Lipid disturbances in a two-year follow-up after successful kidney transplantation

Fecal Metabolomics Reveals Distinct Profiles of Kidney Transplant Recipients and Healthy Controls

Monitoring graft recipients remains dependent on traditional biomarkers and old technologies lacking specificity, sensitivity, or accuracy. Recently, metabolomics is becoming a promising approach that may offer to kidney transplants a more effective and specific monitoring. Furthermore, emerging evidence suggested a fundamental role of gut microbiota as an important determinant of patients’ metabolomes. In the current study, we enrolled forty stable renal allografts recipients compared to twenty healthy individuals. Samples were taken at different time points from patient to patient following transplantation surgery, which varied from 3 months to 22 years post-graft. All patients started the immunosuppression therapy immediately following kidney graft (Day 0). Gas chromatography–mass spectrometry (GC–MS) was employed to perform untargeted analysis of fecal metabolites. Globally, the fecal metabolic signature was significantly different between kidney transplants and the control group. Fecal metabolome was dominated by lipids (sterols and fatty acids) in the stable transplant group compared to the controls (p < 0.05). Overall, 18 metabolites were significantly altered within kidney transplant recipients. Furthermore, the most notable altered metabolic pathways in kidney transplants include ubiquinone and other terpenoid-quinone biosynthesis, tyrosine metabolism, tryptophan biosynthesis, and primary bile acid biosynthesis. Fecal metabolites could effectively distinguish stable transplant recipients from controls, supporting the potential utility of metabolomics in rapid and non-invasive diagnosis to produce relevant biomarkers and to help clinicians in monitoring kidney transplants. Further investigations are needed to clarify the physiological relevance of fecal metabolome and to assess the impact of microbiota modulation.

Changes in clinical indicators related to the transition from dialysis to kidney transplantation-data from the ERA-EDTA Registry

Background

Kidney transplantation should improve abnormalities that are common during dialysis treatment, like anaemia and mineral and bone disorder. However, its impact is incompletely understood. We therefore aimed to assess changes in clinical indicators after the transition from chronic dialysis to kidney transplantation.

Methods

We used European Renal Association–European Dialysis and Transplant Association Registry data and included adult dialysis patients for whom data on clinical indicators before and after transplantation (2005–15) were available. Linear mixed models were used to quantify the effect of transplantation and of time after transplantation for each indicator.

Results

In total, 16 312 patients were included. The mean age at transplantation was 50.1 (standard deviation 14.2) years, 62.9% were male and 70.2% were on haemodialysis before transplantation. Total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol and triglycerides increased right after transplantation but decreased thereafter. All other indicators normalized or approached the target range soon after transplantation and these improvements were sustained for the first 4 years of follow-up. In patients with higher estimated glomerular filtration rate (eGFR) levels (30–60 and >60 mL/min/1.73 m²), the improvement of haemoglobin, ferritin, ionized calcium, phosphate, parathyroid hormone, HDL cholesterol, triglycerides, albumin and C-reactive protein levels was more pronounced than in patients with a lower eGFR (<30 mL/min/1.73 m²).

Conclusions

Except for total cholesterol, LDL cholesterol and triglycerides, all clinical indicators improved after transplantation. These improvements were related to eGFR. Nevertheless, values remained out of range in a considerable proportion of patients and anaemia and hyperparathyroidism were still common problems. Further research is needed to understand the complex relationship between eGFR and the different clinical indicators.

Progression of alterations in lipid metabolism in kidney transplant recipients over 5 years of follow-up

BACKGROUND

Alterations in lipid metabolism frequently affect kidney transplant recipients and contribute to the onset of metabolic and cardiovascular diseases that threaten graft integrity. The purpose of this research study was to investigate the pattern of hyperlipidaemia and its progression, as well as to study potential risk factors in kidney transplant recipients.

METHODS

In this study, 119 kidney transplant recipients of both sexes were monitored over a period of 5 years in our posttransplant clinic. During this period, all patients had pretransplant and posttransplant blood tests to measure levels of the following: total cholesterol, low-density lipoproteins (LDL), high-density lipoproteins (HDL) and triglycerides. Furthermore, the subjects were also weighed and their height measured. Their body mass index was then calculated using the weight (kg)/height (m(2) ) formula.

RESULTS

In the 5 years following the transplant, the patients experienced a significant increase in the levels of their biochemical markers as well as in their BMI. Consequently, a greater number suffered from dyslipidaemia, diabetes and hypertension.

