Age-Dependent Metabolic and Immunosuppressive Effects of Tacrolimus.

Immunosuppression in elderly recipients has been underappreciated in clinical trials. Here, we assessed age-specific effects of the calcineurin inhibitor tacrolimus (TAC) in a murine transplant model and assessed its clinical relevance on human T cells. Old recipient mice exhibited prolonged skin graft survival compared with young animals after TAC administration. More important, half of the TAC dose was sufficient in old mice to achieve comparable systemic trough levels. TAC administration was able to reduce proinflammatory interferon-γ cytokine production and promote interleukin-10 production in old CD4+ T cells. In addition, TAC administration decreased interleukin-2 secretion in old CD4+ T cells more effectively while inhibiting the proliferation of CD4+ T cells in old mice. Both TAC-treated murine and human CD4+ T cells demonstrated an age-specific suppression of intracellular calcineurin levels and Ca2+ influx, two critical pathways in T cell activation. Of note, depletion of CD8+ T cells did not alter allograft survival outcome in old TAC-treated mice, suggesting that TAC age-specific effects were mainly CD4+ T cell mediated. Collectively, our study demonstrates age-specific immunosuppressive capacities of TAC that are CD4+ T cell mediated. The suppression of calcineurin levels and Ca2+ influx in both old murine and human T cells emphasizes the clinical relevance of age-specific effects when using TAC.

Impact of HMG-CoA reductase inhibitors on the incidence of polyomavirus-associated nephropathy in renal transplant recipients with human BK polyomavirus viremia.

BACKGROUND: Up to 20% of renal transplant recipients (RTR) will develop human BK polyomavirus (BKPyV) viremia. BKPyV viremia is a pre-requisite of polyomavirus-associated nephropathy (PyVAN). Risk of BKPyV infections increases with immunosuppression. Currently, the only effective therapy against PyVAN is reductions in immunosuppression, but this may increase the risk of rejection. In vitro data have shown that pravastatin dramatically decreased caveolin-1 expression in human renal proximal tubular epithelial cells (HRPTEC) and suppressed BKPyV infection in these cells. Based on these data, we postulated that statin therapy may prevent the progression of BKPyV viremia to PyVAN. PATIENTS AND METHODS: A multicenter, retrospective study was conducted in adult RTR transplanted between July 2005 and March 2012. All patients with documented BKPyV viremia (viral load >500 copies/mL on 2 consecutive tests) were included. Group I consisted of patients taking a statin before the BKPyV viremia diagnosis (n = 32), and Group II had no statin exposure before or after the BKPyV viremia diagnosis (n = 36). The primary endpoint was the incidence of PyVAN. RESULTS: Demographic data, transplant characteristics, and the degree of immunosuppression (i.e., induction/maintenance therapies, rejection treatment) were similar between the groups, with the exception of more diabetics in Group I. The incidence of PyVAN was comparable between the 2 groups (Group I = 28.1% vs. Group II = 41.7%; P = 0.312). CONCLUSIONS: Despite the proven in vitro effectiveness of pravastatin preventing BKPyV infection in HRPTEC, statins at doses maximized for cholesterol lowering, in RTR with BKPyV viremia, did not prevent progression to PyVAN.

Hepatitis B reactivation and rituximab: a new boxed warning and considerations for solid organ transplantation.

Use of rituximab, a chimeric monoclonal antibody directed at the CD20 antigen, continues to increase in solid organ transplantation (SOT) for several off-label uses. In September 2013, the United States Food and Drug Administration (FDA) issued a Drug Safety Communication to oncology, rheumatology and pharmacy communities outlining a new Boxed Warning for rituximab. Citing 109 cases of fatal hepatitis B virus (HBV) reactivation in persons receiving rituximab therapy with previous or chronic HBV infection documented in their Adverse Event Reporting System (AERS), the FDA recommends screening for HBV serologies in all patients planned to receive rituximab and antiviral prophylaxis in any patient with a positive history of HBV infection. There is a lack of data pertaining to this topic in the SOT population despite an increase in off-label indications. Previous reports suggest patients receiving rituximab, on average, were administered six doses prior to HBV reactivation. Recommendations on prophylaxis, treatment and re-challenging patients with therapy after resolution of reactivation remain unclear. Based on data from the FDA AERS and multiple analyses in oncology, SOT providers utilizing rituximab should adhere to the FDA warnings and recommendations regarding HBV reactivation until further data are available in the SOT population.

