Overview of tacrolimus-based immunosuppression after heart or lung transplantation

Association between time in therapeutic range of tacrolimus blood concentration and acute rejection within the first three months after lung transplantation

BACKGROUND

Tacrolimus is a key drug in immunosuppressive therapy following lung transplantation. The blood tacrolimus levels are likely to fluctuate in the early postoperative period, and failure to maintain the tacrolimus trough level in target ranges is a risk factor for rejection. However, there is little information about the relationship between the time in therapeutic range (TTR) of the tacrolimus trough level (tacrolimus TTR) and clinical outcomes. This study aimed to evaluate the association between tacrolimus TTR and acute rejection (AR) within the first three months after lung transplantation.

METHODS

This was a retrospective study of patients who underwent lung transplantation at a single center. The target tacrolimus trough levels were 10-15 ng/mL, and tacrolimus TTR was calculated using the Rosendaal method. The cut-off value of the tacrolimus TTR was estimated by receiver operating characteristic analysis based on AR.

RESULTS

The study included 90 patients. AR was observed in 26 patients. In this study, ''early-AR'' was defined as any AR within 2 weeks post-transplant (n = 22) and ''late-AR'' was defined as any AR after 1-month post-transplant (n = 4). For early AR, the relationship between tacrolimus TTR and the onset of AR was examined. There were no differences in the tacrolimus TTR between the early-AR group and non-AR group (35.7 ± 22.4 vs 31.5 ± 19.9%, P = 0.416). For late-AR, the relationship with tacrolimus TTR was examined every 10 d. The tacrolimus TTR during postoperative days (POD) 21-30 and POD 31-onset was significantly lower in the late-AR group than the no-AR group (50.0 ± 7.1 vs. 71.8 ± 18.0% and 37.0 ± 26.6 vs. 68.9 ± 31.5%, P < 0.05, respectively). The cutoff value of the tacrolimus TTR during POD 21-30 was estimated as 55.0%.

CONCLUSIONS

Our findings suggest that a lower tacrolimus TTR is a predictor of late AR. A tacrolimus TTR of 55% or higher is necessary to reduce the risk of AR during this period after lung transplantation.

α1-Antitrypsin attenuates acute rejection of orthotopic murine lung allografts

Background

α1-Antitrypsin (AAT) is an acute phase glycoprotein, a multifunctional protein with proteinase inhibitory, anti-inflammatory and cytoprotective properties. Both preclinical and clinical experiences show that the therapy with plasma purified AAT is beneficial for a broad spectrum of inflammatory conditions. The potential effects of AAT therapy have recently been highlighted in lung transplantation (LuTx) as well.

Methods

We used a murine fully mismatched orthotopic single LuTx model (BALB/CJ as donors and C57BL/6 as recipients). Human AAT preparations (5 mg, n = 10) or vehicle (n = 5) were injected to the recipients subcutaneously prior to and intraperitoneally immediately after the LuTx. No immune suppressive drugs were administered. Three days after the transplantation, the mice were sacrificed, and biological samples were assessed.

Results

Histological analysis revealed significantly more severe acute rejection in the transplanted lungs of controls than in AAT treated mice (p < 0.05). The proportion of neutrophil granulocytes, B cells and the total T helper cell populations did not differ between two groups. There was no significant difference in serum CXCL1 (KC) levels. However, when compared to controls, human AAT was detectable in the serum of mice treated with AAT and these mice had a higher serum anti-elastase activity, and significantly lower proportion of Th1 and Th17 among all Th cells. Cleaved caspase-3-positive cells were scarce but significantly less abundant in allografts from recipients treated with AAT as compared to those treated with vehicle.

Conclusion

Therapy with AAT suppresses the acute rejection after LuTx in a mouse model. The beneficial effects seem to involve anti-protease and immunomodulatory activities of AAT.

Biological Predictors of De Novo Tumors in Solid Organ Transplanted Patients During Oncological Surveillance: Potential Role of Circulating TERT mRNA

Background

De novo tumors are a major cause of morbidity and mortality after long-term solid organ transplantation. Chronic immunosuppression strongly affects solid organ transplanted (SOT) patients' immune system by promoting immune evasion strategies and reactivations of viruses with oncogenic potential, ultimately leading to cancer onset. In this scenario, an oncological Surveillance Protocol integrated with biobanking of peripheral blood samples and evaluation of immunovirological and molecular parameters was activated for SOT patients at CRO-IRCCS Aviano, with the aim of identifying suitable biomarkers of cancer development.

Methods

An exploratory longitudinal study was designed based on two serial peripheral blood samples collected at least three months apart. Forty nine SOT patients were selected and stratified by tumor onset during follow-up. Spontaneous T-cell responses to EBV, CMV and tumor associated antigens, EBV-DNA and CMV-DNA loads, and circulating TERT mRNA levels were investigated.

Results

Significantly higher levels of circulating TERT mRNA were observed 3.5-23.5 months before and close to the diagnosis of cancer as compared to tumor-free patients. Plasmatic TERT mRNA levels >97.73 copies/mL at baseline were significantly associated with the risk of developing de novo tumors (HR=4.0, 95%C.I. = 1.4-11.5, p=0.01). In particular, the risk significantly increased by 4% with every ten-unit increment in TERT mRNA (HR=1.04, 95%C.I. = 1.01-1.07, p=0.01).

Conclusions

Although obtained in an exploratory study, our data support the importance of identifying early biomarkers of tumor onset in SOT patients useful to modulate the pace of surveillance visits.

Fetal Lung Tissue Engineering

Lung transplantation may be considered as a final treatment option for diseases such as chronic lung disease, pulmonary hypertension, bronchopulmonary dysplasia, pulmonary fibrosis, and end-stage lung disease. The five-year survival rate of lung transplants is nearly 50%. Unfortunately, many patients will die before a suitable lung donor can be found. Importantly, the shortage of donor organs has been a significant problem in lung transplantation. The tissue engineering approach uses de- and recellularization of lung tissue to create functional lung substitutes to overcome donor lung limitations. Decellularization is hope for generating an intact ECM in the development of the engineered lung. The goal of decellularization is to prepare a suitable scaffold of lung tissue that contains an appropriate framework for the functionality of regenerated lung tissue. In this chapter, we aim to describe the decellularization protocols for lung tissue regenerative purposes.

