JC virus‐associated nephropathy in a renal transplant recipient and comparative analysis of previous cases

G. Kantarci, Z. Eren, A. Demira?, I. Dogan, F. Çakalagaoglu, G. Yilmaz.
JC virus‐associated nephropathy in a renal transplant recipient and comparative analysis of previous cases.
Transpl Infect Dis 2011: 13: 89–92. All rights reserved Abstract: We report JC virus (JCV)‐associated nephropathy in a renal allograft recipient and summarize the clinical and laboratory data of the 8 previous cases. A 28‐year‐old male renal allograft recipient received a preemptive transplant from his father. Six months later, a kidney biopsy was performed because of deterioration of allograft function. Biopsy revealed tubulointerstitial mononuclear infiltrates with normal glomeruli; on hematoxylin and eosin staining, basophilic nuclear inclusions were seen in the nucleus of tubular cells. Urinary cytology failed to demonstrate decoy cells, but polymerase chain reaction of a urinary sample was positive for JCV 3.15 × 10¹⁰ copies/mL. Additionally, polyomavirus (SV40) immunohistochemical staining was performed and was positive in the enlarged nuclei of tubular epithelial cells in the kidney biopsy sample. After the diagnosis of polyomavirus‐associated nephropathy (PVAN) was confirmed by kidney biopsy, immunosuppressive agents were reduced. Intravenous immunoglobulin was administered 5 times at a dose of 500 mg/kg every other 3 weeks. Two months after diagnosis, the serum creatinine became stable and urinary viral load of JCV was decreased. Because viruria was still present, tacrolimus was converted to sirolimus. Four months after immunosuppressive agent conversion from tacrolimus to sirolimus, the viruria had disappeared. Review of the literature and our case demonstrates that male gender, previous acute rejection episode, low incidence of JCV viremia, PVAN pattern B histology, and reducing immunosuppression are the diagnostic touchstones for PVAN due to JCV.     

Prospective monitoring of BK virus replication in renal transplant recipients

Background. BK virus-associated nephropathy (BKVAN) can be diagnosed only with renal graft biopsy. Definitive diagnosis of BKVAN requires demonstration of BK virus (BKV) replication in renal allograft tissues. Non-invasive analysis of urine and blood is considered essential in screening renal transplant recipients.
Patients and methods. This study evaluated prospectively the replication of BKV in plasma and urine with qualitative and quantitative real-time polymerase chain reaction in 32 de novo (group A) and 34 chronic (group B) renal transplant recipients and the long-term impact on graft function.
Results. In group A, 456 samples (228 plasma, 228 urine) were examined and BKV was detected in 31 (31/228, 14%) samples of plasma and 57 (57/228, 25%) samples of urine in 20 (20/32, 62.5%) and 23 (23/32, 72%) recipients, respectively. Incidence of viremia and viruria increased during the first 6 months presenting a peak the third postoperative month (viremia: 28% and viruria: 31%). Immune suppressive treatment with tacrolimus showed significant relation with viremia. Renal graft function in de novo renal transplant recipients remained stable throughout the follow-up period without influence of BKV replication. In group B, incidence of viremia and viruria were 3% (1/34) and 9% (3/34) correspondingly, indicating that after the first post-transplant year the risk of BKV re-activation is diminished.
Conclusion. The highest incidence of BK viremia and viruria is observed the third post-transplantation month, confirming previously published studies in Europe and the United States, and long-term follow up shows that BKV replication decreases significantly after the third post-transplant month and even transient viremia or viruria does not have an impact on renal function.     

Opportunistic non‐BK viral disease after renal transplantation: a game of numbers

A. Gupta, A. Khaira. Opportunistic non‐BK viral disease after renal transplantation: a game of numbers
Transpl Infect Dis 2011: 13: 329–330. All rights reserved     

NECA at reperfusion limits infarction and inhibits formation of the mitochondrial permeability transition pore by activating p70S6 kinase

