Decreased immunoreactivity of visfatin in the pancreas and liver of rats with renovascular hypertension

Hypertension is one of the major endocrine and metabolic disorders, in which visfatin plays a significant role. The objective of this study was to evaluate the immunoreactivity of visfatin in pancreas and liver of “two kidney, one clip” (2K1C) renovascular hypertension model in rats. The studies were carried out on the pancreas and liver of rats. After a 6-week period of the renal artery clipping procedure, 2K1C rats developed a stable hypertension. Paraffin sections were stained with hematoxylin and eosin (for general histological examination) and processed for immunolocalization of visfatin. The intensity of immunohistochemical reaction was measured using Nikon NIS-Elements Advanced Research software. The hypertension significantly weakened the immunohistochemical reaction exhibiting visfatin in the pancreas and liver of hypertensive rats, compared to control animals. The changes induced by hypertension in the visfatin-containing cells in the pancreas and liver of the rats are discussed and needs further study.

Quantitative evaluation of CART-containing cells in urinary bladder of rats with renovascular hypertension

Recent biological advances make it possible to discover new peptides associated with hypertension. The cocaine- and amphetamine-regulated transcript (CART) is a known factor in appetite and feeding behaviour. Various lines of evidence suggest that this peptide participates not only in control of feeding behaviour but also in the regulation of the cardiovascular and sympathetic systems and blood pressure. The role of CART in blood pressure regulation led us to undertake a study aimed at analysing quantitative changes in CART-containing cells in urinary bladders (UB) of rats with renovascular hypertension. We used the Goldblatt model of arterial hypertension (two-kidney, one clip) to evaluate quantitative changes. This model provides researchers with a commonly used tool to analyse the renin-angiotensin system of blood pressure control and, eventually, to develop drugs for the treatment of chronic hypertension. The study was performed on sections of urinary bladders of rats after 3-, 14-, 28-, 42 and 91 days from hypertension induction. Immunohistochemical identification of CART cells was performed on paraffin for the UBs of all the study animals. CART was detected in the endocrine cells, especially numerous in the submucosa and muscularis layers, with a few found in the transitional epithelium and only occasionally in serosa. Hypertension significantly increased the number of CART-positive cells in the rat UBs. After 3 and 42 days following the procedure, statistically significantly higher numbers of CART-positive cells were identified in comparison with the control animals. The differences between the hypertensive rats and the control animals concerned not only the number density of CART-immunoreactive cells but also their localization. After a 6-week period, each of the rats subjected to the renal artery clipping procedure developed stable hypertension. CART appeared in numerous transitional epithelium cells.

As this study provides novel findings, the question appears about the type of connection between hypertension and the functioning and activity of CART in the urinary tract (UT). The study gives rise to the assumption that high blood pressure can be a factor that intensifies CART secretion. In conclusion, the endocrine system of the urinary tract is modified by renovascular hypertension. This may affect the production of hormones and biologically active substances and contribute to the development of possible hypertension complications. In order to fully comprehend the role of the CART peptide in blood pressure regulation, further analyses are necessary.

Evaluation of CART-, glucagon-, and insulin-immunoreactive cells in the pancreas of an experimental rat model of unilateral renal artery stenosis

Hypertension is one of the most frequently occurring diseases worldwide. Approximately 10% of the population with hypertension reveal the secondary type of hypertension. The aim of this study was to evaluate the cells containing CART, insulin and glucagon in the pancreas of rats with renovascular hypertension. An experimental model of hypertension in rats according to Goldblatt (2K1C model of hypertension) was used in the study. The experimental material (pancreas) was collected in the 6th week of the study. Cells containing CART, insulin and glucagon were evaluated using immunohistochemical and morphometric methods. Pancreatic islet cells were evaluated based on the number and intensity of staining. The investigation showed an increase in the number and immunoreactivity of CART containing cells, 6 weeks after partial unilateral ligation of the renal artery. There was a significant decrease in the number of glucagon-IR cells. Although intensity of staining these cells did not change. No differences were observed in the number and staining affinity of insulin-containing cells. On the basis of the study it can be stated that the endocrine system of pancreas undergoes changes in the course of renovascular hypertension. This may affect the production of hormones and contribute to the development of possible hypertension complications.

Distribution of cocaine and amphetamine regulated transcript in ureters and urinary bladder of hypertensive rats

Cocaine and amphetamine regulated transcript (CART), a neuropeptide of the central and peripheral nervous system plays an essential role in maintaining body homeostasis by regulating body temperature, orexia, digestive motility and blood pressure. Very few studies describe the relationship of hyperten¬sion with CART. Therefore, the present research was undertaken to identify, locate and determine the number of CART-immunopositive neuroendocrine cells (NE) and structures in the urinary bladder and ureter of rats with experimentally induced nephrogenic hypertension. The experiments were conducted on 20 Wistar rats in which hypertension was experimentally induced by applying a clamp on the left renal artery based on the two kidney, one clip experimental model (2K1C). After 6 weeks, fragments of the ureters and urinary bladder were sampled from rats with permanent hypertension. Immunohisto¬chemical analyses revealed a salient effect of renovascular hypertension on the neuroendocrine system of rat ureters and urinary bladder. Differences in the number of neuroendocrine cells and in the density of CART-positive structures were identified between the hypertensive and normotensive (control) rats. Hypertension greatly increased the number of NE cells and the density of CART- immunoreactive (IR) structures in the analysed urinary system organs.

