Binod Kumar Yadav

A global multicenter study on reference values: 1. Assessment of methods for derivation and comparison of reference intervals

OBJECTIVES The IFCC Committee on Reference Intervals and Decision Limits coordinated a global multicenter study on reference values (RVs) to explore rational and harmonizable procedures for derivation of reference intervals (RIs) and investigate the feasibility of sharing RIs through evaluation of sources of variation of RVs on a global scale. METHODS For the common protocol, rather lenient criteria for reference individuals were adopted to facilitate harmonized recruitment with planned use of the latent abnormal values exclusion (LAVE) method. As of July 2015, 12 countries had completed their study with total recruitment of 13,386 healthy adults. 25 analytes were measured chemically and 25 immunologically. A serum panel with assigned values was measured by all laboratories. RIs were derived by parametric and nonparametric methods. RESULTS The effect of LAVE methods is prominent in analytes which reflect nutritional status, inflammation and muscular exertion, indicating that inappropriate results are frequent in any country. The validity of the parametric method was confirmed by the presence of analyte-specific distribution patterns and successful Gaussian transformation using the modified Box-Cox formula in all countries. After successful alignment of RVs based on the panel test results, nearly half the analytes showed variable degrees of between-country differences. This finding, however, requires confirmation after adjusting for BMI and other sources of variation. The results are reported in the second part of this paper. CONCLUSION The collaborative study enabled us to evaluate rational methods for deriving RIs and comparing the RVs based on real-world datasets obtained in a harmonized manner.

Non-high density lipoprotein cholesterol versus low density lipoprotein cholesterol as a discriminating factor for myocardial infarction

BackgroundSerum total cholesterol (TC) and LDL cholesterol (LDL-C) have been used as major laboratory measures in clinical practice to assess cardiovascular risk in the general population and disease management as well as prognosis in patients. However, some studies have also reported the use of non-HDL cholesterol (non-HDL-C). As non-HDL-C can be calculated by subtracting HDL-C from TC, both of which do not require fasting blood sample in contrast to LDL-C which requires fasting blood sample, we aimed to compare non-HDL-C with LDL-C as a predictor of myocardial infarction (MI).MethodsThis hospital based cross sectional study was undertaken among 51 cases of MI and equal number of controls. MI was diagnosed based on the clinical history, ECG changes and biochemical parameters. 5 mL of fasting blood sample was collected from each research participant for the analysis of lipid profile. Non-HDL-C was calculated by using the equation; Non-HDL-C = TC – HDL-C. Statistical analysis was performed using SPSS 14.0.Results42 MI cases were dyslipidemic in contrast to 20 dyslipidemic subjects under control group. The differences in the median values of each lipid parameter were statistically significant between MI cases and controls. The lipid risk factors most strongly associated with MI were HDL-C (OR 5.85, 95% CI 2.41-14.23, P value = 0.000) followed by non-HDL-C (OR 3.77, 95% CI 1.64-8.66, P value = 0.002), LDL-C/HDL-C (OR 3.38, 95% CI 1.44-7.89, P value = 0.005), TC/HDL-C (OR 2.93, 95% CI 1.36-7.56, P value = 0.026), LDL-C (OR 2.70, 95% CI 1.20-6.10, P value = 0.017), TC (OR 2.68, 95% CI 1.04-6.97, P value = 0.042) and Tg (OR 2.54, 95% CI 1.01-6.39, P value = 0.047). Area under the receiver operating curve was greater for non-HDL-C than for LDL-C. Non-HDL-C was also found to be more sensitive and specific than LDL-C for MI.ConclusionsHDL-C and non-HDL-C are better discriminating parameters than LDL-C for MI. Thus, we can simply perform test for HDL-C and non-HDL-C both of which do not require fasting blood sample rather than waiting for fasting blood sample to measure LDL-C.

TMBIM6 (transmembrane BAX inhibitor motif containing 6) enhances autophagy and reduces renal dysfunction in a cyclosporine A-induced nephrotoxicity model

Cyclosporine A (CsA) is widely used as an immunosuppressor in transplantation. Previous studies reported that CsA induces autophagy and that chronic treatment with CsA results in accumulation of autophagosomes and reduced autophagic clearance. Autophagy is a prosurvival process that promotes recovery from acute kidney injury by degrading misfolded proteins produced in the kidney. In the present study, we used TMBIM6-expressing HK-2, human kidney tubular cells (TMBIM6 cells) and Tmbim6 knockout (tmbim6−/−) mice. When exposed to CsA, the TMBIM6 cells maintained autophagy activity by preventing autophagosome accumulation. With regard to signaling, PRKKA/AMPK phosphorylation and mechanistic target of rapamycin (serine/threonine kinase) complex 1 (MTORC1) expression and its downstream target TFEB (transcription factor EB), a lysosome biogenesis factor, were regulated in the TMBIM6 cells. Lysosomal activity was highly increased or stably maintained in the presence of TMBIM6. In addition, treatment of tmbim6−/− mice with CsA resulted in increased autophagosome formation and decreased lysosome formation and activity. We also found that tmbim6−/− mice were susceptible to CsA-induced kidney injury. Taken together, these results indicate that TMBIM6 protects against CsA-induced nephrotoxicity both in vitro and in vivo by inducing autophagy and activating lysosomes.