The A₁/A₂ adenosine agonist 5′-(N-ethylcarboxamido) adenosine (NECA) limits infarction when administered at reperfusion. The present study investigated whether p70S6 kinase is involved in this anti-infarct effect. Adult rat ventricular myocytes were isolated and incubated in tetramethylrhodamine ethyl ester (TMRE, 100 nM), which causes cells to fluoresce in proportion to their mitochondrial membrane potential. A reduction in TMRE fluorescence serves as an indicator of collapse of the mitochondrial transmembrane potential. Cells were subjected to H₂O₂ (200 μM), which like ischemia induces loss of mitochondrial membrane potential. Fluorescence was measured every 3 min and to facilitate quantification membrane potential was arbitrarily considered as collapsed when fluorescence reached less than 60% of the starting value. Adding NECA (1 mM) to the cells prolonged the time to fluorescence loss (48.0 ± 3.2 min in the NECA group versus 29.5 ± 2.2 min in untreated cells, P < 0.001) and the mTOR/p70S6 kinase inhibitor rapamycin (5 nM) abolished this protection (31.3 ± 3.4 min). Since cyclosporine A offered similar protection, mitochondrial permeability transition pore formation is a likely cause of the H₂O₂-induced loss of potential. The direct GSK-3β inhibitor SB216763 (3 μM) also prolonged the time to fluorescence loss (49.2 ± 2.1 min, P < 0.001 versus control), and its protection could not be blocked by rapamycin (42.2 ± 2.3 min, P < 0.001 versus control). NECA treatment (100 nM) of intact isolated rabbit hearts at reperfusion after 30 min of regional ischemia decreased infarct size from 33.0 ± 3.8% of the risk zone in control hearts to 11.8 ± 2.0% (P < 0.001), and rapamycin blocked this NECA-induced protection (38.3 ± 3.7%). A comparable protective effect was seen for SB216763 (1 μM) with infarct size reduction to 13.5 ± 2.3% (P < 0.001). NECA treatment (200 nM) of intact rabbit hearts at reperfusion also resulted in phosphorylation of p70S6 kinase more than that seen in untreated hearts. This NECA-induced phosphorylation was blocked by rapamycin. These experiments reveal a critical role for p70S6 kinase in the signaling pathway of NECA’s cardioprotection at reperfusion. Returned for 1st revision: 3 November 2005 1st revision received: 3 February 2006 Returned for 2nd revision: 23 February 2006 2nd revision received: 1 March 2006     

Chronic Treatment with FK506 Increases p70 S6 Kinase Activity Associated with Reduced Nitric Oxide Synthase Activity in Rabbit Hearts

FK506, an immunosuppressant, modulates phosphorylation of nitric oxide (NO) synthase, and induces cardiac hypertrophy in clinical settings. Having recently reported that chronic treatment with an inhibitor of NO synthase induces cardiac hypertrophy associated with the activation of 70-kD S6 kinase (p70^S6K), which plays an important role in cardiac hypertrophy by regulating protein synthesis, we investigated the effects of chronic administration of FK506 on NO synthase and p70^S6K activities in hearts. Twenty rabbits were divided into four groups: untreated rabbits, those treated with low-dose FK506 (0.10 mg/kg), those treated with medium-dose FK506 (0.20 mg/kg), and those treated with high-dose FK506 (0.40 mg/kg). FK506 was administered intravenously twice a day. After 4 weeks of treatment with FK506, calcium-dependent NO synthase activity in myocardium in the high-dose FK506 group was lower (P < 0.05) than in the untreated group. p70^S6K activity in myocardium in the high-dose group was higher (P < 0.05) than in the untreated group. There was a significant (P < 0.05) inverse correlation between NO synthase and p70^S6K activities in myocardium. However, the endothelial-dependent vasodilation of aortic rings or plasma levels of NO metabolites during experimental protocols did not differ among the groups studied. These findings suggest that chronic treatment of FK506 activates p70^S6K and reduces NO synthase activity in rabbit hearts. Reduced NO synthase and/or activated p70^S6K activities in hearts might contribute to the cardiac hypertrophy observed in some patients receiving FK506.     

In vitro effect of cyclosporin A on primary and chronic BK polyoma virus infection in Vero E6 cells

Abstract: Cyclosporin A (CsA) is known to possess antiviral activity against several viruses in vitro, but the effect of CsA on BK polyoma virus (BKV) replication has not been examined. We investigated the impact of CsA on primary, chronic, and high‐level BKV infection using a cell system of kidney cell origin (Vero E6 cells). During the first 2 h post infection, cells treated with CsA up to 3200 μg/L showed a near‐identical BK viral load to untreated cells, with only a very minor reduction in the CsA‐treated cells observed at 4 h. In chronic culture, CsA completely suppressed the primary BKV infection peak in a non‐dose‐dependent manner within the dose range of 200–12,800 μg/L (P<0.05). BKV reactivation was also inhibited in the presence of CsA at doses of 200–3200 μg/L: the mean number of BKV DNA copies/mL remained stable or even decreased slightly compared with a 7‐log increase in the non‐CsA group (P<0.01). CsA did not influence BKV DNA copies/mL in Vero E6 cells with high‐level infection (>10⁹ copies/mL). Cellular protein measurements indicated that the antiviral effect of CsA was not a result of cytotoxicity. These findings from a relevant in vitro kidney cell system indicate that CsA suppresses the primary BKV infection peak and inhibits escape to BKV reactivation; these effects are dose independent and not related to cytotoxicity. The intracellular antiviral mode of action of CsA against BKV does not appear to be via inhibition of viral cell entry pathways.     

