Effects of cyclosporine on the production of the reactive oxygen species in the glial cells

Epileptic Seizures After Allogeneic Hematopoietic Stem Cell Transplantation

Technique in allogeneic hematopoietic stem cell transplantation has greatly advanced over the past decades, which has led to an increase in the number of patients receiving transplantation, but the complex procedure places these transplant recipients at high risk of a large spectrum of complications including neurologic involvement. As a common manifestation of neurological disorders, epileptic seizures after transplantation have been of great concern to clinicians because it seriously affects the survival rate and living quality of those recipients. The aim of this review is to elucidate the incidence of seizures after allogeneic hematopoietic stem cell transplantation, and to further summarize in detail its etiologies, possible mechanisms, clinical manifestations, therapeutic schedule, and prognosis, hoping to improve doctors' understandings of concurrent seizures following transplantation, so they can prevent, process, and eventually improve the survival and outlook for patients in a timely manner and correctly.

Effects of calcineurin inhibitors on paraoxonase and arylesterase activity after a kidney transplant

OBJECTIVES

Cardiovascular disease is a common cause of morbidity and mortality in patients with chronic kidney failure, before and after a kidney transplant. Oxidation of lipoproteins that contain apolipoprotein B may contribute to the initiation of atherosclerosis. Paraoxonase may prevent cardiovascular disease. We compared the effects of different calcineurin inhibitors on risk factors for cardiovascular disease in kidney transplant recipients.

MATERIALS AND METHODS

In 16 kidney transplant recipients, treatment included tacrolimus in 8 patients and cyclosporine in 8 patients. Hemoglobin, glucose, renal function, lipid parameters, high-sensitivity C-reactive protein, homocysteine, malondialdehyde, paraoxonase activity, and arylesterase activity were measured before transplant and at 1, 6, and 12 months after the transplant.

RESULTS

The levels of homocysteine and malondialdehyde did not change significantly in patients who received either tacrolimus or cyclosporine. The high-sensitivity C-reactive protein was decreased (tacrolimus group, 1 mo) and increased (cyclosporine group, 6 and 12 mo) after the kidney transplant. Paraoxonase activity was increased (tacrolimus group, 1 mo). Arylesterase activity was increased (tacrolimus group, 1, 6, and 12 mo; cyclosporine group, 1 and 6 mo). The percentage of change in arylesterase activity was higher at 12 months in the tacrolimus than in the cyclosporine group.

CONCLUSIONS

Tacrolimus may be more effective than cyclosporine in improving risk factors for cardiovascular disease after kidney transplant.

Contribution of aquaporin 9 and multidrug resistance-associated protein 2 to differential sensitivity to arsenite between primary cultured chorion and amnion cells prepared from human fetal membranes

Arsenic trioxide (arsenite, As(III)) has shown a remarkable clinical efficacy, whereas its side effects are still a serious concern. Therefore, it is critical to understand the effects of As(III) on human-derived normal cells for revealing the mechanisms underlying these side effects. We examined the effects of As(III) on primary cultured chorion (C) and amnion (A) cells prepared from human fetal membranes. A significant dose-dependent As(III)-mediated cytotoxicity was observed in the C-cells accompanied with an increase of lactate dehydrogenase (LDH) release. Higher concentrations of As(III) were required for the A-cells to show cytotoxicity and LDH release, suggesting that the C-cells were more sensitive to As(III) than the A-cells. The expression levels of aquaporin 9 (AQP9) were approximately 2 times higher in the C-cells than those in the A-cells. Both intracellular arsenic accumulation and its cytotoxicity in the C-cells were significantly abrogated by sorbitol, a competitive AQP9 inhibitor, in a dose-dependent manner. The protein expression levels of multidrug resistance-associated protein (MRP) 2 were downregulated by As(III) in the C-cells, but not in the A-cells. No significant differences in the expression levels of MRP1 were observed between C- and A-cells. The protein expression of P-glycoprotein (P-gp) was hardly detected in both cells, although a detectable amount of its mRNA was observed. Cyclosporine A, a broad-spectrum inhibitor for ABC transporters, and MK571, a MRP inhibitor, but not PGP-4008, a P-gp specific inhibitor, potently sensitized both cells to As(III)-mediated cytotoxicity. These results suggest that AQP9 and MRP2 are involved in controlling arsenic accumulation in these normal cells, which then contribute to differential sensitivity to As(III) cytotoxicity between these cells.

