Systemic toxicity following administration of sirolimus (formerly rapamycin) for psoriasis: association of capillary leak syndrome with apoptosis of lesional lymphocytes

Integrated Functions of Cardiac Energetics, Mechanics, and Purine Nucleotide Metabolism

Purine nucleotides play central roles in energy metabolism in the heart. Most fundamentally, the free energy of hydrolysis of the adenine nucleotide adenosine triphosphate (ATP) provides the thermodynamic driving force for numerous cellular processes including the actin-myosin crossbridge cycle. Perturbations to ATP supply and/or demand in the myocardium lead to changes in the homeostatic balance between purine nucleotide synthesis, degradation, and salvage, potentially affecting myocardial energetics and, consequently, myocardial mechanics. Indeed, both acute myocardial ischemia and decompensatory remodeling of the myocardium in heart failure are associated with depletion of myocardial adenine nucleotides and with impaired myocardial mechanical function. Yet there remain gaps in the understanding of mechanistic links between adenine nucleotide degradation and contractile dysfunction in heart disease. The scope of this article is to: (i) review current knowledge of the pathways of purine nucleotide depletion and salvage in acute ischemia and in chronic heart disease; (ii) review hypothesized mechanisms linking myocardial mechanics and energetics with myocardial adenine nucleotide regulation; and (iii) highlight potential targets for treating myocardial metabolic and mechanical dysfunction associated with these pathways. It is hypothesized that an imbalance in the degradation, salvage, and synthesis of adenine nucleotides leads to a net loss of adenine nucleotides in both acute ischemia and under chronic high-demand conditions associated with the development of heart failure. This reduction in adenine nucleotide levels results in reduced myocardial ATP and increased myocardial inorganic phosphate. Both of these changes have the potential to directly impact tension development and mechanical work at the cellular level. © 2024 American Physiological Society. Compr Physiol 14:5345-5369, 2024.

Rapamycin Augmentation of Chronic Ketamine as a Novel Treatment for Complex Regional Pain Syndrome

This case report describes the dramatic clinical response of refractory chronic complex regional pain syndrome to combined immunomodulatory treatment. Ketamine and rapamycin markedly minimized pain historically associated with suicidal behavior, increased baseline activity, and allowed for a reduction in palliative polypharmacy. The piecewise mechanism of action is unclear given multiple postulated targets, such as microglia, astroglia, T-regulatory cells, B-regulatory cells, or neurons. Relevant laboratory and genetic information may allow the application of this treatment to other affected individuals.

Capillary leak syndrome: State of the art in 2021

Capillary leak syndrome (CLS) is an increasingly acknowledged multifaceted and potentially lethal disease. Initial nonspecific symptoms are followed by the intriguing CLS hallmark: the double paradox associating diffuse severe edema and hypovolemia, along with hemoconcentration and hypoalbuminemia. Spontaneous resolutive phase is often associated with poor outcome due to iatrogenic fluid overload during leak phase. CLS is mainly triggered by drugs (anti-tumoral therapies), malignancy, infections (mostly viruses) and inflammatory diseases. Its idiopathic form is named after its eponymous finder: Clarkson's disease. CLS pathophysiology involves a severe, transient and multifactorial endothelial disruption which mechanisms are still unclear. Empirical and based-on-experience treatment implies symptomatic care during the acute phase (with the eventual addition of drugs amplifying cAMP levels in the severest cases), and the prophylactic use of monthly polyvalent immunoglobulins to prevent relapses. As CLS literature is scattered, we aimed to collect and summarize the current knowledge on CLS to facilitate its diagnosis, understanding and management.