Phosphorylation of p70S6 kinase predicts overall survival in patients with clear margin‐resected hepatocellular carcinoma

Background/Aims: The mammalian target of rapamycin (mTOR) inhibitors play a key role in regulating signal transduction by blocking the mTOR pathway and combining anticancer and immunosuppressive properties. This study was undertaken to determine the prevalence and clinicopathological relevance of phospho‐p70S6 (p‐p70S6) kinase in hepatocellular carcinoma (HCC) and to investigate the effects of rapamycin on HCC in vitro. Methods: A total of 196 patients with HCCs were treated either with surgical resection (n=106) or liver transplantation (n=90). Tumour tissue was investigated for p‐p70S6, phospho‐AKT, Ki‐67, Cyclin‐D1 and apoptosis, and staining results were correlated with clinicopathologically relevant parameters. Results: Overall, p‐p70S6 was detected in 24.5% (48/196) of HCCs. In the resection group, 26.4% (28/106) of HCC were positive and 22.2% (20/90) in the transplant group. p‐p70S6 was significantly associated with elevated Cyclin‐D1 immunoexpression and was correlated with decreased overall survival (P=0.011) in patients resected with a clear margin. In multivariate COX regression analysis, p‐p70S6 was identified as an independent prognostic parameter in patients resected with a clear margin. Rapamycin induced apoptosis and growth inhibition by G0/G1 cell cycle arrest in vitro. However, in HCC patients p‐p70S6 kinase was not associated with proliferation or apoptosis. Conclusions: Activation of p70S6 kinase indicates aggressive tumour behaviour in patients with clear margin‐resected HCC. Identification of p‐p70S6 kinase in HCC selects high‐risk patients who may benefit from drugs targeting the mTOR pathway.     

Initiation of a screening protocol for polyoma virus results in a decreased rate of opportunistic non‐BK viral disease after renal transplantation

I. Koleilat, L. Kushnir, M. Gallichio, D.J. Conti. Initiation of a screening protocol for polyoma virus results in a decreased rate of opportunistic non‐BK viral disease after renal transplantation.
Transpl Infect Dis 2011: 13: 1–8. All rights reserved Background. Polyoma BK virus nephropathy (PVN) is a leading cause of renal allograft injury and loss. The mainstay of treatment, as there are no target therapies approved by the US Food & Drug Administration, is reduction in immunosuppression. However, current approaches are shifting to screening for viremia as an indicator of oncoming nephropathy, with subsequent reduction in immunotherapy. We attempted not only to replicate these data but also to evaluate the utility of polyoma viremia as a surrogate marker for overimmunosuppression in general, thus allowing prevention not only of PVN but also of other viral opportunistic infections such as cytomegalovirus (CMV) and Epstein–Barr virus (EBV) disease. Patients and methods. We conducted a retrospective cohort analysis of renal transplant recipients at our center. The historical controls (2003–2005, n=134) had received their allograft before the institution of a monthly serum polymerase chain reaction (PCR) polyoma screening protocol. The screened cohort received their allograft afterwards (2006–2008, n=134). Screening was performed using PCR techniques with prompt reduction in immunosuppression for viremic patients. The patients were followed for the development of PVN, acute rejection, renal allograft function, and survival. Results. Polyoma viremia was noted in 16% of the screened population, with none developing PVN after prompt reduction of immunosuppression. Clearance of the viremia occurred by 6 months in 95% of the patients after reduction of immunotherapy. No patient in the screened group developed CMV or EBV disease. Of the controls, 7 (5%) developed PVN and 12 (9%) developed CMV or EBV disease, compared with none of the screened patients (P<0.05). The incidence of acute rejection was comparable between the groups (4% controls, 5% screened). No deleterious effects were noted on patient or allograft survival, allograft function (measured by serum creatinine), rates of fungal infection, or the rate of post‐transplant lymphoproliferative disorder in the screened patients. Conclusions. Monthly PCR monitoring for BK viremia, together with a modest decrease in immunotherapy, is not only safe but also effectively prevents PVN and is associated with a significantly decreased rate of CMV and EBV disease in renal transplant patients. BK viremia may also serve as a surrogate marker for overimmunosuppression.     

