Eiichi Imano

Oral Glucose Tolerance Test Predicts Prognosis of Patients with Liver Cirrhosis

OBJECTIVE:The aim of this study was to evaluate whether oral glucose tolerance test (OGTT) was useful in evaluating the prognosis of patients with liver cirrhosis.METHODS:Fifty-six patients with liver cirrhosis were enrolled in a prospective cohort study. In all cases, glucose tolerance was diagnosed by a 75-g OGTT according to World Health Organization (WHO) criteria. The relationship of clinical variables to the cirrhosis-related prognosis was investigated using univariate and multivariate regression models.RESULTS:Diabetes mellitus (DM) was diagnosed in 21 subjects (38%), impaired glucose tolerance (IGT) in 13 subjects (23%), and normal glucose tolerance (NGT) in 22 subjects (39%) using OGTT. The cumulative survival rates of patients with liver cirrhosis and NGT were 94.7% at 5 yr; liver cirrhosis and IGT, 68.8% at 5 yr; liver cirrhosis and DM, 56.6% at 5 yr. The survival rates of patients with liver cirrhosis and DM significantly differed from those with NGT. Univariate analysis demonstrated that serum albumin, total bilirubin, prothrombin activity, Child-Pugh scores, and glucose intolerance were highly significant prognostic factors. Multiple regression analysis yielded albumin and DM as the most powerful independent negative predictors of survival.CONCLUSIONS:OGTT appears to be useful for evaluating the prognosis of cirrhotic patients.

Heart rate elevation and diabetic retinopathy in patients with type 2 diabetes mellitus and normoalbuminuria

To investigate the role of heart rate (HR) and blood pressure (BP) for diabetic retinopathy, 24-h ambulatory HR and BP were monitored for 162 in patients with type 2 diabetes and normoalbuminuria. The fundus was assessed as no retinopathy, simple diabetic retinopathy (SDR) and proliferative retinopathy (PDR). Comparing the highest with the lowest quartile of diabetic duration, the relative risk for retinopathy was 9.3 and for nocturnal HR, it was 3.6. Comparison among three retinopathy groups (no retinopathy, group 1, n=122; SDR, group 2, n=24; Pre-PDR or PDR, group 3, n=16) showed that 24-h and nocturnal HR were significantly higher in group 3 (80+/-9 and 71+/-9 beats per min) than in group 2 (73+/-8 and 64+/-8) and group 1 (72+/-7 and 60+/-7). In multiple logistic analysis, the odds ratio of diabetic duration and nocturnal HR to the existence of retinopathy was 1.17 (95% CI, 1.10-1.25, P=0.00001) and 1.11 (95% CI, 1.05-1.17, P=0.0002). We concluded that diabetic retinopathy is related to diabetic duration and high heart rate in type 2 diabetes mellitus with normoalbuminuria. Heart rate elevation may be a predictor of advanced retinopathy.

Platelet activation in diabetic patients with asymptomatic atherosclerosis

We studied 27 non-insulin-dependent diabetics without apparent atherosclerosis (AS) to investigate whether abnormal platelet function is related to asymptomatic atherosclerosis in diabetes mellitus. The degree of AS was quantitatively evaluated by determining the intimal plus medial thickness (IMT) of the carotid artery wall with ultrasound high-resolution B-mode imaging. Based on our previous finding that the upper threshold of the IMT was 1.1 mm in healthy subjects, the patients were divided into the AS-positive group with the IMT > 1.1 mm, (n = 17) and the AS-negative group with the IMT < 1.1 mm (n = 10). Among five variables measured as the factors concerned with thrombogenesis, only plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) were significantly higher in the AS-positive group than in the AS-negative group. Chronic administration of pentoxifylline (300 mg/day) significantly reduced the abnormally high plasma levels of beta-TG and PF4 in 7 patients of the AS-positive group to normal levels, without lowering the normal plasma beta-TG and PF4 levels in the remaining 10 patients. Pentoxifylline treatment did not affect the plasma levels of the 3 other variables, von Willebrand factor, 6-keto prostaglandin F1 alpha and thromboxane B2. This study suggests that the progress of atherosclerosis in diabetes mellitus is associated with in vivo platelet activation and platelet activation does not occur in diabetics without carotid atherosclerosis. Pentoxifylline may impede the vicious cycle in which atherosclerosis is accelerated by platelet activation.