Effects of cyclosporine on the antioxidant status and oxidative stress in the glioma cells

OBJECTIVES

After organ transplantation, some patients suffer neurological complications. Among the immunosuppressants, cyclosporine can cause neurological side effects. However, the mechanisms of encephalopathy by cyclosporine are not fully understood. We measured the antioxidant status, the hydrogen peroxide level, and the malondialdehyde level in glioma cells after cyclosporine treatment.

METHODS

The production of hydrogen peroxide was determined using a modified xylenol orange method. The amount of malondialdehyde was measured using the thiobarbituric acid assay. Total antioxidant status was measured using Free Radical Analytical System 4 with kits.

RESULTS

Cyclosporine resulted in the production of hydrogen peroxide by the glioma cells. The increased production of hydrogen peroxide depended on the drug concentration. The antioxidant status was decreased in the glioma cells after cyclosporine treatment. The malondialdehyde level was not changed in glioma cells after cyclosporine treatment.

CONCLUSIONS

Increased production of reactive oxygen species and decreased antioxidant status by cyclosporine in glioma cells may contribute to neurological side effects in transplantation patients.

SERCA2b activity is regulated by cyclophilins in human platelets

OBJECTIVE

The role of cyclophilins (chaperones that are widely expressed in different cell types, including human platelets) was explored in sarcoendoplasmic calcium (Ca(2+)) adenosine triphosphatase (SERCA) activity.

METHODS AND RESULTS

Cyclophilin inhibition by cyclosporin A (CsA) evoked a time- and concentration-dependent reduction of Ca(2+) uptake by SERCA2b. However, other Ca(2+)-adenosine triphosphatases expressed in platelets, such as SERCA3 and plasma membrane Ca(2+) adenosine triphophatase, remained unaltered after CsA treatment. Cypermethrin, a non-CsA-related calcineurin inhibitor, did not alter SERCA2b activity. Furthermore, SERCA2b was affected by other CsA analogues, which do not interfere with calcineurin, such as PKF-211-811-NX5 (NIM811) and sanglifehrin A. Inhibition of the immunophilin family members using FK506 (tacrolimus) did not alter SERCA2b ability to sequester Ca(2+) into the dense tubular system. Coimmunoprecipitation experiments confirmed that cyclophilin A associates with SERCA2b and stromal interaction molecule-1 in resting platelets. This interaction is attenuated by the physiological agonist thrombin but enhanced by treatment with CsA or sanglifehrin A.

CONCLUSIONS

Cyclophilin A is a regulator of SERCA2b in human platelets.

Effect of different calcineurin inhibitors on AOPP and TAS after kidney transplantation

OBJECTIVES

Little is known about the influence of calcineurin inhibitors on advanced oxidation protein products (AOPP) and total antioxidant status (TAS) after renal transplantation.

DESIGN AND METHODS

AOPP and TAS were evaluated in transplanted patients on different calcineurin inhibitors. Thirty-five patients were treated with cyclosporine A (group A) and 33 with tacrolimus (group B).

RESULTS

Over 6 months, the mean levels of AOPP in group A decreased from 205.9+/-125.7 to 140.9+/-78.9 micromol/L and TAS from 1.89+/-0.30 to 1.75+/-0.27 mmol/L. In group B, the mean levels of AOPP decreased from 196.5+/-123.9 to 129.6+/-63.8 micromol/L and TAS from 1.80+/-0.39 to 1.78+/-0.23 mmol/L.

CONCLUSION

No significant differences in AOPP and TAS were found with respect to treatment. The only exception was the higher mean concentration of AOPP at month 1 in group A (p=0.026).