Chemotherapy and Immunosuppressant Therapy-Induced Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) is an entity which is characterized by acute to subacute onset of neurological symptoms like altered mental status, seizures, headaches and other focal neurological deficits. It is diagnosed with the help of MRI findings which typically involve the subcortical white matter of parieto-occipital lobes. In this review, we will discuss the various etiologies and risk factors including some of the most common chemotherapeutic agents and immunosuppressant agents associated with this disorder. We will discuss the mechanism of actions and side effect profiles of a few drugs and their role in causation of PRES. This review article discusses if there is any difference in presentation and imaging findings of PRES caused by cytotoxic agents versus caused by other etiologies. It also highlights the difficulty in management of PRES caused by cytotoxic agents as the discontinuation of these drugs could be life-threatening due to graft rejections or graft versus host disease.

Stability of tacrolimus ophthalmic solution

PURPOSE

The stability of 0.3-mg/mL tacrolimus ophthalmic solution at different storage temperatures was studied.

METHODS

A sterile ophthalmic solution of 0.3 mg/mL tacrolimus was prepared in triplicate under aseptic conditions by diluting tacrolimus in eye drops. Three aliquots of this solution were transferred into polypropylene bottles and stored at 25, 2-8, or -15 to -25 °C. Samples were collected immediately after preparation and at selected time points and assayed in triplicate using high-performance liquid chromatography (HPLC). Samples were also visually examined for macroscopic changes. The 0.3-mg/mL tacrolimus solution was also exposed to acidic treatment and heat to force its degradation and to evaluate the selectivity of the analytic method. The tacrolimus ophthalmic solution was considered stable if at least 90% of the mean initial concentration remained when analyzed by HPLC.

RESULTS

When stored at 2-8 °C and between -15 and -25 °C, at least 90% of the initial tacrolimus concentration remained throughout the 85-day study period. There were no significant differences in tacrolimus concentrations between the starting and ending points (p > 0.05). However, when tacrolimus solution was stored at 25 °C, the percentage of the initial tacrolimus concentration remaining had decreased to less than 90% on day 28.

CONCLUSION

Tacrolimus diluted to 0.3 mg/mL in eye drop solution was stable for 20 days when stored at 25 °C and for at least 85 days when stored at 2-8 °C or between -15 and -25 °C in polypropylene bottles and protected from light.

Dissecting the Multiplicity of Immune Effects of Immunosuppressive Drugs to Better Predict the Risk of de novo Malignancies in Solid Organ Transplant Patients

De novo malignancies constitute an emerging cause of morbidity after solid organ transplant (SOT), significantly affecting the long-term survival of transplant recipients. Pharmacologic immunosuppression may functionally impair the immunosurveillance in these patients, thereby increasing the risk of cancer development. Nevertheless, the multiplicity and heterogeneity of the immune effects induced by immunosuppressive drugs limit the current possibilities to reliably predict the risk of de novo malignancy in SOT patients. Therefore, there is the pressing need to better characterize the immune dysfunctions induced by the different immunosuppressive regimens administered to prevent allograft rejection to tailor more precisely the therapeutic schedule and decrease the risk of de novo malignancies. We herein highlight the impact exerted by different classes of immunosuppressants on the most relevant immune cells, with a particular focus on the effects on dendritic cells (DCs), the main regulators of the balance between immunosurveillance and tolerance.

Rat lung decellularization using chemical detergents for lung tissue engineering

Although pulmonary diseases account for a large number of deaths in the world, most have no treatment other than transplantation. New therapeutic methods for lung treatment include lung tissue engineering and regenerative medicine. Lung decellularization has been used to produce an appropriate scaffold for recellularization and implantation. We investigated 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) with sodium dodecyl sulfate (SDS) and Triton X-100 detergents for effecting rat lung decellularization. We evaluated using conventional histology, immunofluorescence staining and SEM methods for removing nuclear material while leaving intact extracellular matrix proteins and three-dimensional architecture. We investigated different concentrations of CHAPS, SDS and Triton X-100 for different periods. We found that 2 mM CHAPS + 0/1% SDS for 48 h was the best among the treatments investigated. Our method can be used to produce an appropriate scaffold for recellularization by stem cells and for investigations ex vivo and in vivo.

Immunosuppressive effect of the gut microbiome altered by high-dose tacrolimus in mice

The alterations induced in gut microbiota by tacrolimus may affect immune function and organ transplantation. Mice were treated with high-dose tacrolimus for 14 days. The fecal microbiota were analyzed by pyrosequencing the 16S rRNA genes, and the effect on metabolism was predicted using the sequence data. The subgroups of T cells in the serum, gut-associated lymphoid tissue, and draining lymph nodes were determined by flow cytometry. Tacrolimus treatment significantly altered the relative abundance of Allobaculum, Bacteroides, and Lactobacillus and CD4⁺ CD25^hi FoxP3⁺ regulatory T cells in the colonic mucosa and the circulation. These were significantly increased after either tacrolimus treatment or treatment by fecal microbiota transfer from tacrolimus-treated donors. Further, treatment with low-dose tacrolimus plus fecal microbiota transfer from high-dose tacrolimus-altered mice increased skin allograft survival rate in a skin transplantation model. Thus, high-dose tacrolimus alters the compositions and taxa of the gut microbiota. Administration of these conditioned gut microbiota plus low-dose tacrolimus resulted in regulation of colonic and systemic immune responses and an increased allograft survival rate. This study demonstrated a new strategy for controlling allograft rejection by combining an immunosuppressive agent with gut microbiome transplantation.

A Comparative Study of Rat Lung Decellularization by Chemical Detergents for Lung Tissue Engineering

BACKGROUND

Lung disease is the most common cause of death in the world. The last stage of pulmonary diseases is lung transplantation. Limitation and shortage of donor organs cause to appear tissue engineering field. Decellularization is a hope for producing intact ECM in the development of engineered organs.