Dendrimer-Mediated Targeted Delivery of Rapamycin to Tumor-Associated Macrophages Improves Systemic Treatment of Glioblastoma

Glioblastoma exhibits high mortality rates due to challenges with drug delivery to the brain and into solid tumors. This two-pronged barrier necessitates high doses of systemic therapies, resulting in significant off-target toxicities. Recently, dendrimer-nanomedicines (without ligands) have shown promise for targeting specific cells in brain tumors from systemic circulation, for improved efficacy and amelioration of systemic toxicities. A dendrimer-rapamycin conjugate (D-Rapa) is presented here that specifically targets tumor-associated macrophages (TAMs) in glioblastoma from systemic administration. D-Rapa improves suppression of pro-tumor expression in activated TAMs and antiproliferative properties of rapamycin in glioma cells in vitro. In vivo, D-Rapa localizes specifically within TAMs, acting as depots to release rapamycin into the tumor microenvironment. This targeted delivery strategy yields improved reduction in tumor burden and systemic toxicities in a challenging, clinically relevant orthotopic syngeneic model of glioblastoma, demonstrating the significant potential of dendrimers as targeted immunotherapies for improving glioblastoma treatment, still an unmet need.

Design of a Biocompatible Drug-Eluting Tracheal Stent in Mice with Laryngotracheal Stenosis

Laryngotracheal stenosis (LTS) is a pathologic narrowing of the subglottis and trachea leading to extrathoracic obstruction and significant shortness of breath. LTS results from mucosal injury from a foreign body in the trachea, leading to tissue damage and a local inflammatory response that goes awry, leading to the deposition of pathologic scar tissue. Treatment for LTS is surgical due to the lack of effective medical therapies. The purpose of this method is to construct a biocompatible stent that can be miniaturized to place into mice with LTS. We demonstrated that a PLLA-PCL (70% poly-L-lactide and 30% polycaprolactone) construct had optimal biomechanical strength, was biocompatible, practicable for an in vivo placement stent, and capable of eluting drug. This method provides a drug delivery system for testing various immunomodulatory agents to locally inhibit inflammation and reduce airway fibrosis. Manufacturing the stents takes 28-30 h and can be reproduced easily, allowing for experiments with large cohorts. Here we incorporated the drug rapamycin within the stent to test its effectiveness in reducing fibrosis and collagen deposition. Results revealed that PLLA-PCL tents showed reliable rapamycin release, were mechanically stable in physiological conditions, and were biocompatible, inducing little inflammatory response in the trachea. Further, the rapamycin-eluting PLLA-PCL stents reduced scar formation in the trachea in vivo.

[Idiopathic and secondary capillary leak syndromes: A systematic review of the literature]

PURPOSE

The capillary leak syndrome (CLS) is a rare condition characterized by the onset of hypotension, edema, hemoconcentration and hypoalbuminemia. CLS can be idiopathic (Clarkson's disease) or secondary to various conditions and treatments. Here, we review the clinical and biological features, pathophysiology, causes and treatment of this rare condition.

METHODS

We performed a systematic review of the literature (Medline database through February 2014) to identify all articles about CLS. The relevant references were selected by two independent authors.

RESULTS

Secondary CLSs are mostly due to malignant hematological diseases, viral infections, and treatments such as chemotherapies and therapeutic growth factors. Diagnosis of idiopathic CLS is made by exclusion of secondary diseases, especially as a serum monoclonal immunoglobulin is present, or when there is a relapsing disease, no initial lung involvement or preserved consciousness despite low blood pressure. Acute episodes are treated with vasopressor therapy and judicious fluid replacement. Between episodes, patients with Clarkson's disease may be treated with intravenous immunoglobulins. CLS is a severe disease with significantly impaired prognosis.

CONCLUSION

Clarification of the pathophysiological mechanisms of CLS is essential to improve the prognosis of this rare disease with more targeted treatments.

Sirolimus-related systemic thrombotic microangiopathy after renal transplantation

We describe the case of a renal transplant patient who developed de novo biopsy-proven thrombotic microangiopathy (TMA) and deep venous thrombosis after treatment with sirolimus (SRL). We discuss the clinical course, diagnosis and therapeutics of this patient in the context of the literature.

