The production of reactive oxygen species in tacrolimus-treated glial cells

OBJECTIVE

After organ transplantation, some patients suffer from mild neurological symptoms, such as tremor, to severe complications, including seizures and encephalopathy. These neurological side effects can be caused by immunosuppressants such as tacrolimus. However, the mechanism of encephalopathy by tacrolimus is not fully understood.

METHODS

We measured the production of reactive oxygen species (ROS) in glioma cells after tacrolimus treatment. Tacrolimus added to glioma cells was incubated for 60 minutes at 37 degrees C. The production of ROS was evaluated by measuring the fluorescent product from the oxidation of an oxidant-sensitive 2',7'-dichlorofluorescin using VICTOR3TM multilabel counter.

RESULTS

Tacrolimus resulted in the production of the ROS in glioma cells. The production of the ROS was increased in time-dependent fashion.

CONCLUSIONS

These findings indicated that the tacrolimus may contribute the neurological side effects by ROS production.

Case of adult mumps infection after renal transplantation

Viruses are the most common cause of opportunistic infections, important complications of transplantation. Mumps infection in renal transplant recipients is uncommon. This report focused on a 23-year-old woman who received immunosuppressive therapy based on tacrolimus, prednisolone, and mycophenolate mofetil for renal transplantation. Sixteen months after transplantation, she was admitted with pain and swelling in both infra-auricular areas. Laboratory findings demonstrated positive mumps IgM and IgG antibodies and an increased serum amylase level. Computed tomography revealed both parotid glands to be diffusely enlarged. After the diagnosis of mumps parotitis, the patient's immunosuppression was reduced and the clinical course was satisfactory.

Feasibility study on driver's stress detection from differential skin temperature measurement

Prolonged monotonous driving may lower a driver's awareness level as well as increasing their stress level due to the compulsion to maintain safe driving, which may result in an increased risk of a traffic accident. There is therefore an opportunity for technological assessment of driver physiological status to be applied in-car, hopefully reducing the incidence of potentially dangerous situations. As part of our long-term aim to develop such a system, we describe here the investigation of differential skin temperature measurement as a possible marker of a driver's stress level. In this study, healthy male (n=18) & female (n=7) subjects were investigated under environment-controlled conditions, whilst being subjected to simulated monotonous travel at constant speed on a test-course. We acquired physiological variables, including facial skin temperature which consists of truncal and peripheral skin temperatures (Ts) using thermography, beat-by-beat blood pressure (BP), cardiac output (CO), total peripheral resistance (TPR), and normalized pulse volume (NPV) used as an indicator of local peripheral vascular tone. We then investigated the driver's reactivity in terms of skin temperatures with this background of cardiovascular haemodynamics. We found that the simulated monotonous driving produced a gradual drop in peripheral Ts following the driving stress, which, through interpretation of the TPR and NPV recordings, could be explained by peripheral sympathetic activation. On the other hand, the truncal Ts was not influenced by the stress. These findings lead us to suggest that truncal-peripheral differential Ts could be used as a possible index indicative of the driver's stress.

Effect of tacrolimus on the production of oxygen free radicals in hepatic mitochondria

OBJECTIVES

Cyclosporine (CsA) causes side effects that occur mainly in the kidney but also in the liver. Several reports have strongly suggested that the production of oxygen free radicals (OFRs) is a common mechanism of CsA toxicity. However, tacrolimus is believed to suppress the production of OFRs.

METHODS

We obtained the mitochondrial fraction with 96% purity from rat liver using a sucrose density gradient solution. Zero to 100 micromol/L tacrolimus was incubated with the mitochondrial fraction for 6 hours at 37 degrees C. OFRs were evaluated by measuring the fluorescent product from the oxidation of an oxidant-sensitive 2,7-dichlorefluorescein using a VICTOR3 multilabel counter.

