Association of plasma growth arrest-specific protein 6 (Gas6) concentrations with albuminuria in patients with type 2 diabetes

Possible Association of Elevated Plasma Levels of Growth Arrest-Specific Protein 6 and the Soluble Form of Tyrosine Kinase Receptor Axl with Low Hepatitis C Viral Load in Patients with Type 2 Diabetes Mellitus

This study aimed to investigate the plasma levels of Gas6 and soluble Axl (sAxl) in patients with chronic hepatitis C virus (HCV) infection with and without type 2 diabetes mellitus (T2DM). The study involved four groups; 50 patients with chronic HCV, 50 patients with T2DM, 50 patients with chronic HCV and T2DM, and 31 age- and sex-matched healthy controls. T2DM was diagnosed according to American Diabetes Association criteria, HCV antibodies were detected by enzyme-linked immunosorbent assays (ELISA) and confirmed by real-time-polymerase chain reaction. Plasma Gas6 and sAxl levels were assayed in all groups by ELISA. Significant low levels of GAS 6 in HCV/T2DM group versus HCV group were detected (7.92 ± 5.18 vs. 16.09 ± 7.36, respectively, p = 0.000), but higher than T2DM and control groups (p ≥ 0.05), although nonsignificant. HCV load was higher in the HCV group than the HCV/T2DM group (1,888,300 ± 5,595,070 vs. 1,417,900 ± 4,066,460 copies/mL, respectively, p = 0.632). Among HCV group, significant positive correlations were detected between Gas6 and sAxl levels with HCV viral load (r = 0.48, p = 0.000 and r = 0.43, p = 0.002, respectively), while among HCV/T2DM group, significant negative correlations were detected (r = -0.29, p = 0.04 and r = -0.34, p = 0.014, respectively). Significant negative correlations were detected between Gas6/sAxl levels and glycated hemoglobin (r = -0.36, p = 0.01 and r = -0.4, p = 0.003, respectively) in T2DM despite the positive correlations detected in HCV/T2DM (r = 0.27, p = 0.053 and r = 0.55, p = 0.000, respectively). In conclusion, Gas6/Axl system in combined HCV/T2DM diseases may affect the pathogenesis and can alter the biomarkers and complications of both diseases in a manner that differs from a solitary disease.

Growth arrest-specific protein 6 (Gas6) as a noninvasive biomarker for early detection of diabetic nephropathy

BACKGROUND

To investigate the diagnostic level of cystatin C and growth arrest-specific gene 6 (Gas6) levels in elderly type 2 diabetic patients with different degrees of diabetic nephropathy (DN).

METHODS

Four hundred and eighty-two old people, including 130 healthy controls, 130 normoalbuminuric diabetic patients, 122 with microalbuminuria, and 100 with macroalbuminuria, were recruited. Plasma Gas6 and serum cystatin C levels were measured.

RESULTS

Plasma Gas6 concentration was significantly lower in diabetic patients with microalbuminuria or macroalbuminuria, as compared with diabetic subjects with normoalbuminuria; while cystatin C was significantly higher. Gas6 was inversely correlated with BMI, WHR, and HbA1c, while cystatin C was inversely correlated with urea nitrogen and creatinine. Multivariate logistic regression analysis showed that, after adjusted for established diabetes risk factors, higher plasma Gas6 was significantly associated with a decreased risk of DN, while higher serum cystatin C was significantly associated with an increased risk. Receiver operating characteristic curve analysis showed that Gas6 was better than cystatin C as a biomarker for early diagnosis and detection of DN, with a cutoff value of 9.435 ng/mL (86.1% sensitivity and 84.6% specificity).

CONCLUSION

Compared to cystatin C, Gas6 may be potentially a better noninvasive diagnostic biomarker for early detection of DN.

