Clinical impact of cyclosporine cellular pharmacodynamics in minimal change nephrotic syndrome

BACKGROUND: Cellular pharmacodynamics of cyclosporine (INN, cyclosporin) is considered to be closely implicated in clinical efficacy of the drug in kidney transplantation and other immunologic disorders. We applied this strategy to patients with minimal change nephrotic syndrome to predict individual clinical efficacy of cyclosporine. METHODS: Drug sensitivity tests were carried out with peripheral blood mononuclear cells from 31 patients with minimal change nephrotic syndrome. The 50% lymphocyte-mitosis inhibition of cyclosporine on in vitro blastogenesis of peripheral blood mononuclear cells stimulated with concanavalin A were estimated, and interpatient variations of 50% lymphocyte-mitosis inhibition were evaluated. The relationship between cyclosporine-50% lymphocyte-mitosis inhibition and clinical outcomes indicated a decrease of urinary protein and the period required for complete remission under cyclosporine therapy was examined in 14 patients. We also evaluated the correlation between cyclosporine-50% lymphocyte-mitosis inhibition and interleukin-2 production and percentages of interleukin 2 receptor-positive peripheral blood mononuclear cells in vitro. RESULTS: Cyclosporine 50% lymphocyte-mitosis inhibition on peripheral blood mononuclear cell blastogenesis deviated largely between patients from 0.2 to 86.0 ng/mL. We found a statistically significant negative correlation between cyclosporine-50% lymphocyte-mitosis inhibition in vitro and decreasing rates of urinary protein at 1 week after onset of cyclosporine administration (r = -0.655, P < .02). When we arbitrarily divide the 14 patients who received cyclosporine therapy according to their median 50% lymphocyte-mitosis inhibition of cyclosporine into two groups, that is, a high-sensitivity group (50% lymphocyte-mitosis inhibition < 18.1 ng/mL, n = 6) and a low-sensitivity group (50% lymphocytemitosis inhibition > 18.1 ng/mL, n = 8), the period required for complete remission was significantly shorter in the high-sensitivity group (P < .03). The 50% lymphocyte-mitosis inhibition of cyclosporine on interleukin-2 production in culture medium was correlated with 50% lymphocyte-mitosis inhibition of the drug on peripheral blood mononuclear cell blastogenesis (r = 0.806, P < .02). Decreasing rates of interleukin-2R-positive cells by cyclosporine treatment in vitro were negatively correlated with peripheral blood mononuclear cells blastogenesis in the presence of the drug (r = -0.694, P < .02). CONCLUSIONS: Peripheral blood mononuclear cell response to cyclosporine in vitro is closely related to clinical efficacy of the drug in minimal change nephrotic syndrome. Peripheral blood mononuclear cell resistance to cyclosporine was correlated with ability of the cells to express interleukin 2 and interleukin 2R.     

Minimal change nephrotic syndrome

In minimal change nephrotic syndrome (MCNS), selective proteinuria is associated with structural alterations of the glomerular epithelial cells, such as effacement of the foot process. Although the pathogenesis of MCNS has not been completely clarified, clinical and experimental observations suggest that it results from T cell dysfunction in the pathogenesis. Recently, it has been proposed that the occurrence of MCNS has been associated with type 2 Th (Th2) lymphocyte-dependent conditions and some vascular permeability factors, which are induced by T cell disorder. In general, MCNS has the good long-term outcome with sustained remission and preserved renal function, because almost cases are responsible for the treatment. However, some patients show frequent relapses or resistance to this treatment and need large doses of immunosuppressive agents for a long time. Therefore, we should be care for the complications associated with prolonged these therapies.     