Pioglitazone-reduced insulin resistance in patient with Werner syndrome

Werner syndrome is a rare disorder that has provided a useful model for the study of human ageing. Patients with Werner syndrome usually display an aged appearance with various features including loss of hair, cataracts, atrophy of skin and peripheral fat, and diabetes. Mutations in the DNA helicase gene have been shown to be responsible for this disorder. One common feature of Werner syndrome is insulin resistance. However, as is the case in most patients with non-insulin-dependent diabetes mellitus (NIDDM), the precise mechanism underlying the disease is not known. As a step toward understanding the molecular mechanism of insulin resistance in Werner syndrome, we used pioglitazone, a new antidiabetic drug classified as a thiazolidinedione derivative, in a patient with Werner syndrome. Thiazolidinediones improve hyperglycaemia by enhancing insulin sensitivity without stimulating insulin secretion. These drugs have been shown to bind peroxisome proliferator-activated receptor (PPAR ), a dominant activator of fat-cell differentiation. This receptor is likely to mediate the antidiabetic effects of thiazolidinediones, since their affinity to PPAR correlates well with the strength of their effect as insulin sensitisers. A 53-year-old man with Werner syndrome was admitted for glycaemic control. The diagnosis was based on his clinical features and the reduced life-span of cultured fibroblasts. Although he was thin (body-mass index 14·2 kg/m) and had only a small amount of subcutaneous fat (%fat 4·9%), he had a moderate degree of insulin resistance as judged by the exogenous glucose infusion rate (GIR) during euglycaemic hyperinsulinaemic clamp (3·7 mg/kg per min, normal value 10·5 [SD 2·2]). His glycaemia was poorly controlled with a sulfonylurea agent, gliclazide. Written informed consent was obtained and the study was approved by the Institutional Ethical Committee. After 1 week of treatment by dietary restriction alone, pioglitazone 30 mg daily was initiated. After 12 weeks, the GIR had improved to 5·2 mg/kg per min (figure). This effect on the insulin sensitivity was similar to those observed in obese NIDDM patients; according to our data, the average GIR values for NIDDM patients (body-mass index 23 [SD 1·8]%, HbA1c 8·4 [1·4]%) before and after pioglitazone treatment was 8·2 [2·2] and 9·2 [2·0] mg/kg per min, respectively [p=0·003]; Kawamori R, Yamasaki Y, unpublished data). After 12 weeks of pioglitazone treatment, the patient’s fasting plasma glucose had decreased from 187 mg/dL (10·4 mmol/L) to 105 mg/dL (5·8 mmol/L) and glycated haemoglobin from 8·3% to 7·8%. All these glycaemic values deteriorated immediately after discontinuation of pioglitazone (figure). The fasting plasma insulin remained unchanged. These results suggest that pioglitazone was effective in ameliorating impaired insulin sensitivity and thus improved the glycaemic control in our patient. Recently, it was suggested that thiazolidinedione derivatives have direct effects on some tissues other than the adipose tissue, which has been considered to be the target organ of thiazolidinedione derivatives. Among the two isoforms of PPAR , PPAR 1, and PPAR 2, which can be activated to the same extent by a thiazolidinedione derivative, PPAR 1 (and maybe PPAR 2 also) seems to be weakly expressed in skeletal muscle. Also, a weak expression of PPAR 1 can be observed in liver, which seems to increase glucose uptake in response to pioglitazone. Thus, especially for this patient with Werner syndrome whose %fat was as low as 4·9%, the effects of pioglitazone on those non-adipose tissues may have had a role in improving the insulin sensitivity.

Effect of dexamethasone on the synthesis and degradation of' insulin receptor mRNA in cultured IM-9 cells

SummaryThe effect of glucocorticoid (dexamethasone) on insulin receptor mRNA was examined in the IM-9 cell line by dot hybridization analysis using insulin receptor c-DNA probe (phINSR 13-1). Insulin receptor mRNA was found in a dose- and time-dependent manner, to increase during a 24-h culture with glucocorticoid. Although there has been some dispute about the effect of glucocorticoid on degradation of the insulin receptor itself, we have found glucocorticoid had no significant effect on the degradation rate of insulin receptor mRNA. These results suggest that glucocorticoid has the effect of increasing de novo synthesis of insulin receptor mRNA. But the molecular mechanism of glucocorticoids effect still needs to be investigated.

Insulin absorption from conjunctiva studied in normal and diabetic dogs

Abstract— The dynamics of insulin absorption from the ocular conjunctiva of anaesthetized normal and pancreatectomized dogs have been examined. A porcine insulin preparation of 1000 units mL−1 (pH 8.0) was administered as either 1 or 10 units kg−1 to the upper conjunctival sacs of recumbent dogs following an overnight fast. Plasma insulin concentrations increased significantly at 5 min after the insulin administration. Plasma glucose concentrations decreased significantly, in both normal (given 10 units kg−1) and diabetic dogs (given 1 unit kg−1 or 10 units kg−1). There was a dose‐dependent increase in plasma insulin concentration following conjunctival administration. Estimated absorption was significantly higher in diabetic than in normal dogs.