AIM

The goal of the decellularization process is to remove cellular and nuclear material while retaining lung three-dimensional and molecular proteins. Different concentration of detergents was used for finding the best approach in lung decellularization.

MATERIAL AND METHODS

In this study, three-time approaches (24, 48 and 96 h) with four detergents (CHAPS, SDS, SDC and Triton X-100) were used for decellularizing rat lungs for maintaining of three-dimensional lung architecture and ECM protein composition which have significant roles in differentiation and migration of stem cells. This comparative study determined that variable decellularization approaches can cause significantly different effects on decellularized lungs.

RESULTS

Results showed that destruction was increased with increasing the detergent concentration. Single detergent showed a significant reduction in maintaining of three-dimensional of lung and ECM proteins (Collagen and Elastin). But, the best methods were mixed detergents of SDC and CHAPS in low concentration in 48 and 96 h decellularization.

CONCLUSION

Decellularized lung tissue can be used in the laboratory to study various aspects of pulmonary biology and physiology and also, these results can be used in the continued improvement of engineered lung tissue.

Increased Sensitivities of Peripheral Blood Mononuclear Cells to Immunosuppressive Drugs in Cirrhosis Patients Awaiting Liver Transplantation

Successful immunosuppressive therapy is critical for liver transplantation. However, a considerable number of patients show clinical resistance to the therapy and experience rejection episodes, or alternatively exhibits serious adverse effects of drugs. We examined the in vitro response of peripheral blood mononuclear cells (PBMCs) to immunosuppressive drugs in cirrhosis patients awaiting liver transplantation. We evaluated the suppressive efficacy of prednisolone, methylprednisolone, cyclosporine, and tacrolimus on the in vitro blastogenesis of PBMCs obtained from 22 cirrhosis patients and 31 healthy subjects. In vitro drug concentrations giving 50% inhibition of PBMC blastogenesis (IC50s) were calculated. Two out of these 22 patients received liver transplantation from living donors, and their clinical courses were surveyed until 5 weeks after operation. The median IC50 values for prednisolone, cyclosporine, and tacrolimus against blastogenesis of PBMCs from cirrhosis patients were significantly lower than those of PBMCs from healthy subjects (p < 0.01). However, large individual differences were observed in the IC50 values of the immunosuppressive drugs examined, especially in the cirrhosis patients. One recipient exhibiting high PBMC sensitivity to tacrolimus (IC50 = 0.001 ng/ml) showed good clinical course without rejection until 5 weeks after liver transplantation. The other recipient exhibiting relatively low PBMC sensitivity to taclolimus (IC50 = 0.30) showed allograft rejection at 1 week after operation. We concluded from these observations that PBMCs of cirrhosis patients are vulnerable to the immunosuppressive effects of prednisolone and calcineurin inhibitors. However, large individual variations in the IC50 values suggest that patients exhibiting relatively lower sensitivity to these drugs may have risks of rejection, whereas highly sensitive patients are possibly able to reduce the dose of immunosuppressive drugs to avoid serious drug-adverse effects, after liver transplantation.

Heart Retransplant Recipients Have Better Survival With Concurrent Kidney Transplant Than With Heart Retransplant Alone

BACKGROUND

Heart retransplant (HRT) recipients represent a growing number of transplant patients. The impact of concurrent kidney transplants (KTs) in this population has not been well studied. We tested the hypothesis that recipients of HRT with concurrent KT (HRT-KT) would have worse survival than recipients of HRT alone.

METHODS AND RESULTS

A retrospective analysis of the United Network of Organ Sharing database was performed for all patients undergoing HRT from 1987 to 2011. There were 1660 HRT patients, of which 116 (7%) received concurrent KT. Those who received HRT-KT had older age, longer wait-list time, worse kidney function, and more known diabetes. Survival among recipients of HRT-KT was significantly better than that of recipients of HRT alone (P=0.005). A subgroup of 323 HRT patients with severe kidney dysfunction (estimated glomerular filtration rate <30 mL/min per 1.73 m(2) or on dialysis) was studied in more detail, and 76 (24%) received concurrent KT. Those on dialysis at the time of HRT had better survival with versus without concurrent KT (P<0.0001). On multivariable analysis, concurrent KT was independently associated with better outcomes for all patients with HRT and for the subgroup of patients with severe kidney dysfunction.

CONCLUSIONS

Recipients of HRT-KT have better survival than recipients of HRT alone. Further research is needed to determine which HRT patients may benefit the most from concurrent KT.

Nordihydroguiaretic acid attenuates skin tumorigenesis in Swiss albino mice with the condition of topical co-administration of an immunosuppressant

Drug and chemically-induced immunosuppression has been implicated as a confounding factor for cancer development. Management of cancer in such situation is often a challenging task. We tested the efficacy of nordihydroguiaretic acid (NDGA) against immunosuppressant tacrolimus-induced augmentation of mouse skin tumorigenesis. It was observed that topical administration of tacrolimus significantly accelerated the tumor promotion events in dimethylbenz(a)anthracene (DMBA)-initiated and 12-O-tetradecanoylphorbol-13-acetate (TPA) promoted two-stage mouse skin carcinogenesis, which were accompanied by reduced CD4(+)/CD8(+) ratio of lymph nodes and serum IL-2 level. NDGA pre-treatment before each TPA application reduced the tumor incidence, its multiplicity and volume together with improvement in histopathological alterations and decrease in proliferating cell nuclear antigen (PCNA) labeling index (LI). However, NDGA had no significant influence on the immunosuppressive effect of tacrolimus. The present study demonstrates chemopreventive effect of NDGA in normal as well as in the condition of immunosuppression. Thus, NDGA has the potential to inhibit or delay the onset of tumor development during immunosuppressive regimen.

Coxsackievirus B3 replication and pathogenesis

ABSTRACT 

Viruses such as coxsackievirus B3 (CVB3) are entirely host cell-dependent parasites. Indeed, they must cleverly exploit various compartments of host cells to complete their life cycle, and consequently launch disease. Evolution has equipped this pico-rna-virus, CVB3, to use different strategies, including CVB3-induced direct damage to host cells followed by a host inflammatory response to CVB3 infection, and cell death to super-additively promote target organ tissue injury, and dysfunction. In this update, the patho-stratagems of CVB3 are explored from molecular, and systems-level approaches. In summarizing recent developments in this field, we focus particularly on mechanisms by which CVB3 can harness different host cell processes including kinases, host cell-killing and cell-eating machineries, matrix metalloproteinases and miRNAs to promote disease.