Evaluating the impact of pre-transplant desensitization utilizing a plasmapheresis and low-dose intravenous immunoglobulin protocol on BK viremia in renal transplant recipients.

BACKGROUND: A correlation exists between polyomavirus BK (BKV) viremia in renal transplant recipients (RTR) and the degree of immunosuppression. However, the impact of pre-transplant desensitization on the incidence of BKV viremia is unknown. METHODS: This retrospective study evaluated living-donor RTR between January 2004 and December 2008 receiving routine BKV viral load monitoring. Patients were divided into those who underwent pre-transplant desensitization (n = 20) and those who did not (n = 71). The primary endpoint was the incidence of BKV viremia at 1 year post transplant. RESULTS: All demographic data were similar, except for more female patients (65% vs. 36.6%; P = 0.0392) in the desensitized group. More desensitized patients had a previous transplant (75% vs. 12.7%; P < 0.0001) and were more likely to be induced with basiliximab (75% vs. 35.2%; P = 0.0021). Following transplantation, antibody-mediated rejection (AMR) rates were highest in the desensitized group (55% vs. 1.4%; P < 0.0001). The incidence of BKV viremia at 1 year post transplant was significantly higher in desensitized patients (45% vs. 19.7%; P = 0.0385). Desensitization was also associated with a higher prevalence of BKV viremia at any time post transplant (50% vs. 22.5%; P = 0.0245), polyomavirus-associated nephropathy (20% vs. 2.8%; P = 0.0198) and BKV-related allograft loss (10% vs. 0%; P = 0.0464). Also of note, in a subgroup analysis of only our desensitized patients, it did not appear that development of AMR significantly impacted the incidence of BKV viremia in these individuals. CONCLUSIONS: This analysis reveals that pre-transplant desensitization significantly increases the risk for BKV viremia and nephropathy.

Mycophenolate fetal toxicity and risk evaluation and mitigation strategies.

The mycophenolic acid (MPA) preparations are one of the most commonly used immunosuppressants in the United States. However, these agents carry a black box warning regarding their use during pregnancy due to an association with increased risk of miscarriage and congenital defects. To ensure that the benefits of MPA outweigh the risks, the Food and Drug Administration (FDA) required all manufacturers of MPA products to propose risk evaluation and mitigation strategies (REMS). Four years after initially calling for proposals, the FDA approved a single shared REMS system in September 2012. The elements of the MPA REMS include a medication guide and elements to assure safe use (ETASU). The medication guide, which was previously FDA-approved in 2008, should continue to be distributed to patients, and the ETASU requires physicians to complete training and obtain patient signatures on the "Patient-Prescriber Acknowledgement Form." A single, national, voluntary pregnancy registry is available, and pregnant patients should be encouraged to participate. Although the impact of the MPA REMS on clinical practice is not clear, it is a step toward increasing the understanding of fetal risks with MPA products among patients and possibly practitioners.

Cytomegalovirus disease in lung transplantation: impact of recipient seropositivity and duration of antiviral prophylaxis.

