Tacrolimus: in vitro effects on myelopoiesis, apoptosis, and CD11b expression

Targeted Metabolomics Analysis Suggests That Tacrolimus Alters Protection against Oxidative Stress

Tacrolimus (FK506) is an immunosuppressant that is experiencing a continuous rise in usage worldwide. The related side effects are known to be globally dose-dependent. Despite numerous studies on FK506, the mechanisms underlying FK506 toxicity are still not well understood. It is therefore essential to explore the toxicity mediated by FK506. To accomplish this, we conducted a targeted metabolomic analysis using LC-MS on the plasma samples of patients undergoing FK506 treatment. The aim was to identify any associated altered metabolic pathway. Another anti-calcineurin immunosuppressive therapy, ciclosporin (CSA), was also studied. Increased plasma concentrations of pipecolic acid (PA) and sarcosine, along with a decrease in the glycine/sarcosine ratio and a tendency of increased plasma lysine was observed in patients under FK506 compared to control samples. Patients under CSA do not show an increase in plasma PA compared to the control samples, which does not support a metabolic link between the calcineurin and PA. The metabolomics changes observed in patients under FK506 highlight a possible link between FK506 and the action of an enzyme involved in both PA and sarcosine catabolism and oxidative pathway, the Peroxisomal sarcosine oxidase (PIPOX). Moreover, PA could be investigated as a potential biomarker of early nephrotoxicity in the follow-up of patients under FK506.

Drug-Induced Hematological Cytopenia in Kidney Transplantation and the Challenges It Poses for Kidney Transplant Physicians

Drug-induced hematological cytopenia is common in kidney transplantation. Various cytopenia including leucopenia (neutropenia), thrombocytopenia, and anemia can occur in kidney transplant recipients. Persistent severe leucopenia or neutropenia can lead to opportunistic infections of various etiologies. On the contrary, reducing or stopping immunosuppressive medications in these events can provoke a rejection. Transplant clinicians are often faced with the delicate dilemma of balancing cytopenia and rejection from adjustments of immunosuppressive regimen. Differentials of drug-induced cytopenia are wide. Identification of culprit medication and subsequent modification is also challenging. In this review, we will discuss individual drug implicated in causing cytopenia and correlate it with corresponding literature evidence.

Tacrolimus-induced neutropenia in renal transplant recipients

Tacrolimus has become an important cornerstone in the prevention of rejection after kidney transplantation. However, its use has been complicated by several side effects, including chronic allograft nephropathy, diabetes mellitus, arterial hypertension, and neurotoxicity. Tacrolimus-induced neutropenia is a less recognized, but potentially harmful complication. Three patients with severe neutropenia developing within 3 months after kidney transplantation are described. After having excluded other well known causes, tacrolimus was considered the most probable culprit. Definitive proof of this hypothesis was obtained by discontinuation of tacrolimus and switching to cyclosporine, which led to recovery of white blood cell count in all three patients.

Altered immune cell proportions in the radiodermatitis induced hairless mice-1 (HR-1)

Accidental radiation exposures or radiation therapy can cause internal and external damage including radiodermatitis. Even though radiodermatitis is one of the dose limiting factors in radiotherapy, the immunological nature of it is not yet been clearly understood. In this study, we have examined the alteration in immune cell population during the radiodermatitis process. A radiodermatitis model was established in HR-1 mice by locally exposing a posterior dorsal region to 10 Gy X-ray/day for 4 consecutive days. Collagen accumulation, redness, erythema, and dry desquamation of the skin were detected after X-irradiation. The size and total cell number of the spleen decreased immediately after X-irradiation, compared to those of the sham-irradiated mice, and recovered to the normal levels two weeks later. Reduction and recovery of the bone marrow cell population preceded a similar change of the spleen cell population. The proportion of CD4+ T cell increased, while the proportion of CD8+ T cell decreased ahead of the obvious skin damage, in both lymph node and spleen of the irradiated mice. Interestingly, the proportion of splenic monocytes/macrophages was expanded gradually at a similar kinetics with the aggravation of the radiodermatitis. The infiltration of the CD11b+ monocyte/macrophage to the X-irradiated skin also coincided with the development of radiodermatitis. These altered proportions of immune cells may play important roles in radiodermatitis.