Metabolic cardiovascular syndrome after renal transplantation

Diabetes and Cardiovascular Risk in Renal Transplant Patients

End-stage kidney disease (ESKD) is a main public health problem, the prevalence of which is continuously increasing worldwide. Due to adverse effects of renal replacement therapies, kidney transplantation seems to be the optimal form of therapy with significantly improved survival, quality of life and diminished overall costs compared with dialysis. However, post-transplant patients frequently suffer from post-transplant diabetes mellitus (PTDM) which an important risk factor for cardiovascular and cardiovascular-related deaths after transplantation. The management of post-transplant diabetes resembles that of diabetes in the general population as it is based on strict glycemic control as well as screening and treatment of common complications. Lifestyle interventions accompanied by the tailoring of immunosuppressive regimen may be of key importance to mitigate PTDM-associated complications in kidney transplant patients. More transplant-specific approach can include the exchange of tacrolimus with an alternative immunosuppressant (cyclosporine or mammalian target of rapamycin (mTOR) inhibitor), the decrease or cessation of corticosteroid therapy and caution in the prescribing of diuretics since they are independently connected with post-transplant diabetes. Early identification of high-risk patients for cardiovascular diseases enables timely introduction of appropriate therapeutic strategy and results in higher survival rates for patients with a transplanted kidney.

Obesity, Fat Tissue Parameters, and Arterial Stiffness in Renal Transplant Recipients

OBJECTIVE

Arterial stiffness and altered body composition (increased body fat mass [BFM] and decreased lean body mass) are acknowledged risk factors for adverse outcomes after kidney transplantation related to cardiovascular diseases. The aim of the study was the assessment of the relationship between arterial stiffness and fat tissue parameters in renal transplants recipients (RTrs).

METHODS

A group of 344 RTrs with stable disease and a mean age of 52.7 years (62.5% men) who underwent transplantation between 1994 and 2018 were randomly enrolled in the study. The following parameters of arterial stiffness were measured: brachial-ankle and carotid-femoral pulse waves velocities (baPWVs left and right, cfPWVs). The obesity and fat tissue (body mass index [BMI], waist-to-hip ratio [WHR], BFM, fat free mass [FFM], percent body fat [PBF], trunk segmental fat analysis [TSFA], and visceral fat area [VFA]) parameters were assessed with InBody 170.

RESULTS

The median time of dialysis and after kidney transplantation was 58.5 and 78 months, respectively. Obesity according BMI, WHR, and VFA was diagnosed in 49.7%, 45.0%, and 44.5% of patients, respectively. The median value of BFM, FFM, VFA, and TSFA and the mean value of PBF were 19.3 kg, 55 kg, 93.2 cm², 24.9 kg, and 27.3%, respectively. We found significant positive correlations among WHR, VFA, baPWV right, baPWV left, and cfPWV.

CONCLUSIONS

Obesity and visceral fat tissue influence on arterial stiffness. The analysis of magnitude of obesity and body fat tissue parameters can be used as an additional cardiovascular risk factor in RTrs.

Modifiable Variables Are Major Risk Factors for Posttransplant Diabetes Mellitus in a Time-Dependent Manner in Kidney Transplant: An Observational Cohort Study

Modifiable and nonmodifiable risk factors for developing posttransplant diabetes mellitus (PTDM) have already been established in kidney transplant setting and impact adversely both patient and allograft survival. We analysed 450 recipients of living and deceased donor kidney transplants using current immunosuppressive regimen in the modern era and verified PTDM prevalence and risk factors over three-year posttransplant. Tacrolimus (85%), prednisone (100%), and mycophenolate (53%) were the main immunosuppressive regimen. Sixty-one recipients (13.5%) developed PTDM and remained in this condition throughout the study, whereas 74 (16.5%) recipients developed altered fasting glucose over time. Univariate analyses demonstrated that recipient age (46.2 ± 1.3vs. 40.7 ± 0.6 years old, OR 1.04; P = 0.001) and pretransplant hyperglycaemia and BMI ≥ 25 kg/m2 (32.8% vs. 21.6%, OR 0.54; P = 0.032 and 57.4% vs. 27.7%, OR 3.5; P < 0.0001, respectively) were the pretransplant variables associated with PTDM. Posttransplant transient hyperglycaemia (86.8%. 18.5%, OR 0.03; P = 0.0001), acute rejection (P = 0.021), calcium channel blockers (P = 0.014), TG/HDL (triglyceride/high-density lipoprotein cholesterol) ratio ≥ 3.5 at 1 year (P = 0.01) and at 3 years (P = 0.0001), and tacrolimus trough levels at months 1, 3, and 6 were equally predictors of PTDM. In multivariate analyses, pretransplant hyperglycaemia (P = 0.035), pretransplant BMI ≥ 25 kg/m2 (P = 0.0001), posttransplant transient hyperglycaemia (P = 0.0001), and TG/HDL ratio ≥ 3.5 at 3-year posttransplant (P = 0.003) were associated with PTDM diagnosis and maintenance over time. Early identification of risk factors associated with increased insulin resistance and decreased insulin secretion, such as pretransplant hyperglycaemia and overweight, posttransplant transient hyperglycaemia, tacrolimus trough levels, and TG/HDL ratio may be useful for risk stratification of patients to determine appropriate strategies to reduce PTDM.

More potent lipid-lowering effect by rosuvastatin compared with fluvastatin in everolimus-treated renal transplant recipients

BACKGROUND

Dyslipidemia is a risk factor for premature cardiovascular morbidity and mortality in renal transplant recipients (RTRs). Pharmacotherapy with mTOR inhibitors aggravates dyslipidemia, thus necessitating lipid-lowering therapy with fluvastatin, pravastatin, or atorvastatin. These agents may not sufficiently lower lipid levels, and therefore, a more potent agent like rosuvastatin maybe needed.

METHODS

We have aimed to assess the lipid-lowering effect of rosuvastatin as compared with fluvastatin in RTR receiving everolimus. Safety was assessed as the pharmacokinetic (PK) interaction potential of a rosuvastatin/everolimus combination in RTR. A 12-hour everolimus PK investigation was performed in 12 stable RTR receiving everolimus and fluvastatin (80 mg/d). Patients were then switched to rosuvastatin (20 mg/d), and a follow-up 12/24-hour PK investigation of everolimus/rosuvastatin was performed after 1 month. All other drugs were kept unchanged.

RESULTS

In RTR already receiving fluvastatin, switching to rosuvastatin further decreased LDL cholesterol and total cholesterol by 30.2±12.2% (P<0.01) and 18.2±9.6% (P<0.01), respectively. Everolimus AUC0-12 was not affected by concomitant rosuvastatin treatment, 80.3±21.3 μg*h/L before and 78.5±21.9 μg*h/L after, respectively (P=0.61). Mean rosuvastatin AUC0-24 was 157±61.7 ng*h/mL, approximately threefold higher than reported in the literature for nontransplants. There were no adverse events, and none of the patients had or developed proteinuria.

CONCLUSION

Rosuvastatin showed a superior lipid-lowering effect compared to fluvastatin in stable RTR receiving everolimus. The combination of everolimus/rosuvastatin seems to be as safe as the everolimus/fluvastatin combination.