BACKGROUND: A recent randomized trial demonstrated that 1 year of antiviral prophylaxis for cytomegalovirus (CMV) after lung transplantation is superior to 3 months of treatment for prevention of CMV disease. However, it is uncertain if a shorter duration of prophylaxis might result in a similar rate of CMV disease among select lung transplant (LT) recipients who are at lower risk for CMV disease, based on baseline donor (D) and recipient (R) CMV serologies. METHODS: We retrospectively assessed incidence, cumulative probability, and predictors of CMV disease and viremia in LT recipients transplanted between July 2004 and December 2009 at our center, where antiviral CMV prophylaxis for 6-12 months is standard. RESULTS: Of 129 LT recipients, 94 were at risk for CMV infection based on donor CMV seropositivity (D+) or recipient seropositivity (R+); 14 developed CMV disease (14.9%): 11 with CMV syndrome, 2 with pneumonitis, and 1 with gastrointestinal disease by the end of follow-up (October 2010); 17 developed asymptomatic CMV viremia (18.1%). The cumulative probability of CMV disease was 17.4% 18 months after transplantation. CMV D+/R- recipients who routinely received 1 year of prophylaxis were more likely to develop CMV disease compared with D+/R+ or D-/R+ recipients, who routinely received 6 months of prophylaxis (12/45 vs. 2/25 vs. 0/24, P = 0.005). Recipients who stopped CMV prophylaxis before 12 months (in D+/R- recipients) and 6 months (in R+ recipients) tended to develop CMV disease more than those who did not (9/39 vs. 3/41, P = 0.06). CONCLUSIONS: On a 6-month CMV prophylaxis protocol, few R+ recipients developed CMV disease in this cohort. In contrast, despite a 12-month prophylaxis protocol, D+/R- LT recipients remained at highest risk for CMV disease.

Density functional simulations of Sb-rich GeSbTe phase change alloys.

We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge(1)Sb(1)Te(1) and Ge(2)Sb(4)Te(5). Comparison with previous results on the most studied Ge(2)Sb(2)Te(5) allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm(-1) are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge(2)Sb(2)Te(5). All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.

Dyslipidemia and its therapeutic challenges in renal transplantation.

Cardiovascular disease is the leading cause of mortality in kidney transplant recipients. Dyslipidemia is a common finding after renal transplantation and a significant risk factor in the development of coronary heart disease. Although a causal relationship with cardiovascular mortality has not been proven in the transplant population, it is reasonable to extrapolate data from the general population and aggressively treat posttransplant dyslipidemia. Statins are considered the agents of choice, though their use may be complicated by drug misadventures. Pravastatin, fluvastatin and pitavastatin are considered to be the safest statins to use in this population; however, given their low-potency, a high-potency statin, such as atorvastatin, may be necessary in patients with significant dyslipidemia. In this article, we discuss the etiology of and treatment strategies for dyslipidemia in renal transplant recipients based on a literature review of potential therapeutic adverse effects and benefits in this population. We will also evaluate the reasons for and consequences of the latest Food and Drug Administration (FDA) warnings regarding the use of simvastatin.

Managing risk in developing transplant immunosuppressive agents: the new regulatory environment.

Recent adverse experience with a number of medications after their approval, including rofecoxib, erythropoietin and rosiglitazone, has led to an increased focus on safety in drug development in the postmarketing setting. The result was implementation of new measures to address perceived deficits in the system for drug approval and postmarketing safety. The resulting legislation introduced risk evaluation and mitigation strategies (REMS) and postmarketing requirements (PMRs). Although these initiatives have the potential to improve patient outcomes, many healthcare practitioners are not yet familiar with REMS or PMRs or may have misconceptions regarding their goals and limitations. REMS is a program to manage known or potential serious risks associated with pharmaceutical products and is designed to ensure that the benefits of using a particular product outweigh the risks. Although the concepts underlying REMS and PMRs are not novel, the FDA now has legal authority to enforce such measures as part of the drug approval process. This article outlines the objectives and limitations of REMS and PMRs, with a focus on how these regulatory measures may impact the clinical specialty of transplantation. The article also briefly describes efforts to address aspects of drug safety less amenable to management through REMS and PMRs.

Evolution of the role of the transplant pharmacist on the multidisciplinary transplant team.

Transplant pharmacists have been recognized as an essential part of the transplant team by their colleagues along with several governing and professional organizations. The specific education, training and responsibilities of the transplant pharmacist have not been clearly delineated in the literature. Various pharmacists across the country have been called upon to serve on the transplant team necessitating standardization of their fundamental and desirable activities. Therefore, the purpose of this manuscript is to describe the training and role of a transplant pharmacist on the patient care team and provide a roadmap to implementation of novel transplant pharmacy services.