Cystatin C and inflammatory markers in kidney transplant recipients

TNF, IL-6, and IL-10 cytokines levels and their polymorphisms in renal function and time after transplantation

Cytokine polymorphisms can influence their plasma levels and thus affect the immune response in renal transplantation. A total of 146 renal transplant recipients (RTR) were classified into groups according to the estimated glomerular filtration rate (R1: < 60 and R2: ≥ 60 mL/min/1.73 m²) and time after transplantation (T1: 1 to 24, T2: 25 to 60, T3: 61 to 120, and T4: > 120 months after transplantation). The polymorphisms were genotyped by single specific primer-polymerase chain reaction. IL-10 was measured by ELISA and IL-6, and TNF levels were determined using Miliplex®. A higher frequency of the - 308G allele and the - 308G/G genotype, low-producer, was observed in the R1 group compared with R2. In addition, a higher frequency of the - 308A carriers, high-producer, was found in the R2 group. However, no significant difference was observed in cytokine levels when both groups were compared. Higher levels of IL-6 were observed in T1 compared with T2 and T4 groups. Lower IL-6 levels were found in T2 compared with T3 group. Lower levels of IL-10 were also found in T1 group in relation to T2, while higher levels of this cytokine were observed in T2 group compared with T3. The results suggest that the - 308G > A polymorphism in the TNF gene is associated with filtration function after renal transplantation, and IL-6 and IL-10 levels change according to the time after transplantation. Thus, the joint evaluation of - 308G > A polymorphism in TNF gene and IL-6 and IL-10 levels would provide a broader and effective view on the clinical monitoring of RTR.

Remarkable Improvement of Cardiac Function After Pre-emptive Kidney Transplant in a Patient With Severe Mitral Regurgitation Accompanied by Low Cardiac Function: A Case Report

Patients with end-stage renal disease are at a high risk for cardiovascular diseases. It is controversial whether end-stage renal disease patients with low cardiac function can safely accept kidney transplant. Here, we present a 42-year-old kidney transplant recipient with severe mitral regurgitation accompanied by low cardiac function. He wanted to undergo a pre-emptive kidney transplant from his uncle. We decided to perform living kidney transplant prior to cardiac surgery. Despite adequate ultrafiltration and hemodiafiltration before operation, the patient's ejection fraction still remained 35% 1 day before transplant. He showed complete recovery of cardiac function in only 2 days after pre-emptive kidney transplant, although his body weight did not change before and after the operation. Early removal of the uremic toxin or inflammatory cytokines may play a role in rapid improvement of the cardiac function. Increase of vasoactive substances by improvement of kidney function may lead to reduction of afterload and amelioration of cardiac microcirculation. This report also suggests that optimal timing for operation might be important.

The level of intracellular tacrolimus in T cell is affected by CD44+ABCB1+activities triggered by inflammation

Rejection is an important issue in kidney transplant. Although with adequate trough level of tacrolimus, acute rejection occurs, and we are focused on these cases. We hypothesized that the lower concentration of tacrolimus in the peripheral blood mononuclear cell would be a cause of rejection; in this regard, we describe ABCB1, which regulates intracellular concentration of tacrolimus. The effect of inflammation on the intracellular concentration of tacrolimus was evaluated, as was the association between that concentration and ABCB1 and CD44 activities. Seven kidney recipients experiencing acute rejection were prospectively enrolled. Both the whole blood concentration of tacrolimus and intracellular concentration of tacrolimus were measured at the time of enrollment and after stabilization. A human T lymphoblastoid cell line (Jurkat T cell) was treated with various concentrations of tacrolimus for 21 h and then stimulated for 3 h. The levels of mRNA interleukin-2, interleukin-8, and interferon-γ decreased dose dependently by tacrolimus. Furthermore, a fluorescence-activated cell sorter was used to count cells expressing CD44 and ABCB1; changes in intracellular concentration of tacrolimus were explored after tacrolimus treatment and stimulation. Also, B6 splenocytes were tested in the same manner as previous Jurkat T cell experiments. The tacrolimus ratio of three patients was lower at the time of acute rejection than when patients were stabilized. In vitro, the intracellular concentration of tacrolimus decreased after stimulation. Under the same conditions, CD44+ABCB1+cells increased in proportion on tacrolimus treatment and stimulation. This work supports the hypothesis that inflammation reduces the intracellular tacrolimus level, possibly via drug efflux mediated by CD44+ABCB1+and inflammation could lead to acute rejection.

Cystatin C, kidney function, and cardiovascular risk factors in primary hypertension

OBJECTIVE

To investigate the clinical usefulness of serum cystatin C (Scys) and cystatin C-based equations for the screening of chronic kidney disease in primary hypertensive patients, and correlate these markers with risk factors for cardiovascular disease.

METHODS

A cross-sectional study was performed in 199 middle-aged adults at a basic health unit. Kidney function assessment included measurements of serum creatinine (Scr) and Scys levels, 24-hour microalbuminuria (MA), as well as glomerular filtration rate (GFR) through Larsson and Modification of Diet in Renal Disease (MDRD) study equations. Bland- Altman plot analysis was used to calculate the agreement between equations.

RESULTS

High levels of Scys were found in 22% of the patients, even with normal values of GFR estimated by MDRD study equation. Systolic blood pressure and MA correlated better with Scys than Scr, but there was no correlation between Scys and diastolic blood pressure. Gender, age > 60 years, MA, and uric acid were significantly associated with high Scys levels. After multivariate analysis, only age > 60 yrs (RR = 6.4; p < 0.001) and male gender (RR = 3.0; p = 0.006) remained associated with high Scys levels.

CONCLUSION

Cystatin C can be used as a screening marker both for detecting mild declines of renal function and for preventing the risk of cardiovascular events in hypertensive subjects with presumably normal renal function.

How to understand the association between cystatin C levels and cardiovascular disease: Imbalance, counterbalance, or consequence?

The association of cystatin C with renal function has been studied for more than 25 years. Cystatin C has been described to have a better diagnostic performance than creatinine to assess renal function, particularly to detect small reductions in glomerular filtration rate. Recently, cystatin C has emerged as a strong predictor of incident or recurrent cardiovascular events and adverse outcomes in patients without kidney disease. Furthermore, it has been suggested that cystatin C concentrations are directly related to both inflammation and atherosclerosis. Nevertheless, the link between inflammation, atherogenesis, cardiovascular risk, and cystatin C is still poorly understood. This brief report discusses recent data, contrasting findings and possible mechanisms involved in this interaction.