Small dense low-density lipoprotein in renal transplant recipients: a potential target for prevention of cardiovascular complications?

Elevated small dense low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio is associated with an increased risk of metabolic dysfunction associated fatty liver disease in Chinese patients with type 2 diabetes mellitus

INTRODUCTION

It is demonstrated that elevated small dense low-density lipoprotein cholesterol (sdLDL-C), and reduced high-density lipoprotein cholesterol (HDL-C) is associated with Metabolic dysfunction-associated fatty liver disease (MAFLD). This study aims to explore the relationship between sdLDL-C to HDL-C ratio (SHR) and MAFLD in Chinese patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

A cross-sectional study was performed among 1904 patients with T2DM. Weighted multivariable logistic regression analysis was conducted to explore the relationship between the SHR and the risk of MAFLD. In addition, this study used a two-part linear regression model to identify threshold effects. Subgroup analysis, interaction tests and receiver operating characteristic (ROC) curve analysis were also carried out.

RESULTS

The overall MAFLD prevalence reached 48.1%. Multiple logistic regression analysis showed that SHR was positively correlated with the risk of MAFLD (OR = 2.37, 95% CI = 1.80-3.12). Subgroup analysis stratified by age, gender, hypertension and BMI showed that there was a consistent positive correlation. A non-linear relationship and saturation effect between SHR and MAFLD risk were identified, with an inverted L shaped curve and an inflection point at 1.02. The area under the curve (AUC) for SHR in the ROC analysis was significantly greater than sdLDL-C and HDL-C, with a sensitivity of 71.2% and a specificity of 62.1%.

CONCLUSIONS

Elevated levels of SHR is independently associated with an increased risk of MAFLD in patients with T2DM. SHR may be taken as practical indicators to assess the risk of MAFLD in T2DM patients.

Non-Immunologic Causes of Late Death-Censored Kidney Graft Failure: A Personalized Approach

Despite continuous advances in surgical and immunosuppressive protocols, the long-term survival of transplanted kidneys is still far from being satisfactory. Antibody-mediated rejection, recurrent autoimmune diseases, and death with functioning graft are the most frequent causes of late-kidney allograft failure. However, in addition to these complications, a number of other non-immunologic events may impair the function of transplanted kidneys and directly or indirectly lead to their failure. In this narrative review, we will list and discuss the most important nonimmune causes of late death-censored kidney graft failure, including quality of the donated kidney, adherence to prescriptions, drug toxicities, arterial hypertension, dyslipidemia, new onset diabetes mellitus, hyperuricemia, and lifestyle of the renal transplant recipient. For each of these risk factors, we will report the etiopathogenesis and the potential consequences on graft function, keeping in mind that in many cases, two or more risk factors may negatively interact together.

Dyslipidemia in Renal Transplant Recipients

Dyslipidemia is a frequent complication after kidney transplantation (KT) and is an important risk factor for cardiovascular disease (CVD). Renal transplant recipients (RTRs) are considered at high, or very high, risk of CVD, which is a leading cause of death in this patient group. Despite many factors of post-transplant dyslipidemia, the immunosuppressive treatment has the biggest influence on a lipid profile. There are no strict dyslipidemia treatment guidelines for RTRs, but the ones proposing an individual approach regarding CVD risk seem most suitable. Proper diet and physical activity are the main general measures to manage dyslipidemia and should be introduced initially in every patient after KT. In the case of an insufficient correction of lipemia, statins are the basis for hypolipidemic treatment. Statins should be introduced with caution to avoid serious side-effects (e.g., myopathy) or drug-drug interactions, especially with immunosuppressants. To lower the incidence of adverse effects, and improve medication adherence, ezetimibe in combination with statins is recommended. Fibrates and bile sequestrants are not recommended due to their side-effects and variable efficacy. However, several new lipid-lowering drugs like Proprotein convertase subtilisin/Kexin type9 (PCSK9) inhibitors may have promising effects in RTRs, but further research assessing efficacy and safety is yet to be carried out.

Identification of biomarker panels as predictors of severity in coronary artery disease

Matrix metalloproteinases (MMPs) are implicated in atherosclerotic plaque rupture and recondition. Specific tissue inhibitors (TIMPs) control MMP functions. Both MMPs and TIMPs are potential biomarkers of plaque instability. Elevated Apo‐CII and CIII and Apo‐E levels are recognized as cardiovascular disease risk factors. We aimed to establish the best blood biomarker panel to evaluate the coronary artery disease (CAD) severity. Plasma levels of MMP‐3 and MMP‐9, TIMP‐1 and TIMP‐2, Apo‐CII, Apo‐CIII and Apo‐E were measured in 472 patients with CAD evaluated by coronary angiography and electrocardiography, and in 285 healthy controls. MMP‐3 and MMP‐9 plasma levels in CAD patients were significantly increased (P < 0.001) compared to controls (3.54‐ and 3.81‐fold, respectively). Furthermore, these increments are modulated by CAD severity as well as for Apo‐CII and Apo‐CIII levels (P < 0.001). TIMPs levels were decreased in CAD versus controls (P < 0.001) and in inverse correlation to MMPs. Standard ROC curve approach showed the importance of panels of biomarkers, including MMP‐3, MMP‐9, TIMP‐1, TIMP‐2, Apo‐CII and Apo‐CIII, for disease aggravation diagnosis. A high area under curve (AUC) value (0.995) was reached for the association of MMP‐9, TIMP‐2 and Apo‐CIII. The unbalance between MMPs and TIMPs in vascular wall and dyslipidaemia creates favourable conditions for plaque disruption. Our study suggests that the combination of MMP‐9, TIMP‐2 and Apo‐CIII values (‘CAD aggravation panel’) characterizes the severity of CAD, that is electrophysiological state, number of involved vessels, stent disposal and type of stent.

