Comparison of coronary heart disease risk among four diagnostic definitions of metabolic syndrome.

PURPOSE: Metabolic syndrome (MetS) is now well known as one of the major risk factors for coronary heart disease (CHD). Currently, there are several methods used to define MetS. The aim of this study was to determine to what extent current MetS definition reflects CHD risk using the probability of CHD in 10 years based on Framingham risk score algorithms. METHODS: A total of 7575 adults, aged 16-93 years (2532 men and 5043 women), were recruited. We conducted a cross-sectional health survey in China using MetS criteria from four different definitions: modified National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III), International Diabetes Federation (IDF), Chinese and Japanese. RESULTS: Differences in the prevalence of MetS by each definition were small in males (22.9-25.9 %), whereas in females, MetS was three times more prevalent using the IDF definition (29.1 %) versus the Japanese definition (9.7 %). Framingham risk scores in participants with MetS were significantly higher than in those without MetS by all definition criteria (p < 0.001). The CHD risk scores for participants with MetS by each definition showed similar values in males (range 11.5-12.1 %) with no significant differences among definitions. Conversely, in females with MetS the risk score for CHD was low (range 3.5-4.3 %) by each MetS definition. CONCLUSIONS: These findings suggest that further studies are required to establish appropriate criteria of MetS in females.

Search for type 2 diabetes susceptibility genes on chromosomes 1q, 3q and 12q.

To systematically evaluate genetic susceptibility to type 2 diabetes (T2D) in "candidate" regions on chromosomes 1q, 3q and 12q, we examined disease association by using a total of 2,083 SNPs in two-step screening; a screening panel comprised 473 cases and 285 controls and an extended (or combined) panel involved 658 cases and 474 controls. For the total interval screened (40.9 Mb), suggestive evidence of association was provided for several annotated gene loci. For example, in the MCF2L2 gene on 3q, a significant association (a nominal P value of 0.00009) was observed when logistic regression analysis was performed for three associated SNPs (rs684846, rs35069869 and rs35368790) that belonged to different LD groups. Also, in the SLC15A4 gene on 12q, rs3765108 showed a marginally significant association with an overall estimated odds ratio of 0.79 (P=0.001). No significant association was found for known candidate gene loci on 3q, such as ADIPOQ and IGF2BP2. Using the available samples, we have observed disease associations of SNPs derived from two novel gene loci in the Japanese population through high-density searches of diabetes susceptibility in three chromosomal regions. Independent replication will clarify the etiological relevance of these genomic loci to T2D.

Search of type 2 diabetes susceptibility gene on chromosome 20q.

Significant evidence of linkage to type 2 diabetes (T2D) has been shown in a relatively broad region on chromosome 20q, where the hepatocyte nuclear factor-4alpha (HNF4A) has been noted as a positional candidate. To systematically evaluate genetic susceptibility to T2D in the relevant region, we examined the disease association by using 1145 SNPs in two-step screening in the Japanese population. The marker screening enabled us to identify significant disease association in the lipopolysaccharide binding protein (LBP) but not in the HNF4A locus. In a 17.7-Mb interval screened, the strongest association was identified for a SNP, rs2232592, located in the intron of LBP, with an estimated odds ratio of 1.73 (95% CI 1.30-2.31) (P=0.0002) in the whole study panel involving 675 case and 474 control subjects. Our data suggest that the LBP gene may confer genetic susceptibility to T2D and this warrants further replication study.

A low-affinity Ca2+-dependent association of calmodulin with the Rab3A effector domain inversely correlates with insulin exocytosis.

