Tissue inhibitor metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) best predicts the development of acute kidney injury

Background

Acute kidney injury (AKI) is routinely diagnosed by creatinine-based guidelines, which is sub-optimal marker after injury due to renal and non-renal factors. This has necessitated the need for more specific and sensitive biomarkers for early detection of AKI in at risk patients. This prospective cross-sectional study used the biomarkers of cell cycle arrest and Neutrophil Gelatinase Associated Lipocalin (NGAL) to assess AKI among hospitalized patients.

Methods

We conveniently enrolled 151 in-patients at the Trauma and Specialist Hospital, Winneba in Ghana. Socio-demographic and clinical information were collected using structured questionnaires. Blood samples were collected for the estimation of serum creatinine, and AKI diagnosed and staged using the KDIGO guideline. Fresh urine samples were collected and urinary NGAL, TIMP-2 (tissue inhibitor metalloproteinase 2) and IGFBP-7 (insulin-like growth factor binding protein 7) were estimated using ELISA kits.

Results

The cell cycle arrest biomarkers and NGAL were significantly (P < 0.001) higher among participants with AKI than those without AKI. [TIMP-2]∗[IGFBP-7] showed the best diagnostic performance (AUC = 0.94, CI = 0.90–0.98) followed by [IGFBP-7]∗NGAL] (AUC = 0.93, CI = 0.87–0.99), with NGAL having the least (AUC = 0.62, CI = 0.46–0.78). The cut-off for [TIMP-2]∗[IGFBP-7] showed the best predictive ability (95.8% sensitivity, 77.2% specificity, 44.2% PPV and 99% NPV). The cut-off for NGAL, on the other hand, showed the least predictive ability (62.5% sensitivity, 42.5% specificity, 17.0% PPV and 85.7% NPV).

Conclusion

Tissue inhibitor metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) best predicts the development of AKI, and can be used in high risk patients for early diagnosis of AKI.

Fasting plasma glucose and lipid profiles of diabetic patients improve with aerobic exercise training

OBJECTIVE

This study presents the effects of aerobic exercise training on fasting plasma glucose and lipid profiles (FPG/LP) of diabetic patients in Kumasi.

DESIGN

A randomised experimental with control design.

SETTING

The study was conducted at the diabetic unit of KATH in Kumasi, Ghana.

PARTICIPANTS

Twelve diabetic patients [grouped into intervention (IG) and control (CG)] attending the diabetic unit of KATH with diabetes diagnosis durations less than fifty years, ambulant status/age of 20-68years, sedentary and free from complications.

INTERVENTIONS

Eight weeks aerobic exercise training between August 2015 and March 2016.

MAIN OUTCOME MEASURES

Body weight (BW), Body mass index (BMI), fasting plasma glucose (FPG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (T) and total cholesterol (TC).

RESULTS

Body weight (4.85kg, 7.0%), body mass index (4.08kg/m2, 7.3%), FPG (5.28mmol/L, 43.5%), LDL-C (.33mmol/l, 11.9%), TC (.47 mmol/l, 5.3%) and T (.48mmol/l, 29.4%) profiles of the patients in IG declined while HDL-C (.11mmol/l, 7.1%) increased. IG patients improved significantly in FPG [6.27 ± 0.91 < 8.00 ± 0.96; t=-52.00, P = 0.000], BW [58.60 ± 15.34 < 75.35 ± 22.00; t= 3.29, P = 0.040] and BMI [23.45 ±5.03<27.04 ±4.78, t=4.24, P = .050] compared to CG.

CONCLUSION

Patients in IG, in addition to conventional care, experienced non-significant decline in LDL-C, TC, T, increase in HDL-C and significant reduction in FPG, BW, and BMI over those receiving conventional care only. Exercise Scientists are recommended to handle exercise sessions for healthcare prevention and management routines of diabetic patients.

FUNDING

Not declared.