Cytotoxic and genotoxic effects of high concentrations of the immunosuppressive drugs cyclosporine and tacrolimus in MRC-5 cells

Immunosuppressive drugs are used to suppress immune system activity in transplant patients and reduce the risk of organ rejection. The present study evaluated the potential cytotoxic, genotoxic and mutagenic of the immunosuppressive drugs cyclosporine (CsA) and tacrolimus (FK-506) on normal human fibroblasts (MRC-5 cells). Based on plasma concentrations of the immunosuppressive drugs, which were obtained from the records of kidney transplant patients at the Kidney Institute of Londrina, Brazil, 11 concentrations of each immunosuppressive were chosen to evaluate cell viability using the MTT assay. From these results, CsA and FK-506 concentrations of 135, 300, 675, and 1520 ng/ml and 8, 16, 24, and 32 ng/ml, respectively, were evaluated using (i) the comet assay, (ii) the nuclear division index (NDI), (iii) the micronucleus test (CBMN) and (iv) cell proliferation curves generated by quantifying cell numbers and protein levels. In this study, 1520 to 3420 ng/ml CsA decreased cell viability after 48 h of exposure. Genotoxic effects were observed only with a concentration of 1520 ng/ml after 3h of exposure and with concentrations of 675 and 1520 ng/ml after 24h of exposure. Mutagenic effects were observed only for the concentration of 1520 ng/ml. FK-506 decreased cell viability after 72 h of exposure for concentrations up to 20 ng/ml; genotoxic effects were observed with concentrations up to 8 ng/ml for both treatment times (3 and 24h) and mutagenic effects were observed with concentrations of 24 and 32 ng/ml after 24h of treatment. The cell proliferation curves demonstrated the absence of cytostatic effects of these drugs, and these data were confirmed by the NDI analysis. Our results suggest that concentrations lower than 300 ng/ml of CsA and 16 ng/ml of FK-506 are safe for use, as they did not induce genotoxic and mutagenic damage or affect MRC-5 cell viability and proliferation.

A pilot study of the association between sleep disturbance in children with liver transplants and parent and family health-related quality of life

OBJECTIVE

To investigate the relationship between sleep disturbance in children with liver transplants and parent and family health-related quality of life (HRQOL).

METHOD

47 parents of children with liver transplants completed measures of child sleep and family HRQOL. Relationships between sleep and HRQOL and differences in HRQOL between groups with scores above and below the cutoff on a pediatric sleep measure were examined.

RESULTS

Parents endorsed higher rates of sleep-related breathing disorder (SRBD) and restless legs syndrome and periodic limb movements during sleep (RLS/PLMS) and lower HRQOL compared with published data. Significant correlations were found between SRBD and RLS/PLMS and HRQOL, and significant group differences in HRQOL were found between groups above and below the cutoff for behavior problems and RLS/PLMS.

CONCLUSION

There are significant relationships between symptoms of SRBD and RLS/PLMS in children with liver transplants and family HRQOL. Behavior problems may account for these strong relationships.

Adverse effects of immunosuppressant drugs upon airway epithelial cell and mucociliary clearance: implications for lung transplant recipients

Optimal post-transplantation immunosuppression is critical to the survival of the graft and the patient after lung transplantation. Immunosuppressant agents target various aspects of the immune system to maximize graft tolerance while minimizing medication toxicities and side effects. The vast majority of patients receive maintenance immunosuppressive therapy consisting of a triple-drug regimen including a calcineurin inhibitor, a cell cycle inhibitor and a corticosteroid. Although these immunosuppressant drugs are frequently used after transplantation and to control inflammatory processes, limited data are available with regard to their effects on cells other than those from the immunological system. Notably, the airway epithelial cell is of interest because it may contribute to development of bronchiolitis obliterans through production of pro-inflammatory cytokines. This review focuses the current armamentarium of immunosuppressant drugs used after lung transplantation and their main side effects upon airway epithelial cells and mucociliary clearance.

Immunosuppression effects on airway mucociliary clearance: comparison between two triple therapies

BACKGROUND

Tacrolimus and mycophenolate have now become the most widely used combination for maintenance immunosuppressive regimens after lung transplantation in comparison with cyclosporine and azathioprine. However, limited information is available with respect to their effects on cells, other than those from the immunologic compartment. We hypothesized that different triple therapies could have different effects on airway mucociliary clearance, playing an important role in respiratory infections observed after lung transplantation.

METHODS

Ninety rats were assigned to three groups (n = 30 each): control = vehicle, therapy 1 = tacrolimus + mycophenolate + prednisone, and therapy 2 = cyclosporine + azathioprine + prednisone. After 7, 15, or 30 days of treatment by gavage, the animals were killed and the following parameters were studied: mucus transportability, ciliary beating frequency, mucociliary transport velocity, and neutral and acid mucus production.

RESULTS

There was a significant decrease in ciliary beating frequency, mucociliary transport velocity, and neutral mucus production in all immunosuppressed animals; indeed, both therapies, mainly therapy 1, caused an increase in acid mucus production for as long as 15 days of treatment.

CONCLUSIONS

Both triple therapies impaired airway mucociliary clearance of rats, but therapy 1 had a more deleterious effect. These data suggest that these undesirable effects can contribute to the high incidence of respiratory infections observed in patients undergoing lung transplantation.

Tacrolimus versus cyclosporin as primary immunosuppression for lung transplant recipients

BACKGROUND

Lung transplantation is a well-accepted treatment for people with most end-stage lung diseases. Although both tacrolimus and cyclosporin are used as primary immunosuppressive agents in lung transplant recipients, it is unclear which of these drugs is better in reducing rejection and death without causing adverse effects.