The stimulus-response coupling pathway for glucose-regulated insulin secretion has implicated a rise in cytosolic [Ca2+]i as a key factor to induce insulin exocytosis. However, it is unclear how elevated [Ca2+]i communicates with the pancreatic beta-cell's exocytotic apparatus. As Rab3A is a model protein involved in regulated exocytosis, we have focused on its role in regulating insulin exocytosis. By using a photoactivatable cross-linking synthetic peptide that mimics the effector domain of Rab3A and microsequence analysis, we found calmodulin to be a major Rab3A target effector protein in pancreatic beta-cells. Coimmunoprecipitation analysis from pancreatic islets confirmed a Rab3A-calmodulin interaction in vivo, and that it inversely correlated with insulin exocytosis. Calmodulin affected neither GTPase nor guanine nucleotide exchange activity of Rab3A. The calmodulin-Rab3A interaction was pH- and Ca2+-dependent, and it was preferential for GTP-bound Rab3A. However, Rab3A affinity for calmodulin was relatively low (Kd = 18-22 micromol/l at 10(-5) mol/l [Ca2+]) and competed by other calmodulin-binding proteins that had higher affinity (e.g., Ca2+/calmodulin-dependent protein kinase-2 [CaMK-2] [Kd = 300-400 nmol/l at 10(-5) mol/l [Ca2+]]). Moreover, the Ca2+ dependence of the calmodulin-Rab3A interaction (K0.5 = 15-18 micromol/l [Ca2+], maximal at 100 micromol/l [Ca2+]) was significantly lower compared with that of the calmodulin-CaMK-2 association (K0.5 = 40 micromol/l [Ca2+], maximal at 1 mmol/l [Ca2+]). The data suggested that a transient Rab3A-calmodulin interaction might represent a means of directing calmodulin to the cytoplasmic face of a beta-granule, where it can be subsequently transferred for activation of other beta-granule-associated calmodulin-binding proteins as local [Ca2+]i rises to promote insulin exocytosis.

Free fatty acid-induced inhibition of glucose and insulin-like growth factor I-induced deoxyribonucleic acid synthesis in the pancreatic beta-cell line INS-1.

Pancreatic beta-cell mitogenesis is increased by insulin-like growth factor I (IGF-I) in a glucose-dependent manner. In this study it was found that alternative beta-cell nutrient fuels to glucose, pyruvate, and glutamine/leucine independently induced and provided a platform for IGF-I to induce INS-1 cell DNA synthesis in the absence of serum. In contrast, long chain FFA (>/=C(12)) inhibited 15 mM glucose-induced [(3)H]thymidine incorporation (+/-10 nM IGF-I) by 95% or more within 24 h above 0.2 mM FFA complexed to 1% BSA (K(0.5) for palmitate/1% BSA = 65-85 microM for 24 h; t(0.5) for 0.2 mM palmitate/1% BSA = approximately 6 h). FFA-mediated inhibition of glucose/IGF-I-induced ss-cell DNA synthesis was reversible, and FFA oxidation did not appear to be required, nor did FFA interfere with glucose metabolism in INS-1 cells. An examination of mitogenic signal transduction pathways in INS-1 cells revealed that glucose/IGF-I induction of early signaling elements in SH2-containing protein (Shc)- and insulin receptor substrate-1/2-mediated pathways leading to downstream mitogen-activated protein kinase and phosphoinositol 3'-kinase activation, were unaffected by FFA. However, glucose-/IGF-I-induced activation of protein kinase B (PKB) was significantly inhibited, and protein kinase Czeta was chronically activated by FFA. It is possible that FFA-mediated inhibition of ss-cell mitogenesis contributes to the reduction of beta-cell mass and the subsequent failure to compensate for peripheral insulin resistance in vivo that is key to the pathogenesis of obesity-linked diabetes.

In situ characterization of islets in diabetes with a mitochondrial DNA mutation at nucleotide position 3243.