Serum uric acid level in newly diagnosed essential hypertension in a Nepalese population: A hospital based cross sectional study

OBJECTIVE To develop the missing link between hyperuricemia and hypertension. METHODS The study was conducted in Department of Biochemistry in collaboration with Nephrology Unit of Internal Medicine Department. Hypertension was defined according to blood pressure readings by definitions of the Seventh Report of the Joint National Committee. Totally 205 newly diagnosed and untreated essential hypertensive cases and age-sex matched normotensive controls were enrolled in the study. The potential confounding factors of hyperuricemia and hypertension in both cases and controls were controlled. Uric acid levels in all participants were analyzed. RESULTS Renal function between newly diagnosed hypertensive cases and normotensive healthy controls were adjusted. The mean serum uric acid observed in newly diagnosed hypertensive cases and in normotensive healthy controls were (290.05±87.05) μmol/L and (245.24±99.38) μmol/L respectively. A total of 59 (28.8%) participants of cases and 28 (13.7%) participants of controls had hyperuricemia (odds ratio 2.555 (95% CI: 1.549-4.213), P<0.001). CONCLUSIONS The mean serum uric acid levels and number of hyperuricemic subjects were found to be significantly higher in cases when compared to controls.

Single-Nucleotide Polymorphisms of Tight Junction Component Claudin-1 Associated with Leukoaraiosis

BACKGROUND The blood-brain barrier (BBB) plays a major role in the development of leukoaraiosis (LA). The junctional complex of BBB consists of tight junction (TJ) and adherens junction (AJ). Claudin-1 is the integral component of TJ. The aim of this study was to evaluate whether genetic variations in claudin-1 gene are associated with the development of LA. METHODS LA has to be diagnosed based on images. A total of 228 LA cases and 203 controls were enrolled from the individuals who underwent brain magnetic resonance imaging with obtainable vascular risk factors. Genotyping of claudin-1 single-nucleotide polymorphisms (SNPs) (rs17501010, rs893051, and rs9290927) was performed by real-time polymerase chain reaction with LightSNiP reagents (coupled primer and probe) and FastStart DNAMaster HybProbe (Roche Diagnostic, GmBH, Mannheim, Germany) in LightCycler 2.0. RESULTS Among the 3 SNPs of claudin-1, a significant genetic difference was found only between control and LA (both LA-periventricular white matter [PVWM] and LA-subcortical deep white matter) with SNP rs9290927. However, their haplotypes G-G-T and G-C-A were significantly different between LA-PVWM and control, which increase the development of LA-PVWM with odds ratios of 1.45 and .57, respectively. CONCLUSIONS This study demonstrated first evidence of genetic polymorphism of TJ component claudin-1 and their haplotypes associated with LA.

Effects of Long-term Use of Depo-medroxyprogesterone Acetate on Lipid Metabolism in Nepalese Women

Various synthetic progestogens that are used as contraceptives have been reported to influence lipid and lipoprotein fractions differently. Depo-medroxyprogesterone acetate (DMPA), a synthetic progestogen, is used by Nepalese women as a contraceptive agent. Our study aims to determine the effects of long-term use of DMPA on lipid metabolism. We performed this study on 60 healthy Nepalese women who had been using DMPA for more than 2 yr and age- and weight-matched control subjects who were not using hormonal contraceptives. Fasting blood samples were collected from the subjects for the estimation of total cholesterol (TC) and triglyceride (TG) levels, and the levels of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were estimated using the Friedewalds equation. TC and LDL-C levels in DMPA users were significantly higher than those in non-users. Our study concluded that DMPA use induces lipid metabolism changes that can increase the risk of cardiovascular diseases.

Correlation of VEGF genetic polymorphisms and lipid profile to aortic calcification.

BACKGROUND Aortic calcification is developed due to accumulation of a large amount of calcium in the aorta of the heart and it is the leading cause of aortic valve replacement and third leading cause of cardiovascular disease. The purpose of this study was to investigate the relation between aortic calcification and VEGF SNPs (-2578C>A, -1154G>A and +936C>T) and to evaluate the association of these SNPs with biochemical parameter in relation to aortic calcification. METHODS Aortic calcification was diagnosed by examining the posteroanterior chest X-rays by a radiologist and graded into four groups. The real-time polymerase chain reaction with melting curve analysis in LightCycler was used to genotype the VEGF SNPs. RESULTS Among the VEGF SNPs, a significant genetic difference was found only between the aortic calcification and control group with VEGF SNP -2578C>A but haplotypes T-A-A of (+936/-1154/-2578) were significantly different in control and aortic calcification and could enhance the aortic calcification development. By regression analysis, it was found that age, hypertension, diabetes, dyslipidemia, and hyperhomocysteinemia were found significantly different with the different genotypes of VEGF SNPs which may induce aortic calcification development. CONCLUSION Age, hypertension, diabetes, dyslipidemia, and hyperhomocysteinemia were established as aggravating factors for the aortic calcification in association with different VEGF genotypes.