RESULTS

The fluorescence units for OFR production were increased as the time of exposure to tacrolimus passed from 1 to 6 hours. The fluorescence units in 0.1 micromol/L tacrolimus were 6.0 x 10(5) at 1 hour, 7.8 x 10(5) at 2 hours, 9.0 x 10(5) at 3 hours, 10.0 x 10(5) at 4 hours, 11.1 x 10(5) at 5 hours, and 11.4 x 10(5) at 6 hours. However, the fluorescence units were similar although the tacrolimus concentration increases from 0.1 to 100 micromol/L.

CONCLUSIONS

The results in this experiment suggested that tacrolimus induced the production of OFRs depending on the exposure time.

Apoptosis by cyclosporine in mesangial cells

INTRODUCTION

The immunosuppressive agent cyclosporine (CsA) is widely used to treat allograft rejection and various autoimmune disorders. A major limiting factor in the use of CsA is chronic nephrotoxicity. The pathogenesis of CsA-induced nephrotoxicity is not fully understood. Several recent studies have suggested that CsA treatment directly induces apoptosis in several cell types. The present study was undertaken to investigate the effects of CsA on apoptosis of cultured rat mesangial cells (RMCs).

METHODS

RMCs were treated with CsA at concentrations of 0.1 to 40 mumol/L. Cell viability was determined by MTT assay. Apoptotic protein expression was determined by Western blot analysis.

RESULTS

Cell viability was decreased with increasing concentrations of CsA in dose-dependent manner. CsA produced dose-dependent induction of p53, caspase-6, and Bax protein expression. CsA treatment caused proteolytic cleavage of caspase-3 and induced the degradation of 116-kDa PARP into 89-kDa fragment. RMCs with CsA reduced Bcl-2 and cIAP expression.

CONCLUSIONS

In this study, CsA induced apoptosis by up-regulating proapoptotic factors, caspase-3 and -6, p53, Bax, cleaving PARP, and down-regulating antiapoptotic factor, Bcl-2, and cIAP. These results suggested that the increased cell apoptosis exerted by CsA may be one of the mechanisms promoting CsA-induced nephrotoxicity.

Total antioxidant status and oxygen free radicals during hepatic regeneration

OBJECTIVES

The damage induced by oxygen free radicals (OFRs) is caused by an imbalance of the production of versus the antioxidant defenses against OFRs.

METHODS

To understand hepatic damage induced by oxygen free radicals after hepatectomy in rats, total antioxidant status and total production of oxygen free radicals were serially measured in regeneration liver. At 1, 2, 3, 7, and 10 days after hepatectomy of Sprague-Dawley rats, blood was obtained into a capillary tube from a tail vein. Total antioxidant status and total production of oxygen free radicals were measured using the Randox kit, a colorimetric method, and the Free Radical Analytical System. We also measured the amount of malonyldialdehyde, which provides an indirect index of oxidative injury.

RESULTS

The level of malonyldialdehyde after hepatectomy was higher compared with that before hepatectomy. The level of total oxygen free radicals after hepatectomy was higher compared with that before hepatectomy. Total antioxidant status after hepatectomy was lower compared with that before hepatectomy.

CONCLUSIONS

The results suggested that the damage by OFRs to the regenerating liver was caused by increased production of OFRs and decreased antioxidant defense against OFRs.

Polyoma virus-associated nephropathy and concurrent cytomegalovirus infection in the kidney transplant recipients

INTRODUCTION

Cytomegalovirus (CMV) and polyoma virus BK (BKV) may both establish latency following primary infection. Frequent reactivation of these viruses can occur in the kidney transplant recipients. BKV may induce CMV gene expression by stimulating cellular regulator proteins or by its own gene regulator proteins. A high rate of concurrent CMV infections has been noted in kidney transplant recipients with polyoma virus-associated nephropathy (PVAN).

METHODS

PVAN was identified in 10 of 191 patients who received kidney transplants between October 1998 and September 2003. PVAN was confirmed by allograft kidney biopsy. Four of the 10 patients were complicated by concurrent CMV infection.