C-reactive protein (CRP) promoter polymorphisms influence circulating CRP levels in a genome-wide association study of African Americans

C-reactive protein (CRP) is an acute phase reactant protein produced primarily by the liver. Circulating CRP levels are influenced by genetic and non-genetic factors, including infection and obesity. Genome-wide association studies (GWAS) provide an unbiased approach towards identifying loci influencing CRP levels. None of the six GWAS for CRP levels has been conducted in an African ancestry population. The present study aims to: (i) identify genetic variants that influence serum CRP in African Americans (AA) using a genome-wide association approach and replicate these findings in West Africans (WA), (ii) assess transferability of major signals for CRP reported in European ancestry populations (EA) to AA and (iii) use the weak linkage disequilibrium (LD) structure characteristic of African ancestry populations to fine-map the previously reported CRP locus. The discovery cohort comprised 837 unrelated AA, with the replication of significant single-nucleotide polymorphisms (SNPs) assessed in 486 WA. The association analysis was conducted with 2 366 856 genotyped and imputed SNPs under an additive genetic model with adjustment for appropriate covariates. Genome-wide and replication significances were set at P < 5 × 10(-8) and P < 0.05, respectively. Ten SNPs in (CRP pseudogene-1) CRPP1 and CRP genes were associated with serum CRP (P = 2.4 × 10(-09) to 4.3 × 10(-11)). All but one of the top-scoring SNPs associated with CRP in AA were successfully replicated in WA. CRP signals previously identified in EA samples were transferable to AAs, and we were able to fine-map this signal, reducing the region of interest from the 25 kb of LD around the locus in the HapMap CEU sample to only 8 kb in our AA sample.

The prevalence of autoimmune diabetes among diabetes mellitus patients in Kumasi, Ghana

This study investigate the occurrence and the prevalence of autoantibodies and the metabolic characteristics of autoimmune and antibody-negative type 2, diabetes in recently diagnosed diabetes mellitus patients in Kumasi, Ghana. This study involved a total of 120 recently diagnosed (< 1 year) Ghanaian diabetes mellitus patients (17 insulin-requiring and 103 non insulin-requiring) and 60 controls. A standardized questionnaire was used. Blood pressure and anthropometric measurements were taken. Fasting glucose, lipid and lipoprotein concentrations were measured by enzymatic methods and HbA(1C) levels by agglutination test. Serum insulin level and autoantibodies (ICA, GAD ab and IAA) were analyzed by enzyme-linked immunosorbent assay (ELISA). Out of the 17 insulin-requiring, six were positive for either GAD ab or ICA or both. Out of the 103 non insulin-requiring, 16.5% were positive for ICA and/or GAD ab and/or IAA. The prevalence of Latent Auto-immune Diabetes of Adults (LADA) in the non-insulin requiring and in the total diabetic patients, were 13.5 and 11.7%, respectively. The prevalence of autoimmune type 1 diabetes in the studied population was 7.5% and that of autoimmune diabetes in the total diabetic population was 19.2%. Autoimmune and autoantibody-negative type 2, diabetes did not differ (p = ns) in the mean values of clinical and metabolic parameters, except hypertension, central obesity and HbA(1C) values. Autoimmune diabetes occurs in recently diagnosed diabetic patients in Ghana at prevalence comparable to that in developed countries. Both ICA and GAD ab tests are required to identify autoimmune diabetes.