A Prevalence of Thyroid Disorder in Western Part of Nepal

BACKGROUND Nepal is an endemic area with regards to iodine deficiency, as well as a nutritional iodine deficiency is thought to be prevalent in all the Himalayan, sub-Himalayan and the Terai regions of Nepal. Thyroid dysfunction is a major public health problem among the Nepalese population. OBJECTIVES The objective of this study was to find out the prevalence of thyroid dysfunction among the patients who attended the Charak Hospital, Pokhara, Nepal. MATERIALS AND METHODS A hospital based study was undertaken by using the data which was retrieved from the thyroid function tests, which included free T3, free T4 and TSH, from the register which was maintained in the Department of Biochemistry of the Charak Hospital, Pokhara, Nepal, from 1(st) January, 2011 to 30th December, 2012. Descriptive statistics and testing of the hypothesis were used for the analysis by using the EPI INFO and the SPSS version 16 softwares. RESULTS The total number of cases was 1504, which included 23.20% males and 76.80% females. The prevalence of thyroid dysfunction was 17.42%. Females had more thyroid dysfunction than the males. Hypothyroidism (2.26%) and subclinical hypothyroidism (10.50%) had higher prevalences as compared to hyperthyroidism (1.59%) and subclinical hyperthyroidism (3.05%) in the western region of Nepal. A higher prevalence of the thyroid dysfunction was observed in the subjects who ages were above 41-50 years. CONCLUSION Females and people of advanced ages were more vulnerable to thyroid dysfunction in the population. Hypothyroidism and subclinical hypothyroidism were preponderant, followed by subclinical hyperthyroidism.

Determination of Insulin Resistance and Beta-Cell Function Using Homeostatic Model Assessment in Type 2 Diabetic Patients at Diagnosis

Objective: Despite the increasing incidence of type 2 diabetes mellitus (T2DM) in South Asian countries, there have been no studies related to insulin resistance (IR) and beta-cell function (BCF) in Nepal. Measurement of both of these parameters at T2DM diagnosis can be a potential tool in evaluation, risk stratification and monitoring treatment. In this study, we used C-peptide modified homeostatic model assessment (both HOMA1 and HOMA2) and correlated the obtained IR with cardiovascular risk factors. We also intended to find out whether reduced insulin sensitivity or beta-cell failure predominates in new T2DM cases. Also there has been some dilemma in using either body mass index (BMI) or waist-hip ratio (WHR) as a better predictor of IR in our population. Lipoprotein ratios TC/ HDL and TG/HDL also needed evaluation in this regard.Results: Participants were sixty newly diagnosed T2DM patients visiting Tribhuvan University Teaching Hospital (TUTH), Nepal. The mean IR and beta-cell function were HOMA1IR=4.91 ± 1.62; HOMA2IR=2.61 ± 1.06 and HOMA1%B=40.28 ± 23.64; HOMA2%B=47.10 ± 24.67 respectively. Both HOMA1 and HOMA2 showed greater reduction in insulin sensitivity than beta-cell function at diagnosis. ROC curves analysis showed WHR and TC/HDL ratio as better predictors of IR.

Single-nucleotide polymorphisms of the adherent junction component cadherin gene are associated with leukoaraiosis

BACKGROUND Leukoaraiosis (LA) is one of the manifestations of cerebral small vessel disease. Blood-brain barrier (BBB) disruption plays a key role in LA. Cadherin is a component of adherent junctions (AJ), which play a crucial role in cell-cell adhesion, cell-cell recognition and homeostasis in BBB development. We hypothesized that alterations in cadherin genes might be a potential cause of BBB abnormalities that result in LA. METHODS A total of 339 LA individuals (LA-PVWM, 183; LA-DWM 156) were enrolled, who underwent brain magnetic resonance imaging with obtainable vascular risk factors. Genotyping of cadherin single-nucleotide polymorphisms (SNPs) (rs5030625, rs1801026, and rs16260) was performed by real-time polymerase chain reaction with LightSNiP reagents (coupled primer and probe) and FastStart DNAMaster HybProbe (Roche Diagnostic, GmBH, Mannheim, Germany) on a LightCycler 2.0 instrument. RESULTS Two SNPs, rs1801026 and rs16260, were significantly different between the control and LA groups. The combinatorial effects of the three SNPs were also significant. The haplotypes G-T-C and GA-T-A increased the development of LA-PVWM (OR = 1.76 and OR = 40.7, respectively). The haplotypes G-T-A and GA-T-A increased the development of LA-DWM (OR = 2.56 and OR = 10.48, respectively), but G-C-C decreased the development of LA-DWM (OR = 17.57). CONCLUSION This study provides evidence for genetic polymorphisms of the AJ component cadherin gene and the association of its haplotypes with LA.