Correlation of body muscle/fat ratio with insulin sensitivity using hyperinsulinemic-euglycemic clamp in treatment-naïve type 2 diabetes mellitus

AIMS

Fat deposition and obesity are crucial pathological components of diabetes mellitus (DM). In clinical practice, assessment of insulin resistance is important. We hypothesized that body muscle and fat composition might be a key factor for insulin resistance in patients with type 2 DM.

METHODS

Subjects included 61 untreated DM patients. Hyperinsulinemic-euglycemic clamp examination was performed to calculate the M/I value as the insulin resistance reference indicator. Elementary body composition was measured by impedance analysis using InBody770.

RESULTS

Simple regression analysis showed that total muscle quantity/total fat quantity ratio (muscle/fat) was significantly correlated with M/I value (B=0.806, P<0.001). The regression equation was M/I value=3.6934×(muscle/fat ratio)+0.0347 (R(2)=0.6503, P<0.001). Multivariate logistic regression analysis showed that muscle/fat ratio was independently and significantly associated with insulin resistance, defined by M/I value <9 (odds ratio, 0.89; 95% confidence interval, 0.80-0.99, P=0.04). With receiver operating curve analysis, the cutoff value of muscle/fat ratio for insulin resistance was 2.40 and area under the curve was 0.87 (sensitivity 91% and specificity 76%, P<0.001), indicating that muscle/fat ratio was significantly effective for predicting insulin resistance in treatment-naïve DM. The result could provide a possible estimation of the M/I value using the regression equation M/I value=2.5438×(muscle/fat ratio)+48.6194×QUICKI-13.6522 (R(2)=0.7012).

CONCLUSION

In treatment-naïve DM, the muscle/fat ratio, assessed by InBody770 is clinically useful for evaluating the presence of insulin resistance in daily clinical practice.

Combined arteriosclerotic assessment of ankle-brachial index and maximum intima-media thickness via CCTA is useful for predicting coronary artery stenosis in patients with type 2 diabetes

AIMS

Patients with diabetes mellitus (DM) are likely to develop asymptomatic myocardial infarction as a complication. However, coronary artery lesions are difficult to assess in internal medicine. This study aimed to develop a prediction formula for coronary artery stenosis, as determined by coronary computed tomographic angiography (CCTA), by analyzing risk factors in patients with type 2 DM.

METHODS

A prediction formula was developed based on a multivariate analysis of common factors in patients with ⩾50% coronary artery stenosis in a cohort of 327 patients with type 2 DM who underwent CCTA between 2007 and 2009, and cutoff values were calculated (derivation study). The validity of the optimal cutoff value was confirmed in a separate cohort of 317 patients with type 2 DM who underwent CCTA between 2010 and 2011 (validation study).

RESULTS

In the derivation study, five predictive factors (presence/absence of hypertension, estimated glomerular filtration rate, maximum intima-media thickness [max-IMT], ankle-brachial index [ABI], and use/nonuse of diabetic medication) were used to develop a prediction formula. In the validation study, positive predictive value (PPV) and negative predictive value (NPV) of the cutoff value derived from the prediction formula were 53% and 73%, respectively.

CONCLUSIONS

We developed a novel formula to predict coronary artery stenosis using five predictive factors. This formula is useful for determining whether computed tomography (CT) examination is necessary, even in clinical settings without CCTA equipment. Early detection of coronary artery stenosis in patients with DM may also lead to better health outcomes.

Quasicrystal as a Catalyst for the Synthesis of Carbon Nanotubes

The present report describes the catalytic activity of mechanically activated nano quasicrystalline Al65Cu20Fe15 and related nano crystalline Al50Cu28Fe22 for the synthesis of carbon nanotubes (CNTs). CNTs are synthesized by catalytic decomposition of ethanol through nano quasicrystalline Al65Cu20Fe15 and related crystalline Al50Cu28Fe22 alloys as a catalyst. The synthesized multi-walled CNTs exhibits tube diameter ranging from 5 to 25 nm. The synthesized CNTs are characterized by scanning and transmission electron microscopy. It is found that Al65Cu20Fe15 nanoquasicystal shows better catalytic behaviour as compared to nano-crystalline Al50Cu28Fe22 alloys for decomposition of ethanol during the synthesis of multi-walled CNTs.

A pilot study of ezetimibe vs. atorvastatin for improving peripheral microvascular endothelial function in stable patients with type 2 diabetes mellitus

BACKGROUND

Elevated cholesterol in type 2 diabetes mellitus (DM) can cause endothelial dysfunction. An effective clinical therapy to improve endothelial dysfunction remains to be established. Different cardiovascular actions between treatments for the inhibition of cholesterol absorption and the suppression of cholesterol synthesis for achieving improvement in endothelial function are unknown in DM.

