Características biológicas del tejido adiposo: el adipocito como célula endocrina / Biological characteristics of the adipose tissue: adipocyte as an endocrine cell

La obesidad se caracteriza por un aumento de la masa adiposa secundaria a un balance energético positivo mantenido en el tiempo. El incremento en el volumen del tejido adiposo se acompaña de otros cambios en las características biológicas habituales de éste, que se vuelve disfuncional. El depósito visceral de la grasa, la hipertrofia y cambio del perfil secretor de los adipocitos, junto con la infiltración del tejido adiposo por células inflamatorias son algunas de las características que determinan una comunicación alterada del tejido adiposo con otros órganos. Se ha planteado que la disfunción del tejido adiposo, explicaría parte de la etiopatogenia de las enfermedades metabólicas y cardiovasculares asociadas a obesidad; sujetos obesos que mantienen un tejido adiposo funcional no presentan las alteraciones metabólicas propias de la malnutrición por exceso. La modulación de las características biológicas del tejido adiposo permitiría tener un menor riesgo cardiovascular asociado a obesidad.

Obesity is characterized by an increase in the adipose mass, which is due to the deposit of the fatty acids surplus in adipose cells, due to a positive energy balance maintained over the time. Along with the increase in the volume of adipose tissue, there are changes in its normal physiology, driving it toward a dysfunctional tissue. Such changes involve adipocyte hypertrophy and changes in its secretory profile, visceral deposit of fat, increased immune cell infiltration, among others. Adipose tissue dysfunction possibly plays a pivotal role in the pathophysiology of obesity-related metabolic and cardiovascular diseases. The understanding of these changes in adipose tissue function could provide a tool for modulating the metabolic and cardiovascular burden of obesity.

Distribution and ontogeny of gastrin- and serotonin-immunoreactive cells in the proventriculus of developing chick, Gallus gallus domestica

The ontogeny and distribution of gastrin- and serotonin-immunoreactive (IR) cell in the proventriculus of chicks (Gallus gallus domestica, n = 60) in different growth periods was examined immunohistochemically using antisera specific to gastrin and serotonin. Gastrin and serotonin-IR cells were detected in chick proventriculus. Gastrin-IR cells were first evident after 12 days of incubation in lamina epithelialis and compound glands, while serotonin-IR cells were observed only in compound glands at that same time. Gastrin-IR and serotonin-IR cells increased in frequency on incubation day 14 and 16, respectively. Towards the end of incubation, gastrin- and serotonin-IR cell numbers decreased. In adult chicken, both IR cells were present but not lower numbers. The observations demonstrate the presence of gastrin- and serotonin-IR cells in the proventriculus of developing chicks in temporally changing frequencies.

Decrease in intestinal endocrine cells in Balb/c mice with CT-26 carcinoma cells

The density of intestinal endocrine cells, in Balb/c mice with colon 26 (CT-26) carcinoma cells, were examined immunohistochemically at 28 days after implantation. After CT-26 cell administration there was a significant decrease in most of the intestinal endocrine cells (p < 0.01) compared with the control group. The significant quantitative changes in the intestinal endocrine cell density might contribute to the development of the gastrointestinal symptoms commonly encountered in cancer patients.

An immunohistochemical study of the gastrointestinal endocrine cells in the ddY mice

The distributions and frequencies of some endocrine cells in the gastrointestinal (GI) tract of ddY mice were studied with immunohistochemical method using 7 types of antisera against bovine chromogranin (BCG), serotonin, gastrin, cholecystokinin (CCK)-8, somatostatin, glucagon and human pancreatic polypeptide (HPP). All of 7 types of immunoreactive (IR) cells were identified. Most of IR cells in the intestinal portion were generally spherical or spindle in shape (open typed cell) while cells showing round in shape (close typed cell) were found in the intestinal gland and stomach regions occasionally. Their relative frequencies were varied according to each portion of GI tract. BCG-IR cells were demonstrated throughout whole GI tract except for the cecum and they were most predominant in the fundus and pylorus. Serotonin-IR cells were detected throughout whole GI tract and they were most predominant cell types in this species of mice. Gastrin-IR cells were restricted to the pylorus and CCK-8-IR cells were demonstrated in the pylorus, duodenum and jejunum with numerous frequencies in the pylorus. Somatostatin-IR cells were detected throughout whole GI tract except for the cecum and rectum and they showed more numerous frequencies in the stomach regions. In addition, glucagon-IR cells were restricted to the fundus, duodenum and jejunum with rare frequencies, and HPP-IR cells were restricted to the rectum only with rare frequency. In conclusion, some strain-dependent unique distributional patterns of gastrointestinal endocrine cells were found in GI tract of ddY mice.