CONCLUSIONS

Kidney transplants can often trigger hyperlipidaemia, as reflected in higher levels of total cholesterol, low-density lipoproteins and high-density lipoproteins. The results of our study also showed that despite statin therapy, the patients had higher triglyceride levels, which made them more vulnerable to diabetes, hypertension, cardiovascular disease and graft rejection.

Dyslipidemia can be controlled in diabetic as well as nondiabetic recipients after kidney transplant

BACKGROUND

Patients with diabetes have been reported to have greater dyslipidemia after kidney transplant (KTX). Because postKTX management of diabetes has changed markedly since those reports, we hypothesized that lipids can be controlled as well in diabetic as in nondiabetic recipients.

METHODS

We compared lipid levels up to 2 years after KTX (n=192) between diabetic and nondiabetic recipients. The cohort was subdivided into nondiabetic (nonDM-K; n=123), type 2 (DM2-K; n=33), or type 1 diabetes after KTX (DM1-K; n=14), or type 1 after kidney-pancreas transplant (DM1-KP; n=22).

RESULTS

Mean age and body mass index of DM2-K were greater than the others (P<0.01), and diabetes groups had a higher pretransplant A1C than nonDM-K (P<0.001). After KTX, lipid levels were not higher in diabetic than in nondiabetic recipients, and did not increase in any group. Total and low-density lipoprotein cholesterol levels decreased in DM1-K (P<0.001), high-density lipoprotein levels decreased in DM1-KP (P=0.02), and triglyceride levels were unchanged after KTX for all groups. A1C improved in DM1-K and DM1-KP (P<0.0001). There was less improvement in lipid levels with tacrolimus-sirolimus immunosuppression than with other steroid-containing regimens (P<0.05).

CONCLUSIONS

Multiple mechanisms may contribute to better lipid levels in both groups as well as the lack of difference between diabetic and nondiabetic recipients compared with what has been reported previously: greater use of and more effective lipid-lowering agents, no significant weight gain, no difference in renal function between groups, and better control of glucose in the diabetic group. Thus, overall, lipids can be controlled as well in diabetic as in nondiabetic KTX recipients.

Simvastatin down regulates mRNA expression of RANTES and CCR5 in posttransplant renal recipients with hyperlipidemia

Chemokines and hyperlipidemia are involved in the mechanism of chronic allograft nephropathy (CAN). In this study, the mRNA expression of RANTES and its receptor CCR5 on peripheral blood mononuclear cells were measured in renal transplant recipients with hyperlipidemia, and the effect of simvastatin treatment observed to investigate the mechanism and prevention of CAN. Sixty recipients selected from 167 renal transplant recipients were divided into two groups: group A without hyperlipidemia (n = 30) and group B with hyperlipidemia (n = 30). The control group consisted of 30 healthy volunteers. The recipients in group B were treated with simvastatin for 3 months. We estimated serum lipid levels and mRNA expressions of RANTES and CCR5. The mRNA expressions of RANTES and CCR5 were significantly higher in renal transplant recipients compared with controls. The expressions were much higher in group B than in group A patients. In group B patients, serum lipid levels decreased dramatically after simvastatin treatment. Meanwhile, the mRNA expressions of RANTES and CCR5 were reduced significantly after 1.5 months of simvastatin treatment to a level significantly lower than that in group A after 3 months of treatment. The increased expressions of RANTES and CCR5 mRNAs in renal transplant recipients with hyperlipidemia might be involved in CAN due to hyperlipidemia. Simvastatin seemed to reduce the chemokine transcripts in renal recipients with hyperlipidemia.

A long-term study on hyperlipidemia in stable renal transplant recipients

OBJECTIVES

Hyperlipidemia is a common and important risk factor after renal transplantation, but there is little long-term data on its incidence, pattern, and evolution in stable renal allograft recipients on low dose maintenance immunosuppression.

PATIENTS AND METHODS

A retrospective study was conducted on all patients who received kidney transplants from April 1, 1990 to March 31, 2000 at a single center, on their serial lipid profile during the first 3 yr after kidney transplantation.