Multicentric outcome analysis of sirolimus-based immunosuppression in 252 liver transplant recipients

SUMMARY

The use of sirolimus (SRL) in orthotopic liver transplantation (OLT) has been controversial after experimental data suggested an increased risk of hepatic artery thrombosis (HAT). To assess the safety and efficacy of SRL as de novo immunosuppression in OLT recipients. Outcomes of 252 OLT patients who received SRL were compared with outcomes of 291 OLT recipients who received calcineurin inhibitor in a retrospective study. Primary outcomes of this study were: patient- and graft survivals, vascular, biliary, wound complications and rejection rates. Secondary outcomes were: postoperative infection rate, bone marrow and renal function and changes of lipid levels. Patient- and graft survivals, rejection and infection rates were similar. In the SRL group, HAT occurred in 1.2%, biliary complications in 19.4%, and incisional hernias in 9.1%. In the control group the incidence of HAT was 5.8% (P = 0.004), biliary complications 18.5% (P = NS) and incisional hernias 7.2% (P = NS). Patients on SRL experienced significantly higher levels of serum triglycerides but fewer acute cellular rejections. Bone marrow and renal functions were similar in both the groups. Our findings would suggest that SRL is safe and effective for very selected OLT recipients. Randomized controlled trials are necessary to confirm our results.

[Idiopathic capillary leak syndrome]

Idiopathic capillary leak syndrome (ICLS) is a rare and poorly known condition. Since the first description in 1960, about hundred cases have been reported. A French register that was initiated in 1997 provides a better knowledge of the natural course of the disease and highlights some therapeutic issues. ICLS mainly affects middle-aged adults. The prognosis is poor with a 10-year mortality rate around 34%. Severe crisis and complications occurring in intensive care units account for 80% of the mortality. Diagnosis relies on an almost pathognomonic association: recurrent attacks of hypotension and hemoconcentration with paradoxical hypoalbuminemia. A monoclonal gammopathy is found in about 80% of patients. Physiopathology still remains unclear. Paraprotein toxicity has never been demonstrated. As a result, no evidence-based treatment is available neither for acute crisis nor for prophylaxis. Management of acute episodes is mainly symptomatic. Fluid infusion must be cautious because it can induce complications during the recovery phase. Patient education is a major measure to prevent recurrent attacks. Beta-2 stimulants were reported to reduce the frequency and severity of episodes and were considered as the recommended prophylactic measure. However, early data from the French register suggest that intravenous immunoglobulins are more effective in reducing both frequency and severity of the attacks. Inclusion of patients with ICLS in a register is crucial to improve the knowledge about aetiology and treatment of this disorder.

Perioperative management of medications for psoriasis and psoriatic arthritis: a review for the dermasurgeon

BACKGROUND

Psoriasis affects an estimated 3% of the world's population. Many are on chronic immunosuppressive therapy for the cutaneous and joint manifestations of this disorder. The management of these medications in the perioperative period is controversial. Psoriasis and psoriatic arthritis medications can affect wound healing, hemostasis, and infection risk during cutaneous surgery.

OBJECTIVES

The objective of this article is to provide a critical review of various medications used for care of the psoriatic patient and their potential effect on cutaneous surgical procedures.

CONCLUSIONS

This review summarizes current understanding of wound healing, hemostatic effects, and infectious risks regarding many psoriasis medications including nonsteroidal anti-inflammatory drugs, cyclooxygenase inhibitors, corticosteroids, various immunosuppressants, and biologic response modifiers. Recommendations vary depending on the agent in question, type of procedure, and comorbid conditions in the patient. Caution is advised when using many of the medications reviewed due to lack of human data of their effects in the perioperative period.

Sirolimus for angiomyolipoma in tuberous sclerosis complex or lymphangioleiomyomatosis

BACKGROUND

Angiomyolipomas in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis are associated with mutations in tuberous sclerosis genes resulting in constitutive activation of the mammalian target of rapamycin (mTOR). The drug sirolimus suppresses mTOR signaling.