Dietary intake as a link between obesity, systemic inflammation, and the assumption of multiple cardiovascular and antidiabetic drugs in renal transplant recipients

We evaluated dietary intake and nutritional-inflammation status in ninety-six renal transplant recipients, 7.2 ± 5.0 years after transplantation. Patients were classified as normoweight (NW), overweight (OW), and obese (OB), if their body mass index was between 18.5 and 24.9, 25.0 and 29.9, and ≥ 30 kg/m(2), respectively. Food composition tables were used to estimate nutrient intakes. The values obtained were compared with those recommended in current nutritional guidelines. 52% of the patients were NW, 29% were OW, and 19% were OB. Total energy, fat, and dietary n-6 PUFAs intake was higher in OB than in NW. IL-6 and hs-CRP were higher in OB than in NW. The prevalence of multidrug regimen was higher in OB. In all patients, total energy, protein, saturated fatty acids, and sodium intake were higher than guideline recommendations. On the contrary, the intake of unsaturated and n-6 and n-3 polyunsaturated fatty acids and fiber was lower than recommended. In conclusion, the prevalence of obesity was high in our patients, and it was associated with inflammation and the assumption of multiple cardiovascular and antidiabetic drugs. Dietary intake did not meet nutritional recommendations in all patients, especially in obese ones, highlighting the need of a long-term nutritional support in renal transplant recipients.

Clinical diagnosis of metabolic syndrome: predicting new-onset diabetes, coronary heart disease, and allograft failure late after kidney transplant

Metabolic syndrome is associated with coronary heart disease (CHD) and new-onset diabetes after kidney transplant (NODAT). Using data collected from transplant centers worldwide for the Patient Outcomes in Renal Transplantation study, we examined associations of metabolic syndrome (n = 2253 excluding recipients with diabetes pretransplant), CHD (n = 2253), and NODAT (n = 1840 further excluding recipients with diabetes in the first year post-transplant), with the primary outcome of allograft failure. We assessed risk factors associated with secondary outcomes of metabolic syndrome, NODAT, and CHD after adjusting for type of baseline immunosuppression and transplant center effects. Metabolic syndrome prevalence was 39.8% at 12-24 months post-transplant and 35.4% at 36-48 months. Metabolic syndrome was independently associated with NODAT (hazard ratio 3.46, 95% confidence interval 2.40-4.98, P < 0.0001), CHD (2.03, 1.16-3.52, P = 0.013), and allograft failure (1.36, 1.03-1.79, P = 0.028). Allograft failure occurred in 218 patients (14.6%). After adjustment for metabolic syndrome, NODAT (1.63, 1.18-2.24, P = 0.003) and CHD (5.48, 3.27-9.20, P < 0.0001) remained strongly associated with increased risk of allograft failure. Metabolic syndrome, NODAT, and CHD are risk factors for allograft failure. NODAT and CHD are risk factors for allograft failure, independent of metabolic syndrome.

Association between CYP3A5 polymorphisms and blood pressure in kidney transplant recipients receiving calcineurin inhibitors

Abstract Renal cytochrome P450 3A5 (CYP3A5) has been associated with blood pressure (BP) control in humans. We investigated whether CYP3A5 polymorphisms are associated with post- transplant hypertension in a selected population of kidney recipients receiving calcineurin inhibitors. Ninety-two kidney transplant recipients receiving cyclosporine (CyA) or tacrolimus (Tac) were genotyped for CYP3A5 polymorphisms, and the association between the CYP3A5 alleles (*1,*3) and hypertension on post-operative day (POD) 6 and POD 180 was verified, with multiple regression being used to identify the putative co-variates that may predict the extent and severity of hypertension in transplant recipients at different post-transplant times. The CYP3A5*1 carriers had higher systolic (SBP) and diastolic blood pressure (DBP) in both the immediate and delayed post-transplant period when adjusted for anti-hypertensive medication (POD 6: SBP = 161 ± 23 vs. 140 ± 23 mmHg; DBP = 120 ± 15 vs. 87 ± 14 mmHg, p < 0.05. POD 180: SBP = 136 ± 16 vs. 129 ± 14 mmHg; DBP = 89 ± 15 vs. 80 ± 15 mmHg, p < 0.05). The severity of hypertension between the CYP3A5*1 carriers and noncarriers on POD 6 was documented by the significantly different distribution of hypertension classes, but this was not confirmed on POD 180. The CYP3A5 genotype was the only independent variable affecting mean arterial pressure. The results of this study show that CYP3A5 polymorphisms are associated with the severity and degree of hypertension in kidney transplant recipients receiving calcineurin inhibitors regardless of the time of recording. However, the role of concomitant medications such as steroids with strong CYP3A5 inducing activity, should be taken into account.

Prevalence and long-term glucose metabolism evolution of post-transplant diabetes mellitus in Chinese renal recipients

AIM

To assess the prevalence and predictors of post-transplant diabetes mellitus (PTDM) in Chinese renal recipients and describe their long-term evolution of glucose metabolism.

METHODS

887 non-diabetic Chinese adult renal recipients were studied retrospectively, with a median follow-up of 7 years. PTDM patients were categorized into transient PTDM and permanent PTDM. The cumulative incidence and risk factors of PTDM were estimated by Kaplan-Meier and Cox regression.

RESULTS

The cumulative incidence of PTDM at 3 months, 1, 3, 5, 10, 15 and 20 years post-transplant was 10.4%, 11.4%, 13.4%, 15.2%, 22.7%, 27.9% and 38.3%, respectively. 61.9% of PTDM cases were diagnosed within the first three months and 61.6% of them developed persistent diabetes in the future. Risk factors for all PTDM included older age, body mass index (BMI)≥25 kg/m(2), triglycerides≥1.5 mmol/L, rejection, the use of tacrolimus and diltiazem. The predictors of permanent PTDM included age >50 years (RR=2.322, 95% CI 1.255-4.296, P=0.007), BMI≥25 kg/m(2) (RR=1.699, 95% CI 1.014-2.846, P=0.044) and the use of tacrolimus (RR=1.835, 95% CI 1.181-2.851, P=0.007).

CONCLUSIONS

Patients were most susceptible to PTDM within the first three months post-transplant and more than half of them developed persistent diabetes in the future. Age >50 years, overweight and tacrolimus application were risk factors for both PTDM and permanent PTDM.

Metabolic syndrome and new onset diabetes after transplantation in kidney transplant recipients

BACKGROUND

Metabolic syndrome (MS) and new onset diabetes after transplant (NODAT) are common in kidney transplant patients. We studied the relationship between the two conditions and their impact on metabolic and cardiovascular risk profiles.

METHODS

All non-diabetic patients transplanted between 1999 and 2005 who were followed up to 2006 were included. MS and NODAT were determined. Kaplan-Meier survival and various regression analyses were performed to determine the clinical correlates for both conditions and their association with various cardiovascular risk factors.

RESULTS

Among 591 patients, 314 (53.1%) had MS and 90 (15.2%) developed NODAT. The two conditions were highly associated with each other as 84 patients with NODAT also had MS (14.2%). Elevated body mass index and fasting glucose levels at transplant were risk factors for both conditions, whereas weight gain after transplant was associated only with MS. African American, old age, and hypertension-related ESRD were risk factors for NODAT. Finally, the presence of MS was associated with reduced kidney function and elevated uric acid levels, whereas the presence of NODAT with elevated pulse pressure.

CONCLUSIONS

MS and NODAT are highly prevalent and significantly associated with impaired metabolic and cardiovascular risk profiles. Early identification of such conditions may facilitate targeted therapeutic intervention.

New-onset diabetes mellitus in kidney transplant recipients discharged on steroid-free immunosuppression

BACKGROUND

New-onset diabetes after transplant (NODAT) is a serious complication after kidney transplantation. We studied the relationship between steroid-free maintenance regimens and NODAT in a national cohort of adult kidney transplant patients.