RESULTS

A total of 221 (122 male, 99 female; mean age 37.8 +/- 10.0 yr at the time of transplantation) Chinese adult renal allograft recipients were included. A 95.3% of patients were on cyclosporine and prednisolone based immunosuppression. Increases in total cholesterol (TC), low density lipoprotein (LDL), and high density lipoprotein (HDL) were noted, while the level of triglyceride (TG) decreased after renal transplant. The incidence of hypercholesterolemia (defined as TC >/= 6.3 mmol/L or LDL >/= 4.2 mmol/L) within the first year was 28.2 and 20.3%, respectively. The incidence rate decreased significantly in the second (5.4%, p = 0.000 and 6.4%, p = 0.003) and third year (9.5%, p = 0.003 and 4.9%, p = 0.021), but the incidence of patients having a high risk-ratio (defined as TC/HDL >/= 5) remained unchanged (6.9, 4.9 and 10.3% within the first, second, and third year, respectively). Treatment with statin was necessitated in 6.8, 13.6 and 21.7% of the patients at 1, 2, and 3 yr after transplantation, respectively. The prevalence rates of elevated TC and LDL were 18.3 and 18.9% at baseline, 40.6 and 33.3% after 1 yr, 32.8 and 27.3% after 2 yr, and 24.8 and 19.0% after 3 yr, despite treatment. The prevalence of patients with a high risk-ratio was 45.0% at baseline, 30.5% after 1 yr (p = 0.002), 22.6% after 2 yr (p = 0.000) and 21.8% after 3 yr (p = 0.000). Hypercholesterolemia at the time of transplantation was an independent predictor for post-transplant hypercholesterolemia (odds ratio 3.76, 95% confidence interval 1.47-9.62, p = 0.006).

CONCLUSION

Renal transplantation is associated with a characteristic pattern of dyslipidemia, with increased TC, LDL and HDL, and a decrease in TG. Patients with pre-existing hypercholesterolemia were at higher risk for post-transplant hypercholesterolemia. Although the incidence of hypercholesterolemia peaks within the first year after transplantation, this remains a long-term complication in a significant proportion of patients on low dose immunosuppressive medications.

Renal function and lipid metabolism in pregnant renal transplant recipients

OBJECTIVE

To estimate renal function and lipid metabolism in pregnant renal transplant recipients.

STUDY DESIGN

The study covered 64 women during the third trimester of pregnancy including 33 renal transplant recipients (the study group) and 31 healthy women (the control group). Serum concentrations of uric acid, urea, creatinine, electrolytes, total protein, albumin, acid-base balance and blood cell count were examined to assess renal function. Moreover, the levels of the following lipid metabolism parameters were estimated: (1) total lipids (TL), (2) total LDL fraction (TLDL), (3) total cholesterol (TCh), (4) free cholesterol (fCh), (5) free/total cholesterol (fCh/TCh) ratio, (6) phospholipids (PhL), (7) total cholesterol/phospholipids (fCh/PhL) ratio, (8) triglycerides (TG), (9) HDL-cholesterol (HDL-Ch), (10) LDL-cholesterol (LDL-Ch) and (11) LDL-Ch/HDL-Ch ratio. 'The effect of immunosuppressants (cyclosporine, prednisone and azathioprine) on serum lipid levels was estimated in the study group. The mean maternal age, gestational age and BMI did not differ in both groups.

RESULTS

Pregnant renal transplant recipients presented mild renal insufficiency during the third trimester resulting in the increase in serum level of uric acid (P<0.001), urea (P<0.001), creatinine (P<0.001), and Cl- (P<0.001). Proteinuria (1.19+/-1.9 g/24 h) leading to hypoproteinemia (P<0.001) and hypoalbuminemia (P<0.05) confirmed renal function impairment in the study group. Additionally, the diagnosis of renal insufficiency was supported by mild acidosis reflected by a drop in pH (P<0.001). standard HCO3- (P<0.001) and base excess (P<0.001). The women with renal grafts presented vital lipid metabolism disturbances illustrated by the elevated levels of: (1) TL by 72% (P<0.001), (2) TLDL by 21% (P<0.001), (3) TCh by 16% (P<0.001), (4) fCh by 34% (P<0.001), (5) fCh/TCh ratio by 21% (P<0.001), (6) PhL by 28% (P<0.001), (7) TG by 53% (P<0.001), (8) LDL-Ch by 13% (P<0.05) and (9) LDL-Ch/HDL-Ch ratio by 23% (P<0.001). No difference in HDL-Ch level between the two groups was found. Hyperlipidemia in pregnant kidney recipients was associated with immunosuppressive treatment and depended on cyclosporine treatment regimen. Treatment with azathioprine and prednisone was associated with elevated serum levels of examined lipids.

CONCLUSION

Serum lipid abnormalities are significantly influenced by the administered dosages of immunosuppressants.