METHODS

Stable patients with type 2 DM and mildly elevated low-density lipoprotein cholesterol were enrolled. We evaluated peripheral microvascular endothelial function using reactive hyperemia peripheral arterial tonometry (RH-PAT) examination and calculated a natural logarithmic transformed value for the RH-PAT index (LnRHI). We randomly assigned 33 patients to each monotherapy: cholesterol synthesis suppression using atorvastatin (5 mg/day, n=16) or cholesterol absorption inhibition using ezetimibe (10 mg/day, n=17). Patients were prospectively followed for 6 months. Serum lipids and LnRHI were repeatedly examined before and after each therapy.

RESULTS

LDL significantly decreased in both groups, but the percent changes of LDL showed a greater decrease in the atorvastatin group compared with the ezetimibe group (-34.5±7.8% vs. -21.9±9.6%, p<0.01). Serum levels of non-esterified free fatty acids (NEFA) significantly decreased in the ezetimibe group but not in the atorvastatin group (ezetimibe group: 561.1±236.8 to 429.7±195.9, p<0.01; atorvastatin group: 538.8±319.5 to 520.2±227.3, p=0.75). The percent decrease in NEFA was significantly greater in the ezetimibe group compared with the atorvastatin group (-19.9±27.4% vs. 11.3±44.1%, p<0.05). LnRHI showed a significant increase in the ezetimibe group but not in the atorvastatin group (ezetimibe group: 0.471±0.157 to 0.678±0.187, p<0.01; atorvastatin group: 0.552±0.084 to 0.558±0.202, p=0.64). The percent changes in LnRHI were significantly greater in the ezetimibe group compared with the atorvastatin group (63.3±89.2% vs. 7.4±41.2%, p<0.05).

CONCLUSIONS

In patients with type 2 DM, ezetimibe monotherapy significantly reduced LDL and NEFA, and improved peripheral microvascular endothelial dysfunction. Ezetimibe could potentially exhibit beneficial effects on lipid disorders and microvascular endothelial dysfunction in DM.

Liraglutide, a glucagon-like peptide-1 analog, increased insulin sensitivity assessed by hyperinsulinemic-euglycemic clamp examination in patients with uncontrolled type 2 diabetes mellitus

AIMS

Glucagon-like peptide-1 (GLP-1) analog promotes insulin secretion by acting on pancreatic β-cells. This antihyperglycemic treatment for type 2 diabetes mellitus (DM) has attracted increased clinical attention not only for its antihyperglycemic action but also for its potential extrapancreatic effects. We investigated whether liraglutide, a GLP-1 analog, could enhance insulin sensitivity as assessed by the hyperinsulinemic-euglycemic clamp in type 2 DM patients.

MATERIALS

We prospectively enrolled 31 uncontrolled type 2 DM patients who were hospitalized and equally managed by guided diet- and exercise-therapies and then introduced to either liraglutide- or intensive insulin-therapy for 4 weeks. Insulin sensitivity was assessed by the glucose infusion rate (GIR) using hyperinsulinemic-euglycemic clamp before and after the therapies.

RESULTS

Values of HbA1c, postprandial plasma glucose, and body mass index (BMI) were significantly decreased by hospitalized intensive insulin-therapy or liraglutide-therapy. GIR was significantly increased by liraglutide-therapy but not by insulin-therapy, indicating that liraglutide-therapy significantly enhanced insulin sensitivity. BMI decreased during liraglutide-therapy but was not significantly correlated with changes in GIR. Multivariate logistic regression analysis demonstrated that liraglutide-therapy significantly correlated with increased insulin sensitivity in uncontrolled DM patients.

CONCLUSIONS

Liraglutide may exhibit favorable effects on diabetes control for type 2 DM patients by increasing insulin sensitivity as an extrapancreatic action. Clinical trial registration Unique Identifier is UMIN000015201.

Case of anti-glomerular basement membrane antibody-induced glomerulonephritis with cytomegalovirus-induced thrombotic microangiopathy

Although the involvement of cytomegalovirus (CMV) infections in the development of thrombotic microangiopathy (TMA) in HIV patients and transplant recipients has been reported, it is still controversial whether CMV itself can cause TMA. We report herein a rare case with rapid improvement of TMA by ganciclovir treatment in a patient who is neither HIV-positive nor a transplant recipient, suggesting a pathogenic role for CMV in TMA.

Supercooling and vitrification of aqueous glycerol solutions at normal and high pressures

The supercooling and vitrification of aqueous glycerol solutions was studied at high pressures. Homogeneous ice nucleation temperatures (T(H)) were obtained for aqueous glycerol solutions of R=50, 30, 20, 12, and 10 (R: moles of water/moles of glycerol) up to 300MPa. The R=20 glycerol solution formed a glass above 200MPa at a cooling rate of 200°C/min, indicating that pressure enhances glass-formation of aqueous glycerol solutions. The (dT(g)/dP) values were obtained for vitrified aqueous glycerol solutions of R=3, 5, 10, and 20. These data can be used for the development of cryo-preservation liquids for living cells at high pressures.