Insulin resistance and endothelial dysfunction in type 2 diabetic patients with non‐alcoholic steatohepatitis

Diabetes 2008; 57: 1034–1042. 2 Colombo C, Porzio O, Liu M, Massa O, Vasta M, Salardi S et al. Seven mutations in the human insulin gene linked to permanent neonatal ⁄ infancy-onset diabetes mellitus. J Clin Invest 2008; 118: 2148–2156. 3 Aguilar-Bryan L, Bryan J. Neonatal diabetes mellitus. Endocr Rev 2008; 29: 265–269. 4 Flanagan SE, Patch AM, Mackay DJ, Edghill EL, Gloyn AL, Robinson D et al. Mutations in ATP-sensitive K+ channel genes cause transient neonatal diabetes and permanent diabetes in childhood or adulthood. Diabetes 2007; 56: 1930–1937. 5 Molven A, Ringdal M, Nordbø AM, Raeder H, Støy J, Lipkind GM et al. Mutations in the insulin gene can cause MODY and autoantibody-negative type 1 diabetes. Diabetes 2008; 57: 1131–1135. 6 Bonfanti R, Colombo C, Nocerino V, Massa O, Lampasona V, Iafusco D et al. Insulin gene mutations as a cause of diabetes in children negative for 5 type 1 diabetes autoantibodies. Diabetes Care 2009; 32: 123–125. 7 Kahn SE, D’Alessio DA, Schwartz MW, Fujimoto WY, Ensinck JW, Taborsky GJ Jr et al. Evidence of cosecretion of islet amyloid polypeptide and insulin by beta-cells. Diabetes 1990; 39: 634–638. 8 Lyttle BM, Li J, Krishnamurthy M, Fellows F, Wheeler MB, Goodyer CG et al. Transcription factor expression in the developing human fetal endocrine pancreas. Diabetologia 2008; 51: 1169–1180. 9 Gradwohl G, Dierich A, LeMeur M, Guillemot F. Neurogenin 3 is required for the development of the four endocrine cell lineages of the pancreas. Proc Natl Acad Sci USA 2000; 97: 1607–1611. 10 Wang J, Cortina G, Wu SV, Tran R, Cho JH, Tsai MJ et al. Mutant neurogenin-3 in congenital malabsorptive diarrhea. N Engl J Med 2006; 355: 270–280. 11 del Bosque-Plata L, Lin J, Horikawa Y, Schwarz PE, Cox NJ, Iwasaki N et al. Mutations in the coding region of the neurogenin 3 gene (NEUROG3) are not a common cause of maturity-onset diabetes of the young in Japanese subjects. Diabetes 2001; 50: 694–696. 12 Jensen JN, Hansen L, Ekstrøm CT, Pociot F, Nerup J, Hansen T et al. Polymorphisms in the neurogenin 3 gene (NEUROG) and their relation to altered insulin secretion and diabetes in the Danish Caucasian population. Diabetologia 2001; 44: 123–126.

Rapid screening method of abnormal insulin-receptor gene expression : allele-specific oligonucleotide hybridization by using silent polymorphisms

An asymmetrical reduction in the levels of the insulin receptor mRNA transcribed from one allele was reported in some patients with severe insulin resistance and non-insulin-dependent diabetes mellitus (NIDDM). To detect this abnormality, we designed the less laborious method; Allele-specific oligonucleotide hybridization of the amplified mRNA (cDNA) by using silent polymorphisms in the insulin receptor gene (nucleotide positions at 1686 and 1698). The allelic frequencies of C-1686 and T-1686 were 0.63 and 0.37, respectively (0.60 and 0.40 in 10 normal subjects, and 0.67 and 0.33 in 20 NIDDMs; n.s.). Similarly, the allelic frequencies of A-1698 and G-1698 were 0.47 and 0.53, respectively (0.50 and 0.50 in the normal subjects, and 0.45, and 0.55 in the NIDDMs; n.s.). These results suggest that these two polymorphisms are very common in Japanese. Nineteen (64%) out of 30 cases are heterozygous at one or two position(s), suggesting that it is possible to distinguish the mRNA transcribed from each of two alleles of the insulin receptor gene with using allele-specific oligonucleotide hybridization. Although we successfully measured the ratio of mRNA expression from two alleles of the gene in 20 NIDDMs, there was no patient whose mRNA transcribed from one allele of the insulin receptor gene was extremely decreased. We showed that allele-specific oligonucleotide hybridization method is useful for the screening of abnormal insulin-receptor gene expression.

5′-flanking DNA of the human insulin receptor gene and long terminal repeat of mouse mammary tumour virus bind to the same nuclear protein(s)

SummaryThe interaction of nuclear protein extracted from rat liver and 5′-flanking DNA of the human insulin receptor gene was investigated with the aid of gel mobility shift analysis. When 5′-flanking DNA (-1255/-1206 or -385/-345 base pairs) was incubated with nuclear protein, two or three 32P-DNA species (protein binding DNA fragment(s) and free DNA fragment) were detected. These bands did not disappear in spite of increasing amounts of synthetic poly(dI-dC), showing that nuclear protein binds specifically to 5′-flanking DNA of the insulin receptor gene. Increasing amounts of long terminal repeat of mouse mammary tumour virus resulted in a reciprocal decrease in nuclear protein binding to 5′-flanking DNA of insulin receptor gene. These results suggest that 5′-flanking DNA of insulin receptor gene binds to the same nuclear protein to which long terminal repeat of mouse mammary tumour binds.