Giorgio Catalano

Fat depot-related differences in gene expression, adiponectin secretion, and insulin action and signalling in human adipocytes differentiated in vitro from precursor stromal cells

Aim/hypothesisThe distinct metabolic properties of visceral and subcutaneous adipocytes may be due to inherent characteristics of the cells that are resident in each fat depot. To test this hypothesis, human adipocytes were differentiated in vitro from precursor stromal cells obtained from visceral and subcutaneous fat depots and analysed for genetic, biochemical and metabolic endpoints.MethodsStromal cells were isolated from adipose tissue depots of nondiabetic individuals. mRNA levels of adipocyte-specific proteins were determined by real-time RT-PCR. Insulin signalling was evaluated by immunoblotting with specific antibodies. Glucose transport was measured by a 2-deoxy-glucose uptake assay. Adiponectin secretion in the adipocyte-conditioned medium was determined by a specific RIA.ResultsWith cell differentiation, mRNA levels of PPARG, C/EBPα (also known as CEBPA), AP2 (also known as GTF3A), GLUT4 (also known as SLC2A4) were markedly upregulated, whereas GLUT1 (also known as SLC2A1) mRNA did not change. However, expression of C/EBPα, AP2 and adiponectin was higher in subcutaneous than in visceral adipocytes. By contrast, adiponectin was secreted at threefold higher rates by visceral than by subcutaneous adipocytes while visceral adipocytes also showed two- to threefold higher insulin-stimulated glucose uptake. Insulin-induced phosphorylation of the insulin receptor, IRS proteins, Akt and extracellular signal-regulated kinase-1/2 was more rapid and tended to decrease at earlier time-points in visceral than in subcutaneous adipocytes.Conclusions/interpretationSubcutaneous and visceral adipocytes, also when differentiated in vitro from precursor stromal cells, retain differences in gene expression, adiponectin secretion, and insulin action and signalling. Thus, the precursor cells that reside in the visceral and subcutaneous fat depots may already possess inherent and specific metabolic characteristics that will be expressed upon completion of the differentiation programme.

Microcirculation and Reperfusion Injury in Organ Transplantation

There are many interesting aspects regarding hemorheology and tissue oxygenation in organ transplantation (such as liver, kidney, heart, etc.). The ischemia-reperfusion injury syndrome is a very important problem. Much damage in organs appears to be induced by reperfusion injury syndrome. In fact, not only immunological etiopathogenesis but also biochemically-mediated microcirculation alterations can modulate the organ damage induced by ischemia-reperfusion injury during organ transplantation. During ischemia-reperfusion injury, xanthine oxidase activity, the increase in oxygen free-radicals, and the activation of neuthrophils are all very important. Platelet activating factor (PAT) and LTB4 (promoting neuthrophils adhesiveness), activated by the xanthine oxidase-derived oxidants during reperfusion, activates the final post-ischemia injury. Much research is necessary in order to gain a fuller knowledge of the microcirculation conditions and oxygenation during organ transplantation.

The effects of weight loss due to gastric banding and lifestyle modification on red blood cell aggregation and deformability in severe obese subjects

Objective:To investigate the changes in the aggregation index (AI) and the elongation index (EI), in severe obese subjects (MbObS) undergoing laparoscopic adjustable gastric banding (LAGB). AI and EI are measured by Laser assisted Optical Rotational Red Cell Analyzer (LORCA) and are markers of erythrocyte aggregation and deformability, respectively.Design and subjects:Before, 3 and 6 months after LAGB plus lifestyle changes (Mediterranean diet plus daily moderate exercise), we evaluated AI, EI, body mass index (BMI), total (ToT) cholesterol (Chol), high-density lipoprotein (HDL)-Chol, low-density lipoprotein (LDL)-Chol, triglycerides and fasting glucose and insulin levels in 20 MbObS. The Students t-test was used for comparisons between independent groups and the analysis of variance to assess differences in AI and EI at the 3 time points. Pearsons correlation coefficient was used to assess correlation among continuous variables and multiple linear regression analysis to assess predictive factors for AI and EI changes.Results:BMI and all blood parameters showed a statistically significant decline 3 and 6 months after LAGB as compared with basal, except for EI and HDL-Chol that significantly increased. Stepwise selection of predictors shows that at 3 and 6 months, EI values depended on HDL-Chol values at the same time point. In the EI model, blood glucose was also statistically significant at 6 months.Conclusion:Our data show a significant improvement in EI after LAGB-induced weight loss, which correlates with an improved lipid pattern and support the idea that the rapid weight loss induced by LAGB plus lifestyle changes might reduce the thromboembolic risk and the high mortality risk found in MbObS.

Alteration of Brain Oxygenation During “Piggy Back” Liver Transplantation

Relevant changes in cerebral circulation occur during “Piggy Back” liver transplantation. Particularly at the washout-reperfusion time the cerebral perfusion suddenly changes from its lowest to its highest values. Further investigation is required to evaluate whether patients with the greatest change in cerebral oxygenation at this time point will suffer neurological complications after transplantation.

Solid papillary neoplasm of the pancreas: a case report.

Solid pseudopapillary neoplasm of the pancreas, solid and cystic, is a rare disease compared to ductal adenocarcinoma. The tumor most often affects women of African race aged in their twenties or thirties. We report the case of a 48-year-old man affected by solid pseudopapillary neoplasm of the pancreas treated by distal splenopancreasec-tomy. The patient was discharged on the 10th postoperative day in good general condition, feeling normal and with blood chemistry values within normal limits. The main characteristic differentiating papillary tumors of the pancreas from ductal adenocarcinoma is that in the latter case surgical eradication is a definitive solution and no other treatment is required, as confirmed by our case and those reported in the literature.

Post ischemic no-reflow after 60 minutes hepatic warm ischemia in pigs

Prolonged liver ischemia is a frequently required condition in liver surgery. During major resection for cancer or in cases of severe trauma, it may be necessary to interrupt blood inflow or outflow, by clamping the pedicle of Glissons capsule (Pringles maneuver), or even resorting to total vascular exclusion, by clamping the supra and subhepatic inferior vena cava, to limit intraoperative blood loss. Although it is universally acknowledged that the organ can tolerate prolonged ischemia for a period of up to 60 minutes, the anatomical and functional variations of the liver parenchyma inevitably induced by the procedure are receiving ever greater attention. Ischemia-reperfusion damage is also an essential factor during liver transplant and the degree of damage suffered will affect the functional efficiency of the graft. In the present experimental study, the alterations of the liver microcirculation induced by warm ischemia lasting 60 minutes were studied by continuous measurement of the microcirculation with an intraparenchymal probe (Periflux).

Effects of preservation solutions on blood

Celsior solution does not aggregate erythrocytes, whereas Wisconsin solution massively does. This feature could make CS preferable to UW during organ procurement.