RESULTS

Two patients had only serological evidence of CMV infection and one patient had CMV gastritis. These three patients were treated with intravenous ganciclovir with good results. Disseminated ganciclovir-resistant CMV disease was demonstrated in the remaining patient. This 34-year-old kidney transplant recipient with PVAN died of multiorgan failure despite antiviral therapy with both ganciclovir and foscarnet.

CONCLUSION

PVAN with concurrent CMV infection in kidney transplant recipients showed variable clinical courses including mortality. Further studies are needed to elucidate the influence of PVAN on the pathogenesis of CMV infection.

Effects of cyclosporine and tacrolimus on the oxidative stress in cultured mesangial cells

OBJECTIVES

Cyclosporine (CsA) and tacrolimus (Tac) are two primary immunosuppressive agents used for the prevention of graft rejection. However, their use is associated with significant side effects, most notably nephrotoxicity. The mechanisms of this toxicity are not fully understood, but they seem to be associated with increases in the production of oxygen free radicals (OFRs). This present work examined the effect of CsA and Tac on the production of OFRs in cultured rat renal mesangial cells (RMCs).

METHODS

Varying concentrations of CsA and Tac (0 to 40 micromol/L) were added to RMCs and incubated for 60 minutes at 37 degrees C. The production of OFRs was evaluated by measuring the fluorescent product from the oxidation of an oxidant-sensitive 2', 7'-dichlorofluorescin.

RESULTS

At 60 minutes, the relative fluorescence units (RFU) for OFRs production in RMCs exposure to CsA were increased by 2.5%, 11.5%, 22.5%, 57.2%, and 174% at 2.5, 5, 10, 20, and 40 micromol/L, respectively. Tac increased the RFU by 15.9%, 13.6%, 14.8%, 13.2%, 21.4%, 13.2%, and 28.1% at 0.1, 1, 2.5, 5, 10, 20, and 40 micromol/L, respectively. In RMCs, the RFU produced by CsA was higher than that by Tac.

CONCLUSIONS

The results of this experiment suggest that CsA and Tac induced renal injury by OFRs.

Cyclosporine-Induced Apoptosis in Osteosarcoma Cells

INTRODUCTION

Posttransplant bone disease is one of the complications of cyclosporine (CsA), which is widely used as an immunosuppressive agent in the field of kidney transplantation. Cyclosporine treatment causes osteopenia as a result of altered bone turnover, but the pathogenic mechanisms of this process remain unclear. This study examined the ability of CsA to induce apoptosis in a rat osteoblast cell line.

RESULTS

We induced apoptosis in rat osteoblastic ROS 17/2.8 cells by exposure to CsA. MTT assay showed that CsA exhibited significant cytotoxic effects on ROS 17/2.8 cells in a dose-dependent manner. Western blot analysis showed enhanced processing of caspase-8, Bax, and p53 after CsA treatment. Expression of cleaved poly (ADP-ribose) polymerase (PARP) was elevated by CsA treatment. Pro-caspase-3 and Bcl-2 proteins were decreased by CsA.

CONCLUSIONS

These results suggested that CsA induced apoptosis of osteoblasts.

Interleukin-18 gene polymorphisms in Korean patients with Behçet's disease

OBJECTIVE

There is strong evidence that Th1-type cytokines play an important role in the pathogenesis of Behçet's disease (BD). Interleukin (IL)-18 is a proinflammatory cytokine that mediates Th1-polarized immune responses, and elevated levels of IL-18 have been observed in the sera and bronchoalveolar lavage fluid of patients with active BD. Therefore, the aim of this study was to investigate the potential associations of two single nucleotide polymorphisms (SNPs) at positions -137 (G/C) and -607 (C/A) in the promoter region of the IL-18 gene with a susceptibility to BD in the Korean population.

