Leptin and adipose tissue maldistribution in HIV-infected male patients with predominant fat loss treated with antiretroviral therapy.

BACKGROUND: Metabolic disturbances and fat maldistribution are main features of the antiretroviral-related lipodystrophy syndrome (LDS). Different phenotypes of fat distribution abnormalities can be observed: fat loss, fat accumulation, or a mixed pattern. In patients with predominant loss of fat, the roles of leptin, lipids, and glucose homeostasis disturbances have not yet been clearly established. METHODS: The study comprised 34 HIV-infected male patients receiving antiretroviral treatment that included protease inhibitors. A lipoatrophic phenotype, defined as fat loss in face or extremities, both normal weight and waist:hip ratio, and absence of fat accumulation elsewhere, was present in all cases. Fat distribution disturbances were confirmed by abdominal and midthigh computed tomography-calculated adipose tissue content. Fasting plasma glucose, insulin, proinsulin, total leptin, testosterone, and lipid profiles were measured. After 2 hours, 75-g oral glucose tolerance test (OGTT), glucose, insulin, and proinsulin levels were also obtained. Insulin resistance was calculated using the homeostasis model assessment for insulin resistance (HOMA-r) method. Both healthy study subjects ( n = 385) and antiretroviral-naive HIV-positive patients ( n = 13) were used as controls. RESULTS: Of these LDS patients, 5.8% showed diagnostic criteria for diabetes and 17.8% for impaired glucose tolerance. A lipid pattern characterized by high total cholesterol and high low density lipoprotein (LDL) plasma levels, hypertriglyceridemia, and normal high density lipoprotein (HDL) levels was observed. Fasting insulin and 2-hour post OGTT insulin levels, and insulin resistance index were significantly higher in LDS patients than in antiretroviral-naive HIV-positive patients. Plasma leptin levels were significantly lower in lipoatrophic patients than in healthy control individuals. Patients with LDS presented with significant midthigh fat reduction and visceral fat accumulation compared with findings in antiretroviral-naive HIV-positive patients. A significant correlation was found between plasma leptin levels and midthigh fat content. CONCLUSION: Peripheral fat loss in extremities in LDS patients with lipoatrophic phenotype is also associated with low plasma leptin levels, visceral fat accumulation, and metabolic disturbances related to an increased cardiovascular risk. In LDS patients, plasma leptin levels could be a marker of subcutaneous adipose tissue content.     

Irregular connexin43 expressed in a rare cardiac hamartoma containing adipose tissue in the crista terminalis

Cardiac hamartomas are very rare and are demarcated masses of enlarged, hypertrophied, mature myocytes and collagen tissue. Cardiac hamartomas are generally circumscribed in the right ventricle or atrium, but not reported in the crista terminalis (CRT). The CRT is crucial in electrophysiology, is related to arrhythmogenesis, and is targeted by radiofrequency catheter procedures. Previous works only described the benign natures of prominent CRT using non-invasive methods. This study describes an unusual cardiac hamartoma originating from the CRT and extending toward the tricuspid valve. Microscopically, this hamartoma comprised dense collagen and adipose tissue, mixed with hypertrophy, but with disarrayed cardiomyocytes. An irregular gap junction, connexin43, was demonstrated in this cardiac hamartoma.     

Multiple oncocytic cysts with tyrosine-crystalloids in the parotid gland

A case of multiple oncocytic cysts with intraluminal tyrosine-rich crystalloids involving the parotid gland is described. The microscopic and ultrastructural findings are presented.     

Fibrous hamartoma of infancy. Radiologic-pathologic study of 21 cases: 8 with predominant pseudoangiomatous pattern

Fibrous hamartoma of infancy (FHI) is a very rare benign soft tissue lesion that principally affects the axilla, trunk, and upper extremities of children younger than 2 years. It is usually cured by local excision. Histologically, these lesions have a triphasic morphology in an organoid pattern: mature adipose tissue, fibroblastic/myofibroblastic trabeculae, and small round cell nests in a myxoid matrix. However, morphologic variants have recently been described. Focal areas with a pseudoangiomatous pattern have been found in some FHI, but few cases with predominant pseudoangiomatous areas have been previously described in the medical literature. We report 21 new cases of FHI, 8 of them with a predominant pseudoangiomatous pattern. Our cases with a predominant pseudoangiomatous pattern did not present specific radiological findings.     

皮下脂肪组织与内脏脂肪组织

肥胖不仅指过多的脂肪积聚,还包括脂肪的分布异常。内脏脂肪的增加是多种代谢性疾病（如2型糖尿病、心血管疾病等）的高危因素。脂肪组织通过分泌脂肪细胞因子和炎症因子调节胰岛索敏感性和参与胰岛素信号通路。因此,研究脂肪组织分布与内分泌特点对防治肥胖及其相关疾病具有重要的意义。     

Dendritic cells and adipose tissue

Visceral adipose tissue inflammation in obesity is an established risk factor for metabolic syndrome, which can include insulin resistance, type 2 diabetes, hypertension and cardiovascular diseases. With obesity and related metabolic disorders reaching epidemic proportions globally, an understanding of the mechanisms of adipose tissue inflammation is crucial. Within the immune cell cohort, dendritic cells (DC) play a key role in balancing tolerance and immunity. Despite decades of research into the characterization of DC in lymphoid and non‐lymphoid organs, their role in adipose tissue function is poorly understood. There is now an increasing interest in identification and characterization of DC in adipose tissue and understanding their function in regulating tissue metabolic homeostasis. This review provides an overview of the study of DC in adipose tissue, focusing on possible mechanisms by which DC may contribute to adipose tissue homeostasis.     