METHODS

A total of 25,837 previously nondiabetic kidney transplant patients, engrafted between January 1, 2004, and December 31, 2006, were included in the study. Logistic regression analysis was used to compare the risk of developing NODAT within 3 years after transplant for patients discharged with and without steroid-containing maintenance immunosuppression regimens. The effect of transplant program-level practice regarding steroid-free regimens on the risk of NODAT was studied as well.

RESULTS

The cumulative incidence of NODAT within 3 years of transplant was 16.2% overall; 17.7% with maintenance steroids and 12.3% without (P<0.001). Patients discharged with steroids had 42% greater odds of developing NODAT compared with those without steroids (adjusted odds ratio [AOR]=1.42, 95% confidence interval [CI]=1.27-1.58, P<0.001). The maintenance regimen of tacrolimus and mycophenolate mofetil or mycophenolate sodium was associated with 25% greater odds of developing NODAT (AOR=1.25, 95% CI=1.08-1.45, P=0.003) than the regimen of cyclosporine and mycophenolate mofetil or mycophenolate sodium. Several induction therapies also were associated with lower odds of NODAT compared with no induction. Patients from programs that used steroid-free regimens for a majority of their patients had reduced odds of NODAT compared with patients from programs discharging almost all of their patients on steroid-containing regimens.

CONCLUSION

The adoption of steroid-free maintenance immunosuppression at discharge from kidney transplantation in selected patients was associated with reduced odds of developing NODAT within 3 years.

Low physical activity and risk of cardiovascular and all-cause mortality in renal transplant recipients

BACKGROUND AND OBJECTIVES

Low physical activity (PA) is a risk factor for mortality in the general population. This is largely unexplored in renal transplant recipients (RTRs). We studied whether PA is associated with cardiovascular and all-cause mortality in a prospective cohort of RTR.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Between 2001 and 2003, 540 RTRs were studied (age, 51 ± 12 years; 54% male). PA was assessed using validated questionnaires (Tecumseh Occupational Activity Questionnaire and the Minnesota Leisure Time Physical Activity Questionnaire). Cardiovascular and all-cause mortality were recorded until August 2007.

RESULTS

Independent of age, PA was inversely associated with metabolic syndrome, history of cardiovascular disease, fasting insulin, and triglyceride concentration, and positively associated with kidney function and 24-hour urinary creatinine excretion (i.e., muscle mass). During follow-up for 5.3 years (range, 4.7 to 5.7 years), 81 RTRs died, with 37 cardiovascular deaths. Cardiovascular mortality was 11.7, 7.2, and 1.7%, respectively, according to gender-stratified tertiles of PA (P=0.001). All-cause mortality was 24.4, 15.0, and 5.6% according to these tertiles (P<0.001). In Cox regression analyses, adjustment for potential confounders including history of cardiovascular disease, muscle mass, and traditional risk factors for cardiovascular disease did not materially change these associations.

CONCLUSIONS

Low PA is strongly associated with increased risk for cardiovascular and all-cause mortality in RTRs. Intervention studies are necessary to investigate whether PA improves long-term survival after renal transplantation.

Risk factors and outcomes associated with posttransplant diabetes mellitus in kidney transplant recipients

BACKGROUND

Although our understanding of the risk factors involved in the occurrence of posttransplant diabetes mellitus (PTDM) as well as its outcomes has improved, it still remains incomplete. Our study attempts to analyze the risk factors as well as the outcomes associated with PTDM in the renal transplant patients at the Cleveland Clinic.

METHODS

Our study is a retrospective, case-control study. We screened 209 charts of 217 patients who received single-organ kidney transplant at the Cleveland Clinic between January 1996 and December 1998. PTDM was defined by the American Diabetes Association criteria of either a fasting blood glucose >or=126 mg/dL or random blood sugars >or=200 mg/dL confirmed on a second occasion. Kidney transplant recipients who developed PTDM (cases) were compared with kidney transplant recipients who did not develop diabetes but were matched for the time of transplant (controls).

RESULTS

Forty-nine patients (23%) developed PTDM. The data of 47 cases and 47 controls were analyzed. Age >or=40 years, body mass index >or=30, pretransplant triglyceride levels >150 mg/dL, and presence of graft rejection were significant risk factors for developing PTDM. Smoking was associated with increased risk of PTDM but failed to achieve statistical significance. Compared with controls, PTDM patients had higher risk of cardiovascular disease, infections, and graft rejection.

CONCLUSION

Our results show that PTDM is a significant problem after kidney transplantation, and those who have high risk should be closely monitored after transplant and aggressively treated if they develop diabetes to minimize the risk of complications.

Abnormal glucose metabolism and metabolic syndrome in non-diabetic kidney transplant recipients early after transplantation

BACKGROUND

Abnormal glucose metabolism (AGM) and metabolic syndrome (MS) are individually associated with a poor cardiovascular outcome in kidney transplant recipients. We prospectively studied the relationship between AGM and MS in non-diabetic kidney transplant recipients early after transplantation.

METHODS

A total of 203 de novo kidney transplant recipients underwent standard 2-hr glucose tolerance test 10 weeks after transplantation. Demographic and clinical characteristics were collected. AGM was defined as impaired fasting glucose, impaired glucose tolerance, and new onset diabetes after transplant according to the WHO criteria, and MS was defined according to the National Cholesterol Education Expert Panel criteria.

RESULTS

Overall, 97 patients (47.8%) met the diagnosis of AGM and 98 patients (48.3%) met the criteria of MS. AGM and MS are highly associated (chi, P<0.001). Fasting plasma glucose levels before the transplant are independent predictors common for AGM and MS. Age predicts AGM with and without MS, whereas body mass index before transplant predicts MS. Patients with impaired glucose tolerance and new-onset diabetes after transplant displayed significant worsening of their fasting plasma glucose levels during the 10-week observational period. MS and the components of MS, but not AGM, were associated with reduced transplant renal function (P=0.002).

CONCLUSION

The early screening of AGM and MS should be emphasized, and the role of early therapeutic interventions aimed at both conditions explored. The long-term follow-up of these patients will yield more insight on the significance of such findings.

Early high pulse pressure is associated with graft dysfunction and predicts poor kidney allograft survival

BACKGROUND

Pulse pressure (PP), which reflects the pulsatile component of the blood pressure (BP), is known as a major predictor of cardiovascular events and death. In the elderly and type 2 diabetic patients, PP is associated with low glomerular filtration rate and albuminuria. Because kidney allograft survival is closely related to BP levels, we investigated the impact of early high PP, systolic, diastolic, and mean arterial BP on kidney allograft survival.

METHODS

Renal hemodynamic and function studies using isotopic methods were prospectively performed in 493 renal transplant patients at 3 months posttransplantation to determine the impact of the different BP components on allograft survival using a proportional hazard model.

RESULTS

After a median follow-up of 6.3 years, 91 allografts were lost. High PP was associated with high systolic, diastolic, and mean arterial pressure, heart rate, recipient age, glycemia, and low glomerular filtration rate. Moreover, PP emerged as the strongest BP component influencing overall and death-censored kidney allograft survival.

CONCLUSION

High PP is an early marker of poor allograft outcome that could be corrected by therapeutic intervention.