AMPK-associated signaling to bridge the gap between fuel metabolism and hepatocyte viability

The adenosine monophosphate-activated protein kinase (AMPK) and p70 ribosomal S6 kinase-1 pathway may serve as a key signaling flow that regulates energy metabolism; thus, this pathway becomes an attractive target for the treatment of liver diseases that result from metabolic derangements. In addition, AMPK emerges as a kinase that controls the redox-state and mitochondrial function, whose activity may be modulated by antioxidants. A close link exists between fuel metabolism and mitochondrial biogenesis. The relationship between fuel metabolism and cell survival strongly implies the existence of a shared signaling network, by which hepatocytes respond to challenges of external stimuli. The AMPK pathway may belong to this network. A series of drugs and therapeutic candidates enable hepatocytes to protect mitochondria from radical stress and increase cell viability, which may be associated with the activation of AMPK, liver kinase B1, and other molecules or components. Consequently, the components downstream of AMPK may contribute to stabilizing mitochondrial membrane potential for hepatocyte survival. In this review, we discuss the role of the AMPK pathway in hepatic energy metabolism and hepatocyte viability. This information may help identify ways to prevent and/or treat hepatic diseases caused by the metabolic syndrome. Moreover, clinical drugs and experimental therapeutic candidates that directly or indirectly modulate the AMPK pathway in distinct manners are discussed here with particular emphasis on their effects on fuel metabolism and mitochondrial function.     

Mammalian target of rapamycin signal inhibitors could play a role in the treatment of BK polyomavirus nephritis in renal allograft recipients

A.I. Sánchez Fructuoso, N. Calvo, I. Perez‐Flores, R. Valero, B. Rodríguez‐Sánchez, D. García de Viedma, P. Muñoz, A. Barrientos. Mammalian target of rapamycin signal inhibitors could play a role in the treatment of BK polyomavirus nephritis in renal allograft recipients.
Transpl Infect Dis 2011: 13: 584–591. All rights reserved Abstract: BK virus (BKV) nephropathy is a common viral infection in renal transplant patients, with a prevalence of 1–9% at approximately 12 months after surgery. While it is widely agreed that reduction of immunosuppression should be the first intervention after diagnosis of BKV infection, there is no consensus on whether calcineurin inhibitors or antiproliferative drugs should be reduced first. Furthermore, target levels of immunosuppressive drugs are poorly defined, as are criteria for replacing one immunosuppressive agent with another. Results. We report our series of 15 renal transplant patients who underwent surgery between September 2004 and March 2010 and who developed BKV infection. The first 8 patients were treated with reduction of immunosuppression; 7 of these patients received cidofovir and 6 received intravenous immunoglobulin. The remaining 7 renal transplant recipients received mammalian target of rapamycin inhibitors (imTOR). In this group, we observed faster and more efficacious BKV clearance in plasma and urine and a steady improvement in allograft function, with no episodes of acute allograft rejection during follow‐up. The polymerase chain reaction assay for BKV in urine became positive in 2 patients in whom imTOR were stopped due to severe side effects. Conclusions. The use of imTOR should be considered a first step in the treatment of renal transplant recipients with BKV infection. In our experience, this change in treatment was safe and resulted in viral clearance.     

Effect of phorbol ester and platelet-derived growth factor on protein kinase C in rat hepatic stellate cells.

BACKGROUND/AIMS: Hepatic stellate cells (HSC) play a key role in hepatic fibrogenesis and thus, it is important to understand the intracellular signalling pathways that influence their behaviour. This study investigated the expression and regulation of protein kinase C (PKC) in HSC. RESULTS: Western blot analysis indicates that rat HSC express at least four PKC isoforms, PKC-alpha, PKC-delta, PKC-epsilon and PKC-zeta. PKC-alpha and PKC-zeta were located predominantly in the cytosol and were redistributed to the membrane by the PKC agonist, phorbol 12-myristate 13-acetate (PMA), while PKC-delta and PKC-epsilon were highly membrane-bound and did not undergo translocation by PMA. PKC-alpha, PKC-delta and PKC-zeta were rapidly downregulated by PMA. However, PKC-epsilon was resistant to downregulation. We also examined phosphorylation of myristoylated alanine-rich C kinase substrate (MARCKS), a specific substrate of PKC, as another approach to assess activation of PKC. Platelet-derived growth factor (PDGF) and PMA increased the phosphorylation of MARCKS, suggesting that PDGF can induce PKC activation. PDGF-induced stimulation of extracellular signal-regulated kinase, phosphatidylinositol 3-kinase and p70-S6 kinase was not abrogated by downregulation of PKC-alpha, PKC-delta and PKC-zeta. Prolonged PKC inhibition did not inhibit the fibrogenic phenotype. CONCLUSION: Multiple PKC isoforms are expressed in rat HSC and are differentially regulated by PMA. PDGF activates certain mitogenic signalling pathways independent of PKC-alpha, PKC-delta and PKC-zeta. Specific PKC isoforms may modulate different cell functions in HSC.     

