Fabry Disease Prevalence in Renal Replacement Therapy in Turkey

BACKGROUND

Fabry disease (FD) is an X-linked lysosomal storage disorder resulting from lack of alpha-galactosidase A (AGALA) activity in lysosomes.

OBJECTIVE

In this multicenter study, we aimed to evaluate the prevalence of FD in renal transplant (Tx) recipients in Turkey. We also screened dialysis patients as a control group.

METHODS

All Tx and dialysis patients were screened regardless of the presence of a primary disease. We measured the AGALA activity in all male patients as initial analysis. Mutation analysis was performed in male patients with decreased AGALA activity and in female patients as the initial diagnostic assay.

RESULTS

We screened 5,657 patients. A total of 17 mutations were identified. No significant difference was observed between the groups regarding the prevalence of patients with mutation. We found FD even in patients with presumed primary kidney diseases. Seventy-one relatives were analyzed and mutation was detected in 43 of them. We detected a patient with a new, unknown mutation (p.Cys223) in the GLA gene.

CONCLUSIONS

There are important implications of the screening. First, detection of the undiagnosed patients leads to starting appropriate therapies for these patients. Second, the transmission of the disease to future generations may be prevented by prenatal screening after appropriate genetic counseling. In conclusion, we suggest screening of kidney Tx candidates for FD, regardless of etiologies of chronic kidney disease.

The relationship between hemoglobin levels and endothelial functions in diabetes mellitus

BACKGROUND AND OBJECTIVES

Hemoglobin (Hb) is the main carrier and buffer of nitric oxide. Evidence has been produced that Hb concentration is inversely related with endothelial function in human diseases. Testing whether this association exists also in diabetic patients stage 1 to 2 chronic kidney disease (CKD) is important because anemia in these patients starts at an earlier stage than in other renal diseases. The relationship was investigated between Hb and flow-mediated dilation (FMD) levels of the patients with diabetic nephropathy in a cross-sectional design.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Eighty-nine diabetics with mild to moderate proteinuria and normal to mildly reduced GFR who were normotensive, nondyslipidemic, and cardiovascular-events free were enrolled. None of the patients was taking metformin or renin-angiotensin system blockers.

RESULTS

FMD was inversely related with Hb levels. Furthermore, there was an inverse link between proteinuria and FMD. However, further analysis of this association showed that the FMD-proteinuria link was confined to patients with proteinuria exceeding 150 mg/d, while no such association existed in patients with proteinuria <150 mg/d. Adjustment of the Hb-FMD relationship for pertinent Framingham risk factors, proteinuria, homeostasis model assessment (HOMA) index, and GFR levels had a modest influence on this association, which remained significant.

CONCLUSIONS

Endothelial function is inversely associated with Hb levels in diabetic patients with stage 1 to 2 CKD, and proteinuria is an effect modifier of this association. Overall, the observations of this study generate the hypothesis that proteinuria exposes a situation wherein Hb may limit the endothelium-mediated vasoregulation in diabetes.

Asymptomatic kindred of patients with coronary events have increased peripheral T-cell activities

T cells are involved in the pathogenesis of atherosclerosis. We aimed to search for any association between the peripheral T-cell activities and atherogenic risk factors in healthy subjects. Fifty male volunteers (age 22.0 +/- 2.4 years) were enrolled. No subject had any chronic disease or was under any drug treatment. Lymphocytes were isolated from heparinized venous blood and the proliferative responses to phytohemagglutinin (PHA) were measured from the amount of radioactive thymidine uptake by the lymphocyte DNA. T-cell activity responses of patients with a family history of coronary events were compared with others. The activity responses of smokers were compared with nonsmokers. Subjects with a positive family history of coronary events had higher PHA stimulated T-cell response and delta cpm (P < 0.05 for each). Total and low-density lipoprotein cholesterol levels of the subjects with a positive family history of cardiovascular events were positively correlated with the PHA-activated T-cell responses (P = 0.022, r = 0.604 and P = 0.015, r = 0.635, respectively). There was no significant difference between the T-cell activity responses of smokers and nonsmokers. No correlation was found between the biochemical parameters and T-cell activities in these groups. Peripheral T-cell activity responses to PHA are higher in the asymptomatic relatives of patients with coronary events. This may be a clue for the familial tendency of atherosclerotic diseases. Further follow-up studies are necessary to investigate the relationship.