OBJECTIVES

To assess the benefits and harms of tacrolimus versus cyclosporin for primary immunosuppression in lung transplant recipients.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 10 April 2013 through contact with the Trials Search Co-ordinator using search terms relevant to this review. We also searched Science Citation Index Expanded and the Transplant Library to 20 April 2013.

SELECTION CRITERIA

We included all randomised controlled trials (RCT) that compared any dose and duration of administration of tacrolimus versus cyclosporin as primary immunosuppressive treatment in lung transplant recipients. Our selection criteria required that all included patients received the same additional immunosuppressive therapy within each study.

DATA COLLECTION AND ANALYSIS

Three authors extracted data. For dichotomous data we used risk ratio (RR) and used mean difference (MD) for continuous data, each with 95% confidence intervals (CI). Methodological components of the included studies were used to assess risk of systematic errors (bias). Trial sequential analysis was used to assess risk of random errors (play of chance).

MAIN RESULTS

We included three studies that enrolled a total of 413 adult patients that compared tacrolimus with microemulsion or oral solution cyclosporin. All studies were found to be at high risk of bias. Tacrolimus seemed to be significantly superior to cyclosporin regarding the incidence of bronchiolitis obliterans syndrome (RR 0.46, 95% CI 0.29 to 0.74), lymphocytic bronchitis score (MD -0.60, 95% CI -1.04 to -0.16), treatment withdrawal (RR 0.27, 95% CI 0.16 to 0.46), and arterial hypertension (RR 0.67, 95% CI 0.50 to 0.89). However, the finding for arterial hypertension was not confirmed when analysed using a random-effects model (RR 0.54, 95% CI 0.17 to 1.73). Furthermore, trial sequential analysis found that none of the meta-analyses reached the required information sizes and cumulative Z-curves did not cross trial sequential monitoring boundaries. Diabetes mellitus occurred more frequently among people in the tacrolimus group compared with the cyclosporin group when the fixed-effect model was applied (RR 4.24, 95% CI 1.58 to 11.40), but no difference was found when the random-effects model was used for analysis (RR 4.43, 95% CI 0.75 to 26.05). Again, trial sequential analysis found that the required information threshold was not reached and cumulative Z-curve did not cross the trial sequential monitoring boundary. No significant difference between treatment groups was observed regarding mortality (RR 1.06, 95% CI 0.75 to 1.49), incidence of acute rejection (RR 0.89, 95% CI 0.77 to 1.03), numbers of infections/100 patient-days (MD -0.15, 95% CI -0.30 to 0.00), cancer (RR 0.21, 95% CI 0.04 to 1.16), kidney dysfunction (RR 1.41, 95% CI 0.93 to 2.14), kidney failure (RR 1.57, 95% CI 0.28 to 8.94), neurotoxicity (RR 7.06, 95% CI 0.37 to 135.19), and hyperlipidaemia (RR 0.60, 95% CI 0.30 to 1.20). Trial sequential analysis showed the required information thresholds were not reached for any of these outcome measures.

AUTHORS' CONCLUSIONS

Tacrolimus may be superior to cyclosporin regarding bronchiolitis obliterans syndrome, lymphocytic bronchitis, treatment withdrawal, and arterial hypertension, but may be inferior regarding development of diabetes. No difference in mortality and acute rejection was observed between patients treated with tacrolimus and cyclosporin. There were few studies comparing tacrolimus and cyclosporin after lung transplantation, and the numbers of patients and events in the included studies were limited. Furthermore, the included studies were deemed to be at high risk of bias. Hence, more RCTs are needed to assess the results of the present review. Such studies ought to be conducted with low risks of systematic errors (bias) and of random errors (play of chance).

Immunosuppression in the era of biological agents

Immunosuppression is the mayor mechanism to prevent allograft rejection and to induce tolerance. Since the first solid organ transplant, the development of safe and effective immunosuppressive regimens was a constant over the last decades. A lot of immunosuppressants have been discovered, and today the immunosuppressive agents are classified in two broad groups: Xenobiotic immunosuppressants and biological immunosuppressants. Xenobiotics, like corticoids and calcineurin and mTOR inhibitors, mainly interfere with the intracellular molecular mechanisms of the various types of cells involved in the immune response and generally these immunosuppressants are used early on in the transplantation process to prevent rejection as well as in long-term maintenance therapy. On the other hand, target molecules of biological immunosuppressants are on the surface of these immunological cells and normally in clinical immunosuppressive protocols have been used as auxiliary agents of xenobiotics to prevent rejection as well as in the treatment of acute rejection. However, these xenobiotics and biological agents have multiple side effects; that is why there has been a search for new drugs to minimise these side effects and to improve patients' quality of life. In this way, new biological agents have been proposed as maintenance immunosuppressive agents. The majority of these new immunosuppressive agents are polyclonal or monoclonal antibodies and recently the so-called fusion proteins may be the start of a new era of biological immunosuppression for maintenance regimens.

Use of sublingual tacrolimus in lung transplant recipients

BACKGROUND

In lung transplant recipients (LTRs), tacrolimus is often utilized as a core component of immunosuppressive regimens. Although tacrolimus can be delivered orally or intravenously, oral tacrolimus is associated with fewer adverse effects. Various reports have suggested that sublingual tacrolimus may be used as an alternative to oral tacrolimus; however, information regarding converting between routes is limited. We aimed to identify a dose conversion ratio between oral and sublingual tacrolimus in LTRs.

METHODS

We identified adult LTRs at the University of California, San Francisco, who transitioned between oral and sublingual tacrolimus between 2005 and 2010 (n = 34). For tacrolimus, we obtained steady-state blood concentrations and total daily doses before and after the route conversion. Blood concentrations divided by daily doses were calculated for each route. The conversion ratio was then defined as: (blood concentration(sublingual)/daily dose(sublingual))/(blood concentration(oral)/daily dose(oral)). This ratio was tested in inpatient vs outpatient settings and in the presence of impaired gastric emptying. Adverse effects, including nephrotoxicity, hepatotoxicity and anaphylaxis, were evaluated.