Primitive neuroectodermal tumor of cerebrum with adipose tissue

Primitive neuroectodermal tumors (PNETs) of the central nervous system are uncommon embryonal neoplasms, rarely occurring in adults. Differentiation into specific mesenchymal tissues, such as cartilage, bone, skeletal muscle, smooth muscle, or adipose tissue, is rare. We report a case of a 51-year-old woman with a PNET of cerebrum that showed extensive mature adipose tissue differentiation. This is the second case, to our knowledge, of PNET of cerebrum with adipose tissue elements that has been described.     

Combining decellularized human adipose tissue extracellular matrix and adipose-derived stem cells for adipose tissue engineering

Repair of soft tissue defects resulting from lumpectomy or mastectomy has become an important rehabilitation process for breast cancer patients. This study aimed to provide an adipose tissue engineering platform for soft tissue defect repair by combining decellularized human adipose tissue extracellular matrix (hDAM) and human adipose-derived stem cells (hASCs). To derive hDAM incised human adipose tissues underwent a decellularization process. Effective cell removal and lipid removal were proved by immunohistochemical analysis and DNA quantification. Scanning electron microscopic examination showed a three-dimensional nanofibrous architecture in hDAM. The hDAM included collagen, sulfated glycosaminoglycan, and vascular endothelial growth factor, but lacked major histocompatibility complex antigen I. hASC viability and proliferation on hDAM were proven in vitro. hDAM implanted subcutaneously in Fischer rats did not cause an immunogenic response, and it underwent remodeling, as indicated by host cell infiltration, neovascularization, and adipose tissue formation. Fresh fat grafts (Coleman technique) and engineered fat grafts (hDAM combined with hASCs) were implanted subcutaneously in nude rats. The implanted engineered fat grafts maintained their volume for 8 weeks, and the hASCs contributed to adipose tissue formation. In summary, the combination of hDAM and hASCs provides not only a clinically translatable platform for adipose tissue engineering, but also a vehicle for elucidating fat grafting mechanisms.     

Differential responses of white adipose tissue and brown adipose tissue to caloric restriction in rats

Caloric restriction (CR) slows the aging process and extends longevity, but the exact underlying mechanisms remain debatable. It has recently been suggested that the beneficial action of CR may be mediated in part by adipose tissue remodeling. Mammals have two types of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT). In this study, proteome analysis using two-dimensional gel electrophoresis combined with MALDI-TOF MS, and subsequent analyses were performed on both WAT and BAT from 9-month-old male rats fed ad libitum or subjected to CR for 6 months. Our findings suggest that CR activates mitochondrial energy metabolism and fatty acid biosynthesis in WAT. It is likely that in CR animals WAT functions as an energy transducer from glucose to energy-dense lipid. In contrast, in BAT CR either had no effect on, or down-regulated, the mitochondrial electron transport chain, but enhanced fatty acid biosynthesis. This suggests that in CR animals BAT may change its function from an energy consuming system to an energy reservoir system. Based on our findings, we conclude that WAT and BAT cooperate to use energy effectively via a differential response of mitochondrial function to CR.     

Heterotopic pancreatic tissue associated with intra- and extrahepatic choledochal cysts

A case report of heterotopic pancreas in intra- and extrahepatic biliary tracts in a 36-year-old female who suffered from intra- and extrahepatic choledochal cysts with an anomalous pancreatobiliary duct system. Histologic examination of the resected specimen showed pancreatic tissues located along the wall of the biliary tract with choledochal cysts. The pancreatic tissue consisted of acinar cells and duct elements without Langerhans' islets; the acinar cells were positive immunohistochemically for alpha-amylase and negative for endocrine hormones. Ultrastructural study revealed zymogen granules in the acinar cells. In the present case the heterotopic exocrine pancreatic tissue seems to be etiologically related to choledochal cysts as well as to the anomalous arrangement of the pancreatobiliary duct.     

脂肪组织和脂肪细胞因子的研究进展

脂肪组织是一个活跃的内分泌和旁分泌器官，分泌许多细胞因子和生物活性因子。脂肪组织的分泌功能存在节律性，全身各脂肪库脂肪因子的表达和分泌具有特异性，提示其复杂的生物学功能。脂肪组织是促炎症反应介质的丰富来源，这些介质参与炎症、凝血和纤溶反应，可直接引起血管损伤、胰岛素抵抗和动脉粥样硬化；脂肪细胞因子是肥胖和代谢综合征的分子联系。