Markers of the hepatic component of the metabolic syndrome as predictors of mortality in renal transplant recipients

Cardiovascular disease (CVD) is a leading cause of mortality in renal transplant recipients (RTRs). Metabolic syndrome (MS) is highly prevalent in RTRs. Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic component of MS. We investigated associations of NAFLD markers with MS and mortality. RTRs were investigated between 2001 and 2003. NAFLD markers, alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and alkaline phosphatase (AP) were measured. Bone and nonbone fractions of AP were also determined. Death was recorded until August 2007. Six hundred and two RTRs were studied (age 52+/-12 years, 55% men). At baseline 388 RTRs had MS. Prevalence of MS was positively associated with liver enzymes. During follow-up for 5.3[4.5-5.7] years, 95 recipients died (49 cardiovascular). In univariate Cox regression analyses, GGT (HR=1.43[1.21-1.69], p<0.001) and AP (HR=1.34[1.11-1.63], p=0.003) were associated with mortality, whereas ALT was not. Similar associations were found for cardiovascular mortality. Adjustment for potential confounders, including MS, diabetes and traditional risk factors did not materially change these associations. Results for nonbone AP mirrored that for total AP. ALT, GGT and AP are associated with MS. Of these three enzymes, GGT and AP are associated with mortality, independent of MS. These findings suggest that GGT and AP are independently related to mortality in RTRs.

Dietary intakes of fiber and magnesium and incidence of metabolic syndrome in first year after renal transplantation

OBJECTIVE

Considering the high prevalence of metabolic syndrome (MetS) and the associated cardiovascular disease mortality after renal transplant, and considering that the lack of prospective studies regarding the role of fiber and magnesium in MetS prevention after transplant precludes definitive recommendations, we prospectively evaluated the potential role of fiber and magnesium intake in the incidence of MetS at 1 year after renal transplantation.

DESIGN

This was a prospective cohort study.

SETTING, PARTICIPANTS, AND MEASUREMENTS

We included 160 recipients of kidney transplant (100 men and 60 women) aged over 18 years who were free of MetS or diabetes at time of transplant, and followed these patients for 1 year.

METHODS

The usual dietary intakes were assessed with a Willett-format 168-item food-frequency questionnaire. We defined MetS according to modified Adult Treatment Panel III guidelines. We categorized participants by tertiles of dietary fiber and magnesium. To determine associations of fiber and magnesium intake with MetS incidence 1 year posttransplant, we used multivariable logistic regression.

RESULTS

After controlling for potential confounders, including baseline body mass index and energy intake, subjects within the highest tertile of fiber intake had a lower odds ratio for incident MetS (odds ratio, 0.41; 95% confidence interval, 0.08 to 0.99; P < .05 for trend) than those in the lowest tertile. There was no significant overall association between magnesium intake and MetS.

CONCLUSIONS

These findings support current dietary recommendations to increase intakes of fiber-rich foods as a primary preventive approach against MetS and cardiovascular disease, which are very prevalent after renal transplant.

Metabolic syndrome and coronary artery calcification in renal transplant recipients

BACKGROUND

Coronary artery calcification (CAC) and metabolic syndrome (MS) have been associated with increased cardiovascular risk. The study objective was to examine the association of MS with CAC presence and progression in renal transplant recipients.

METHODS

We measured the CAC progression in asymptomatic recipients who had no prior history of coronary artery disease.

RESULTS

MS was common (55.4%). Median CAC scores were 0, 33.1, 98, and 261.9 for patients with one, two, three, and four or more positive components of the MS, respectively. Severe CAC scores were more common in recipients with MS (P=0.04). Although recipients with MS had higher mean CAC scores at baseline and significant CAC progression (483 [590.6] vs. 619 [813.8], P=0.01), MS was not an independent predictor of annualized rate of CAC change in a multivariate model.

CONCLUSION

Future studies to evaluate if MS treatment improves cardiovascular outcomes are imperative.

Unmasking glucose metabolism alterations in stable renal transplant recipients: a multicenter study

BACKGROUND AND OBJECTIVES

Emerging information indicates that glucose metabolism alterations are common after renal transplantation and are associated with carotid atheromatosis. The aims of this study were to investigate the prevalence of different glucose metabolism alterations in stable recipients as well as the factors related to the condition.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A multicenter, cross-sectional study was conducted of 374 renal transplant recipients without pre- or posttransplantation diabetes. A standard 75-g oral glucose tolerance test was performed.

RESULTS

Glucose metabolism alterations were present in 119 (31.8%) recipients: 92 (24.6%) with an abnormal oral glucose tolerance test and 27 (7.2%) with isolated impaired fasting glucose. The most common disorder was impaired glucose tolerance (17.9%), and an abnormal oral glucose tolerance test was observed for 21.5% of recipients with a normal fasting glucose. By multivariate analysis, age, prednisone dosage, triglyceride/high-density lipoprotein cholesterol ratio, and beta blocker use were shown to be factors related to glucose metabolism alterations. Remarkably, triglyceride levels, triglyceride/high-density lipoprotein cholesterol ratio, and the proportion of recipients with impaired fasting glucose were already higher throughout the first posttransplantation year in recipients with a current glucose metabolism alteration as compared with those without the condition.

CONCLUSIONS

Glucose metabolism alterations are common in stable renal transplant recipients, and an oral glucose tolerance test is required for its detection. They are associated with a worse metabolic profile, which is already present during the first posttransplantation year. These findings may help planning strategies for early detection and intervention.

Unmasking glucose metabolism alterations in stable renal transplant recipients: a multicenter study

BACKGROUND AND OBJECTIVES

Emerging information indicates that glucose metabolism alterations are common after renal transplantation and are associated with carotid atheromatosis. The aims of this study were to investigate the prevalence of different glucose metabolism alterations in stable recipients as well as the factors related to the condition.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A multicenter, cross-sectional study was conducted of 374 renal transplant recipients without pre- or posttransplantation diabetes. A standard 75-g oral glucose tolerance test was performed.

RESULTS

Glucose metabolism alterations were present in 119 (31.8%) recipients: 92 (24.6%) with an abnormal oral glucose tolerance test and 27 (7.2%) with isolated impaired fasting glucose. The most common disorder was impaired glucose tolerance (17.9%), and an abnormal oral glucose tolerance test was observed for 21.5% of recipients with a normal fasting glucose. By multivariate analysis, age, prednisone dosage, triglyceride/high-density lipoprotein cholesterol ratio, and beta blocker use were shown to be factors related to glucose metabolism alterations. Remarkably, triglyceride levels, triglyceride/high-density lipoprotein cholesterol ratio, and the proportion of recipients with impaired fasting glucose were already higher throughout the first posttransplantation year in recipients with a current glucose metabolism alteration as compared with those without the condition.

CONCLUSIONS

Glucose metabolism alterations are common in stable renal transplant recipients, and an oral glucose tolerance test is required for its detection. They are associated with a worse metabolic profile, which is already present during the first posttransplantation year. These findings may help planning strategies for early detection and intervention.

Comprehensive management of post-transplant diabetes mellitus: from intensive care to home care

Post-transplant diabetes mellitus (PTDM) is a common complication of solid organ and hematopoietic transplantation. This clinically oriented review article briefly summarizes the pathophysiology of PTDM, then presents a comprehensive clinical approach to diagnosis and therapy. Topics include the key clinical aspects of PTDM screening, diagnosis, and management during all phases following transplantation from the intensive care unit, to the inpatient ward, to the outpatient arena.

