Vitamin D status and bone density in steroid-treated children with glomerulopathies: effect of cholecalciferol and calcium supplementation.

PURPOSE: The aim of this study was to assess vitamin D status and bone density in steroid-treated children with glomerulopathies and to evaluate the effect of prophylactic vitamin D and calcium supplementation. MATERIAL AND METHODS: Retrospective analysis was performed on 55 children aged 4-18 yrs with glomerulopathies. The following data were analyzed: antropometrical parameters, bone densitometries, parathormone, 25-hydroxyvitamin D (25-OHD), urinary calcium excretion and medications received for prevention of low bone mass. RESULTS: A significant number of children (38%) had decreased spinal bone mineral density (BMD z-score < -2.0) and the majority of them (89%) had hypovitaminosis D (25-OHD < 30 ng/ml), 75% were vitamin D insufficient (25-OHD < 20 ng/ml) and 16% were vitamin D deficient (25-OHD < 10 ng/ml). The mean serum 25-OHD concentration was comparable to that of controls (19.32 ± 12.87 vs. 15.05 ± 8.52 ng/ml). Nearly all patients (82%) were receiving preparations of calcium and/or vitamin D to improve bone health. Patients on cholecalciferol had higher mean concentration of 25-OHD compared to those who were not receiving it (p=0.027) and to the controls (p=0.047). In 23 children on vitamin D and calcium supplementation for an average 6-month time, we observed an increase in the mean BMD values (p=0.004), however, mean BMD z-score and 25-OHD concentrations did not significantly change over time. CONCLUSIONS: Vitamin D and bone density deficits are remarkably common in steroid-treated children with glomerulopathies, despite vitamin D and calcium repletion. In order to enhance the effectiveness of vitamin D supplementation for improvement of bone density, we suggest regular assessment of serum concentration of 25-OHD that can guide subsequent dose adjustment of vitamin D.

Intracellular cytokines of peripheral blood lymphocytes in nephrotic syndrome.

Idiopathic nephrotic syndrome (NS) is probably caused by abnormalities in T-lymphocyte function. The presence of several immunological abnormalities in these patients supports this hypothesis, but to date there is no agreement about immunological status and its influence on the course of NS. Thirty-six children with NS [19 with first episode (group I) and 17 in remission (>6 months) of NS (group II), aged 4-17 years, mean 7.1 years] were included in the study. Nineteen age-matched healthy children constituted the control group. Anti-cytokine antibodies were used in conjunction with antibodies against cell surface antigens to study cytokine synthesis in different lymphocyte populations. In the present study the intracellular synthesis of interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-4, and IL-6 was measured. The intracellular synthesis of IL-2 was higher in group I compared with the controls, both in the whole population of T-lymphocytes (12.1+/-6.2% vs. 7.6+/-6.7%, P=0.0281) and in the subpopulation of CD8- lymphocytes (17.3+/-8.5% vs. 7.2+/-4.8%, P=0.0001). No significant differences in IFN-gamma intracellular expression were found. The intracellular synthesis of IL-4 was lower in group I compared with the controls, both in the whole population of T-lymphocytes (1.98+/-1.92% vs. 3.6+/-3.3%, P=0.012) and in the subpopulation of CD8- lymphocytes (2.4+/-2.3% vs. 6.5+/-6.4%, P=0.0002). Similarly, the intracellular expression of IL-6 was lower in group I compared with the control group, in the whole population of T-lymphocytes (0.85+/-0.6% vs. 2.2+/-3.1%, P=0.004), in the CD8- subpopulation (1.1+/-1.1% vs. 2.2+/-2.0%, P=0.006), and in the CD8+ subpopulation (1.1+/-0.9% vs. 2.8+/-3.4%, P=0.0008). The results of this study indicate that the acute episode of NS is associated with increased intracellular synthesis of IL-2 and decreased intracellular synthesis of IL-4 and IL-6.

[Dietary antioxidants and total antioxidant status in children with nephrotic syndrome]. / Spozycie substancji antyoksydacyjnych a calkowity potencjal antyoksydacyjny u dzieci chorych na zespól nerczycowy.

UNLABELLED: Several studies indicate the pathophysiological importance of reactive oxygen species in patients with nephrotic syndrome (NS). The present study was designed to determine the effect of dietary antioxidants on antioxidant enzymes (SOD, GPX, GR) activity and on total antioxidant status (TAS) in children with nephrotic syndrome. 36 children with NS (19 with first episode and 17 with relapse of NS) aged 4-16 were included into the study. Total antioxidant status was estimated using two-reagent Randox Total Antioxidant Status test in plasma. All patients had normal blood pressure, normal serum creatinine level and ingested a diet appropriate for age (with individual differences). Total antioxidant status was estimated using two-reagent Randox Total Antioxidant Status test in the plasma. Glutathione peroxidase (GPX), superperoxide dysmutase (SOD) and glutathione reductase (GR) activity was using antioxidant kits (Randox). A 3-day dietary intake record was obtained from each patient and then analyzed with computer program FOOD 2.0. Laboratory investigations were performed before steroid treatment. RESULTS: 1) in children with NS TAS was significantly reduced comparing to controls (0.84 +/- 0.14, 1.21 +/- 0.62 mmol/l, p = 0.002), 2) low manganese intake was found to have negative influence on TAS (TAS = 0.38 + 14.252*Mn, p > 0.001). 3) low intake of all components of antioxidant system was found: zinc (5.6 +/- 3.5 mg/kg b.w./24 h vs 8.6 +/- 4.0 mg/kg b.w./24 h), copper (0.021 +/- 0.013 mg/kg b.w./24 h vs 0.044 +/- 0.014 mg/kg b.w./24 h), manganese (0.029 +/- 0.0021 mg/kg b.w./24 h vs. 0.067 +/- 0.023 mg/kg b.w./24 h), vitamin E (0.15 +/- 0.04 mg/kg b.w./24 h vs 0.26 +/- 0.06 mg/kg b.w./24 h) and vitamin C (0.34 +/- 0.17 mg/kg b.w./24 h vs 0.87 +/- 0.19 mg/kg b.w./24 h). CONCLUSION: In children with NS reduced antioxidant protection maybe partly associated with low intake of some vital components of the antioxidant system.