METHODS

Ninety-eight patients with BD and 105 healthy controls were studied. All of the subjects were genotyped using sequence specific PCR. The genotypes and alleles between patients with BD and controls were compared using the chi2 test, together with Yate's correction where appropriate. Haplotype analysis was assessed using the EH program.

RESULTS

The genotype and allele distributions of the two SNPs did not differ significantly between patients with BD and controls. The haplotype frequencies of the IL-18 promoter polymorphisms were also similar between patients with BD and controls. However, the frequency of the GG genotype at position -137 was significantly higher in BD patients with ocular lesions than in those without ocular lesions (p = 0.026, pc = 0.048, OR = 4.1).

CONCLUSION

Although the IL-18 gene polymorphisms were not associated with a susceptibility to BD in the Korean population, the patients carrying the GG genotype at position -137 had a higher risk of developing the ocular lesions. Further studies in other populations are required to confirm these results.

Genome-wide linkage analysis of mandibular prognathism in Korean and Japanese patients

The existence of familial aggregation of mandibular prognathism (MP) suggests that genetic components play an important role in its etiology. In this study, a genome-wide linkage analysis to identify loci susceptible to MP was conducted with 90 affected sibling-pairs in 42 families, comprised of 40 Korean sibling-pairs and 50 Japanese sibling-pairs. Two non-parametric linkage analyses, GENEHUNTER-PLUS and SIBPAL, were applied and detected nominal statistical significance of linkage to MP at chromosomes 1p36, 6q25, and 19p13.2. The best evidence of linkage was detected near D1S234 (maximum Z(lr) = 2.51, P = 0.0012). In addition, evidence of linkage was observed near D6S305 (maximum Z(lr) = 2.23, P = 0.025) and D19S884 (maximum Z(lr) = 1.93, P = 0.0089). Identification of the susceptible genes in the linkage regions will pave the way for insights into the molecular pathways that cause MP, especially overgrowth of the mandible, and may lead to the development of novel therapeutic tools.

Viral infection following kidney transplantation: long-term follow-up in a single center

INTRODUCTION

Viral infections are a leading cause of posttransplantation morbidity and mortality. The use of more potent immunosuppressive agents is responsible in part for the increasing incidence of some viral infections. This study summarized our experience with viral infections in 561 kidney transplant recipients.

METHODS

The spectrum of viral infections in 561 consecutive kidney transplant recipients was examined retrospectively from November 1982 to November 2002.

RESULTS

During a mean follow-up of 64.0 months, 193 virus infections in 156 of 561 kidney transplant recipients were recorded, an incidence of 34.2%. The most common viruses were cytomegalovirus (36.3%), varicella zoster virus (29.0%), herpes simplex virus (23.8%), BK virus (4.7%), hepatitis B virus (3.6%), and hepatitis C virus (2.6%). Among the CMV infections, 77.1% developed subclinical CMV infection and 22.9% had CMV disease. Generalized herpes zoster infection occurred in three cases and chicken pox in six cases. During a mean follow-up of 64.0 months, two of 159 patients died of CMV pneumonia.

CONCLUSION

Viral infections among the kidney transplant recipients continue to be a major problem despite significant progress in understanding the pathogenesis of viral infection and the advent of antiviral therapy.

BK virus infection in kidney transplant recipients

INTRODUCTION

Nephropathy associated with the polyomavirus type BK virus (BKV) has emerged as a cause of allograft failure linked to immunosuppressive regimens containing tacrolimus or mycophenolate mofetil (MMF). The outcome in BKV nephropathy is generally unfavorable, namely 50% of patients lose graft function. We herein report nine cases of BKV nephropathy after kidney transplantation.

METHODS

From October 1998 to May 2003, 138 of 169 consecutive kidney transplant patients received tacrolimus-based immunosuppression, and 31 received cyclosporine-based immunosuppression. Additionally, 88.2% of the patients received mycophenolate mofetil (MMF). The diagnosis of BK infection was made by the presence of decoy cells in the urine and by allograft biopsy.