The effect of renal transplantation on adiponectin and its isoforms and receptors

Insulin resistance (IR) and other proatherogenic risk factors associated with end-stage kidney disease (ESKD) are improved by renal transplantation. Adiponectin is a protein with insulin-sensitizing, anti-inflammatory, and antiatherogenic properties. It exists in several isoforms, but the high molecular weight (HMW) isoform correlates best with insulin sensitivity. Paradoxically, the levels of this protein and its HMW isoform are increased in ESKD. We measured the homeostasis model assessment for insulin resistance (HOMA-IR), plasma adiponectin and its isoforms, and messenger RNA for adiponectin receptors (AdipoR1 and AdipoR2) on peripheral blood mononuclear cells in 54 stable transplant recipients, 50 patients established on hemodialysis, and 52 controls; groups were matched for body mass index and sex. HOMA-IR values were significantly higher in patients with ESKD compared with controls (P < .0005) and transplant patients (P < .05) but there was no difference between the latter 2 groups. Adiponectin levels were also higher in patients with ESKD compared with controls (P < .0005), and although levels were lower in the transplant group, they remained higher than in controls (P < .0001). However, although the absolute amount of HMW isoform in transplant patients remained higher than in controls (P < .0001), the proportion was similar, and less than in patients with ESKD (P < .005). The absolute amount of the HMW isoform correlated with superior metabolic indices in all 3 cohorts. AdipoR1 and AdipoR2 messenger RNA levels after transplantation were significantly lower than those of ESKD subjects (P < .0001, P < .01), but transplant patients had less AdipoR1 than controls, although their AdipoR2 levels were higher. AdipoR1 correlated with AdipoR2 in all 3 cohorts. We conclude that HOMA-IR was lower in the transplant group compared with the group on hemodialysis and this coincided with lower total adiponectin levels and absolute amount of the HMW isoform and AdipoR on peripheral blood mononuclear cells. Lower AdipoR after transplantation may be secondary to immunosuppression and/or an improvement in glomerular filtration rate and the uremic milieu.

Metabolic Syndrome After Kidney Transplantation

BACKGROUND

Metabolic syndrome (MS) includes some risk factors for development of diabetes and cardiovascular disease, obesity (BMI > 30), high triglycerides, low HDL cholesterol, hypertension and impaired glucose tolerance. Following the definition of the Adult Treatment Panel III criteria, a diagnosis of MS was established when 3 or more factors were present. In renal transplant patients MS has been reported to negatively influence both patient and graft survivals. The present study sought to verify the effect of MS among our cases.

METHODS

298 cadaveric renal transplant recipients operated between January 1, 1996 and December 31, 2001 with absence of diabetes before transplantation, stable renal function 1 year posttransplantation and at least 4 years follow up were retrospectively evaluated from the end of the first post-operative year.

RESULTS

50 patients out of 298 (16,7%) had MS at the beginning of the study, including 37 of them with 3 and 13 with 4 risk factors. Only one patient with MS died of cardiovascular disease. Graft failure was observed in 23.5% MS patients versus 9,7% patients without the Syndrome (p:n.s.) Only Creatinine and the incidence of Cardiovascular Diseases at 4 years were statistically higher in MS patients (P < .001).

CONCLUSIONS

These results suggested that MS is a risk factor for increasing CVD morbidity and decreased graft function, but early treatment of risk factors as soon as they become apparent can limit the adverse effects on patient and graft survival.

Cardiovascular complications after renal transplantation and their prevention

By the time of renal transplantation, end-stage renal disease patients have a huge burden of cardiovascular disease (CVD) and are heavily saturated with atherosclerotic risk factors. Worsening of preexisting risk factors or new CVD risk factors may develop in the posttransplant period consequent in part to the diabetogenic and atherogenic potential of immunosuppressive drugs. The annual risk of a fatal or non-fatal CVD event of 3.5 to 5% in kidney transplant recipients is 50-fold higher than the general population. Renal allograft dysfunction, proteinuria, anemia, moderate hyperhomocysteinemia and elevated serum C-reactive protein concentrations, each dependently confer greater risk of CVD morbidity and mortality in the posttransplant period. Long-term care of renal transplant recipients should programmatically incorporate the recommendations of the National Kidney Foundation Working Groups and European Best Practice Guidelines Expert Group on Renal Transplantations into the management of hypertension, dyslipidemia, smoking, and posttransplant diabetes mellitus. Timely utilization of coronary revascularization procedures should be undertaken as these treatments are equally effective in the kidney transplant population.

The impact of early-diagnosed new-onset post-transplantation diabetes mellitus on survival and major cardiac events

The impact of early-diagnosed new-onset post-transplantation diabetes mellitus (PTDM) on cardiovascular (CV) disease is not well described. The objectives of the present prospective single-center observational study were to assess the long-term effects of early-diagnosed new-onset PTDM on major cardiac events (MCE; cardiac death or nonfatal acute myocardial infarction) and patient survival. Diabetic status and CV risk factors were assessed in 201 consecutive renal allograft recipients 3 months after transplantation (baseline) during a period of 16 months (1995-96). Follow-up data until January 1, 2004 were obtained from the Norwegian Renal Registry. The 8-year (range 7-9 years) cumulative incidence of MCEs was 7% (nine out of 138) in recipients without diabetes, 20% (seven out of 35) in patients with new-onset PTDM and 21% (six out of 28) in patients with diabetes mellitus before transplantation (DM). Proportional hazards regression analyses (forward stepwise regression) revealed that patients with PTDM had an approximately three-fold increased risk of MCEs as compared with nondiabetic patients (hazard ratio (HR)=3.27, 95% confidence interval (CI)=1.22-8.80, P=0.019). A total of 61 patients (30%) died. Eight-year patient survival was 80% in the nondiabetic group, 63% in the PTDM group and 29% in the DM group, respectively. Pretransplant diabetes (HR=5.09, 95% CI=2.60-9.96, P<0.001), age (HR=1.03, 95% CI=1.01-1.05, P=0.016), cytomegalovirus (CMV) infection (HR=2.66, 95% CI=1.27-5.53, P=0.009), and creatinine clearance (HR=0.98, 95% CI=0.96-1.00, P=0.046), but not PTDM (HR=1.20, 95% CI=0.58-2.49, P=0.621), were independent predictors of death in the multiple Cox regression model. Early-diagnosed PTDM is a predictor of MCEs, but not of all-cause mortality, the first 8 years after renal transplantation.

Early posttransplant serum osteoprotegerin levels predict long-term (8-year) patient survival and cardiovascular death in renal transplant patients

The primary objectives of this analysis were to examine the effects of early posttransplantation (10 wk) serum levels of osteoprotegerin (OPG), mannose-binding lectin (MBL), and MBL-associated serine proteases (MASP; MASP-2 and MASP-3) on long-term (8-yr) patient survival, graft survival, and cardiovascular (CV) death. During a period of 16 mo (1995 to 1996), a total of 173 consecutive renal transplant recipients without diabetes before transplantation were included in a prospective study that was designed to address the impact of metabolic CV risk factors on survival and CV end points. Baseline sera from 172 patients were available for analysis. Follow-up data until January 1, 2004, were obtained from a national renal registry. Patients with high (fourth quartile) serum levels of OPG had significantly higher all-cause mortality (hazard ratio [HR] 6.3; 95% confidence interval [CI] 3.3 to 11.8; P<0.001) and CV death (HR 10.8; 95% CI 3.8 to 30.4; P<0.001) than patients with lower OPG concentrations. After multiple Cox regression analysis, high serum levels of OPG remained an independent predictor of all-cause mortality (HR 6.0; 95% CI 3.1 to 11.6, P<0.001) and CV death (HR 8.2; 95% CI 2.5 to 26.4; P<0.001). Multiple linear regression analysis revealed that age, creatinine clearance, and high-sensitivity C-reactive protein all were independently associated with OPG (R2=0.42). No significant association between OPG and death-censored graft loss was revealed. Serum levels of MBL, MASP-2, and MASP-3 were not significantly associated with patient survival, CV death, or graft loss. Early measured posttransplantation serum OPG is a highly significant independent predictor of death from any cause or CV death in white renal transplant recipients.