Elevated levels of immunoglobulin E may indicate steroid resistance or relapse in adult primary nephrotic syndrome, especially in minimal change nephrotic syndrome

Immunoglobulin E (IgE) antibodies may play a role in the development of kidney diseases that are related to hypersensitivity reactions. Patients with idiopathic nephrotic syndrome often exhibit increased serum IgE levels and this may be related to sensitivity to steroid treatment. In the present study, the serum IgE levels in 120 patients with different types of primary nephrotic syndrome (PNS) were analysed and found to be significantly elevated in cases of minimal change nephrotic syndrome (MCNS) compared with membranous nephropathy or membrano-proliferative glomerulonephritis. No difference in serum IgE level was observed between cases of steroid-sensitive nephrotic syndrome (SSNS) or steroid-resistant nephrotic syndrome, although the serum IgE level was significantly elevated in SSNS patients in relapse compared with SSNS patients in remission. In MCNS patients, 73.6% exhibited SSNS regardless of their serum IgE level at diagnosis. It is concluded that elevated levels of IgE may be a feature of steroid resistance or relapse, indicating prognostic significance in adult PNS, particularly in MCNS.     

伴IgA沉积的微小病变肾病综合征患者血清IgA1糖基化缺陷的检测

目的 通过对伴IgA沉积的微小病变肾病综合征（MCNS-IgA）患者血清中IgA1分子糖基化缺陷程度的检测,探讨MCNS-IgA的可能的病理分类归属. 方法 选择北京大学人民医院肾内科MCNS-IgA患者10例,微小病变肾病综合症（MCNS）患者10例、大量蛋白尿IgAN （H-IgAN）患者10例为对照.用双抗体夹心ELISA法检测各组患者血清IgA1的相对浓度,用黑木凝集素检测IgA1分子的α2,6唾液酸水平,花生凝集素检测IgA1分子的半乳糖水平,蜗牛凝集素检测IgA1分子的N-乙酰氨基半乳糖水平,计算经血清IgA1浓度校正的各糖基水平.观察MCNS-IgA组患者血清IgA1分子糖基化缺陷情况,并且与H-IgAN及MCNS组进行比较.结果 与MCNS组相比,MCNS-IgA肾病患者血清IgA1的α2,6唾液酸（1.232±0.250比较1.379±0.623,P=0.455）、半乳糖缺失（0.204±0.053 vs 0.229±0.088,P=0.454）水平及N-乙酰氨基半乳糖暴露（0.191±0.039 vs0.205±0.068,P=0.626）水半无明显差异.但其血清IgA1分子α2,6唾液酸缺失（1.232±0.250vs 0.756±0.243,P=0.015）及N-乙酰氨基半乳糖的暴露（0.191±0.039比0.258±0.066,P=0.025）显著低于H-IgAN组,半乳糖缺失少,但未达统计学差异（0.204±0.053比0.139±0.038,P=0.052）. 结论 MCNS-IgA组患者血清IgA1糖基化水平上显示了与IgA肾病不同的特点,提示其可能是微小病变伴IgA分子的非特异性沉积.     

Developmental pharmacodynamics of cyclosporine.

OBJECTIVE: To determine the relationship between human development and in vitro cyclosporine (INN, ciclosporin) pharmacodynamics. METHODS: Fifty-six subjects ranging in age from 3 months to 39 years were studied in this prospective laboratory investigation at a university children's hospital and clinical pharmacology laboratory. Peripheral blood monocytes were separated from whole blood and cultured with phytohemagglutinin A (5 microg/mL) and cyclosporine (0, 6.25, 12.5, 25, 50, 100, 500, 1000, 2500, and 5000 ng/mL). Peripheral blood monocytes cultures were assayed for cell proliferation and supernatant interleukin-2 concentration with use of radionuclide DNA tagging and enzyme-linked immosorbent assay, respectively. After concentration-effect modeling, summary pharmacodynamic parameters, including the maximal drug effect (Emax) and cyclosporine concentration at which 50% of maximal effect (IC50) and 90% of maximal effect (IC90), were determined. These parameters were compared between four consecutive subject age groups: infants (0-1 years), children (>1-4 years), preadolescents (>4-12 years), and adults (>12 years). RESULTS: The peripheral blood monocytes of the infants showed a twofold lower mean IC50 (peripheral blood monocyte proliferation) and sevenfold lower mean IC90 (interleukin-2 expression) than peripheral blood monocytes from older subjects. The three older age groups were similar with respect to mean IC50 and Emax (peripheral blood monocyte proliferation). Lymphocyte subtype proportions measured in peripheral blood monocytes preparations from each age group were generally similar. The experimental conditions (eg, general anesthesia and cyclosporine solvents) did not affect peripheral blood monocytes proliferation, but the highest experimental cyclosporine concentration (ie, 5000 ng/mL) was associated with decreased peripheral blood monocytes viability. CONCLUSIONS: Cyclosporine pharmacodynamics in vitro are related to age. This factor, if neglected, may be a source of iatrogenic risk during pediatric immunosuppressive therapy.     