Cumulative prior dose of cisplatin as a cause of the nephrotoxicity of high-dose chemotherapy followed by autologous stem-cell transplantation

BACKGROUND

Nephrotoxicity is one of the most frequent dose-limiting factors of high-dose chemotherapy to create tolerance of autologous peripheral blood stem-cell transplantation (PBSCT) for the treatment of malignant diseases. The relative importance of factors that may be responsible for the development of nephrotoxicity varied in different trials.

METHODS

The factors affecting nephrotoxicity in the early period of high-dose ifosfamide, carboplatin and etoposide treatment (ICE) followed by autologous PBSCT was investigated in 47 patients. ICE was given as a conditioning regimen for 6 days. Nephrotoxicity was defined as an increase in the serum creatinine concentration of 0.5 mg/dl or more over individual baseline levels.

RESULTS

Eleven patients developed nephrotoxicity (23.4%). There was no significant difference in baseline renal function between patients with nephrotoxicity and those without. No differences were found between the two groups in terms of average total doses of ICE, infections and antibiotic use. The age of patients was higher in those with nephrotoxicity (37+/-3.7 vs 26+/-1.7 years, P=0.019). The cumulative cisplatin dose administered prior to this regimen was higher in the group that developed nephrotoxicity (470 vs 227 mg/m(2), P=0.02). The overall mortality rate was 17%, but the transplant-related deaths were higher in the presence of nephrotoxicity (54.5 vs 5.5%, P=0.001).

CONCLUSIONS

The cumulative dose of cisplatin is a strong risk factor for the development of nephrotoxicity in patients who receive high doses of ICE followed by PBSCT. Nephrotoxicity may occur with much lower doses than the currently recommended maximum doses.

A successful and simplified filgrastim primed single apheresis method without large volume apheresis for peripheral blood stem cell collection

BACKGROUND

There is a tendency to use only one apheresis collection to reduce the morbidity and the cost of peripheral blood stem cell collection. We studied whether rapid and complete engraftment could be achieved by single apheresis by using only Filgrastim without large volume apheresis in previously treated patients.

METHODS

Engraftment of single apheresis in 25 patients was compared with those of multiple apheresis in 26 patients; 52% of patients in the single apheresis group and 62% of patients in the multiple apheresis group were heavily pretreated. All patients received 10-15 microg/kg/day of Filgrastim starting on day 14 after 3-4 cycles of induction chemotherapy. Apheresis was performed using Cobe Spectra on day 4, 5 or 6 in the single apheresis group and every other day in the multiple apheresis group after day 3.

RESULTS

The median collection volume was 250 ml (250-300 ml) in the single apheresis group and 750 ml (200-1500 ml) in the multiple apheresis group. The median CD34(+) cell number was not significantly different in the two groups (11.79 vs. 9.38x10(6)/kg). The median times to achieve leukocytes > or =1x10(9)/l and platelets > or =50x10(9)/l counts were 10 days (8-21 days) and 15 days (9-38 days) in the single apheresis group vs 11 days (8-23 days) and 20 days (10-32 days) in the multiple apheresis group, respectively (p<0.05). Antibiotic use was less in the single apheresis group than the multiple apheresis group (9 vs. 12 days, p<0.05).

CONCLUSION

Adequate numbers of peripheral stem cells were harvested by G-CSF in a single apheresis without large volume apheresis even in heavily pretreated patients. Rapid and complete engraftment occurred in all patients and it was faster in single than multiple apheresis.

Is leptin associated with hypertensive retinopathy?

