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Aims/hypothesis. Adipose tissue expresses some bioactive molecules, which may be involved in the development of obesity-associated metabolic disorders and cardiovascular diseases. Vascular endothelial growth factor (VEGF) an important angiogenic factor is implicated in normal and pathological vessel formation. The aim of this study is to investigate clinically the association between blood serum VEGF concentrations and body fat accumulation as well as distribution. The study also aims to show the effect of serum VEGF protein on gene expression of transcriptional factor E26 transformation-specific-1 (Ets-1) and matrix metalloproteinase (MMP)-3. Methods. Serum VEGF concentrations were measured in 38 overweight or obese subjects. Fat distribution in the abdominal subcutaneous as well as visceral fat areas was assessed by computed tomography scans at umbilical level. Furthermore, the changes of serum VEGF concentrations following body weight reduction therapy were analyzed in eight subjects recruited from the original pool of subjects. Semi-purified circulating VEGF proteins were obtained by heparin-sepharose and its biological activities were shown to alter gene expressions in human aortic endothelial cells. Results. Serum VEGF concentrations were positively correlated with BMI (r=0.433, p=0.007) and visceral fat area (r=0.488, p=0.002). Stepwise regression analysis showed the visceral fat area as the most important determinant factor for VEGF circulating levels. Following body weight reduction therapy, VEGF concentrations as well as visceral fat area were decreased. The serum semi-purified VEGF protein enhanced expressions of Ets-1 and MMP-3 in human aortic endothelial cells. Conclusion/interpretation. Increased serum VEGF concentrations associated with visceral fat accumulation could influence vascular endothelial function. [Diabetologia (2003[Diabetologia ( ) 46:1483[Diabetologia ( -1488 Keywords Adipose tissue, vascular endothelial growth factor, body fat distribution, diet therapy, computed tomography. Corresponding author: Dr. K. Takahashi, Department of Clinical Cell Biology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-0856, Japan E-mail: kazuot@intmed02.m.chiba-u.ac.jp Abbreviations: PAI-1, plasminogen activator inhibitor-1; IL-6, interleukin-6; VEGF, vascular endothelial growth factor; HAEC, human aortic endothelial cells; FBS, fetal bovine serum; MMP-3, matrix metalloproteinase-3; ETS-1, E26 transformation-specific-1; HOMA, homeostasis model assessment for insulin resistance.

Recently, environmental chemicals have appeared in daily human life, and these chemicals have been incidentally taken in by humans. The serum concentrations of some of these chemicals have been found to be associated with the onset and incidence rate of diabetes mellitus. It has been suggested that one of the environmental chemicals, bisphenol A (BPA), has hormone-like activity. It has also been demonstrated that some hormones affect insulin resistance and fat distribution in the body. To study the effects of these environmental chemicals on glucose metabolism, the effect of BPA on glucose transport in mouse 3T3-F442A adipocytes was investigated. The 3T3-F442A adipocytes were incubated with various concentrations of BPA in a medium. Deoxyglucose uptake assay was performed with and without insulin. Immunoblot analysis was performed with a glucose transporter (GLUT) 4-specific antibody and antiphosphotyrosine antibody. The BPA treatment enhanced basal and insulin-stimulated glucose uptake, and caused an increased amount of GLUT4 protein. Thus, the enhanced glucose uptake resulting from the BPA treatment was at least partially due to the increased amount of GLUT4. Tyrosine phosphorylation of insulin receptor substrate-1 with insulin stimulation was not significantly affected. In conclusion, it was demonstrated that BPA, one of the chemicals that we intake incidentally, affects the glucose transport in adipocytes, and also that the environmental chemicals may be identified as one of the environmental factors that affect diabetes and obesity.

We conclude that GADab(+) non-insulin-deficient patients differ from GADab(+) patients with insulin deficiency with respect to clinical characteristics, humoral autoimmunity to other organ-specific autoantibodies, as well as HLA class II genes.

To examine the prevalence of abnormalities in the insulin receptor structure gene in Japanese with non-insulin-dependent diabetes mellitus (NIDDM), a population of 51 patients with NIDDM was screened for mutations in this gene. Patient genomic DNAs of both alleles corresponding to 22 exons of the gene were amplified by polymerase chain reaction (PCR). The PCR products on pUC19 were sequenced. Three patients with heterozygous missense mutation Thr831-->Ala831 in exon 13 and one patient with heterozygous missense mutation Tyr1334-->Cys1334 in exon 22 of the beta-subunits were identified. Linkage analysis of one of the families plus statistical studies showed that the mutation Thr831-->Ala831 is possibly responsible for the onset of NIDDM. In COS cells transiently expressing both mutant receptor cDNAs and a cDNA of a M(r) 85,000 regulatory subunit of phosphatidylinositol 3-kinase (PI 3-kinase), the mutation Tyr1334-->Cys1334 impaired binding of the receptor with the M(r) 85,000 subunit of PI 3-kinase, but linkage analysis of the family showed that the mutation did not cosegregate with NIDDM in the pedigree. Therefore, one missense mutation (Thr831-->Ala831) in the insulin receptor, as found in three patients, is possibly involved in the etiology of a subset of the 51 NIDDM patients.