of the stria terminalis and some epithelial cells from the choroid plexus and ependymal cells. Stained fibers occurred in the median eminence and infundibulum. Double immunostaining revealed a partial co-localization of corticosteroid-binding globulin with oxytocin and, to a lesser extent, with vasopressin in the paraventricular and the supraoptic nuclei. Double immunofluorescence staining showed coexistence of these substances in axonal varicosities in the median eminence. We conclude that neurons of the human hypothalamus are capable of expressing corticosteroid-binding globulin, in part co-localized with the classical neurohypophyseal hormones. The distribution of CBG immunoreactive neurons, which is widespread but limited to specific nuclei, indicates that CBG has many physiological functions that may include neuroendocrine regulation and stress response.