METHODS

We conducted a 24-month, nonrandomized, open-label trial to determine whether sirolimus reduces the angiomyolipoma volume in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis. Sirolimus was administered for the first 12 months only. Serial magnetic resonance imaging of angiomyolipomas and brain lesions, computed tomography of lung cysts, and pulmonary-function tests were performed.

RESULTS

Of the 25 patients enrolled, 20 completed the 12-month evaluation, and 18 completed the 24-month evaluation. The mean (+/-SD) angiomyolipoma volume at 12 months was 53.2+/-26.6% of the baseline value (P<0.001) and at 24 months was 85.9+/-28.5% of the baseline value (P=0.005). At 24 months, five patients had a persistent reduction in the angiomyolipoma volume of 30% or more. During the period of sirolimus therapy, among patients with lymphangioleiomyomatosis, the mean forced expiratory volume in 1 second (FEV1) increased by 118+/-330 ml (P=0.06), the forced vital capacity (FVC) increased by 390+/-570 ml (P<0.001), and the residual volume decreased by 439+/-493 ml (P=0.02), as compared with baseline values. One year after sirolimus was discontinued, the FEV1 was 62+/-411 ml above the baseline value, the FVC was 346+/-712 ml above the baseline value, and the residual volume was 333+/-570 ml below the baseline value; cerebral lesions were unchanged. Five patients had six serious adverse events while receiving sirolimus, including diarrhea, pyelonephritis, stomatitis, and respiratory infections.

CONCLUSIONS

Angiomyolipomas regressed somewhat during sirolimus therapy but tended to increase in volume after the therapy was stopped. Some patients with lymphangioleiomyomatosis had improvement in spirometric measurements and gas trapping that persisted after treatment. Suppression of mTOR signaling might constitute an ameliorative treatment in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis. (ClinicalTrials.gov number, NCT00457808.)

Conversion from calcineurin inhibitor to sirolimus for renal function deterioration in kidney allograft recipients

BACKGROUND

Calcineurin inhibitors play an important role in chronic allograft dysfunction. Sirolimus is an interesting alternative in renal transplant patients because it is less nephrotoxic than calcineurin inhibitors.

METHODS

A chart review of the clinical outcome of kidney transplant patients converted to sirolimus with progressive allograft dysfunction is reported herein. Fifteen patients (average age: 32.3 years, 44 months mean time of conversion) were included. Indication for conversion was a >20% increase in serum creatinine over the last 6 months or progression to the range of 2-4.5 mg/dL. Patients underwent abrupt cessation of cyclosporine and sirolimus addition at 2-5 mg/day.

RESULTS

Concomitant immunosuppression remained unchanged during conversion. Targeted sirolimus level was 8-12 ng/mL. Serum creatinine dropped from pre-conversion level of 2.75 +/- 0.83 to 2.14 +/- 0.67 and 1.97 +/- 0.66 mg/dL at 3 and 6 months (p <0.05). There was a significant decrease in blood urea nitrogen, hemoglobin and serum calcium at 3 months post-conversion as well as serum calcium and potassium at 6 months post-conversion (p <0.05). There were no rejection episodes. Patient and graft survival was 100% with three infectious complications.

CONCLUSIONS

Monitored sirolimus conversion with sharp withdrawal of calcineurin inhibitor is an alternative for patients with deteriorating renal function and chronic allograft nephropathy.

Basic immunosuppressive drugs outside solid organ transplantation

Immunosuppressive drugs are the backbone of solid organ transplantation. The introduction of new immunosuppressive drugs led to improved patient and organ survival rates. Nowadays, acute rejection can be reduced to a minimum. Individualization and avoidance of drug-related adverse effects became a new goal to achieve. The potency of immunosuppressive drugs makes them attractive for use in various autoimmune diseases; therefore, the experience on immunosuppressive drugs outside the field of organ transplantation is analysed in this review.