Hypoadiponectinemia is associated with insulin resistance and glucose intolerance after renal transplantation: impact of immunosuppressive and antihypertensive drug therapy

The objectives of this analysis were (1) to assess whether low serum adiponectin concentrations are associated with insulin resistance, metabolic syndrome, and new-onset posttransplantation diabetes mellitus (PTDM) and (2) to examine the possible effects of immunosuppressive and antihypertensive therapies on circulating adiponectin levels after renal transplantation. A total of 172 consecutive previously nondiabetic renal transplant recipients were examined 3 mo after transplantation, the majority (n = 167) with an oral glucose tolerance test. Serum adiponectin was measured by an in-house time-resolved immunofluorometric assay. Insulin secretion and insulin sensitivity were estimated by previously validated oral glucose tolerance test-derived indexes. One- and 6-yr follow-up data were available in subgroups of patients. Lower adiponectin levels were significantly associated with insulin resistance but not with insulinopenia. Patients with low adiponectin levels (first quartile) had significantly higher odds of PTDM (odds ratio [OR] 3.6; 95% confidence interval [CI] 1.1 to 12.7; P = 0.049) and metabolic syndrome (OR 3.9; 95% CI 1.6 to 9.5; P = 0.003) than patients in the upper (fourth) quartile. The increased risk for PTDM in patients with low adiponectin levels remained significant after adjustment for age, steroid dose, and family history of diabetes. Treatment with beta blockers was independently associated with lower serum adiponectin levels, and total steroid dose was associated with higher serum adiponectin levels. Low baseline adiponectin levels were also associated with significantly higher odds of PTDM at 6 yr (OR 6.9; 95% CI = 1.1 to 41.8; P = 0.037). Serum adiponectin levels correlate with posttransplantation insulin sensitivity and glucose tolerance. Glucocorticoids and beta blockers seem to have opposite effects on circulating adiponectin levels.

Free fatty acids are associated with obesity, insulin resistance, and atherosclerosis in renal transplant recipients

BACKGROUND

Insulin resistance (IR) may be implicated in the pathogenesis of atherosclerosis in renal transplant recipients (RTRs) and be contributed to, in part, by free fatty acids (FFAs), produced in excess in centrally obese individuals. The aim of this study was to determine the prevalence of IR and the relationships between FFAs, central obesity, and atherosclerosis in a cohort of prevalent RTRs.

METHODS

Observational data were collected on 85 RTRs (mean age 54 years; 49% male, 87% Caucasian). Fasting serum was analyzed for FFAs, glucose, and insulin; IR was calculated using the homeostasis model assessment (HOMA-IR) score. Vascular structure was assessed by carotid intima-media thickness (IMT) measurement. Linear regression analyses were performed to determine the factors associated with IR and atherosclerosis.

RESULTS

IR occurred in 75% of RTRs, and FFA levels were independently associated with its occurrence (beta: -0.55, 95% CI: -1.02 to -0.07, P = 0.02). Other variables independently associated with IR were male sex, body mass index, central obesity, diabetes, systolic blood pressure and corticosteroid use. There was a significant correlation between FFA levels and IMT (r = 0.3, P=0.01). On multivariate analysis, IMT correlated with elevated FFA (beta: 0.07, 95% CI: 0.02-0.12, P = 0.007), diabetes mellitus (P = 0.05), older age (P < 0.002), and a body mass index >25 kg/m (P = 0.002).

CONCLUSIONS

FFAs are associated with the development of IR and may be involved in the pathogenesis of atherosclerosis in RTRs. Additional studies are required to explore these associations further before considering whether an interventional trial aimed at lowering FFA would be a worthwhile undertaking.

Rosiglitazone therapy of posttransplant diabetes mellitus

BACKGROUND

The new onset of posttransplant diabetes mellitus (PTDM) is a common problem after solid organ transplantation. Because insulin resistance plays a significant role in the development of PTDM, we treated 40 consecutive patients with PTDM after liver and kidney transplantation with the insulin sensitizer rosiglitazone (ROSI).

METHODS

Thirty-three of 40 patients with PTDM were initially stabilized with twice-daily NPH and regular insulin. All patients subsequently began ROSI 4 mg per day. Patients were followed for a mean of 26 weeks and insulin was adjusted using home blood glucose data and hemoglobin A1C (HBA1C).

RESULTS

During 12 months of study, 32/107 liver transplant patients (30%) and 8/205 kidney transplant patients (4%) patients developed PTDM. After 3-4 months of insulin and ROSI therapy, insulin was able to be discontinued in 30/33 (91%) patients with PTDM. In all, 12/40 (30%) patients maintained normal HBA1C levels (5.6+/-0.8%) with ROSI monotherapy, whereas 25/40 (63%) required ROSI and a sulfonylurea to meet this goal. Three of 40 (7.5%) had persistent insulin dependence. 25/40 (63%) continued on 4 mg/day of ROSI, and 15/40 (37%) required an increase to 8 mg/day. Mild edema developed in 13% of patients; significant weight gain did not occur.

CONCLUSIONS

Rosiglitazone is the first highly effective oral agent for PTDM. The majority of patients with PTDM may be safely treated with ROSI +/- a sulfonylurea. After the expected 3-6 week delay in the onset of ROSI action, most patients with PTDM will no longer require long-term insulin therapy.

One-year post-transplant weight gain is a risk factor for graft loss

Metabolic syndrome (MS) and obesity participate in the pathogenesis of kidney disease. We explored the impact of MS and post-transplant weight gain on graft survival. Two hundred ninety-two renal transplant recipients (RTRs) were included in the study. Various parameters (e.g. anthropometric, biological) were measured at the time of transplantation as well as 1 year post-transplant. The proportion of patients with overweight or obesity significantly increased during the first year post-transplant (p = 0.04). Mean weight gain was 2.7 +/- 5.8 kg. Thirty patients (10.3%) lost their graft during follow-up. In multivariate analysis, patients with an increase in body mass index (BMI) of more than 5% at 1 year post-transplant had an increased risk of graft loss with (HR: 2.82 [95% CI: 1.11-7.44], p = 0.015) or without death censoring (HR: 2.31 [95% CI: 1.06-5.04], p = 0.035). Low creatinine clearance (HR: 4.72 [95% CI: 1.63-13.69], p = 0.004), high urinary protein excretion (HR: 3.21 [95% CI: 1.27-8.18], p = 0.014) and delayed graft function (DGF) (HR: 2.621 [95% CI: 1.07-6.39], p = 0.036) were also independent risk factors for graft loss. MS did not independently predict graft loss, partly due to significant interactions with low-grade inflammation. We conclude that post-transplant weight gain significantly reduces graft survival.