Changes in lipid and carbohydrate metabolism under mTOR- and calcineurin-based immunosuppressive regimen in adult patients after liver transplantation

BACKGROUND

Cardiovascular disease is a leading cause of long-term mortality after liver transplantation (LT). Life long immunosuppression harbors the risk of metabolic alterations. We aimed to analyze the impact of calcineurin (CNI)-only containing regimen (group A) compared to mTOR-containing regimen (group B) on lipid and carbohydrate metabolism.

PATIENTS/METHODS

92 adult patients after LT, University of Mainz (group A-78 patients, group B-14 patients; 65 M/27 F; mean age 59+/-10.2years; mean time from LT 5.8+/-5years). Clinical data, comorbidities, and medication were assessed. Fasting lipid profile including small dense LDLs (sdLDL) and oral glucose tolerance tests were performed.

RESULTS

Group B had significantly higher levels of total cholesterol (TC), LDL-cholesterol (LDL-C), triglycerides (TG) and sdLDL, with persistence of higher TC, TG, sdLDLs (mg/dl) after exclusion of patients under lipid lowering medication. Concentrations above the upper limits of normal were found: for LDL-C in 9% of group A/35.7% of group B (p=0.016); for TG: in 32.1% of group A/92.9% in group B (p=0.0001). A positive correlation between time since LT (years) and sdLDL (mg/dl) was found in group B (p=0.018). In patients without previously known diabetes, NODAT and impaired glucose tolerance developed in 27.9% of group A/44.4% of group B (n.s.).

CONCLUSION

Patients under mTOR-containing regimen are at higher risk to develop dyslipidemia with increased atherogenic sdLDLs compared to patients under CNI-only-containing regimen and display more frequently a dysglycemic status, with uncertain relevance for long-term cardiovascular risk. A careful monitoring after LT is needed to identify early metabolic risk and manage this appropriately.

Post-transplant dyslipidemia: Mechanisms, diagnosis and management

Post-transplant dyslipidemia is highly prevalent and presents unique management challenges to the clinician. The two major outcomes to consider with post-transplant therapies for dyslipidemia are preserving or improving allograft function, and reducing cardiovascular risk. Although there are other cardiovascular risk factors such as graft dysfunction, hypertension, and diabetes, attention to dyslipidemia is warranted because interventions for dyslipidemia have an impact on reducing cardiac events in clinical trials specific to the transplant population. Dyslipidemia is not synonymous with hyperlipidemia. Numerous mechanisms exist for the occurrence of post-transplant dyslipidemia, including those mediated by immunosuppressive drug therapy. Statin therapy has received the most attention in all solid organ transplant recipient populations, although the effect of proper dietary advice and adjuvant pharmacological and non-pharmacological agents should not be dismissed. At all stages of treatment appropriate monitoring strategies for side effects should be implemented so that the benefits from these therapies can be achieved. Clinicians have a choice when there is a conflict between various transplant society and lipid society guidelines for therapy and targets.

LDL-migration index (LDL-MI), an indicator of small dense low-density lipoprotein (sdLDL), is higher in non-alcoholic steatohepatitis than in non-alcoholic fatty liver: a multicenter cross-sectional study

Background

Non-alcoholic fatty liver disease (NAFLD) is associated with increased risks of atherosclerotic diseases, including cardiovascular disease. However, the difference in risk between patients with non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH) has not yet been determined. Accumulating evidence has shown that high amounts of small dense low-density lipoprotein (sdLDL) are closely associated with atherosclerotic diseases. This study investigated differences in risk factors for atherosclerotic diseases, especially LDL-migration index (LDL-MI), an indicator of sdLDL, between patients with NAFL and NASH.

Methods

LDL-MI was analyzed in a primary cohort of 156 patients with NAFLD, including 53 with NAFL and 103 with NASH, and a validation cohort of 69 patients with NAFLD, including 25 with NAFL and 44 with NASH.

Results

In the primary cohort, NASH was associated with elevated LDL-MI (p = 0.039). Multiple regression analysis showed that NASH and the non-use of lipid lowering medications were independently correlated with higher LDL-MI in all patients with NAFLD. Among patients not on lipid lowering medications, those with NASH had significantly higher LDL-MI than those with NAFL (p = 0.001). These findings were confirmed in a validation cohort, in that LDL-MI was significantly higher in patients with NASH than with NAFL (p = 0.043).