Generalized, pruritic, ulcerating maculopapular rash necessitating cessation of sirolimus in a liver transplantation patient

The use of sirolimus as an alternative to calcineurin antagonists has enabled the continuation of immunosuppression in patients with renal impairment with preservation of kidney function. Sirolimus is generally well tolerated, with the main causes of cessation of therapy related to its effect on blood lipid profile as well as leukopenia and thrombocytopenia. We report a case of a debilitating ulcerating maculopapular rash necessitating cessation of the drug in a liver transplantation patient. A 56-year-old Caucasian liver transplantation patient presented with a diffuse, debilitating rash attributed to sirolimus use. This ultimately necessitated cessation of the immunosuppressant with subsequent resolution of her symptoms. From a review of the current literature, this is a highly unusual adverse reaction to sirolimus.

Cutaneous adverse events in renal transplant recipients receiving sirolimus-based therapy

BACKGROUND

Sirolimus is an immunosuppressive drug recently developed for organ transplantation. Its mechanism of action, independent of calcineurin, is different from that of cyclosporine and tacrolimus, two calcineurin inhibitors (CIs). Because the toxicity of CIs is partly the result of calcineurin blockade, sirolimus exhibits a different toxicity profile. In this study, we evaluated the profile, frequency, and severity of cutaneous adverse events in renal transplant recipients receiving sirolimus-based therapy.

PATIENTS AND METHODS

A systematic and in-depth evaluation of skin, mucous membranes, nails, and hair was performed in 80 renal transplant recipients receiving sirolimus-based therapy. The mean duration of the graft was 6 years and of sirolimus treatment was 18 months. Mycophenolate mofetil and steroids were combined with sirolimus for 74 patients. Sirolimus was used as first immunosuppressive therapy for 36 patients, and 44 patients were switched from CIs to sirolimus.

RESULTS

Seventy-nine patients (99%) experienced cutaneous adverse events. Twenty patients (25%) demonstrated serious adverse events, and six patients (7%) stopped sirolimus during the 3 months after the study because of cutaneous events. The most frequent of these were pilosebaceous apparatus involvement, including acne-like eruptions (46%), scalp folliculitis (26%), and hidradenitis suppurativa (12%); edematous complaints, including chronic edemas (55%) and angioedema (15%); mucous membrane disorders, including aphthous ulceration (60%), epistaxis (60%), chronic gingivitis (20%), and chronic fissure of the lips (11%); and last, nail disorders including chronic onychopathy (74%) and periungual infections (16%).

CONCLUSIONS

Skin disorders are frequent in renal transplant recipients receiving sirolimus as a long-term therapy. Despite the usually mild nature of skin events, they are often the reason for stopping sirolimus.

Novel pharmacological approaches in the treatment of psoriasis

Progress in the understanding of psoriasis as a T-cell mediated inflammatory disease has led to the development of new immunomodulatory therapies. Currently the main focus is on the so-called biologics (or biological agents), including fusion proteins, monoclonal antibodies, cytokines and selective receptors. They mainly target single steps in the complex cascade of humoral and cellular inflammatory immuno-mechanisms that finally lead to the accelerated growth of epidermal and vascular cells in the psoriatic lesions. The most promising and advanced biological agents are discussed along with their influence on the critical pathophysiological steps in psoriasis, including depletion of T cells, blockade of initial T-cell activation and T-cell receptor (TCR) stimulation, blockade of costimulatory signals and T-cell proliferative signals as well as restoration of the T helper type 1 (Th1)/Th2 balance by diminishing type 1 cytokines and administration of type 2 cytokines. In addition to the biological agents, further development of 'classical' dermatological therapies, such as retinoids, or the discovery of new indications for non-dermatological agents contribute to the novel pharmacological approaches in the treatment of psoriasis.