An immunohistochemical Study on the Pancreatic Endocrine Cells of the C57BL/6 Mouse

The regional distribution and relative frequency of the pancreatic endocrine cells in the C57BL/6 mouse were studied by immunohistochemical method using four types of specific mammalian antisera against insulin, glucagon, somatostatin and human pancreatic polypeptide (PP). The pancreas of mouse could be divided into three portions; pancreatic islets, pancreatic duct and exocrine portions, and pancreatic islets were further subdivided into three regions (central, mantle and peripheral regions) according to their located types of immunoreactive cells and pancreatic duct portions were also subdivided into two regions (epithelial and connective tissue regions). In the pancreatic islet portions, although some cells were also demonstrated in the mantle regions, most of insulin-immunoreactive cells were located in the central regions and they were randomly dispersed in the whole pancreatic islets. Glucagon-immunoreactive cells were detected in the mantle and peripheral regions. Their relative frequencies in the peripheral regions were somewhat numerous than those of the mantle regions. Somatostatin-immunoreactive cells were detected in the mantle and peripheral regions. However, no PP-immunoreactive cells were demonstrated in the pancreatic islets of C57BL/6 mouse. In the pancreatic duct portions, rare glucagon-immunoreactive cells were situated in the epithelial regions. Cell clusters that consisted of glucagon- or somatostatin- immunoreactive cells were found in some case of connective tissue regions of pancreatic ducts. However, insulin- and PP-immunoreactive cells were not detected in the epithelial nor connective tissue regions. In the exocrine portions, all four types of immunoreactive cells except for PP cells were demonstrated in the C57BL/6 mouse. However, no PP-immunoreactive cells were demonstrated. In conclusion, regional distribution of endocrine cells in the pancreas of C57BL/6 mouse was similar to that of mammals, especially other rodents except for topographically different distribution of endocrine cells compared to that of other rodents.

Immunohistochemical Study of the Pancreatic Endocrine Cells in the BALB/c mice: An Unique Distributional Pattern of Glucagon

The regional distribution and relative frequency of insulin-, glucagon-, somatostatin- and pancreatic polypeptide (PP)-producing endocrine cells in the pancreas of BALB/c mouse were investigated by immunohistochemical method. The pancreas of mice was divided into two portions; pancreatic islets and exocrine portions, and pancreatic islets were further subdivided into two regions (central and peripheral regions) and the relative frequency and regional distribution of immunoreactive cells against insulin, glucagon, somatostatin and PP antisera were monitored. In the pancreatic islet portions, insulin-immunoreactive cells were located in the central regions and they were randomly dispersed in the whole pancreatic islets in some case of the small islets. Quite different from those of other mammals, glucagon-immunoreactive cells were dispersed throughout central to peripheral regions in case of large islets and in the smaller ones, most of these cells were situated in the peripheral regions. Somatostatin-immunoreactive cells were detected in the peripheral regions with various frequencies. Although some cells were demonstrated in the central regions of pancreatic islets, most of PP-immunoreactive cells were located in the peripheral regions. In the exocrine portions, all four types of immunoreactive cells were demonstrated in the BALB/c mouse. Some peculiar distributional patterns of pancreatic endocrine cells were found in BALB/c mouse, especially in case of glucagon-immunoreactive cells.

Regional Distribution and Relative Frequency of Gastrointestinal Endocrine Cells in Large Intestines of C57BL/6 Mice

The regional distributions and relative frequencies of some gastrointestinal endocrine cells in the three portions (cecum, colon and rectum) of the large intestinal tract of C57BL/6 mice were examined with immunohistochemical method using 7 types of specific antisera against chromogranin A (CGA), serotonin, somatostatin, human pancreatic polypeptide (HPP), glucagon, gastrin and cholecyctokinin (CCK)-8. In this study, all 3 types of immunoreactive (IR) cells were identified. Most of these IR cells in the large intestinal portion were generally spherical or spindle in shape (open-typed cell) while cells with a round shape (close-typed cell) were found in the intestinal gland. Their relative frequencies varied according to each portion of the large intestinal tract. CGA-IR cells were found throughout the whole large intestinal tract but were most predominant in the colon. Serotonin-IR cells were detected throughout the whole large intestinal tract and showed highest frequency in the colon. Peculiarly, glucagon-IR cells were restricted to the colon with a low frequency. However, no somatostatin-, HPP-, gastrin- and CCK-8-IR cells were found in the large intestinal tract. In conclusion, some peculiar distributional patterns of large intestinal endocrine cells were identified in C57BL/6 mice.