Th1/Th2 balance and CD45-positive T cell subsets in primary nephrotic syndrome.

T cells are involved in the pathogenesis of nephrotic syndrome (NS). The aim of the study was to determine whether the activity of T-helper-1 (Th1) and T-helper-2 (Th2) cells and the distribution of the lymphocyte subsets, namely CD45RA+CD4+ ("naive" helper T cells, suppressor-inducer), CD45RA+CD8+ ("naive" suppressor T cells, suppressor-effector), CD45RO+CD4+ ("memory" helper T cells), are predictive for steroid sensitivity in children with primary NS. These parameters were assessed at the onset of disease, before initiation of steroid therapy. Two groups of NS children were retrospectively formed according to steroid sensitivity (SS) or resistance (SR). The activity of Th1 and Th2 cells was defined by the production of interleukin-2 (IL-2), interferon-gamma, IL-4, and IL-10 in the supernatants of CD4+ T cell cultures activated with autologous monocytes presenting tetanus toxoid (TT). Peripheral lymphocyte subsets were determined using double- or triple-color flow cytometry. In SS children with NS we found a decreased proliferative response of CD4+ T cells to TT stimulation, cytokine synthesis indicating the predominance of Th2 activity, and an increased percentage of activated suppressor-inducer (CD45RA+ CD4+CD25+, 5.18+/-0.8, P<0.001) and suppressor-effector (CD45RA+CD8+CD25+, 2.05+/-0.6, P<0.01) cells, with the concomitant reduction of activated memory cells (CD45RO+CD4+CD25+, 0.2+/-0.1, P<0.001). In children with SRNS we found an increased proliferative response of CD4+ T cells to TT, a rise in activated memory (CD45RO+CD4+CD25+, 3.82+/-0.7, P<0.01) and suppressor-inducer peripheral T cells (CD45RA+ CD4+CD25+, 3.85+/-0.6, P<0.01), but a low percentage of activated suppressor-effector (CD45RA+CD8+ CD25+, 0.5+/-0.2, P<0.05) T cells. We conclude that prior to treatment the distribution of lymphocyte subpopulations in peripheral blood together with Th1 and Th2 cell activity provides a useful tool for evaluating the likelihood of steroid sensitivity in patients with primary NS.

[Resistance to therapy in primary nephrotic syndrome: effect of MDR1 gene activity]. / Odpornosc na leczenie w przebiegu pierwotnego zespolu nerczycowego: wplyw aktywnosci genu MDR1.

MDR1 gene encodes for a transmembranous glycoprotein, gp-170, which acts as a drug export pump and is also a cyclosporine(CsA)-binding protein. This study aimed at evaluating MDR1 expression in NS sensitive(S) and resistant(R) to therapy (steroids/S/, cyclophosphamide/C/, CsA) patients. Twenty six boys, 13 girls aged 3-8 years were included to the study. MDR1 was analysed using: 1) evaluation of gp-170 activity according to DiC2/3/ [3,3-Diethyloxa-carbocyanine Iodide] by means of flow cytometry and as 2) mRNA expression of MDR1 determined by RT-PCR. The analysis was performed in the lymphocyte subset CD4/CD45RA presenting suppressor-inducer activity. Negative control, Jurkat-T-cell line, not expressing the MDR1 phenotype, was transfected with viral expression vector containing a full-length cDNA for the human MDR1 gene. We found that: in SR-NS the high expression of MDR1 was associated mainly with the suppressor-inducer T-cells (CD45RA+CD4+) and was subsequently enhanced during an ineffective treatment with C and/or CsA. C-R-NS and CsA-R-NS were partially reversible by S- and R-Verapamil; this was in vitro confirmed by inhibition of export pump activity, gp-170. SS-NS, C-S-NS and CsA-S-NS presented the low expression and activity of MDR1 comparing to R-children (p < 0.001) and healthy controls (p < 0.00001). Resistance to therapy in NS patients seems to be resulted from the enhanced expression of MDR1 gene and subsequent high activity of export pump P-gp-170. Calcium channel blockers may reverse the MRD1-related resistance in the therapy of NS. Analysis of MDR1 may help to detect of suspected therapy resistance in NS.