Relationships of the size of abdominal and perirenal fat depots with markers of meta‑inflammatory and renal damage in patients with resistant hypertension

Abstract

Objective. To study possible correlations between the quantitative characteristics of fat depots in the abdominal and perirenal regions according to magnetic resonance imaging (MRI) data with metabolic and immunoinflammatory parameters, renal function, blood pressure (BP), as well as anthropometric data in patients with resistant hypertension (RH).Design and methods. Sixty-three patients (26 men) with RH aged 60 [54; 64] years who were receiving individual treatment with antihypertensive medication (mean, 4,3 ± 1,1 drug per day) were included in the study. Systolic/diastolic/pulse BP (SBP/DBP/PBP) was 157,7 ± 15,4 / 86,3 ± 13,6 / 71,3 ± 14,5 mm Hg. Mean body mass index (BMI) 34,1 [31,0; 38,5] kg/m2, waist circumference (WC) 108 [102; 113] cm (95,2 % with abdominal obesity). Diabetes mellitus type 2 suffered 51,6 %, chronic kidney disease C3–30,6 %. Clinical and laboratory examinations were performed. Creatinine level with estimated glomerular filtration rate (CKD-EPI), biomarker levels were assessed by ELISA. MRI was performed in a high-field tomograph with a magnetic field induction on 1,5 T. Mean parameter values in apparently healthy volunteers were considered normal. The area of visceral adipose tissue (S VAT) and subcutaneous adipose tissue (S SAT) was determined at the L4-L5 level (normal 123,5 [101,0; 169,0] and 216,5 [167,0; 287,0] cm2, respectively); kidney diameter — the anterior-posterior size of the kidney at the level of the renal vein (normal 5,0 [4,4; 5,4] cm); the thickness of perirenal adipose tissue (PRAT) as the difference between the distance between the sheets of Gerota’s fascia at the level of the renal vein and the diameter of the kidney (normal 1,2 [0,9; 2,4] cm); thickness of anterior subcutaneous adipose tissue (SATT) at the level of the umbilicus (normal 2,7 [1,8; 3,8] cm), the ratio of PRAT/SATT (normal 0,72 ± 0,61).Results. An increase was observed in all fat depots: S VAT 271,2 ± 104,4 cm2, S SAT 309,5 [236,0; 400,0] cm2, PRAT 2,7 [1,8; 3,9] cm, SATT 3,0 [2,3; 3,7] cm. Anthropometric parameters were associated with S VAT and S SAT. The thickness of PRAT correlated only with weight (r = 0,44) and WC (r = 0,41), whereas SATT correlated with BMI (r = 0,49). The PRAT/SATT ratio was not dependent on BMI. S VAT was associated with the level of PBP (r = 0,30). The following associations were observed with metainflammatory markers: TNF-α with S VAT (r = 0,31) and S SAT (r = 0,43) and with BMI (r = 0,32) and WC (r = 0,38); hsCRP with S SAT (r = 0,30), PRAT thickness (r = 0,34), and SATT (r = 0,34); leptin level correlated only with subcutaneous adipose tissue (S SAT, r = 0,60 and SATT, r = 0,69) and BMI (r = 0,51). Kidney size was 5,5 [5,0; 6,0] cm and was not associated with BMI. A decrease in kidney size was associated with a decrease in estimated glomerular filtration rate (r = 0,36). Glomerular filtration rate was associated with PRAT, as was creatinine (r = 0,43), which was also correlated with S VAT (r = 0,32). No correlations were found between renal function and anthropometric data.Conclusions. In patients with RH, there is an increase in the size of fat depots in the abdominal and perirenal regions according to MRI, which are closely related to anthropometric parameters and markers of inflammation. A direct correlation between the serum concentration of leptin and the size of subcutaneous adipose tissue has been established. An increase in the ratio of PRAT/SATT indicates an increase in the predominantly visceral component of adipose tissue and is associated with an increase in PBP, which reflects vascular stiffness. The decrease in the filtration function of the kidneys is correlated with an increase in the size of perirenal fat depots in the absence of direct links with dimensions of subcutaneous adipose tissue and anthropometric characteristics.