Changes in the pancreas of diabetic patients with the A-to-G mitochondrial DNA (mtDNA) mutation at nucleotide position 3243 base pair (bp) have not previously been described. The clinical phenotypes of diabetes associated with the mtDNA 3243 mutation range from NIDDM to IDDM. We sought the presence of the mutation and studied volume of beta-, alpha-, and delta-cells, mitochondrial enzyme activity, and presence of apoptosis in diabetic pancreases obtained at autopsy. Pancreases were obtained from 16 patients with IDDM, from 18 patients with NIDDM, and from 11 nondiabetic patients. Mitochondrial enzyme activity was determined for cytochrome c oxidase (COX), the subunits of which are partially encoded by mtDNA, and for succinate dehydrogenase (SDH), the subunits of which are solely encoded by nuclear DNA. The volumes of islet beta-, alpha-, and delta-cells were estimated by computerized morphometry. Pancreatic cells were examined for apoptosis by an in situ end-labeling procedure. The mtDNA 3243 mutation was detected in 1 of 16 (6%) pancreases from the IDDM patients; none of the pancreases from 18 NIDDM patients and 11 nondiabetic patients had the mutation. The single patient with the mtDNA 3243 mutation was a 56-year-old woman with IDDM, aged 39 years at diabetes onset, whose mother was diagnosed with NIDDM. The patient had a history of secondary failure of oral hypoglycemic agents and had a marked decrease in the number of beta-cells. The islet beta-cells and non-beta-cells of the patient showed extremely decreased COX enzyme activity. The islet cells in the patient showed a high activity when examined for SDH. Some pancreatic exocrine cells also showed decreased COX activity with high SDH activity. In IDDM, NIDDM, and nondiabetic patients without the mtDNA 3243 mutation, only weak staining for SDH of the islet cells showed. The percentage of heteroplasmy of the mtDNA 3243 mutation in pancreatic micropunched islet specimens was 63 +/- 5% (mean +/- SD) in the islets, 32 +/- 3% in the exocrine pancreas, and 8 +/- 1% in peripheral polymorphonuclear cells. Apoptotic cells were not observed in the IDDM pancreas in the patient with the mtDNA 3243 mutation. The fact that higher levels of mutated mtDNA at 3243 bp were found in affected islets rather than in other tissue suggests that the distribution of the mutant may determine the effect on islet function. A characteristic decrease in the mitochondrial enzyme with COX activity and accelerated SDH activity of the affected islets may provide new insights into the pathogenesis of mitochondrial diabetes.

Apolipoprotein E in progressive supranuclear palsy in Japan.

Progressive supranuclear palsy (PSP) is a rare neurodegenerative disease which shows several psychiatric and neurologic symptoms: pseudobulbar palsy, supranuclear ocular palsy, extrapyramidal rigidity, gait ataxia, and dementia. Almost all cases seem to be sporadic; therefore, the elucidation of risk factors is important to clarify the pathological mechanism. Apolipoprotein E4 (ApoE4) is now well established as a risk factor of Alzheimer's disease (AD). Here we report the ApoE allele frequency in PSP, which shares pathological findings such as neurofibrillary tangle (NFT) with AD. NFT is an important sign for the derangement of normal cytoskeletons in degenerating neurons. Although there was no significant increase in epsilon 4 allele frequency in the present series of PSP cases compared with that in the Japanese controls, there was a significant increase in the epsilon 2 allele frequency in PSP compared to controls.

Relationship between insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus: beta-cell function, islet cell antibody, and haptoglobin in parents of IDDM patients.

To examine the relationship between non-insulin-dependent diabetes mellitus (NIDDM) and insulin-dependent diabetes mellitus (IDDM), we studied beta-cell function, HLA type, and serologic markers of IDDM and NIDDM in the parents of IDDM patients. Fifty-two parents of 33 IDDM patients were examined in terms of islet-cell antibody (ICA) status, haptoglobin phenotype, HLA type, and insulin responses during an oral glucose tolerance test (OGTT). Twenty-seven parents were prospectively evaluated for up to 113 months. They were divided into the following three groups based on pattern of ICA positivity during the follow-up period: group 1, persistently positive ICA (n = 4); group 2, fluctuating ICA (n = 7); and group 3, persistently negative ICA (n = 16). Twenty-three percent (12 of 52) of the parents of IDDM patients had NIDDM, and 12% (six of 52) of the matched controls did. The prevalence of ICA in the parents (11 of 52, 21%) was greater than in normal controls (one of 112, P < .01). Diabetic parents tended to show a higher prevalence of ICA (six of 12, 50%) than nondiabetic parents (six of 40, 15%; P = .06). ICA-positive parents showed higher glucose levels and lower insulin responses than ICA-negative parents. Three of four parents in group 1 slowly progressed to an insulin-dependent state during 25 +/- 3 months of follow-up evaluation. Parents in group 2 and group 3 did not show any changes in glucose levels or insulin responses during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Marked islet amyloid polypeptide-positive amyloid deposition: a possible cause of severely insulin-deficient diabetes mellitus with atrophied exocrine pancreas.