Previous studies have demonstrated that elevated plasma leptin concentrations are associated with essential hypertension. It has also recently been shown that leptin plays a promoting role in angiogenesis, and the vascular endothelium expresses the long form of leptin receptor. Those data led us to hypothesize that leptin might contribute to end-organ damage in hypertension. Thus, in the present study we evaluated the relationship between plasma leptin concentrations and hypertensive retinopathy (HR). One hundred and eleven patients newly diagnosed with essential hypertension [EHT; mean age, 43.5 +/-10.7 yr; body mass index (BMI), 28.1 +/- 4.4 kg/m2; male/female ratio, 71/40] and 79 healthy normotensive control subjects (NT; mean age, 43.6 +/- 9.2 yr; BMI, 28.2 +/- 3.3 kg/m2; male/female ratio, 50/29) were enrolled in the study. For the assessment of retinopathy according to the Keith-Wagener classification, direct and indirect ophthalmoscopy were performed in all subjects after dilatation of the pupils. Plasma leptin levels were significantly higher in EHT (11.8 +/- 11.1 ng/mL) than in NT (7.2 +/- 5.1 ng/mL) (P = 0.003). Plasma leptin concentrations were strongly correlated with BMI in both EHT (r = 0.45; P = 0.001) and NT (r = 0.38; P = 0.001) groups. Plasma leptin in patients with grade 2 HR (24.8 +/- 15.8 ng/mL; n = 22) was significantly higher than that in patients with grade 1 HR (16.1 +/- 4.9 ng/mL; n = 29; P = 0.001), grade 0 HR (5.1 +/- 3.1 ng/mL; n = 60; P = 0.001), and NT (P = 0.001). Plasma leptin in patients with grade 1 HR was also significantly higher than that in patients without retinopathy (P = 0.001) or in NT (P = 0.001). The estimated threshold of plasma leptin concentration for HR was 10.2 ng/mL. This critical leptin level served largely to separate patients with retinopathy from those without retinopathy. In summary, our results show that plasma leptin concentrations increase progressively with higher grades of hypertensive retinopathy even after correction for BMI, suggesting that a critical leptin level is needed for the development of retinopathy. Elevated concentrations of plasma leptin might be secondary to release of leptin by the vascular endothelium damaged by high blood pressure, as an epiphenomenon. However, a pathogenic role for leptin in hypertensive retinopathy cannot be excluded.

Plasma leptin levels strongly correlate with plasma renin activity in patients with essential hypertension

Previous studies demonstrated elevated plasma leptin and angiotensinogen (PRA) levels in essential hypertension. However, a few studies investigated the relationship between leptin and angiotensinogen levels in both lean and overweight/ obese hypertensives. The aim of the present study was therefore to examine the relationship between blood pressure, leptin and plasma renin activity in normotensives and in both lean and overweight/obese patients with essential hypertension. Two groups of subjects who were carefully matched for age, gender, waist:hip ratio and body mass index (BMI) were studied: 28 normotensives (NT) (age: 40.1+/-9.1 years old, BMI: 28.1+/-3.6 kg/m2, male/female: 18/10) and 33 newly diagnosed mild to moderate essential hypertensives (EHT) (age: 38.9+/-10 years old, BMI: 27.9+/-4.8 kg/m2, male/female: 22/11). No significant differences in age, gender, waist:hip ratio, fasting blood glucose and BMI were detected between EHT and NT groups. However, systolic and diastolic pressures, mean arterial blood pressures, plasma leptin levels and PRA were significantly higher in EHT group than in NT group (P = 0.001). Plasma leptin levels were strongly correlated with BMI in EHT (r=0.67, P = 0.001) and NT groups (r=0.44, P = 0.001). Plasma leptin levels were correlated with plasma PRA levels in both EHT and NT groups (r = 0.66 and r = 0.44; both P < 0.05, respectively). There was no correlation between leptin or PRA and systolic, diastolic pressures, or mean arterial blood pressures. Furthermore, the patients were divided as lean (n=16) and overweight/obese (n = 17) and compared with BMI-matched controls. In both subgroups, plasma leptin and PRA levels were also higher than those of controls. Our results showed that elevated plasma leptin and PRA are associated with hypertension in both lean and overweight/obese hypertensives. Moreover, plasma leptin was significantly correlated with plasma angiotensinogen levels. These findings suggest that adipose mass is an important determinant of blood pressure, although the mechanism is not clear.