Urinary Alpha 1 Microglobulin in Non Alcoholic Fatty Liver Disease and Its Association with Liver Fibrosis

Background: NAFLD is the most common cause of CLD worldwide with definite diagnosis based on Liver Biopsy. Recent studies have provided a strong insight into the liver kidney cross talk between NAFLD and CKD. Alpha-1 Microglobulin (A1M) is a glycoprotein secreted by liver. Glomeruli freely filter the unbound form of A1M, then reabsorbed and broken down by proximal tubular epithelial cells. Hence elevated A1M levels in urine strongly suggest defective reabsorption capacity of proximal tubules indicating kidney function decline. A1M also has reductase properties, thus protecting against oxidative tissue damage. Methods: 30 NAFLD cases with normal eGFR and urine routine microscopy and age and sex matched controls were enrolled into the study. Urinary A1M levels were estimated in both the groups. Subjects were further divided into 3 groups based on grades of fatty liver on ultrasonography and FIB-4 score was calculated. The relationship of Urinary A1M with grades of fatty liver and FIB-4 index was estimated. Results: Urinary A1M was significantly higher in cases as compared to controls (W= 899.0, p=<0.001). Urinary levels of A1M positively correlated with grade of fatty liver. (χ2=23.701, p <0.001), and with FIB-4 index (rho = 0.87, p = <0.001) respectively. All our patients had normal eGFR, normal Urine routine microscopy which indicates that Urinary A1M acts as an important marker to detect early renal injury in NAFLD as compared to eGFR and proteinuria. There was a strong negative correlation between eGFR (mL/min/1.73m2) and Urinary A1M (mg/L)(rho = -0.72, p = <0.001). Conclusions: Our study showed promising results regarding the role of Urinary A1M in detecting fibrosis as well as renal injury in NAFLD. Based on our findings, it is suggested that urinary A1M may be used in assessing fibrosis and renal injury in NAFLD, even with normal range eGFR.