Circulating and adipose tissue gene expression of zinc-alpha2-glycoprotein in obesity: its relationship with adipokine and lipolytic gene markers in subcutaneous and visceral fat

CONTEXT

Zinc-alpha2-glycoprotein (ZAG) is a soluble protein similar to the class I major histocompatibility complex heavy chain, which has been implicated in lipid catabolism. We hypothesized that ZAG mRNA expression in adipose tissue may be linked with lipolytic and adipokine gene expression and have a close relationship with clinical phenotype.

OBJECTIVES

The objective of the study was to analyze ZAG gene expression in human adipose tissue from lean and obese subjects. ZAG circulating plasma levels and its relationship with cardiometabolic risk factors were also studied.

DESIGN

Seventy-three Caucasian (43 male and 30 female) subjects were included. Plasma and adipose tissue [sc (SAT) and visceral (VAT)] from the same patient were studied. mRNA of PPARgamma, hormone-sensitive lipase (HSL), adipose triglyceride lipase, adiponectin, omentin, visfatin, and ZAG were quantified. Plasma concentrations of ZAG were determined with ELISA.

RESULTS

ZAG plasma levels showed a negative correlation with insulin (r = -0.39; P = 0.008) and the homeostasis model assessment for insulin resistance index (r = -0.36; P = 0.016). No differences in ZAG circulating levels according to body mass index classification were observed. ZAG expression in SAT was significantly reduced in overweight and obese individuals compared with lean subjects (P < 0.001 and P = 0.007, respectively). ZAG mRNA expression in both SAT and VAT depots were negatively correlated with many clinical and metabolic cardiovascular risk factors. After multiple linear regression analysis, SAT ZAG was mainly predicted by adiponectin mRNA expression (B = 0.993; P < 0.0001) and plasma triglyceride levels (B = -0.565; P = 0.006). VAT ZAG expression was predicted by adiponectin expression (B = 0.449; P < 0.0001), and HSL VAT expression (B = 0.180; P = 0.023).

CONCLUSIONS

The present study provides evidence of a role of ZAG gene in adipose tissue metabolism, with a close association with adiponectin gene expression in sc and visceral fat.

Follow-up study of the revascularization process of cryopreserved islets of Langerhans

Cryopreservation of islets of Langerhans is a necessary procedure since human pancreatic islet transplantation has become a reality for the clinical treatment of Type I, insulin-dependent diabetes mellitus. Although successful cryopreservation of rodent and human islets is a well-established technique for islet storage after isolation and purification, little is known about the influence of the freeze-thaw procedure on the islets' potential to induce angiogenesis and revascularization, a major process necessary for the viability of grafted cells. In this study, the revascularization process of cryopreserved islets transplanted in the liver and in the renal subcapsular space of diabetic and nondiabetic rats is analyzed by a double indirect immunofluorescence technique. Frozen-thawed pancreatic islets were cooled slowly to -40 degrees C, stored at -196 degrees C, and thawed rapidly. Lewis rat were grafted with either Lewis (isografts) or Wistar (allografts) overnight-cultured and frozen-thawed islets obtained by collagenase digestion. Rats were killed different days after implantation, and the livers and kidneys bearing the grafted islets were snap-frozen and immunohistochemically stained with a double immunofluorescence technique using a rabbit anti-factor VIII antiserum (which labels endothelial cells) and a guinea pig anti-insulin antibody. Overnight-cultured islet grafts completed revascularization by Days 4-7 after transplantation, as shown by the detection of endothelial cells within and surrounding the islets. The identical staining pattern of revascularization was observed in islets frozen-thawed before transplantation. It is concluded that islet cryopreservation is a suitable technique for long-term storage prior to transplantation since it does not interfere with the neovascularization process of islet grafts.

Quality of life after successful pancreas-kidney transplantation

Quality of life assessment has emerged as an important approach to evaluate the effect of pancreas transplantation in diabetic patients with end-stage renal failure (ESRD). The aim of this study was to evaluate the impact of the ESRD treatment modality on the quality of life in patients with Type I (insulin-dependent) diabetes mellitus. Thirty-two patients of similar age, sex and diabetes duration, treated for more than 1 year with simultaneous kidney and pancreas transplantation (Group 1, n = 12), or kidney transplantation (Group 2, n = 10), or hemodialysis (Group 3, n = 10) were studied. Quality of life was assessed using a questionnaire (34 questions with 103 possible answers) including social (sickness pension, working capacity) and subjective (general health perception), index of Spizer and index of reintegration to normal life of Wood Dauphine) quality of life indicators, working capacity, as well as physical ability (Karnofsky index), sports training and sexual activity. Patients in Group 1 showed highest scores on general health perception (p = 0.012), Karnofsky index (p = 0.076) and sexual activity (p = 0.026). There were no significant differences between groups on social index, as well as index of Spizer, index of reintegration to normal life and sport activity. Patients on hemodialysis treatment presented the lowest scores in all the items evaluated. In conclusion, in our experience simultaneous pancreas and kidney transplantation is the treatment modality that offers better quality of life to diabetic patients with ESRD; however, this does not translate into a higher socio-labor yield.

Natural history of islet cell antibodies during the clinical period of type 1 diabetes. High titres at diagnosis are associated with longer persistence

The natural history of islet cell antibodies (ICA), using standardized Juvenile Diabetes Foundation (JDF) units, was studied for two years in 64 type 1 (insulin dependent) diabetic patients, aged 7-45 years prospectively from clinical onset. While ICA were present among 44/64 (68.8%) of the newly diagnosed patients, only 9.3% remained positive at 24 months. The only factor which showed significant predictive value for ICA survival was high initial JDF ICA titres: Maximal persistence of ICA was observed in patients with 80 JDF units at diagnosis (100% at 12 and 24 month). This persistence was lower in patients with 40 JDF units at diagnosis (77% at 12 month, 40% at 24 month) and the lowest for patients with 5 JDF at diagnosis (14% at 12 month, 0% at 15 month). 14/20 (70%) of patients negative for the ICA test at diagnosis became positive during follow-up, but always with a low titre (5-10 JDF units) and for a short period (3-6 months). It is concluded that initial titre is the most important variable in predicting the maintenance of ICA during the first two years of clinical type 1 diabetes.