Genome-wide search for susceptibility genes to type 2 diabetes in West Africans: potential role of C-peptide

C-peptide is a substance that the pancreas releases into the circulation in equimolar amounts to insulin and has demonstrated important physiological effects which relate to the vascular field, in particular the microcirculation. For this analysis, we included 321 full and 36 half sibling pairs affected with type 2 diabetes (T2D) from West Africa. A genome-wide panel of 390 tri-nucleotide and tetra-nucleotide repeats with an average distance of 8.9 cM was performed on a total of 691 persons. Variance components based on multipoint linkage approach as implemented in SOLAR were performed for log C-peptide. Significant linkage evidences were observed on 10q23 at D10S2327 with a LOD score of 4.04 (nominal p-value=0.000008, empirical p-value=0.0004); and on 4p15 at D4S2632 with a LOD score of 3.48 (nominal p-value=0.000031, empirical p-value=0.0013). Other suggestive evidence of linkage were observed on 15q14 at D15S659 with a LOD score 2.41 (nominal p-value=0.000435, empirical p-value=0.0068), and on 18p11 near D18S976 with a LOD score 2.18 (nominal p-value=0.000771 and empirical p-value=0.0094). Interestingly, five positional candidate genes for diabetes and related complications are located in our linkage region (the pituitary adenylate cyclase activating polypeptide (PACAP in 18p11); the peroxisome proliferator-activated receptor gamma coactivator 1 (PPARGC1 in 4p15); PTEN, PPP1R5, and IDE located in 10q23. In conclusion, we identified four major genetic loci (10q23, 4p15, 15q14, and 18p11) influencing C-peptide concentration in West Africans with T2D.

Polymorphism of the endothelial nitric oxide synthase gene is associated with diabetic retinopathy in a cohort of West Africans

PURPOSE

In addition to chronic hyperglycemia, there is increasing evidence that genetic factors may be important in the development of diabetes retinopathy (DR). Specifically, polymorphisms of the endothelial nitric oxide synthase gene (eNOS) have been reported to be associated with multiple health conditions including DR, hypertension, nephropathy, and cardiovascular diseases in several ethnic groups. However, there is a paucity of similar data in African Americans and other African populations. To address this issue, we investigated the potential association between polymorphisms of the eNOS gene and diabetes-related phenotypes in 384 persons with type 2 diabetes and 191 controls from two West African countries (Ghana and Nigeria).

METHODS

We genotyped the deletion/insertion (4a/b) and the G894T polymorphisms of eNOS gene in a total of 575 persons.

RESULTS

The b/b genotype of the polymorphism was associated with a 2.4 fold increased risk of DR (95% CI 1.39-4.09). In contrast, we did not observe any association between the genotypes or alleles of G894T polymorphism with DR, hypertension, or nephropathy.

CONCLUSIONS

We observed a significant association between the 4a/b polymorphism of the eNOS and DR in our West African cohort.

A genome-wide search for linkage to renal function phenotypes in West Africans with type 2 diabetes

BACKGROUND

Reduced renal function often is a major consequence of diabetes and hypertension. Although several indices of renal function (eg, creatinine clearance) are clearly heritable and show linkage to several genomic regions, the specific underlying genetic determinants are still being sought. The purpose of this study is to conduct a genome-wide search for regions linked to 3 renal function phenotypes, serum creatinine, creatinine clearance, and glomerular filtration rate (GFR), in persons with type 2 diabetes.

METHODS

A genome-wide panel of 372 autosomal short tandem repeat markers at an average spacing of 9 centimorgan were typed in 691 patients with type 2 diabetes (321 sib pairs and 36 half-sib pairs) in an affected sib pair study in West Africa. Linkage analysis was conducted with the 3 phenotypes by using a multipoint variance components linkage method.

RESULTS

Creatinine clearance showed higher logarithm of odds (LOD) score than the other 2 phenotypes. Linkage to creatinine clearance was observed on chromosomes 16 (marker D16S539, LOD score of 3.56, empirical P = 0.0001), 17 (D17S1298, LOD score of 2.08, empirical P = 0.0018), and 7 (D7S1818, LOD score of 1.84, nominal P = 0.00181, empirical P = 0.0022). Maximum LOD scores for serum creatinine were observed on chromosomes 10 (D10S1432, LOD score of 2.53, empirical P = 0.0001) and 3 (D3S2418, LOD score of 2.21, empirical P = 0.0003) and for GFR on chromosomes 6 (D6S1040, LOD score of 2.08, empirical P = 0.0001) and 8 (D8S256, LOD score of 1.80, empirical P = 0.0001). Several of these results are replications of significant findings from other genome scans.