RESULTS

The conversion ratio of sublingual to oral tacrolimus was 0.46 ± 0.20 (mean ± SD). The ratio was not associated with hospital setting (p = 0.82) or with impaired gastric emptying (p = 0.31). When comparing sublingual to oral tacrolimus administration, there were no differences in serum creatinine, liver function tests or anaphylaxis.

CONCLUSIONS

Tacrolimus administered sublingually at approximately half of the oral dose achieves therapeutic blood concentrations and is safe in LTRs. Delivery via the sublingual route using this conversion ratio may aid clinicians in maintaining therapeutic tacrolimus blood concentrations while avoiding the need for intravenous administration.

Cyclosporine monotherapy in cardiac transplantation: review of the literature

The immunosuppressive therapy after organ transplantation should be tailored to balance the tolerance and the reaction of the recipient against the graft to avoid lack of immunosuppression or an excess of drugs. The drugs currently used may induce serious side effects with negative impact on recipient's survival and quality of life even if lack of immunosuppression may induce acute graft rejection and patient's death. The introduction of new drugs as mammalian target of rapamycin (mTOR) inhibitors allows tailoring of the immunosuppressive therapy on patient characteristics, by the use of drug association and the reduction of the overall dose. There are few cases where the necessity of reduction of the immunosuppressive therapy should be considered, as what happens in cases of severe systemic infections. Some anecdotal reports of the use of cyclosporine monotherapy (CM) in heart transplantation have been presented many years ago: the main limitations of these reports were the reasons of the switch to CM and the limited number of patients that did not allow clarification of the indications and the applicability of the CM. The aim of our review is to offer an up-to-date research of the use of CM after heart transplantation for physicians enrolled in the management of such complicated patients. The discussion will start from the kidney and liver transplantation and will arrive to the heart transplantation. However, we suggest a very careful selection of patients to be treated with CM because the use must be restricted to cases of severe side effects caused by multiple therapies because the multiple approaches has the main advantage of the synergistic action of the drugs. In conclusion, CM must be use for selected low-immunologic-risk patients, and it could be carefully used for stable patients over the long-term follow-up when the risk of acute rejection has nearly disappeared. Our article is of historical interest since we do not use anymore cyclosporine monotherapy.

Dangerous drug interactions leading to hemolytic uremic syndrome following lung transplantation

Background

To report our experience of a rather uncommon drug interaction, resulting in hemolytic uremic syndrome (HUS).

Methods

Two consecutive cases of hemolytic uremic syndrome were diagnosed in our service. In both patients the use of macrolides in patients taking Tacrolimus, resulted in high levels of Tacrolimus.

Results

The first patient was a 48 years old female with Bilateral emphysema. She underwent Single Sequential Lung Transplantation. She developed reperfusion injury requiring prolonged stay. Tacrolimus introduced (Day 51). The patient remained well up till 5 months later; Erythromycin commenced for chest infection. High Tacrolimus levels and a clinical diagnosis of HUS were made. She was treated with plasmapheresis successfully.

The second case was a 57 years old female with Emphysema & A1 Antithrypsin deficiency. She underwent Right Single Lung Transplantation. A2 rejection with mild Obliterative Bronchiolitis diagnosed 1 year later and she switched to Tacrolimus. She was admitted to her local Hospital two and a half years later with right middle lobe consolidation. The patient commenced on amoxicillin and clarithromycin. Worsening renal indices, high Tacrolimus levels, hemolytic anemia & low Platelets were detected. HUS diagnosed & treated with plasmapheresis.

Conclusions

There are 21 cases of HUS following lung transplantation in the literature that may have been induced by high tacrolimus levels. Macrolides in patients taking Cyclosporin or Tacrolimus lead to high levels. Mechanism of action could be glomeruloconstrictor effect with reduced GFR increased production of Endothelin-1 and increased Platelet aggregation.

Species-dependent hepatic metabolism of immunosuppressive agent tacrolimus (FK-506)

The current study aims to investigate species-related differences in the in-vitro hepatic metabolism of tacroliums using liver microsomes obtained from rat, hamster, guinea pig, rabbit, pig, dog, baboon and humans. Tacrolimus metabolism was characterized using high-performance liquid chromatography- ultraviolet light (HPLC-UV) and two soft ionization mass spectrometric techniques; matrix-assisted lasers desorption/ionization (MALDI) and time-of-flight-secondary ion mass spectrometry (TOF-SIMS). The extent of tacrolimus metabolism, when normalized to the cytochrome P-450 content, was in the order: rat < hamster < rabbit < pig < guinea pig < dog < human < baboon. Tacrolimus metabolism exhibited significant qualitative and quantitative differences between the animal species tested. Desmethyl- (MI-MIII), didesmethyl- (MIV-MVI), monohydroxy- (MVII), dihydroxy- (MVIII), epoxide- (MIX), dihydrodiol- (MX), monodesmethyl and monohydroxy- (MXI-MXIII), and didesmethyl and monohydroxy- (MXIV-MXVI) tacroliums metabolites were identified in the species tested. MI-MX were identified in all the species tested; MXI-MXVI were identified in all species except rat, rabbit and guinea pig; and MXIV-MXVI were identified only in baboon. The current investigation was unable to detect any phase II metabolites due to the limitations of the test system used. The analytical methods were not able to differentiate optical and positional isomers of metabolites due to the nature of the analytical tools used, therefore groups of metabolites were identified based on their molecular weights and available information. From the current in-vitro metabolism studies, the pattern of tacroliums metabolism in baboons closely resembled that in humans and thus it is ideal for studying tacroliums metabolism-related work of clinical relevance.

Gene profiling of cyclosporin-enhanced transitional cell carcinoma in rat model

OBJECTIVE

We sought to study the effect of cyclosporine (CsA) on development of malignancy.

MATERIALS AND METHODS

The observation was performed in a rat model, in which transitional cell carcinoma of urinary bladder was induced with N-butyl-N-(-4-hydroxybutyl) nitrosamine. CsA was added in the food for the rats. At the end of 30 weeks, we examined the tumor burden in the urinary bladders, and compared gene expressions between the CsA-enhanced and non-CsA-enhanced tumor groups by gene profiling.