Studies on the turnover of triglyceride and esterified cholesterol in subjects with the nephrotic syndrome

Factors involved in the hyperlipidemia of nephrosis have been studied in seven patients. The turnover of triglyceride was measured in plasma very low density lipoproteins after the injection of glycerol-(14)C. The turnover of esterified cholesterol was measured in whole plasma and in very low density lipoproteins after the injection of mevalonic acid-2-(3)H.Urine protein loss was found to be significantly correlated with the plasma concentrations of triglyceride and free cholesterol, suggesting that increasing loss of protein is associated with the formation of larger lipoproteins. Lactescent plasmas were found in the subjects with the greatest protein loss.The turnover rate of triglyceride tended to be higher among subjects with higher than with lower triglyceride concentrations and was on the average higher than among six normotriglyceridemic subjects. However, there was also evidence for decreased clearance of glyceride from plasma. The hypertriglyceridemia of nephrosis appeared to reflect both increased formation of glyceride and decreased removal of glyceride from plasma.The turnover of esterified cholesterol was significantly higher in whole plasma of nephrotic subjects than in normocholesterolemic nonnephrotic patients. Esterified cholesterol turnover in very low density lipoproteins was raised in the two subjects in whom a major part of total esterified cholesterol was carried in this lipoprotein fraction.These studies were repeated in one subject after remission was induced. The cessation of urinary loss of protein was associated with reductions in the concentrations and turnover of triglyceride and esterified cholesterol.The increased turnover of plasma lipids in nephrosis may reflect the general increase in the formation of protein.     

小剂量环孢素A联合小剂量激素治疗原发性肾病综合征疗效观察

目的 观察小剂量环孢素A（CsA）联合小剂量强的松在原发性肾病综合征治疗中的疗效、不良反应及其与足量强的松的比较.方法 67例原发性肾病综合征均经肾活检病理检查证实,前瞻性非随机观察18个月以上.治疗组（n=41）：小剂量CsA联合小剂量强的松,其中难治性肾病综合征8例,强的松0.5 mg· kg-1·d-1 ＋CsA 2.5 mg·kg-1·d-1,强的松最大剂量30 mg/d,连服2～3个月后每隔2～4周强的松、CsA在原剂量基础上交替递减10％或持续应用原剂量.对照组（n=26）：足量强的松组,强的松1.0 mg·kg-1·d-1,强的松最大剂量60 mg/d,连服2～3个月后每隔2～4周在原剂量基础上递减10％.其中10例联合环磷酰胺（CTX）治疗,CTX0.8 g·次-1·月-1,加入生理盐水500 ml静脉滴注,或口服0.1 g/d,CTX总量6.0～8.0g.观察两组治疗前、治疗3、6、9、12、18个月24h尿蛋白定量（MTP）、肝功能（TP、ALB、ALT）、肾功能（Cr、UA）、血糖、血脂（TC、LDL）及不良反应.结果 两组患者治疗后MTP及ALB水平较治疗前均明显好转（P＜0.01）,治疗18个月后治疗组和对照组总有效率（显效＋有效）分别为80.5％和84.6％,两组间无统计学差异（P＞0.05）.治疗组12个月时完全缓解率有升高趋势（P＜0.01）,但18个月后又降至正常,28例显效患者18个月后停CsA随访3年中有5例（17.9％）复发,复发后再次治疗仍然有效.治疗组不良反应：齿龈增生1例,血压升高4例,血尿酸升高6例,停药后或用药均可控制.结论 与足量强的松治疗原发性肾病综合征比较,小剂量CsA联合小剂量强的松具有等同疗效,又可减少CsA及激素毒副作用,为治疗原发性肾病综合征提供了一个比较经济有效安全的方法.     