CONCLUSION

A genome-wide scan for serum creatinine, creatinine clearance, and GFR in a West African sample showed linkage regions that may harbor genes influencing variation in these phenotypes. Potential candidate genes in these regions that have been implicated in diabetic nephropathy and/or renal damage in models of hypertension include CYBA (or P22PHOX) (16q24), NOX1 (10q22), and NOX3 (6q25.1-q26).

Prevalence and predictors of microalbuminuria in patients with diabetes mellitus: a cross-sectional observational study in Kumasi, Ghana

OBJECTIVE

To evaluate the prevalence and predictors of microalbuminuria in diabetics in Kumasi, Ghana.

DESIGN

Prospective, cross-sectional study of diabetic patients.

SUBJECTS

Patients with diabetes, 20 to 78 years of age.

MAIN OUTCOME MEASURES

Microalbuminuria

METHODS

All patients (109) attending an outpatient diabetic clinic at the Komfo Anokye Teaching Hospital Diabetes Centre in Kumasi, Ghana from January to July 2005 were enrolled in the study.

RESULTS

The mean overall age of the cohort was 54.1 +/- 10.9 years, and 28% were male. The proportion of subjects who had microalbuminuria was 43.1% (n=47). The median duration of diabetes before development of microalbuminuria was 10 years. Duration of diabetes, blood urea nitrogen, serum concentration of creatinine, and triglyceride were significantly higher in patients with microalbuminuria (P<.05). Urinary potassium concentration and fractional excretion of potassium were also significantly higher in the patients with microalbuminuria.

CONCLUSIONS

The prevalence of microalbuminuria in patients with diabetes in this study was 43%. Significant predictors of microalbuminuria included duration of diabetes and serum concentration of creatinine. To reduce renal failure among these patients, strategies to mitigate its occurrence are needed. This includes strict glycemic control, control of hypertension, and the early blockade of the renin-angiotensin system.

Agouti-related protein promoter variant associated with leanness and decreased risk for diabetes in West Africans

OBJECTIVE

The role of the central melanocortin system in the development of obesity has been extensively studied. Single-nucleotide polymorphisms (SNPs) within several candidate genes have been associated with food intake and obesity-related phenotypes; however, few of these associations have been replicated. SNPs in the agouti-related protein (AGRP) gene coding (Ala67Thr, 199G/A) and promoter (-38C/T) have been reported to be associated with body mass index (BMI), fat mass (FM) and percent body fat, in populations of European and African descent. In this study, we evaluated the association between the functional AGRP -38C/T promoter SNP and weight-related traits, namely BMI, FM and fat-free mass (FFM), as well as diabetes status.

DESIGN

An association study of the AGRP -38C/T SNP and indices of obesity and diabetes status.

SUBJECTS

A well-characterized population of 538 West Africans from Ghana and Nigeria recruited in the AADM (Africa America Diabetes Mellitus) study (mean age 52 years, 41.3% males, 71% diabetic).

MEASUREMENTS

Genotyping of the AGRP -38C/T SNP, BMI, FM, FFM and fasting plasma glucose.

RESULTS

Women carrying two copies of the variant T allele had significantly lower BMI (OR=0.47; 95% CI, 0.25-0.87). Also, men with at least one copy of the variant T allele were over two times less likely to be diabetic than other men (OR=0.44; 95% CI, 0.22-0.89).

CONCLUSION

Our results replicate previous findings and implicate the AGRP -38C/T SNP in the regulation of body weight in West Africans.

Genomewide scan and fine mapping of quantitative trait loci for intraocular pressure on 5q and 14q in West Africans

PURPOSE

High intraocular pressure (IOP) is a major risk factor for glaucoma, one of the leading causes of blindness worldwide. Because it has been demonstrated that African populations are at increased risk for glaucoma, the authors investigated the genetic basis of IOP in a sample of West Africans with type 2 diabetes (T2D) from Ghana and Nigeria.