Benefit-Risk Assessment of Sirolimus in Renal Transplantation

Sirolimus (rapamycin) is a macrocyclic lactone isolated from a strain of Streptomyces hygroscopicus that inhibits the mammalian target of rapamycin (mTOR)-mediated signal-transduction pathways, resulting in the arrest of cell cycle of various cell types, including T- and B-lymphocytes. Sirolimus has been demonstrated to prolong graft survival in various animal models of transplantation, ranging from rodents to primates for both heterotopic, as well as orthotopic organ grafting, bone marrow transplantation and islet cell grafting. In human clinical renal transplantation, sirolimus in combination with ciclosporin (cyclosporine) efficiently reduces the incidence of acute allograft rejection. Because of the synergistic effect of sirolimus on ciclosporin-induced nephrotoxicity, a prolonged combination of the two drugs inevitably leads to progressive irreversible renal allograft damage. Early elimination of calcineurin inhibitor therapy or complete avoidance of the latter by using sirolimus therapy is the optimal strategy for this drug. Prospective randomised phase II and III clinical studies have confirmed this approach, at least for recipients with a low to moderate immunological risk. For patients with a high immunological risk or recipients exposed to delayed graft function, sirolimus might not constitute the best therapeutic choice--despite its ability to enable calcineurin inhibitor sparing in the latter situation--because of its anti-proliferative effects on recovering renal tubular cells. Whether lower doses of sirolimus or a combination with a reduced dose of tacrolimus would be advantageous in these high risk situations remains to be determined. Clinically relevant adverse effects of sirolimus that require a specific therapeutic response or can potentially influence short- and long-term patient morbidity and mortality as well as graft survival include hypercholesterolaemia, hypertriglyceridaemia, infectious and non-infectious pneumonia, anaemia, lymphocele formation and impaired wound healing. These drug-related adverse effects are important determinants in the choice of a tailor-made immunosuppressive drug regimen that complies with the individual patient risk profile. Equally important in the latter decision is the lack of severe intrinsic nephrotoxicity associated with sirolimus and its advantageous effects on arterial hypertension, post-transplantation diabetes mellitus and esthetic changes induced by calcineurin inhibitors. Mild and transient thrombocytopenia, leukopenia, gastrointestinal adverse effects and mucosal ulcerations are all minor complications of sirolimus therapy that have less impact on the decision for choosing this drug as the basis for tailor-made immunosuppressive therapy. It is clear that sirolimus has gained a proper place in the present-day immunosuppressive armament used in renal transplantation and will contribute to the development of a tailor-made immunosuppressive therapy aimed at fulfilling the requirements outlined by the individual patient profile.

Cardiac morbidity and mortality related to orthotopic liver transplantation

This article briefly discusses the cardiac status of liver transplant recipients and their preoperative cardiac evaluation. It describes in detail perioperative and early and late postoperative complications as well as the cardiac problems associated with immunosuppression. The preoperative cardiovascular status of patients is important in determining how they cope with the stresses imposed by liver transplantation. Minor early cardiac events are common and may influence longer term cardiac morbidity. Immunosuppressive therapy may have short term effects but is likely to adversely affect long term cardiac risk.

Predictors of success in conversion from calcineurin inhibitor to sirolimus in chronic allograft dysfunction