RESULTS

There were nine cases of BKV nephropathy in kidney transplant recipients, an incidence of 5.3%. All patients with BKV nephropathy received tacrolimus, MMF, and steroids. The median time to diagnosis of BKV infection was 7.8 months after transplantation. All patients experienced an elevated serum creatinine, which stabilized or decreased in seven patients with altered or decreased immunosuppression. After a mean follow-up of 11.1 months, 2 (22.2%) of nine patients lost the graft.

CONCLUSION

Because BKV nephropathy is a rare but serious complication after kidney transplantation, it should be included in the clinical differential of transplant dysfunction. In the absence of documented antiviral treatment, early diagnosis and judicious use of immunosuppressive agents is indicated to minimize the occurrence of BKV infection.

A case of fungal sepsis due to aspergillus spondylitis followed by cytomegalovirus infection in a renal transplant recipient

Although advances in immunosuppressive therapy have led to increased survival of renal transplant recipients, there are greater risks of developing infectious complications. Because of its rarity and the lack of medical awareness, aspergillus spondylitis is often misdiagnosed as tuberculous spondylitis, especially in its early stages. We report a case of aspergillus spondylitis in a renal transplant followed by cytomegalovirus (CMV) retinitis.

CASE

A 59-year-old woman was admitted due to general weakness and abdominal discomfort. She had undergone renal transplantation 3 years previously. One month before admission, she was diagnosed with CMV retinitis and treated with IV ganciclovir. On admission, she suffered from lower abdominal pain. Colonoscopy revealed multiple circular or patchy ulcers with surrounding severe mucosal edema in the sigmoid colon findings consistent with intestinal tuberculosis. On hospital day 30, she complained of lower extremity paresthesia and weakness. An MRI of the spine revealed a well-demarcated paraspinal mass around the L2-4 body; tuberculous spondylitis was initially considered. But despite antituberculosis medication, the patient progressed to spastic paraparesis and sensory changes in both lower legs, requiring urgent surgical decompression. At hospital day 60, she suffered persistent fever and developed thrombocytopenia. Wound discharge continued and paraparesis became denser. A CT of the spine showed progression of the paraspinal abscess from the L2 body to the iliac crest. CT-guided psoas muscle drainage was performed. Fungal culture showed Aspergillus species. Despite antifungal therapy, the patient died after a prolonged hospital stay due to fungal sepsis and septic shock from aspergillosis.

A case of primary cutaneous aspergillosis in a renal transplant recipient

Opportunistic fungal infections are life-threatening complications which are a major cause of morbidity and mortality in immunocompromized hosts such as those who have undergone organ transplantation. Aspergillosis comprises a spectrum of disease caused by a ubiquitous saprophytic mold. Invasive aspergillus is a serious life-threatening complication in immunocompromised hosts. Primary cutaneous aspergillosis occurs relatively less frequently and is poorly characterized. We report a case of cutaneous aspergillosis in a 51-year-old renal transplant recipient, which was successfully treated with local excision and concomitant antifungal therapy.

CASE

A 51-year-old male renal transplant recipient presented with cutaneous nodules on the dorsum of the right hand. He underwent renal transplantation for end-stage renal disease due to adult dominant polycystic kidney disease (ADPKD) 3 years prior. Initially he suffered an acute rejection episode that was treated with steroid pulse and OKT3 therapy. Eventually he was stabilized on a combination of tacrolimus, prednisone, and mycophenolate mofetil. Three years after transplantation, he developed painless multiple (largest one 5 x 3 cm sized) nodules on the dorsum of his right hand. He was afebrile with no systemic symptoms. A skin biopsy showed a dense solid infiltration of giant cells, histiocytes, and lymphoplasma cells admixed with intra- and extracellular fungal hyphae and spores. The hyphae were septate and acute angle branching, which was consistent with aspergillosis. Oral itraconazole 200 mg/d for 5 weeks was ineffective. Treatment with liposomal amphotericin B for 4 weeks was initiated and MMF was discontinued. The medication was well tolerated with no hepatotoxic effects. Although new lesions did not appear, existing ones did not significantly improve after 4 weeks of treatment. Therefore, most lesions were excised surgically and liposomal amphotericin B continued for 2 weeks followed by treatment with oral fluconazole for 2 months. Ten moths later there was no evidence of recurrence.

