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The aim of this post-mortem ultrastructural and immunohistochemical study is to explore the characteristics of acute myocardial ischemia in the context of sudden death, using the combination of two different methods, both more insightful than ordinary histology. Transmission electron microscope and immunohistochemistry, in addition to the traditional histology, were applied to study human heart specimens collected during forensic autopsies. The whole series was sub-grouped into cases (n=17) and controls (n=10). The control group consisted of unnatural death with a short agonal period (immediately lethal injuries). Heart samples of the two cohorts of subjects were prepared for electron microscopy. On the other hand, each specimen, formalin fixed and paraffin embedded, was stained with haematoxylin and eosin and immunoreacted with the following primary antibodies: antiFibronectin, antiConnexin-43, anti npCx43 (dephosphorylated form of Connexin43), antiZonula occludens-1. Immunopositivity of each marker in the myocardium was semi-quantitatively graded. Electron microscopy revealed a number of interesting differences between acute myocardial ischemia and controls, regarding the morphology of nucleus, mitochondria and intercellular junctions. By immunohistochemistry, fibronectin was found to be markedly increased in the extracellular matrix of the acute myocardial ischemia cases, with a remarkable difference in respect of controls. Connexin 43 staining disclosed a slightly increase in the cytoplasm of acute myocardial ischemia cases with respect to the controls, whereas no relevant differences were seen between cases and controls at intercellular junctions. Dephosphorylated form of Cx43 showed an evident difference of staining in cases compared to controls and overall this difference more evident in the cytoplasm. Zonula occludens 1, described as an important marker for functional modification of cardiac muscle fibers, resulted negative or very weak in the vast majority of both cases and controls. The present study attempts to simultaneously apply electron microscopy and immunohistochemistry, in order to figure out the morphological changes that might lead to pathological processes underlying the sudden, unexpected death due to acute myocardial ischemia, and consequently to find useful diagnostic markers of very early ischemic injury. Both methods showed significant differences between acute myocardial ischemia and controls, regarding, overall nuclei, mitochondria, and intercellular junctions.Â.

Recent studies indicate that the processes mediated by the (T1R2/T1R3) glucose/sugar receptor of gustatory cells in the tongue, and hormones like leptin and ghrelin contribute to the regulation of glucose homeostasis. Altered plasma levels of leptin and ghrelin are associated with obesity both in humans and rodents. In the present study, we evaluated the ultrastructure of the mucosa, and the expression of molecules implicated in the regulation of glucose homeostasis (GLUT2, SGLT1, T1R3, ghrelin and its receptor) in the trachea of an animal model of obesity (Zucker rats). We found that the tracheal epithelium of obese animals was characterized by the presence of poorly differentiated cells. Ciliated and secretory cells were the cell lineages with greatest loss of differentiation. Severe epithelial alterations were associated with marked deposit of extracellular matrix in the lamina propria. The expression pattern of GLUT2 and SGLT1 glucose transporters was similar in the trachea of both the Zucker rat genotypes, whereas that of T1R3 was reduced in ciliated cells of obese rats. A different immunolocalization for ghrelin was also found in the trachea of obese rats. In conclusion, the tracheal morphological alterations in obese animals seem to compromise the expression of molecules involved in the homeostasis of glucose.

Technological developments based on the use of autologous white adipose tissue (WAT) attracted attention to minor fat depots as possible sources of adipose tissue. In plastic surgery, the trochanteric fatty pad is one of the most used WAT depots for its location and organoleptic characteristics that make it particularly suitable for reconstructive procedures. Despite its wide use in clinic, the structure of this depot has never been studied in detail and it is not known if structural differences exist among trochanteric fat and other subcutaneous WAT depots. The present study was performed on trochanteric fat pad with the aim to clarify the morphology of its adipocytes, stroma and microcirculation, with particular reference to the stem niches. Histological and ultrastructural studies showed that the main peculiar feature of the trochanteric fat concerns its stromal component, which appears less dense than in the other subcutaneous WATs studied. The intra-parenchymal collagen stroma is poor and the extracellular compartment shows large spaces, filled with electron-light material, in which isolated collagen bundles are present. The adipocytes are wrapped in weak and easily detachable collagen baskets. These connective sheaths are very thin compared to the sheaths in other subcutaneous WAT depots. The capillaries are covered by large, long and thin elements surrounded by an external lamina; these perivascular cells are poor in organelles and mainly contain poly-ribosomes. In conclusion, when compared to other WAT deposits, the trochanteric fatty pad shows structural peculiarities in its stroma and microcirculation suggesting a high regenerative potential. Resistance, dissociability, microvascular weft and high regenerative potential make the trochanteric fatty pad a privileged source for harvesting in autologous WAT-based regenerative procedures.

The developments in the technologies based on the use of autologous adipose tissue attracted attention to minor depots as possible sampling areas. Some of those depots have never been studied in detail. The present study was performed on subcutaneous adipose depots sampled in different areas with the aim of explaining their morphology, particularly as far as regards stem niches. The results demonstrated that three different types of white adipose tissue (WAT) can be differentiated on the basis of structural and ultrastructural features: deposit WAT (dWAT), structural WAT (sWAT) and fibrous WAT (fWAT). dWAT can be found essentially in large fatty depots in the abdominal area (periumbilical). In the dWAT, cells are tightly packed and linked by a weak net of isolated collagen fibers. Collagenic components are very poor, cells are large and few blood vessels are present. The deep portion appears more fibrous then the superficial one. The microcirculation is formed by thin walled capillaries with rare stem niches. Reinforcement pericyte elements are rarely evident. The sWAT is more stromal; it is located in some areas in the limbs and in the hips. The stroma is fairly well represented, with a good vascularity and adequate staminality. Cells are wrapped by a basket of collagen fibers. The fatty depots of the knees and of the trochanteric areas have quite loose meshes. The fWAT has a noteworthy fibrous component and can be found in areas where a severe mechanic stress occurs. Adipocytes have an individual thick fibrous shell. In conclusion, the present study demonstrates evident differences among subcutaneous WAT deposits, thus suggesting that in regenerative procedures based on autologous adipose tissues the sampling area should not be randomly chosen, but it should be oriented by evidence based evaluations. The structural peculiarities of the sWAT, and particularly of its microcirculation, suggest that it could represent a privileged source for regenerative procedures based on autologous adipose tissues.