RESULTS

CsA feeding increased tumor burden: 2.3 +/- 0.9 versus 1.1 +/- 0.5 g (P < .05). Gene profiling showed many variations involved in CsA enhanced malignant development. Twenty-three genes with known functions were upregulated, and 46 genes with known functions downregulated. In all, 111 genes were involved in the CsA-enhanced malignant development. The regulated genes in the present study constituted 23 pathways mostly involved in carcinogenesis.

CONCLUSIONS

CsA plays an important role in tumor development through gene regulation, which may constitute pathways to malignant progression.

Comparative study of the cellular pharmacodynamics of calcineurin inhibitors between patients with chronic renal failure awaiting renal transplantation and cirrhosis patients awaiting liver transplantation

The in vitro response of peripheral blood mononuclear cells (PBMCs) to the suppressive effects of calcineurin inhibitors is known to correlate with the clinical efficacy of drugs used in renal transplantations. The present study was conducted to examine the differences of PBMC responses to calcineurin inhibitors between chronic renal failure (CRF) patients awaiting renal transplantation and cirrhosis patients awaiting liver transplantation. The study included 99 CRF patients awaiting renal transplantation and 27 cirrhosis patients awaiting liver transplantation. Twenty milliliters of venous blood was taken 1-7 days before transplantation. The in vitro drug concentrations giving 50% inhibition of PBMC blastogenesis stimulated with concanavalin A (IC(50)s) were calculated. The suppressive effects of tacrolimus against PBMC blastogenesis were more than 10-100 times stronger than those of cyclosporine. The median IC(50) value for cyclosporine against the CRF PBMCs was not significantly different from the median IC(50) value against the cirrhosis PBMCs. In contrast, tacrolimus sensitivity in cirrhosis PBMCs is approximately seven times higher than that in CRF PBMCs. The median IC(50) value for tacrolimus against cirrhosis PBMCs was significantly lower and therefore the effect was stronger in comparison to the CRF PBMCs (p < 0.001). These data suggest that the PBMCs of cirrhosis patients, in comparison to those of CRF patients, are highly sensitive to the suppressive effect of tacrolimus. However, PBMC sensitivity to cyclosporine was not significantly different between the CRF and cirrhosis patients. These observations raise the possibility that treatment with tacrolimus, rather than cyclosporine, may therefore be a better choice to reduce the risks of allograft rejection in liver transplantation.

Pharmacokinetic optimization of immunosuppressive therapy in thoracic transplantation: part I

Although immunosuppressive treatments and therapeutic drug monitoring (TDM) have significantly contributed to the increased success of thoracic transplantation, there is currently no consensus on the best immunosuppressive strategies. Maintenance therapy typically consists of a triple-drug regimen including corticosteroids, a calcineurin inhibitor (ciclosporin or tacrolimus) and either a purine synthesis antagonist (mycophenolate mofetil or azathioprine) or a mammalian target of rapamycin inhibitor (sirolimus or everolimus). The incidence of acute and chronic rejection and of mortality after thoracic transplantation is still high compared with other types of solid organ transplantation. The high allogenicity and immunogenicity of the lungs justify the use of higher doses of immunosuppressants, putting lung transplant recipients at a higher risk of drug-induced toxicities. All immunosuppressants are characterized by large intra- and interindividual variability of their pharmacokinetics and by a narrow therapeutic index. It is essential to know their pharmacokinetic properties and to use them for treatment individualization through TDM in order to improve the treatment outcome. Unlike the kidneys and the liver, the heart and the lungs are not directly involved in drug metabolism and elimination, which may be the cause of pharmacokinetic differences between patients from all of these transplant groups. TDM is mandatory for most immunosuppressants and has become an integral part of immunosuppressive drug therapy. It is usually based on trough concentration (C(0)) monitoring, but other TDM tools include the area under the concentration-time curve (AUC) over the (12-hour) dosage interval or the AUC over the first 4 hours post-dose, as well as other single concentration-time points such as the concentration at 2 hours. Given the peculiarities of thoracic transplantation, a review of the pharmacokinetics and TDM of the main immunosuppressants used in thoracic transplantation is presented in this article. Even more so than in other solid organ transplant populations, their pharmacokinetics are characterized by wide intra- and interindividual variability in thoracic transplant recipients. The pharmacokinetics of ciclosporin in heart and lung transplant recipients have been explored in a number of studies, but less is known about the pharmacokinetics of mycophenolate mofetil and tacrolimus in these populations, and there are hardly any studies on the pharmacokinetics of sirolimus and everolimus. Given the increased use of these molecules in thoracic transplant recipients, their pharmacokinetics deserve to be explored in depth. There are very few data, some of which are conflicting, on the practices and outcomes of TDM of immunosuppressants after thoracic transplantation. The development of sophisticated TDM tools dedicated to thoracic transplantation are awaited in order to accurately evaluate the patients' exposure to drugs in general and, in particular, to immunosuppressants. Finally, large cohort TDM studies need to be conducted in thoracic transplant patients in order to identify the most predictive exposure indices and their target values, and to validate the clinical usefulness of improved TDM in these conditions. In part I of the article, we review the pharmacokinetics and TDM of calcineurin inhibitors. In part II, we will review the pharmacokinetics and TDM of mycophenolate and mammalian target of rapamycin inhibitors, and provide an overall discussion along with perspectives.

Tacrolimus and azathioprine versus cyclosporine and mycophenolate mofetil after lung transplantation: a retrospective cohort study

BACKGROUND

The efficacy and safety of different combinations of immunosuppressive regimens after lung transplantation are unknown.

METHODS

We examined 120 consecutive transplant recipients between July 2001 and July 2005, of whom 37 received cyclosporine and mycophenolate mofetil (Cyc/MMF) and 83 received tacrolimus and azathioprine (Tac/Aza) as the initial immunosuppressive regimen along with an interleukin-2 antagonist induction therapy. The primary outcome was the rate of histologically confirmed acute rejection.