An insulin-deficient 51-year-old man was put on dietary therapy and sulfonylurea (SU). Although there was good glycemic control for 2 years, the fasting blood glucose (FBG) level increased gradually over the subsequent 4-year period, and there was a marked increase in body weight. Secondary failure of SU therapy 20 years after the initial diagnosis led to insulin therapy. The FBG became unstable, and the C-peptide response disappeared. The patient died of nonketotic hyperosmolar coma and pneumonia at the age of 87. At autopsy, the pancreas showed marked atrophy (32 g) with extensive fatty degeneration. Islets replaced by islet amyloid polypeptide (IAPP)-positive amyloid (IAPP-AM) amounted to 77% in the tail, 74% in the body, and 73% in the head of the pancreas. All islets were positive for IAPP-AM throughout the pancreas, except for a pancreatic polypeptide-rich lobe, where none were positive. IAPP-AM-positive islets had also undergone fatty change of the surrounding pancreatic acinar cells. beta-Cells decreased remarkably in number and were displaced to the periphery of the islets by the IAPP-AM deposits. These findings suggest that IAPP-related diabetes could have a progressive course, with secondary oral hypoglycemic agent failure and the subsequent development of severe insulin deficiency similar to that seen in insulin-dependent diabetes mellitus.

Immunogenetic and clinical characterization of slowly progressive IDDM.

OBJECTIVE: To examine the clinical and immunogenetic heterogeneity of IDDM. RESEARCH DESIGN AND METHODS: We divided 207 IDDM patients into groups based on the interval from clinical onset to initiation of insulin therapy: group A (< 3 mo, acute clinical-onset group, n = 134), group B (3-12 mo, intermediate group, n = 31), and group C (> or = 13 mo, slowly progressive group, n = 42). Immunogenetic and clinical markers were compared between group A and group C. RESULTS: The mode age of onset was higher in group C (52 yr) than group A (10 yr). Group C had a higher prevalence of islet cell antibodies (42.9%, 18 of 42) than group A (25.4%, 34 of 134, P = 0.05). Serum C-peptide immunoreactivity assayed by radioimmunoassay in response to a 100-g oral glucose tolerance test was significantly higher in group C than in group A. Group C patients were also more likely to have a family history of NIDDM (26.1%, 11 of 42) among their first-degree relatives than group A patients (11.2%, 15 of 134, P = 0.039). The prevalences of family history of IDDM and endocrine autoimmune diseases were not different between groups C and A. The frequency of complications of endocrine autoimmune disease was not different between group A (6.7%, 9 of 134) and group C (2.3%, 1 of 42). Significant associations with two class I major histocompatibility complex antigens (HLA-A24 and -Bw54) and one class II antigen (HLA-DR4) were observed in group A. Group A patients were associated with three diabetogenic HLA-DQ haplotypes including DQA1*0301-DQB1*0401, DQA1*0301-DQB1*0302, and DQA1*0301-DQB1*0303. In contrast, group C lacked the association with class I antigens, although HLA-DR4 and HLA-DQA1*0301-DQB1*0401 were more common in this group than in control subjects. CONCLUSIONS: These results indicate that the clinical subtype with slowly progressive course (slowly progressive IDDM) has distinct findings including late-age onset, high prevalence of islet cell antibodies, preserved beta-cell function, and high family history of NIDDM. An additive effect of class I and class II major histocompatibility complex antigens is suggested as an explanation for the acute clinical manifestations and more severe beta-cell destruction in group A patients.