History of nephrotic syndrome

The history of nephrotic syndrome can go back to beginning of the era. In old Alexandria, urine was conceived to be produced in kidneys. In 1827, Bright classified diseases with proteinuria into three categories, and lipoid nephrosis seemed to be included in group 1. Mechanisms of urinary protein leakage have been in great controvesies, and nowadays defects of slit-membrane protein are supposed to play important roles. In the middle of the 20th centuries, electron microscopy and renal biopsy technique were adopted in practical use. Since then, the treatment and research of nephrotic syndrome have been remarkably progressed. Clinical strategies including diet therapy, immuno-suppressive and antihypertensive drugs and other modalities have improved the prognosis of nephrotic syndrome.     

Epidemiology of nephrotic syndrome

Causes of nephrotic syndrome are varied with age, the times, geographical location and race. In children, minimal change nephrotic syndrome (MCNS) is common; however, membranous nephropathy (MN) is most frequent in adult. Incidence of membranoproliferative glomerulonephritis (MPGN) is decreased in advanced nations, although it remains a common in developing countries. In advanced nations, incidence of focal and segmental glomerular sclerosis (FGS) is increased, particularly in black populations. In Japan, MCNS was most frequent (37.7%), and then, MN was 23.3%, FGS was 7.2% and MPGN was 8.3% by a former research (in 1985). The recent research (in 1994) showed that MCNS was 41.5%, and next MN was 24.7%. FGS was increased to 11.8% and MPGN was decreased to 4.9%.     

Improved outcomes in nephrotic syndrome

Nephrotic syndrome can now be treated effectively in most cases. All patients should be treated with a low-salt diet, diuretics to reduce edema, and statins to normalize serum lipid concentrations. Patients with nephrotic syndrome are prone to deep vein thrombophlebitis, renal vein thrombosis, and pulmonary emboli. Depending on the condition, additional treatment may include corticosteroids, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), cyclosporine, cytotoxic agents, or mycophenolate.     

Pharmacokinetics and pharmacodynamics of fluvastatin in heart transplant recipients taking cyclosporine A

