Coronary artery calcification in kidney transplant recipients with long-term follow-up

OBJECTIVES

Kidney transplantation (KT) is associated with increased incidence of hypertension, hyperlipidemia, metabolic syndrome, and posttransplant diabetes mellitus that promote the development of coronary artery calcification (CAC). The aim of the current study was to elucidate the extent of CAC and its risk factors among KT patients.

METHODS

A cross-sectional study was performed to evaluate the severity of CAC in our KT patients. Multidetector computed tomography was performed to assess the coronary artery calcium score (CACS). Patients were further stratified according to the CACS as: group 1: 0-10, group 2: 11-100, group 3: 101-300, group 4: 301-1000, and group 5: >1000. Clinical as well as demographic data were compared among groups. Linear regression analysis was performed to determine factors that were associated with CAC.

RESULTS

A total of 99 patients were enrolled in the study. The mean age was 53.5 ± 11.8 years and duration of follow-up post-KT was 11.2 ± 5.9 years. The distribution of CACS in groups 1 through 5 was: 41.4%, 20.2%, 11.1%, 15.2%, and 12.1%, respectively. A significantly higher CACS was found in males, patients with pretransplant diabetes mellitus, older current age, older age at KT, hypertension, higher body weight, higher fasting plasma sugar level and lower high-density lipoprotein (HDL) cholesterol. Twenty-nine (29.3%) patients fulfilled criteria for metabolic syndrome (MS). The CACS was significantly higher in patients with MS than in those without MS. An incremental CACS was found to be correlated with increasing number of MS components (P = .003). Multivariate linear regression revealed that female gender, current age, hypertension, and HDL cholesterol were associated with CAC.

CONCLUSION

KT was associated with high CACS in a significant proportion of patients with long-term follow-up. Several risk factors were identified. Some of them were potentially treatable and should be taken into consideration in the management of KT recipients.

Serum adiponectin levels in renal transplant recipients with and without metabolic syndrome

OBJECTIVES

Adiponectin (APN) is an adipocyte-derived protein that has anti-inflammatory, anti-atherogenic, and insulin-sensitizing effects. Lower serum APN level is associated with various inflammatory and metabolic diseases in the general population. Kidney transplant (KT) recipients are at higher risk for developing several metabolic disorders, including metabolic syndrome (MS). The aim of the current study was to assess the change of APN level in KT recipients with and without MS.

METHODS

Prevalent KT recipients followed at our hospital were enrolled for the cross-sectional study of MS. The modified Adult Treatment Panel III criteria adopted for the Asian population were used to define MS. Overnight fasting blood samples were obtained for biochemistry and APN. APN was assayed with a commercially available enzyme-linked immunosorbent assay (ELISA) kit. The simplified Modification of Diet in Renal Disease (MDRD) equation was used for the calculation of estimated glomerular filtration rate (eGFR). Univariate and multivariate logistic regression were performed to determine parameters that were associated with serum APN level.

RESULTS

A total of 271 KT recipients (male:female = 133:138), with a mean age of 52.3 ± 12.6 years, were enrolled for the study of MS. The mean duration of follow-up posttransplantation was 9.02 ± 5.91 years. MS was found in 72 of 271 KT recipients (26.6%). Patients with MS were older, had significantly higher body weight, waist circumference, serum creatinine, fasting plasma sugar, and hemoglobin A1c, but lower serum APN level and eGFR than did patients without MS. Univariate logistic regression revealed the following variables were associated with APN level: MS, gender, body weight, body height, waist circumference, body mass index, serum creatinine, fasting blood sugar, triglyceride, high-density lipoprotein (HDL) cholesterol, and eGFR. Multivariate analysis revealed that gender, body weight, serum creatinine, triglyceride, and HDL cholesterol were associated with APN level.

CONCLUSION

Our results revealed that KT recipients with MS had significantly lower serum APN levels, even in the presence of lower eGFR, than those without MS.

D-serine added to clozapine for the treatment of schizophrenia

OBJECTIVE

D-Serine is a full agonist at the glycine site on the N-methyl-D-aspartate (NMDA) receptor. Previous administration of D-serine to schizophrenic patients taking nonclozapine antipsychotics improved positive, negative, and cognitive symptoms, whereas the partial agonist D-cycloserine improved negative symptoms of patients taking conventional antipsychotics but worsened symptoms in clozapine-treated patients. To study the difference between full and partial agonists at the NMDA receptor glycine site, the clinical effects of adding D-serine to clozapine were assessed.

METHOD

In a 6-week double-blind trial, 20 schizophrenic patients received placebo or D-serine (30 mg/kg per day) in addition to clozapine. Clinical efficacy, side effects, and serum levels of D-serine were determined every other week.

RESULTS

The patients exhibited no improvement with D-serine, nor did their symptoms worsen, as previously reported with D-cycloserine.

CONCLUSIONS

The results suggest either that clozapine may have an agonistic effect on the NMDA system or that clozapine-treated patients do not respond to D-serine.