Reference intervals for growth arrest-specific 6 protein in adults

The objective of this study was to establish reference intervals for growth arrest-specific 6 (GAS6), a vitamin K-dependent protein, in human adult plasma according to the Guideline of Clinical and Laboratory Standards Institute (CLSI) C28-A3. Blood samples were collected from 308 healthy volunteers aged 18-72 (157 female, 151 male). A non-parametric approach was used to calculate the reference interval. The plasma GAS6 reference interval was determined, with 90% confidence interval: the lower limit (2.5 percentile) was 2.5 (1.9-3.1) μg/L and the upper limit (97.5 percentile) = 18.8 (18.0-22.3) μg/L. Harris-Boyd's test did not suggest partitioning by age or gender: medians for males [7.8 (5.8-10.7) μg/L] and females [9.9 (7.1-13.5) μg/L]. Three age-subgroups were tested: 18-29 years (n = 168); 30-44 years (n = 73); 45-72 years (n = 67). The intra- and inter-assay variations were 12.6% (mean, 5.2 ± 0.7 μg/L) and 14.0% (mean, 9.2 ± 1.3 μg/L), respectively. The mean recovery was 104%. This study reports plasma GAS6 reference intervals established first according to the guideline of CLSI C28-A3.

Growth arrest-specific 6 and cardiometabolic risk factors in patients with psoriasis

OBJECTIVES

An increased risk for cardiovascular disease with psoriasis has been reported. Growth Arrest-Specific 6 (GAS6) amplifies pro-inflammatory endothelial cell activation via TAM receptors. However, it also inhibits inflammation by multiple mechanisms including phagocytosis. The objective of this study was to investigate whether plasma GAS6 levels are associated with conventional cardiometabolic (CM) risk factors in patients with psoriasis.

METHODS

Forty patients diagnosed with psoriasis (22 male, mean age: 43.3 ± 13.8 years) and 40 age-/sex-matched healthy controls (22 male, mean age: 39.3 ± 8.9 years) were included in the study. CM risk factors (hypertension, hyperlipidemia, diabetes mellitus, and cigarette smoking) were identified. GAS6 levels were measured by ELISA.

RESULTS

There were no significant differences between the plasma GAS6 levels of patients with psoriasis compared to the control group (6.6 ± 2.0 ng/mL, 7.6 ± 2.8 ng/mL, respectively, P > 0.05). However, GAS6 levels of patients with psoriasis having a smoking history (n = 11) were significantly lower than both patients with psoriasis who had no smoking history (n = 29) and controls (5.5 ± 1.7 ng/mL, 6.9 ± 1.9 ng/mL, 7.6 ± 2.8 ng/mL, respectively, P < 0.05). Similarly, psoriasis patients with at least one CM risk factor showed lower GAS6 levels compared to subjects without any CM risk factor (5.7 ± 1.7 ng/mL, 7.3 ± 2.0 ng/mL, P < 0.01). There was no correlation between the GAS6 level, disease duration or PASI score (r = 0.150, -0.150, and P = 0.310, 0.398, respectively).

CONCLUSIONS

This pilot study provides the first evidence in humans for an association between low plasma GAS6 levels and conventional risk factors in psoriasis. Further large scale, prospective studies are needed to confirm these results.

GAS6 intron 8 c.834 + 7G > A gene polymorphism in diabetic nephropathy

BACKGROUND - AIM: In animal experiments, growth arrest-specific 6 (Gas6) protein plays a key role in the development of mesangial cell and glomerular hypertrophy in the early phase of diabetic nephropathy, and diabetic nephropathy is prevented by warfarin-induced inhibition of GAS6 protein. It was shown that GAS6 intron 8 c.834 + 7G > A polymorphism is protective against type 2 diabetes mellitus, and AA genotype is associated with higher blood levels of GAS6 protein. Our aim is to investigate whether this polymorphism is a risk factor for diabetic nephropathy in type 2 diabetes mellitus.

METHOD

Eighty-seven patients with diabetic nephropathy were compared with 66 non-diabetic controls in terms of GAS6 intron 8 c.834 + 7G > A polymorphism. Patients with history of stroke, ischemic heart disease were excluded. Each patient was examined by the ophthalmologist to determine diabetic retinopathy.

RESULTS

Frequency of GG, GA and AA genotypes are similar in diabetic nephropathy and control groups according to GAS6 intron 8 c.834 + 7G > A polymorphism (p =  .837). Rate of diabetic retinopathy was 54.02%. In the subgroup analysis, GA genotype was significantly more frequent than GG genotype in patients with diabetic retinopathy when compared to without diabetic retinopathy (p =  .010).

CONCLUSION

In our study, GAS6 intron 8 c.834 + 7G > A polymorphism was not associated with diabetic nephropathy in type 2 diabetes mellitus. However, heterozygous state of this polymorphism may be a risk factor for diabetic retinopathy in patients with diabetic nephropathy.