During the last decades, transplantation has become an established tool for the treatment of terminal organ failure. Beside immunological factors, hyperlipidemia is the main problem after heart transplantation, causing rapid transplant coronary artery disease (TxCAD) and poor long-term prognosis at the beginning of the transplantation. Heart transplant recipients are now effectively treated with lipid lowering substances, of which HMG-CoA-reductase inhibitors are the most potent. However, treatment with these substances correlates with an increased risk for the development of rhabdomyolysis due to therapy with the immunosuppressive cyclosporine A. Our study monitored the safety and efficacy of treatment with the HMG-CoA reductase inhibitor fluvastatin in heart transplant recipients compared to healthy controls. We investigated 10 patients receiving immunosuppressive therapy consisting of cyclosporine A, prednisone, and azathioprine who had increased concentrations of LDL-cholesterol (LDL-C), and 10 age-matched healthy controls. The patients were treated with 40 mg/day fluvastatin for 4 weeks and 20 mg/day for 4 additional weeks. Control individuals received 40 mg/day fluvastatin for 4 weeks only. Parameters of fluvastatin pharmacokinetics (maximum concentration of the drug (C(max.)), time (t(max.)) to reach C(max.), area under the concentration vs. time curve (AUC(0h-24h)), elimination half-life time (t(1/2))), apparent total body clearance (CL), blood cyclosporine A concentration, plasma lipids, and safety parameters were determined in both study groups at the beginning of the study and after 4 weeks. The latter were determined in the patient group also after 8 and 12 weeks. Treatment with 40 mg/day fluvastatin caused a significant decrease in total cholesterol (patients: 5.47 +/- 1.32 mmol/L vs. 7.30 +/- 1.83 mmol/L; controls: 4.69 +/- 0.64 mmol/L vs. 5.81 +/- 0.72 mmol/L), LDL-C (patients: 3.28 +/- 1.25 mmol/L vs. 5.00 +/- 1.85 mmol/L; controls: 2.58 +/- 0.63 mmol/L vs. 3.50 +/- 0.70 mmol/L), and triglycerides (patients: 1.99 +/- 0.77 mmol/L vs. 2.50 +/- 1.00 mmol/L; controls: 1.24 +/- 0.46 mmol/L vs. 1.72 +/- 0.67 mmol/L) in both study groups, whereas HDL-C was not significantly changed (patients: 1.29 +/- 0.35 mmol/L vs. 1.17 +/- 0.32 mmol/L; controls: 1.55 +/- 0.30 mmol/L vs. 1.53 +/- 0.26 mmol/L). Values of C(max.) and AUC(0h-24h) were higher in the patient group than in the control group (day 1, patients vs. controls, C(max.): 869.4 +/- 604.0 ng/mL vs. 211.9 +/- 113.9 ng/mL; AUC(0h-24h): 1948.8 +/- 1347.9 ng/mL*h vs. 549.4 +/- 247.4 ng/mL*h), whereas the corresponding value of CL was lower in the patient group (33.3 +/- 24.5 L/h vs. 107.9 +/- 95.8 L/h), and the values of t(max.) and t(1/2) showed no differences. In addition, values of C(max.) and AUC(0h-24h) after administration of 40 mg/day fluvastatin for 4 weeks in both groups were slightly higher than at the beginning, whereas the value of CL was slightly lower (day 28, patients vs. controls, C(max.): 1530.4 +/- 960.4 ng/mL vs. 254.7 +/- 199.8 ng/mL; AUC(0h-24h): 2615.3 +/- 1379.4 ng/mL*h vs. 841.8 +/- 421.4 ng/mL*h; CL: day 28, 21.4 +/- 15.3 L/h vs. 61.5 +/- 36.6 L/h). Except for an intermittent increase of creatine kinase, safety parameters showed no increases within the observation period. Our data suggest that fluvastatin effectively lowers plasma concentrations of cholesterol and LDL-C in patients after heart transplantation, however, the metabolism of fluvastatin is affected by concomitant therapy with cyclosporine A. Serum concentrations of fluvastatin should be monitored in cases of concomitant therapy with other substances interfering in the metabolism by competing cytochrome enzymes.     

Cyclosporin therapy in minimal change nephritis

In 5 cases with minimal change nephritis Cyclosporine A has been added to the conventional steroid therapy, when relapse of nephrotic syndrome occurred while reducing the daily prednisolone dose. The intended cyclosporine trough level ranged from 250 ng/ml to 450 ng/ml whole blood, estimated by the RIA method. Proteinuria disappeared in 4 out of the 5 cases, in the other one urinary protein excretion was strikingly reduced. In the 4 cases with complete remission of proteinuria prednisolone was tapered. These patients have cyclosporine A as the sole immunosuppressive drug since 56 weeks and do not show proteinuria. Side effects of cyclosporine therapy have been slight deterioration of kidney function in 2 out of the 5 cases and the occurrence of hypertension in 4 patients.