Comparative evaluation of gastric ghrelin cells and levels of hormone in the serum of healthy women and men

Due to difficulties in obtaining human material, most of the data concerning the site of occurrence and synthesis of ghrelin are based on animal studies. There are only few reports describing ghrelin-containing cells in the human digestive tract, based on the limited human material obtained during surgery or biopsy. The aim of this study was to compare and evaluate the distribution and morphology of ghrelin cells in the stomach and the levels of hormone in the serum of healthy men and women. The study included 18 subjects with normal gastric mucosa (12 men and 6 women). Immunohistochemistry was performed using rabbit anti-ghrelin (human) antiserum. Ghrelin level in serum was measured by ELISA. The total number of ghrelin positive cells was greater in the stomach of women than men. Ghrelin-immunoreactive cells were more elongated and larger in the stomach of women. The serum ghrelin level was higher in men than in women. Ghrelin concentration in serum correlates negatively with body mass index and weight in both genders, whereas the correlation between ghrelin level and age was positive in women and negative in men. The number of cells containing ghrelin in the stomach does not reflect the serum hormone levels. The differences in gastric ghrelin cells and ghrelin levels in serum between women and men, indicate that secretion of hormone can be under control sex hormones or other unknown factors.

Cocaine- and amphetamine-regulated transcript : identification and distribution in human gastrointestinal tract

Cocaine- and amphetamine-regulated transcript (CART) was identified in the central and peripheral nervous system, including the gastrointestinal tract of rodents and pig. CART was also expressed in neuroendocrine cells of the rats stomach antral mucosa. The knowledge of the presence and functional role of CART peptide in the human alimentary tract is very limited due to difficulties in obtaining human samples (especially from healthy individuals). The presence of CART peptide in the gastrointestinal tract of the human was investigated immunohistochemically. CART-immunoreactive (IR) neural structures were observed in all studied fragments of alimentary tract. CART-like immunoreactive nerve fibers were numerous within the muscle in layers of muscularis externa and in the myenteric plexus of all gastrointestinal segments (from esophagus to colon), while they were moderate or few in density in other layers of gastrointestinal tract. The presence of CART peptides in the neuroendocrine cells was demonstrated predominantly in the pyloric, duodenum and fundus, and only few in the rest parts of the small intestine. CART-IR neuroendocrine cells could not be detected in the mucosa of large intestine. The present study reports for the first time a detailed description of the CART distribution pattern within the human alimentary tract. Our findings may hopefully provide some contribution towards a more complete and comprehensive understanding of the function and role of the CART peptide in the alimentary system.

Immunohistochemical identification and localisation of gastrin and somatostatin in endocrine cells of human pyloric gastric mucosa

The detailed description of the distribution of endocrine cells G and D producing important hormones that regulate activation of other cells in the human stomach may be a valuable source of information for opinions about mucosa changes in different diseases of the alimentary tract. The density and distribution of immunoreactive G and D cells in the pylorus of humans (donors of organs) were evaluated. The pylorus samples were collected after other organs were harvested for transplantation. The number of G cells in the pyloric mucosa of healthy people was higher than the number of D cells. G and D cells were distributed between columnar cells of epithelium mucosa. Multiform endocrine cells generally occurred: gastrin in the middle third of the mucosa and somatostatin cells in the basal half of the pyloric mucosa. The investigation of the pyloric part of the healthy human stomach showed a characteristic distribution of cells that reacted with antisera against gastrin and somatostatin.

The relationship and co-localization of vasoactive intestinal peptide (VIP)- and Leu5-enkephalin (LENK)-immunoreactivity in the female genital tract of the pig

The vasoactive intestinal peptide (VIP) and opioid family member Leu5-enkephalin (LENK) have already been established as playing independently significant roles in the functioning of the female genital tract. However, the mutual influence of both neuropeptides on female genital function has not been examined until now. Therefore, the aim of this study was to compare the distribution of VIP- and/or LENK-immunoreactive (IR) structures throughout the female genital tract of the pig. Immunohistochemical examination revealed that the great majority of the immunopositive structures co-expressed both peptides. Nevertheless, a small population of exclusively VIP- or LENK-IR processes and perikarya were also distinguished. The muscular layer of the organs examined revealed the greatest density of VIP- and/or LENK-IR nerve fibers. The mucosa of the ampulla, isthmus, cervix and vagina was supplied with a moderate number of single labeled LENK-IR processes, while exclusively VIP-IR fibers were found mainly in vaginal mucosa. The infundibulum was found to be poorly supplied with single labeled VIP- or LENK-IR fibers. The paracervical ganglion (PCG), the expected source of VIP- and/or LENK-IR nerve fibers innervating the organs under investigation, has been found to contain double labeled LENK-/VIP-IR as well as single labeled VIP-IR perikarya. The great number of specific co-localization between VIP and LENK in nerve processes of the porcine female genital organs may indicate a functional regulatory interaction between the neuropeptides studied, requiring further study.