Primary immunosuppression with tacrolimus in kidney transplantation: Three-year follow-up in a single center

INTRODUCTION

The 1-year results of the phase III US Multicenter Trial comparing tacrolimus- and cyclosporine (Sandimmun)-based immunosuppressive therapy in kidney transplantation revealed a significant reduction in the incidence and severity of acute rejection episodes among patients maintained on tacrolimus. This retrospective, nonrandomized, single-center study represented 3-year data for patient and graft survival and safety in the tacrolimus-treated patients.

METHODS

Among 97 consecutive kidney transplant recipients 41 who received tacrolimus and 56 cyclosporine-based immunosuppression were followed for 3 years for patient and graft survivals and for the incidence of acute rejection episodes as well as serious adverse events.

RESULTS

The 3-year patient and graft survival rates for tacrolimus and cyclosporine were similar (91.0% vs 90.2%, 96.5% vs 95.0%). However, the incidence of acute rejection episodes was significantly lower in the tacrolimus (17.1%) compared with the cyclosporine group (35.7%, P = .043). There was a higher incidence of headache, posttransplant diabetes, and alopecia reported in the tacrolimus group, whereas hypertension, hypercholesterolemia, and hirsutism were more frequent in the cyclosporine group. The incidences of hand tremor, hyperkalemia, and viral infections were comparable in both groups. Two patients in the tacrolimus group were converted to cyclosporine due to nephrotoxicity and posttransplant diabetes, respectively, whereas 12 patients in the cyclosporine group were converted to tacrolimus as rescue therapy for acute rejection (41.7%), gingival hyperplasia (33.3%), nephrotoxicity (8.3%), neurotoxicity (8.3%), and hirsutism (8.3%), respectively.

CONCLUSION

The 3-year results of tacrolimus treatment show excellent efficacy and safety in kidney transplantation. Due to different side-effect profiles, it is necessary to develop individualized immunosuppressive strategies in kidney transplant recipients.

A photoregulated ligand for the nuclear import receptor karyopherin alpha

The ability to orchestrate the transport of proteins between nucleus and cytoplasm provides cells with a powerful regulatory mechanism. Selective translocation between these compartments is often used to propagate cellular signals, and it is an intimate part of the processes that control cell division, viral replication, and other cellular events. Therefore, precise experimental control over protein localization, through the agency of light, would provide a powerful tool for the study and manipulation of these events. To this end, a prototype photoregulated nuclear localization signal (NLS) was derived from a native NLS. A library of 30 mutants of the bipartite NLS from Xenopus laevis nucleoplasmin containing a novel, photoisomerizable amino acid was prepared by parallel, solid-phase synthesis and screened in vitro for binding to the nuclear import receptor karyopherin alpha, which mediates the nuclear import of cellular proteins. A single peptide was identified in which the cis and trans photoisomers bind the receptor differentially. The strategy used to obtain this peptide is systematic and empirical; therefore, it is potentially applicable to any peptide-receptor system.

A case of glomerulonephritis in association with pyogenic liver abscess

Glomerulonephritis associated with visceral abscess is being increasingly recognized. The association of glomerulonephritis with visceral suppuration in the absence of endocarditis was first described by Whitworth and associates. Abscesses were most frequently located in the respiratory tract but have been reported at numerous other sites, including appendix, uterus, aorto-femoral bypass graft and cutaneous wound. This report documents the apparently rare occurrence of glomerulonephritis with acute renal failure in association with pyogenic liver abscess. The need for awareness of glomerulonephritis as a cause of acute renal failure in pyogenic liver abscess is highlighted.