METHODS

Genomewide linkage analysis was conducted for loci linked to IOP (measured by applanation tonometry) in 244 affected sibling pairs with T2D using 372 autosomal short-tandem repeat markers at an average spacing of 9 cM.

RESULTS

Multipoint variance components linkage analyses revealed suggestive linkage on chromosome 5 (5q22) with a logarithm of odds (LOD) score of 2.50 (nominal P = 0.0003; empiric P = 0.0004) and on chromosome 14 (14q22) with an LOD score of 2.95 (nominal P = 0.0001; empiric P = 0.0003). Fine mapping at a marker density of 2 cM in the 5q region confirmed the linkage signal, with an increase in peak LOD score to 4.91.

CONCLUSIONS

The strong signal on chromosome 5 lies in the region in which a novel gene, WDR36, in the GLC1G locus was recently identified as causative for adult-onset primary open-angle glaucoma and provides additional evidence that chromosome 5 contains susceptibility loci for glaucoma in multiple human populations. The evidence provided in this study is particularly important given the evolutionary history of these West African populations and the recent ancestral relationship to African Americans-a population with one of the highest rates of diabetes and associated complications (including glaucoma) in the world.

A genome wide quantitative trait linkage analysis for serum lipids in type 2 diabetes in an African population

Lipid abnormalities are strongly linked with coronary heart disease and are common in type 2 diabetes. However, little is known about the genetic determinants of serum lipids in African populations. An autosomal genome scan was performed for linkage to five plasma lipid phenotypes (total cholesterol, triglycerides (TG), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C) and VLDL-cholesterol (VLDL-C)) in the Africa-America Diabetes Mellitus (AADM) study. Two hundred and ninety-five affected sibling pairs with type 2 diabetes mellitus enrolled from Ghana and Nigeria were genotyped for 390 microsatellite markers with an average inter-marker distance of 9cM. Multipoint variance components linkage analysis showed that HDL-C had a LOD score of 4.34 near marker D7S3061 and 3.00 near marker D7S513. Some clustering of linkage evidence to several lipid phenotypes was observed on chromosomes 5 (LDL-C, total cholesterol, VLDL-C), chromosome 7 (HDL-C, TG) and chromosome 19 (total cholesterol, LDL-C, TG). Principal component analysis of the five phenotypes yielded two factors, one (TG, HDL-C and VLDL) of which was linked to QTLs on chromosomes 2, 5 and 7, while the other (total cholesterol and LDL-C) was linked to a different set of QTLs on chromosomes 2, 5 and 18. Several of these regions have been reported to be linked to lipids in other studies. Follow up investigations are warranted in view of the central role serum lipids play in the aetiopathogenesis of cardiovascular disease.

A genome-wide scan for quantitative trait loci linked to obesity phenotypes among West Africans

OBJECTIVE

To identify quantitative trait loci (QTL) for three obesity phenotypes: body mass index (BMI), fat mass (FM) and percent body fat (PBF) in West Africans with type 2 diabetes (T2DM).

DESIGN

An affected sibling pair (ASP) design, in which both siblings had T2DM. Obesity was analyzed as a quantitative trait using a variance components approach.

SUBJECTS

Sib-pairs affected with T2DM from the Africa America Diabetes Mellitus (AADM) study, comprising 321 sibling pairs and 36 half-sibling pairs.

MEASUREMENTS

Weight was measured on an electronic scale to the nearest 0.1 kg, and height was measured with a stadiometer to the nearest 0.1 cm. Body composition was estimated using bioelectric impedance analysis (BIA). Genotyping was carried out at the Center for Inherited Disease Research (CIDR) with a panel of 390 trinucleotide and tetranucleotide repeats.