Islet amyloid polypeptide (IAPP) gene analysis in a Japanese diabetic with marked islet amyloid deposition.

Islet amyloid polypeptide (IAPP) is a major constituent of pancreatic amyloid deposits in many patients with non-insulin-dependent diabetes mellitus (NIDDM). We analyzed the IAPP gene in a Japanese diabetic with marked islet amyloid deposition. Pancreatic specimens were obtained from an 87-year-old NIDDM patient who had had diabetes for 37 years. All islets (100/100) in his pancreas had IAPP-positive amyloid deposition, and 70% of the area of the islet was replaced by amyloid. We amplified the coding regions as well as the upstream region of the IAPP gene by polymerase chain reaction (PCR). The products of PCR were sequenced, and the sequences of the coding regions were identical to the Caucasian ones. However, the nucleotides of two positions of 5'-upstream and one position of intron 2 were different from the Caucasian data: the upstream region of the IAPP gene in the patient had cytosine substituted for thymine at -259, and had two alleles including cytosine and adenine at -229, respectively. The nucleotide of position 539, that is guanine, was deleted. A possible difference in the IAPP promoting region between the Japanese and Caucasian population was suggested.

Overexpression of glucose transporter modulates insulin biosynthesis in insulin producing cell line.

Glucose transporter (GT) has been suggested to be involved in the insulin biosynthesis. However, the functional relationship between GT and insulin biosynthesis is not well understood. In this report, we have generated rat pancreatic B cell lines (RINr) that stably overexpress a cDNA encoding the brain type GT. These cell lines showed 3- to 4-fold increase in insulin mRNA and protein. These results suggest that GT might have some relationship to the insulin biosynthesis in the pancreatic B cells.

Pancreatic cytokeratin: an antigen of pancreatic exocrine cell autoantibodies in type 1 (insulin-dependent) diabetes mellitus.

Autoantibodies reacting with human pancreatic exocrine cells were investigated by immunofluorescent techniques in 107 patients with Type 1 (insulin-dependent) diabetes mellitus, 20 first-degree relatives of the Type 1 diabetic patients, 347 patients with Type 2 (non-insulin-dependent) diabetes, 34 with alcoholic pancreatitis, 26 with rheumatoid arthritis and 107 normal control subjects. Both immunoblotting analysis and double-immunostaining methods were used to characterize the antigens targeted by the pancreatic exocrine cell autoantibodies. Sera positive for human pancreatic exocrine cell cytoplasm, producing a "fine fibrillar" pattern, were found in 21% (23/107) of the Type 1 diabetic patients. The autoantibodies were present in 39% (15/38) of Type 1 diabetic patients diagnosed within 3 months, and the prevalence decreased with duration of diabetes. The antibodies were of the IgM class in 87% (13/15) of recent-onset Type 1 diabetes cases, but IgG-autoantibodies became more prevalent with increasing duration of diabetes. Three out of 347 (0.9%) Type 2 diabetic patients and 4 of 20 (20%) first-degree relatives of Type 1 diabetic patients had autoantibodies targeted against pancreatic exocrine cells. None of the patients with alcoholic pancreatitis or rheumatoid arthritis and none of the control subjects had these antibodies. Immunoblotting analysis and double-immunostaining demonstrated that the autoantibodies reacted with 40 kilodalton cytokeratin in pancreatic exocrine cell cytoplasm. The antibody was absorbed by the Triton X-100-insoluble fraction of pancreatic extract. These results indicate the presence of distinct autoantibodies to pancreatic exocrine cells in Type 1 diabetes. This suggests the provocative concept that the cytoskeletal system of pancreatic exocrine cells is involved in the pathogenetic process of Type 1 diabetes.