Chronic allograft dysfunction (CAD) is a major cause of graft loss in long-term kidney transplant recipients. To identify predictors of successful conversion from calcineurin inhibitor (CNI) to sirolimus (SRL) we investigated 59 renal transplant patients with CAD without histological signs of acute rejection. They received 12-15 mg SRL once, then 4-5 mg/day, target trough level 8-12 ng/mL. CNI dose was reduced by 50% simultaneously, and withdrawn at 1-2 months. Concomitant immunosuppression remained unchanged. After 1 year patient survival was 100% and graft survival 92%. In responders (54%) creatinine improved (2.75 +/- 0.75 to 2.22 +/- 0.64 mg/dL; p < 0.01). In nonresponders (46%) creatinine deteriorated (3.15 +/- 1.02 to 4.44 +/- 1.60 mg/dL; p < 0.01). Baseline renal function did not differ, however, baseline proteinuria (519 +/- 516 vs. 1532 +/- 867 mg/day, p < 0.01), histological grade of chronic allograft nephropathy (CAN) (1.2 +/- 0.5 vs. 1.9 +/- 0.6; p < 0.01), grade of vascular fibrous intimal thickening (1.2 +/- 0.7 vs. 1.7 +/- 0.7; p = 0.048) and number of acute rejections before conversion (0.73 +/- 0.69 vs. 1.27 +/- 0.96; p < 0.05) differed significantly between responders and nonresponders. In a multivariate analysis low proteinuria was the only independent variable. Proteinuria below 800 mg/day has a positive predictive value of 90%. Proteinuria at conversion below 800 mg/day is the only independent predictor for positive outcome in conversion from CNI to SRL in CAD.

Sirolimus-Associated Hepatotoxicity in Liver Transplantation

BACKGROUND

Sirolimus is an immunosuppressant that exerts anti-rejection activity by inhibiting T-cell activity and is used to treat chronic rejection and calcineurin-related nephrotoxicity. Unlike tacrolimus and cyclosporine, it has no effect on calcineurin activity in liver transplant recipients.

OBJECTIVE

To report correlates of survival outcomes in a series of patients with putative sirolimus-related hepatotoxicity after liver transplant.

METHODS

We retrospectively reviewed the medical records of patients who underwent a liver transplant for chronic hepatitis C virus (HCV) and who received sirolimus immunosuppressive therapy between November 2000 and November 2003. Extracted data included sirolimus serum concentrations, frequency of sirolimus-related adverse effects, drug-related clinical hepatitis, and survival outcomes.

RESULTS

Ten patients were found to have been treated with sirolimus for either renal insufficiency (n = 6) or chronic rejection (n = 4). Six patients had liver biopsies, while the remaining 4 patients were clinically diagnosed with rejection. Two of the 6 patients demonstrated changes consistent with sinusoidal congestion and one with eosinophilia, consistent with an allergic drug reaction. HCV viral load increased slightly, from 600 000 to 700 000 IU/mL. Mean baseline transaminase levels were 45 IU/L for aspartate aminotransferase and 50 IU/L for alanine aminotransferase, with peak levels of 210 and 180 IU/L, respectively. The time to transaminase increase was a mean of 21 days when sirolimus was added, with resolution within 27 days (mean) after its discontinuation. No changes were evident in antiviral therapy. Combination sirolimus and tacrolimus concentrations were maintained at >10 ng/mL; average monotherapy with sirolimus was 12 ng/mL, and average time on therapy was 25 weeks.

CONCLUSIONS

Sirolimus-related hepatotoxicity is an important complication after liver transplant. Immediate recognition is critical to avoid confusion with other causes of abnormal serum aminotransferases after liver transplant, and discontinuation of the drug may be required.

A Retrospective Review of Liver Transplant Patients Treated with Sirolimus from a Single Center: An Analysis of Sirolimus-Related Complications

BACKGROUND

Sirolimus (SRL) is a powerful immunosuppressant used primarily in calcineurin inhibitors (CNI)-related nephrotoxicity. However, reports of drug-related side effects are increasing. The aim of our report is to review the frequency and timing of these complications within our transplant patient population.

METHODS

We retrospectively reviewed the medical records of liver-transplanted patients treated with sirolimus between November 1998 and April 2002. The data collected included SRL serum levels, frequency of reported and documented SRL-related side effects, and survival outcomes. Statistical evaluation included Pearson chi-square and the Fisher's exact tests.