Comparative study of endocrine cells in the principal pancreatic islets of two teleosts, Silurus asotus (Siluridae) and Siniperca scherzeri (Centropomidae)

The regional distribution and relative frequency of some endocrine cells in the principal pancreatic islets of two teleosts, Silurus asotus Linne (Siluridae) and Siniperca scherzeri Steindachner (Centropomidae), which have similar feeding habits, were observed using specific antisera against insulin, glucagon, somatostatin and bovine pancreatic polypeptide (bovine PP) using the peroxidase antiperoxidase (PAP) method. Spherical to spindle shaped cells were demonstrated in the principal pancreatic islets in both species of teleost fishes. However, they were not detected in the exocrine portions nor the pancreatic ducts. Insulin-immunoreactive cells were located in the central regions of the principal pancreatic islets at high frequency in both species. Glucagonimmunoreactive cells were restricted to the peripheral regions of the principal pancreatic islets in both species. They formed a mantle zone in the peripheral regions of Silurus asotus with moderate frequency, and occupied a narrower mantle zone in Siniperca scherzeri with moderate frequency. In addition, glucagonimmunoreactive cell cores were also found in the peripheral zone of some principal pancreatic islets of Siniperca scherzeri. Somatostatin-immunoreactive cells were dispersed in the central zone of the principal pancreatic islets of Silurus asotus with moderate frequency, but were located in the peripheral regions with low frequency in Siniperca scherzeri. Bovine PPimmunoreactive cells were found in the peripheral region and the mantle zone of the principal pancreatic islets with low and rare frequency, respectively in both species. In conclusion, the regional distribution and relative frequency of endocrine cells in the principal pancreatic islets of Silurus asotus showed general patterns similar to those of other teleostean fishes. But, some speciesdependent distributional patterns and/or relative frequencies, particularly in glucagon-, somatostatin- and bovine PP-immunoreactive cells, were detected in the principal pancreatic islets of Siniperca scherzeri

An immunohistochemical study on the pancreatic islets cells of the Mongolian gerbils, Meriones unguiculatus

In order to study the regional distribution and relative frequency of the immunoreactive endocrine cells in the pancreatic islets of the Mongolian gerbil, pancreatic sections of Meriones unguiculatus were immunostained using an immunohistochemical (PAP) method with four types of specific antisera against insulin, glucagon, somatostatin and human pancreatic polypeptide (PP). The pancreatic islets were subdivided into three portions (central region, mantle zone and peripheral region) according to their composition of immunoreactive cells. Spherical to spindle shaped insulin, glucagon, somatostatin and PP-immunoreactive cells were observed in this study. Insulin-immunoreactive cells were present in the central regions with high frequency, and a few of these cells were also demonstrated in the mantle zones. Glucagon-immunoreactive cells were mainly restricted to the mantle zones. However, rare examples were found in the peripheral regions. As for the glucagon-immunoreactive cells, somatostatin-immunoreactive cells were detected in the mantle zones and peripheral regions with moderate and rare frequencies, respectively. PP-immunoreactive cells were found in the mantle zones and peripheral regions with rare and moderate frequencies, respectively. In the mantle and the peripheral regions, cytoplasmic process of glucagon-, somatostatin- and PP-immunoreactive cells were intermingled. In conclusion, the regional distribution of endocrine cells in the pancreatic islets of Mongolian gerbil was found to be similar to that of other mammals, especially other rodents, except for the topographical different distribution of somatostatin which differs that of other rodents.

THE ARGYROPHIL CELLS IN RAT GASTROINTESTINAL TRACT——A COMPARATIVE STUDY BETWEEN IMMUNOHISTOCHEMICAL AND SLIVER IMPREGNATION TECHNIQUES / 解剖学报

The aim of this study is to investigate comparatively the relationship between the endocrine and argyrophil cells in the rat gastrointestinal tract by means of the IGS, PAP immunohistochemical and Grimelius technique in the same sections. The results showed that the SS cells and almost G ceils can not be identified by Grimelius technique. The Grimelius technique had high specifity to reveal EC cells in the antrum of stomach and the intestine. Our technique is relatively simple and reliable, and may be used for consecutive demonstration of argyrophil cells and bioactive peptide-containing cells.