Obesity is associated with worsening cardiovascular risk factor profiles and proteinuria progression in renal transplant recipients

Obesity is associated with adverse cardiovascular (CV) parameters and may be involved in the pathogenesis of allograft dysfunction in renal transplant recipients (RTR). We sought the spectrum of body mass index (BMI) and the relationships between BMI, CV parameters and allograft function in prevalent RTR. Data were collected at baseline and 2 years on 90 RTR (mean age 51 years, 53% male, median transplant duration 7 years), categorized by BMI (normal, BMI < or = 24.9 kg/m2; pre-obese, BMI 25-29.9 kg/m2; obese, BMI > or = 30 kg/m2). Proteinuria and glomerular filtration rate (eGFR(MDRD)) were determined. Nine percent RTR were obese pre-transplantation compared to 30% at baseline (p < 0.001) and follow-up (25 +/- 2 months). As BMI increased, prevalence of metabolic syndrome and central obesity increased (12 vs 48 vs 85%, p < 0.001 and 3 vs 42 vs 96%, p < 0.001, respectively). Systolic blood pressure, fasting blood glucose and lipid parameters changed significantly with BMI category and over time. Proteinuria progression occurred in 65% obese RTR (23 (13-59 g/mol creatinine) to 59 (25-120 g/mol creatinine)). BMI was independently associated with proteinuria progression (beta 0.01, p = 0.008) but not with changing eGFR(MDRD.) In conclusion, obesity is common in RTR and is associated with worsening CV parameters and proteinuria progression.

Nutritional Status and Body Composition Evolution in Early Post–Renal Transplantation: Is There a Female Advantage?

OBJECTIVE

Chronic renal failure is associated with metabolic derangements, affecting proteins, amino acids, and lipids. Usually these patients follow a restricted diet. Kidney transplant patients enjoy a recovery of renal function, but their therapeutics may entail significant changes in general metabolism. We compare the anthropometric results during the first 3 months after successful transplant for male and female patients versus a healthy group.

METHODS

Eighteen patients (11 men and 7 women) were studied. Anthropometry was assessed before and at month 1 and month 3 posttransplant including body weight (Wt), body mass index (BMI), triceps (TSF), biceps (BSF), subscapular (SCSF), and suprailiac skinfolds (SISF), midarm circumference (MAC), midarm muscle circumference (MAMC), corrected arm muscle area (CT.AMA), total body muscle mass (MM), body density (D), fat mass (FM), and fat-free mass (FFM). The healthy group was evaluated three times in the first year.

RESULTS

Pretransplant men showed lower Wt, BMI, TSF, BSF, SCSF, SISF, MAC, MAMC, CT.AMA, MM, FM and FFM than controls, while women displayed no differences from controls. By the third month, men showed only a partial recovery and women higher TSF and SCSF than controls.

CONCLUSIONS

Uremic men before transplant displayed undernutrition indices. During the first 3 months posttransplant men showed an incomplete recovery of anthropometric parameters. Quite differently, women started close to normal and had significantly increased body weight and fat content posttransplant. We suggest that nutritional requirements post-kidney grafting may be significantly different among male compared to female patients.

Insulin resistance, LDL particle size, and LDL susceptibility to oxidation in pediatric kidney and liver recipients

BACKGROUND

Dyslipidemia is common after solid organ transplantation. We have described hypertriglyceridemia in about 50% of our pediatric kidney, and in about 30% of our liver recipients. The aim of the present study was to find out whether this post-transplantation hypertriglyceridemia after pediatric solid organ transplantation is associated with insulin resistance and the occurrence of small, dense low-density lipoprotein (LDL).

METHODS

Fifty kidney and 25 liver recipients (aged 4 to 18 years) on triple immunosuppression, and 181 control children participated in the study for an average of 5.3 and 6.4 years after kidney and liver transplantation (range 1 to 11 years), respectively. Homeostasis model assessments for insulin resistance (HOMA) were calculated and fasting lipoprotein lipid profile, apolipoprotein A-I and B concentrations, LDL particle diameter, and indices of LDL susceptibility to copper-induced oxidation determined.

RESULTS

Kidney patients had significantly higher serum total, high-density, and low-density lipoprotein cholesterol, triglyceride, apolipoprotein A-I and B concentrations than liver patients or control subjects (P < 0.003 for all). HOMA indices higher than the 95th percentile of Canadian normal children were seen in 50.0% of kidney (of liver 41.2%) recipients younger than 11 years, and in 27.3% of older recipients (of liver 37.5%). Smaller sized LDL or LDL of increased oxidizability was not more frequent in patients than in control children.

CONCLUSION

Pediatric kidney recipients had significantly higher lipid and insulin concentrations than healthy control children. Combined hyperlipidemia and features of the dysmetabolic syndrome were common in children after kidney and liver transplantation. However, no small, dense LDL, or LDL prone to oxidation was seen in either group.

Post-Transplantation Diabetes Mellitus

Post-transplantation diabetes mellitus (PTDM) is defined as sustained hyperglycemia developing in any patient without history of diabetes before transplantation, that meets the current diagnostic criteria by the American Diabetes Association or the World Health Organization. Several risk factors have been identified: age, nonwhite ethnicity, and glucocorticoid therapy for rejection and chronic immunosuppression with cyclosporine and especially tacrolimus. The pathophysiology of this condition resembles that of type 2 diabetes mellitus: pretransplantation end-stage liver/renal and heart disease are insulin-resistant states, and after transplantation, glucocorticoids induce further peripheral insulin insensitivity. The "second hit" appears to be an acquired (yet reversible) insulin secretion defect resulting from the calcineurin inhibitors cyclosporine and tacrolimus. An international panel of experts has recently published the proceeding of a Consensus Conference proposing strategies for the screening, prevention and management of PTDM. Future directions include pre- and post-transplantation glucose load testing for high-risk individuals and pharmacological agents to decrease insulin resistance and to preserve beta-cell function.

Short-term treatment with rosiglitazone improves glucose tolerance, insulin sensitivity and endothelial function in renal transplant recipients

BACKGROUND

Insulin resistance (IR) contributes to the development of glucose intolerance (post-transplant diabetes mellitus or impaired glucose tolerance) following renal transplantation. Furthermore, endothelial dysfunction (ED) is associated with IR. Glucose intolerance, IR and ED are all independent risk factors for cardiovascular disease. Therefore, treatment with insulin sensitizers may benefit glucose-intolerant renal transplant recipients. The main objectives of the present study were to investigate the effect of 4 weeks' treatment with the PPAR-gamma agonist rosiglitazone on insulin sensitivity, plasma glucose and endothelial function in renal transplant recipients with glucose intolerance. Safety parameters were also addressed.

METHODS

A total of 10 glucose-intolerant renal transplant recipients were treated with rosiglitazone (initially 4 mg/day increasing to 8 mg/day after 1 week). A hyperinsulinaemic euglycaemic glucose clamp, an oral glucose tolerance test and endothelial function assessment with laser Doppler flowmetry were performed both at baseline and at follow-up.

RESULTS

Treatment with rosiglitazone was followed by a significantly improved mean glucose disposal rate (from 6.5 to 9.1 g/kg/min; P = 0.02) and a significant decline in fasting and 2 h plasma glucose (from 6.4 to 5.8 mmol/l, P = 0.01 and from 14.2 to 10.6 mmol/l, P = 0.03, respectively). Furthermore, a significant improvement in endothelial function was demonstrated (AUC(ACh); from 389 to 832 AU x min, P = 0.04). No serious adverse events or hypoglycaemic episodes were observed.

CONCLUSIONS

Four weeks' treatment with rosiglitazone was associated with increased insulin sensitivity, lowered fasting and 2 h plasma glucose and improved endothelial function in renal transplant recipients with glucose intolerance. The drug was well tolerated and may be a good alternative for treating these patients.