RESULTS

The obesity-related phenotype showing the strongest linkage evidence was PBF on chromosome 2 (LOD 3.30 at 72.6 cM, marker D2S739). Suggestive linkage to FM was found on chromosomes 2 (LOD 2.56 at 80.4 cM) and 5 (LOD 2.25 at 98 cM, marker D5S1725). The highest LOD score for BMI was 1.68 (chromosome 4, 113.8 cM). The areas of linkage for the three phenotypes showed some clustering as all three phenotypes were linked to the same regions of 2p13 and 5q14, and our study replicated linkage evidence for several regions previously reported in other studies.

CONCLUSION

We obtained evidence for several QTLs on chromosome 2, 4 and 5 to three obesity phenotypes. This study provides data on the genetics of obesity in populations that are currently under represented in the global effort directed at understanding the pathophysiology of excess adiposity in free living individuals.

A genome-wide search for type 2 diabetes susceptibility genes in West Africans: the Africa America Diabetes Mellitus (AADM) Study

The incidence of type 2 diabetes is growing rapidly, not only in developed countries but also worldwide. We chose to study type 2 diabetes in West Africa, where diabetes is less common than in the U.S., reasoning that in an environment where calories are less abundant, incident cases of type 2 diabetes might carry a proportionately greater genetic component. Through the Africa America Diabetes Mellitus (AADM) study, we carried out a genome-wide linkage analysis of type 2 diabetes in a cohort of 343 affected sibling pairs (691 individuals) enrolled from five West African centers in two countries (Ghana: Accra and Kumasi; Nigeria: Enugu, Ibadan, and Lagos). A total of 390 polymorphic markers were genotyped, and multipoint linkage analysis was conducted using the GENEHUNTER-PLUS and ASM programs. Suggestive evidence of linkage was observed in four regions on three chromosomes (12, 19, and 20). The two largest logarithm of odds scores of 2.63 and 1.92 for chromosomes 20q13.3 and 12q24, respectively, are particularly interesting because these regions have been reported to harbor diabetes susceptibility genes in several other populations and ethnic groups. Given the history of forced migration of West African populations during the slave trade, these results should have considerable relevance to the study of type 2 diabetes in African Americans.

Dyslipidemia in outpatients at General Hospital in Kumasi, Ghana: cross-sectional study

AIM

To determine the prevalence of dyslipidemia among hospital patients in Kumasi, Ghana, whose diet consists mostly of carbohydrates and little proteins, and assess the effect of age, sex, and the presence of hypertension and diabetes mellitus on serum cholesterol concentration.

METHODS

The hospital-based study included 248 patients (145 women and 103 men) selected by strict random sampling from patients visiting Komfo Anokye Teaching Hospital between May 1, 1999, and April 30, 2000. The patients were divided into four groups: patients with hypertension, diabetes mellitus, both conditions, and without either disease. We measured lipid concentration in the serum of patients and assessed its correlation with age, sex, body mass index, and the presence or absence of diabetes mellitus or hypertension.

RESULTS

Almost half of the patients (45%) had serum total cholesterol concentration >5.17 mmol/L and 26% had also serum triglyceride concentration >1.69 mmol/L. High-density lipoprotein (HDL)-cholesterol dyslipidemia (HDL< 1.03 mmol/L) was found in 30.5% of the patients, and low-density lipoprotein (LDL)-cholesterol dyslipidemia (LDL>2.58 mmol/L) in 72%. Serum total cholesterol concentration was significantly high in the patients with hypertension alone (p=0.01). LDL-cholesterol and serum triglyceride concentrations appeared higher in those who had both hypertension and diabetes, but this was not statistically significant. Serum HDL-cholesterol was higher in the group with diabetes alone but also failed to achieve statistical significance.

CONCLUSION

Dyslipidemia is common in patients visiting hospital in Kumasi, although the regular diet is based on carbohydrates and poor in fat. Steps are needed to curb lipid-related disorders.