RESULTS

The rate of acute rejection did not vary by treatment regimen (0.42 vs 0.34 episodes per 100 person-days in Cyc/MMF and Tac/Aza groups, respectively, p = 0.22). The mean cumulative lymphocytic bronchiolitis score was greater in the Cyc/MMF group (1.8 +/- 1.9) compared with the Tac/Aza group (1.2 +/- 2.0; p = 0.03). Pulmonary function at 1 year was better in the Tac/Aza group, even when adjusted for recipient age, gender, and transplant procedure. Survival and the rate of bronchiolitis obliterans syndrome did not vary by group.

CONCLUSIONS

Outcomes after lung transplantation did not meaningfully vary between those assigned to Cyc/MMF compared with Tac/Aza combined with IL-2 inhibitor induction therapy.

Tacrolimus and mycophenolate mofetil as first line immunosuppression after lung transplantation

The optimal maintenance therapy after lung transplantation remains to be established. The aim of this study was to analyse the impact of tacrolimus and mycophenolate mofetil (MMF) as first line immunosuppression on long-term survival and Bronchiolitis Obliterans Syndrome (BOS). From January 1996 through December 2006, all 155 recipients receiving tacrolimus and MMF as maintenance immunosuppression were included in this study. Tacrolimus and MMF was discontinued in 36 patients (23.2%). The overall survival rates were 91.6% at 6 months, 86.4% at 1 year, 74.9% at 3 years, 60.3% at 5 years and 32.4% at 10 years. The overall freedom from acute rejection was 74.6%, 63.2% and 59.4% at 1, 3, and 5 years respectively. The overall BOS-free survival was 95.6% at 1 year, 88.4% at 3 years, 69.5% at 5 years and 30.5% at 10 years. The development of BOS > or = 1 was associated with a significantly increased risk of death and reduced long-term survival. The combination of tacrolimus and MMF offers safe and reliable maintenance immunosuppression after lung transplantation. However, substantial improvements of long-term survival and freedom from BOS might only be achieved by a change in organ allocation policies and patient management beyond differential immunosuppressive protocols.

Successful management of immunosuppression in a patient with severe hyperammonemia after lung transplantation

Hyperammonemia after lung transplantation is a rare complication of unknown etiology. Its management is largely supportive and outcomes have been variable. More disconcerting is its immunosuppressive management because the precipitating factors leading to this potentially lethal entity are unknown, but are suspected to be drug-related. We describe the successful management of a lung transplant recipient with severe hyperammonemia.

Heat-shock protein expression and topical treatment with tacrolimus in oral lichen planus: an immunohistochemical study

Oral lichen planus (OLP) is a chronic inflammatory mucosal disease of unknown etiology. Usually asymptomatic, the disorder is occasionally complicated by extensive painful erosions. Topical corticosteroids are the mainstay of treatment, but a new topical therapy with tacrolimus has been described previously. The aim of the current study was to examine the expression of heat-shock protein 70 (HSP70) in biopsy specimens from 11 OLP lesions before and after topical treatment with tacrolimus. Immunostaining was performed with anti-HSP70 antibody as the primary layer. Clinically, there was a rapid improvement with topical tacrolimus treatment in 10 out of the 11 patients. The moderate increase in HSP70 expression after treatment with tacrolimus was not significant. It was concluded that topical tacrolimus has no effect on the expression of HSP70 in OLP.

Effect of various immunosuppressive monotherapies on survival and histopathology of monkey islet xenografts in rats

BACKGROUND

The isolation and testing of monkey islets after transplantation in small animal models provides basic information about their functional capacity. We describe the effect of cyclosporine A (CsA), tacrolimus (FK506) or prednisolone monotherapy on preventing monkey islet graft rejection after xenoTx in a rat model. Histopathological aspects are reported.

METHODS

Indian bonnet monkey (Macaca radiata radiata) islets were isolated by a simple stationary digestion technique using collagenase. The islets were purified with dextran density gradients and were transplanted under the renal capsule of normal or diabetic rats. The rats received a daily dose of CsA, or FK506, or prednisolone, and the grafts were removed at different intervals to determine islet survival. The effect of discontinuation of CsA on islet graft survival was also monitored. Histological examination of islets transplanted into normal or streptozotocin-induced diabetic rats was carried out. In diabetic rats, islet survival was determined by the graft's ability to achieve euglycemia.

RESULTS

Reversal of diabetes was achieved in all transplanted diabetic rats, demonstrating the efficacy of the isolated monkey islets. Histological examination indicated that monkey islets survived in the presence of continuous high-dose immunosuppressive monotherapy in rats. Various types of infiltrating cells were observed in the grafted area at varying times after transplantation, depending on the immunosuppressive treatment. After discontinuation of CsA, the grafts were protected for a short period.

CONCLUSIONS

This study provided evidence for monkey islet survival after transplantation into rats receiving immunosuppressive monotherapy. Basic information on infiltrating cell types may be important in the study of xenograft rejection.

Effect of inhaled tacrolimus on cellular and humoral rejection to prevent posttransplant obliterative airway disease

This study aimed to investigate the pharmacokinetics after tacrolimus aerosol inhalation and to assess its efficacy to suppress acute and chronic airway allograft rejection. Orthotopic tracheal transplantations were performed and tacrolimus (4 mg/kg) was administered orally (PO) or via aerosol (AER). Tracheal tissue level AUCs(0-12) were similar in both treatment groups, but blood AUCs(0-12) were approximately 5.5-fold lower with AER (p < 0.001). Interestingly, only PO animals showed elevated BUN, cholesterol and triglycerides on POD 60 (p < 0.05). Histology of grafts harvested after 6 and 60 days revealed that both treatment groups were similarly effective in suppressing graft mononuclear infiltration (p < 0.001). Cellular immune activation (assessed by IFN-gamma- and IL-4-ELISPOTS), however, was far more effectively suppressed by tacrolimus PO (p < 0.001). In both treatment groups, the vigorous alloreactive IgM-antibody surge was effectively inhibited (p < 0.001). Due to the insufficient systemic cellular immunosuppression, discontinuation of tacrolimus AER resulted in a far stronger (3.5-fold) graft infiltration on POD 8 compared to PO (p < 0.001). Tacrolimus aerosol reduces systemic side effects and effectively protects the airway graft from early cellular rejection and chronic obliterative airway disease.