Conclusion

This study is the first to show that LDL-MI, an indicator of sdLDL, was higher in patients with NASH than with NAFL, suggesting that the risk of atherosclerotic diseases may be higher in NASH than NAFL. Patients with NASH should be followed closely, especially for the progression of liver pathology and atherosclerotic diseases.

Trial Registration

UMIN000009614

Dyslipidemia following kidney transplantation: diagnosis and treatment

Lipid abnormalities are a common complication of kidney transplantation, occurring in up to 60% of patients. In fact, impairment of lipid metabolism is often present before renal transplantation due to the uremic state. After transplantation and recovery of renal function, lipid disturbances usually persist but show a different profile due to the various effects of immunosuppressive drugs on lipid metabolism. Actually, steroids, calcineurin inhibitors, and mammalian target of rapamycin inhibitors usually lead to quantitative and qualitative abnormalities of very low-density, low-density, and high-density lipoproteins. As cardiovascular diseases remain the leading cause of death in renal transplant recipients, management of dyslipidemia and other traditional risk factors, such as smoking, arterial hypertension, diabetes mellitus, and obesity, is of great importance to prevent cardiovascular complications and chronic allograft dysfunction. This review addresses the causes of dyslipidemia, the role of immunosuppressive drugs, and current recommendations to manage lipid disorders in renal transplant recipients.

Disturbed lipids, lipoproteins and triglyceride-rich lipoproteins as well as fasting and nonfasting non-high-density lipoprotein cholesterol in post-renal transplant patients

Serum levels of lipids and lipoproteins were determined in 98 post-renal transplant fasting patients, and lipids and non-high density lipoprotein-cholesterol (non-HDL-C) and lipid ratios in the same post-renal transplant non-fasting patients were compared. The reference group was 87 healthy subjects. All patients were divided into two groups: patients with dyslipidemia (n = 69) and patients with normolipidemic (n = 29). The post-renal transplant patients (TX) with dyslipidemia had a significantly increased concentration of triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), non-HDL-C, apoB, and TRL and lipid ratios, and decreased HDL-C level and lipoprotein ratios. The lipids, lipoproteins, and lipoprotein ratios were significantly beneficial in TX patients with normolipidemic than in those with dyslipidemia. However, TRL concentration and lipid ratios were significantly increased and apoAI/apoCIII significantly decreased as compared to the reference group. The TX patients with dyslipidemia showed a significant correlation between TG and apoB:CIII (r = 0.562, p < 0.001) and apoCIII (r = 0.380, p < 0.004), but those with normolipidemic showed a significant correlation only between TG and apoCIII (r = 0.564, p < 0.008). Regression and Bland-Altman analyses showed excellent correlation between fasting and nonfasting non-HDL-C levels (r = 0.987, R(2) + 0.987) in TX patients both with dyslipidemia and normolipidemic. We think the finding that nonfasting labs that are reliable for non-HDL-C as well as total cholesterol is important, as fasting labs are not always available. Disturbances of lipids, lipoproteins, and TRLs depend not only on the kind of treatment, but due to multiple factors can accelerate cardiovascular complications in post-renal transplant patients with dyslipidemia and also with normolipidemic. Further studies concerning this problem should be completed.

New onset dyslipidemia after renal transplantation: is there a difference between tacrolimus and cyclosporine?

Lipid abnormalities including increased total cholesterol (TC), triglycerides (TG) and low density lipoprotein cholesterol (LDL-C) have been frequently reported in renal transplantation and could be involved in the high frequency of cardiovascular diseases in this population.

PATIENTS AND METHODS

Two hundred ninety-five patients were transplanted between January 1995 and October 2000 in our center. Two hundred two patients were included in this study. Seventy-six patients received tacrolimus (Tac), and 126 patients cyclosporine (CsA). Lipid parameters were assessed the day of transplantation and 1 year posttransplantation.

RESULTS

Serum lipids were similar between the two groups at D0. At M12, TC and LDL-C were significantly higher in the CsA group (6.14 +/- 1.37 vs 5.28 +/- 1.32 mmol/L; P < .05 and 3.98 +/- 1.05 vs 3.26 +/- 1.03 mmol/L; P < .05 CsA vs Tac, respectively). TG were comparable in both groups (1.86 +/- 1.07 vs 1.62 +/- 0.92 mmol/L; P = .55; CsA vs Tac). Incidence of de novo hypercholesterolemia was significantly higher in the CsA group (28 vs 8%) whereas incidence of hyperTG was similar in both groups. Prevalence of LDL-C was significantly higher in the CsA group (65% vs 31%; P < .001), whereas there was no difference in high density lipoprotein (HDL)-C levels.

DISCUSSION

Mean serum lipid levels and incidence and prevalence of hyperTC, especially LDL-C, was significantly higher in patients receiving CsA when compared with Tac. TG and HDL-C levels were similar. Although the study was retrospective, our results confirm that CsA increases lipid levels, whereas Tac does not.

CONCLUSION

Lipid disorders are frequently observed in renal transplant recipients. CsA, but not Tac, significantly increases incidence and prevalence of high TC and LDL-C.