Impact of kidney transplantation on the progression of cardiovascular disease

Kidney transplantation, of all the treatment modalities for end-stage renal disease, affords the greatest potential for prolonged survival and improved quality of life. Great strides in immunosuppressant therapy have improved graft survival and forced clinicians to consider other health-care needs of kidney transplant recipients. Chief among these needs is the prevention and treatment of cardiovascular disease. Cardiovascular disease is the most common cause of death among patients with a working renal allograft. Because therapies for primary and secondary prevention are successful in the general population, transplant clinicians are increasingly focused on preventing or limiting the progression of cardiovascular disease. Initiation of aggressive management of conventional atherosclerotic risk factors and uremia-related risk factors, ideally during the early stages of chronic kidney disease (CKD) or after kidney transplantation, and efforts to delay the progression of kidney disease will hopefully reduce the cardiovascular burden in transplant recipients.

ROSIGLITAZONE TREATMENT OF DIABETES MELLITUS AFTER SOLID ORGAN TRANSPLANTATION

BACKGROUND

Diabetes mellitus is a common clinical problem after solid organ transplantation. Whether patients have preexisting diabetes or develop posttransplant diabetes, insulin therapy is usually required. Achieving excellent diabetic control is an important target in reducing the incidence of cardiovascular disease after transplantation.

METHODS

The authors treated 18 patients with type 2 diabetes after transplantation with rosiglitazone. Eleven patients had preexisting type 2 diabetes and seven patients developed posttransplant diabetes. Rosiglitazone was added to insulin or glyburide to improve elevated hemoglobin Hb A1C levels in patients with preexisting diabetes or was used to try to avoid insulin therapy in posttransplant diabetics. Blood levels of cyclosporine, tacrolimus, creatinine, and HbA1C were followed for a mean of 381 days (range, 133-718 days).

RESULTS

The addition of rosiglitazone did not cause any significant changes in serum creatinine, cyclosporine, or tacrolimus. There were no significant changes in cyclosporine or tacrolimus doses. Mean HbA1C improved from 8.1+/-1.5% to 6.9+/-1.3% (P =0.01) in the 18 patients and from 8.6+/-1.5% to 6.7+/-0.5% (P =0.035) in the 7 patients with posttransplant diabetes. All patients with posttransplant diabetes were well controlled without insulin therapy.

CONCLUSIONS

Rosiglitazone is a safe and effective oral agent for the treatment of diabetes mellitus after solid organ transplantation. It is the first agent to allow successful oral therapy for patients with posttransplant diabetes, and is a well-tolerated alternative to insulin for these patients.

Plasma fibrinolytic capacity in renal transplant recipients: effect of steroid-free immunosuppression therapy

BACKGROUND

Cardiovascular disease is the most common cause of death among renal transplant recipients (RTRs). Impaired fibrinolytic capacity caused by an increase in plasminogen activator inhibitor type 1 (PAI-1) levels is involved in the onset of atherosclerosis and thrombotic complications. Long-term steroid treatment may induce arterial hypertension and metabolic and prothrombotic changes (including up-regulation of PAI-1 synthesis), which increase the cardiovascular risk. We evaluated plasma fibrinolytic behavior in two groups of RTRs treated with different immunosuppressive regimens.

METHODS

Twenty-seven RTRs were randomized to receive long-term (17 patients) or perioperative short-term (10 patients) steroids in addition to immunosuppression with cyclosporine A plus everolimus (Certican; Novartis, Basel, Switzerland) (7 patients) or FK506 plus mycophenolate mofetil (20 patients). In each patient, fibrinolytic capacity was studied with the 20-min venous occlusion test 1 and 6 months after transplantation. The following were assayed: euglobulin lysis time, tissue-type plasminogen activator antigen, and PAI-1 antigen and activity.

RESULTS

One month after transplantation, a severe impairment of fibrinolytic capacity, mainly caused by an increase in PAI-1 antigen and activity levels, was seen in patients with and without steroid treatment. Six months after transplantation, an improvement in fibrinolytic potential as the result of a decrease in PAI-1 levels was observed only in patients without steroid therapy. None of the steroid-treated patients demonstrated PAI-1 values correlating with body mass index, blood pressure, and metabolic parameters, thus confirming the effect of exogenous factors on PAI-1 expression. Moreover, all patients revealed a slight impairment of stimulated endothelial tissue-type plasminogen activator release, regardless of any steroid treatment, which was probably attributable to calcineurin inhibitor-induced endothelial dysfunction.

CONCLUSIONS

Our study suggests that steroid-free immunosuppression is associated with a better fibrinolytic capacity in RTRs. This finding may contribute toward reducing the risk of cardiovascular events.

Insulin resistance as putative cause of chronic renal transplant dysfunction

Transplantation is the preferred organ replacement therapy for most patients with end-stage renal disease. Despite impressive improvements over recent years in the treatment of acute rejection, approximately half of all grafts will loose function within 10 years after transplantation. Chronic renal transplant dysfunction, also known as transplant atherosclerosis, is a leading cause of late allograft loss. To date, no specific treatment for chronic renal transplant dysfunction is available. Although its precise pathophysiology remains unknown, it is believed that it involves a multifactorial process of alloantigen-dependent and alloantigen-independent risk factors. Obesity, posttransplant diabetes mellitus, dyslipidemia, hypertension, and proteinuria have all been identified as alloantigen-independent risk factors. Notably, these recipient-related risk factors are well-known risk factors for cardiovascular disease, which cluster within the insulin resistance syndrome in the general population. Insulin resistance is considered the central pathophysiologic feature of this syndrome. It is therefore tempting to speculate that it is insulin resistance that underlies the recipient-related risk factors for chronic renal transplant dysfunction. Recognition of insulin resistance as a central feature underlying many, if not all, recipient-related risk factors would not only improve our understanding of the pathophysiology of chronic renal transplant dysfunction, but also stimulate development of new treatment and prevention strategies.

Treatment of hypertension in renal transplant recipients

PURPOSE OF REVIEW

Hypertension is very common in renal transplant recipients and is a significant risk factor for mortality from cardiovascular diseases and for development of graft dysfunction.

RECENT FINDINGS

Recent guidelines for the treatment of hypertension (Joint National Committee on Prevention, Detection, and Treatment of High Blood Pressure VI Report and World Health Organization Guidelines) do not directly address post-transplant hypertension. Specific recommendations for the drug treatment of hypertension in renal allograft recipients have not been given in the Clinical Practice Guidelines of the American Society of Transplantation or those of the European Renal Association.

SUMMARY

The present paper summarizes some important aspects of post-transplant hypertension and discusses potential treatment strategies aimed at reducing blood pressure and thus improving patient and allograft survival.

Cardiovascular disease after renal transplantation

Cardiovascular disease is a major hazard limiting the life expectancy of renal transplant recipients and the most frequent cause of late allograft loss. Patients with renal disease have usually been exposed for both traditional, and for them unique, risk factors over a prolonged period of time and may carry the burden of advanced atherosclerotic disease already at the time of transplantation. The observed survival benefit of transplantation is probably from elimination of the numerous uremia-related risk factors. However, immunosuppressive therapy and the chronic inflammatory state, together with genetic susceptibility and not infrequently impaired renal function, may bring about new potentially atherogenic conditions. Metabolic risk factors may jeopardize both patient and graft survival. Several observational studies provide evidence for the negative impact of preexisting metabolic abnormalities on long-term outcomes. Identification of modifiable cardiovascular risk factors may enable risk reduction also in renal transplant recipients. Results of ongoing intervention trials are awaited. The observed improvement of patient survival after renal transplantation during the past decade may reflect the increasing awareness and more optimal care of patients throughout the course of renal disease.