Herpesvirus Infection in Patients Following Bone Marrow Transplantation: Influence of Viral Reactivation on Prognosis

Viral infections are an important cause of death following bone marrow transplantation. We investigated the clinical significance of herpesvirus infection.

The nine subjects consisted of five patients with CML, two with ALL, and one each with AML and the myelodysplastic syndrome. Viral markers were investigated in bronchoalveolar lavage fluid and peripheral blood lymphocytes before and 35 days after bone marrow transplantation, as well as in peripheral blood lymphocytes at 100 days afterwards.

Cytomegalovirus DNA became positive in four patients after bone marrow transplantation. Human herpesvirus-6 DNA became positive in two patients and human herpesvirus 7 DNA became negative in the same two patients. Two of the nine patients died of disease recurrence. Two other patients died of complications, and both of them became positive human herpesvirus-6 after the procedure. These results suggested the possibility that infection with not only cytomegalovirus but also other human herpesvirus can influence the prognosis and complications of bone marrow tansplantation.     

膦甲酸钠治疗与预防肾移植后巨细胞病毒感染的临床研究

目的：研究膦甲酸钠在肾移植术后巨细胞病毒（ＣＭＶ）感染的治疗及预防中的作用，及患者的耐受性，方法：对１９９５年９月～１９９６年６月间１２０例肾移植术后ＣＭＶ感染患者，按照临床症状分期及实验室检查进行临床对照研究，实验组使用膦甲酸钠，对照组为Ｚｏｖｉｒａｘ，疗程为３～４周，治疗后随访３个月评估疗效，结果：静止期ＣＭＶ感染者，空白对照组３３．３％（８／２４）发生ＣＭＶ的活动性感染，而实验组无一例发生，     

Cytomegalovirus-associated bleeding diathesis in renal transplant recipients

Cytomegalovirus (CMV) infection is reported to be capable of modifying endothelial surface with subsequent increased risk of thromboembolic complications. Nevertheless, there are only sparse reports on its role in the development of bleeding diathesis. Here we report two renal transplant recipients who manifested severe coagulation disorders associated with acute CMV infection. Antiviral therapy was followed by consistent correction of coagulation abnormalities.     

Changes in growth-related kinases in head, neck and limb muscles with age

Sarcopenia coincides with declines in several systemic processes that signal through the MAP kinase and Akt-mTOR-p70S6k cascades typically associated with muscle growth. Effects of aging on these pathways have primarily been examined in limb muscles, which experience substantial activity and neural changes in addition to systemic hormonal and metabolic changes. Head and neck muscles are reported to undergo reduced sarcopenia and disuse with age relative to limb muscles, suggesting muscle activity may contribute to maintaining mass with age. However many head and neck muscles derive from embryonic branchial arches, rather than the somites from which limb muscles originate, suggesting that developmental origin may be important. This study compares the expression and phosphorylation of MAP kinase and mTOR networks in head, neck, tongue, and limb muscles from 8- and 26-month old F344 rats to test the hypothesis that physical activity and developmental origin contribute to preservation of muscle mass with age. Phosphorylation of p38 was exaggerated in aged branchial arch muscles. Phosphorylation of ERK and p70S6k T421/S424 declined with age only in the biceps brachii. Expression of p70S6k declined in all head and neck, tongue and limb muscles although no change in phosphorylation of p70S6k on T389 could be resolved. A systemic change that results in a loss of p70S6k protein expression may reduce the capacity to respond to acute hypertrophic stimuli, while the exaggerated p38 signaling in branchial arch muscles may reflect more active muscle remodeling.     

肾移植术后严重巨细胞病毒感染治疗经验

目的：总结８例尸体肾移植术后严重巨细胞病毒（ＣＭＶ）感染的治疗经验。方法：通过检测ＣＭＶ－ＩｇＭ或（和）检测血中ＣＭＶ－ＤＮＡ（ＰＣＲ法）结合临床症状及胸片确立诊断。以丙氧鸟苷治疗，配合静脉滴注大剂量丙种球蛋白，适当减少免疫抑制剂，治疗／预防二重感染，加强营养等综合治疗，结果：治愈６例，死亡２例，结论：严重ＣＭＶ感染致死率高，丙氧鸟苷加综合治疗措施的疗效是比较成功的。