RESULTS

Overall, 205 patients were identified, with 30 patients removed from the analysis for different reasons. Of the remaining 175 patients, 91 (52%) patients developed a complication other than an increase in serum triglycerides and/or cholesterol. The most frequent complications were: bilateral lower extremity edema (57.1%), dermatitis (25.3%), oral ulcers (24.2%), joint pain (23.0%), pleural effusion (16.5%) and increase in abdominal girth (9.9%). Other complications included: generalized edema (5.5%), pericardial effusion (5.5%), facial edema (2.2%), and upper extremity edema (1.3%). In addition, we reported two cases of hepatic artery thrombosis, one case of wound dehiscence with evisceration that required surgical repair, and one case of skin cancer. Interestingly, we found that a previous history of myocardial ischemia correlates with the development of SRL side effects.

CONCLUSIONS

SRL is a powerful immunosuppressant but not devoid of side effects. These results have elevated our level of suspicion when instituting SRL and may help with early recognition and prevention of drug related complications.

Ten years of sirolimus therapy in orthotopic liver transplant recipients

BACKGROUND

Sirolimus therapy has been used in orthotopic liver transplant (OLT) recipients diagnosed with a variety of diseases; chronic graft rejection (CR), calcineurin associated renal toxicity, preemptive immune suppression, calcineurin related neurotoxicity, preemptive therapy in transplant recipients with history of hepatocellular carcinoma, and steroid resistant allograft rejection.

METHODS

A search for the medical literature and experiences involving sirolimus was done.

RESULTS

Several animal and human reports evaluating the use sirolimus in liver transplant recipients are found and discussed.

CONCLUSION

Sirolimus has been used for multitude of indications, primarily based on anecdotal experiences. However, reports of sirolimus related side effects have decreased the transplant communities' enthusiasm towards promoting this agent as a safe immune suppression agent.

Early experience with sirolimus in lung transplant recipients with chronic allograft rejection

BACKGROUND

Chronic lung allograft rejection, commonly manifest as obliterative bronchiolitis (OB/BOS), hinders long-term survival after lung transplantation (LT). OB/BOS is traditionally treated with augmented immunosuppression and results in short-term stabilization in pulmonary function for most patients. However, peribronchiolar fibroproliferation and airway obstruction usually recur despite initial improvements seen with increases in immunosuppression. In this observational, uncontrolled study, the effect of sirolimus, a novel immunosuppressant with anti-proliferative activity, was assessed in LT patients with OB/BOS.

METHODS

Between June 1999 to November 2000, LT recipients with newly diagnosed or progressive OB/BOS received sirolimus in combination with a calcineurin inhibitor (CI) and prednisone. Pulmonary function, laboratory data and adverse effects were monitored for the first 24 weeks of therapy.

RESULTS

Sirolimus was utilized in 12 LT recipients with OB/BOS. After drug initiation, 58% of patients required a reduction in CI dose to maintain appropriate CI trough concentrations. Despite CI dose reduction, serum creatinine rose in 75% of patients. Unexpected adverse effects included anemia of chronic disease (100%), edema (50%) and malignancy (17%). For the group, the rate of change in FEV(1) and FEF(25%-75%) was unchanged with sirolimus, but individual responses varied.

CONCLUSIONS

For the group, the decline in pulmonary function was not affected by the addition of sirolimus. However, among individuals with rapidly declining pulmonary mechanics, sirolimus resulted in stabilization or improvement in pulmonary function. Significant adverse effects resulted from combination sirolimus plus CI therapy. Until optimal dosing strategies and a more complete adverse effect profile are established, combination therapy should be utilized cautiously in these patients.

Neue Entwicklungen in der systemischen Psoriasistherapie

The current standard systemic therapeutic modalities for psoriasis have many potential side effects. Progress made in the understanding of the pathophysiology of psoriasis as a T-cell-mediated dermatosis provide options for new more precise therapeutic approaches. These immunological therapeutic strategies involve the inhibition/depletion of activated T-lymphocytes, the inhibition of antigen presentation and thus the regulation of T-cell activation, the inhibition of adhesion of inflammatory cells, the inhibition of effects of proinflammatory mediators and the administration of antiinflammatory cytokines. This article summarizes these new systemic therapeutic approaches. Clinical results in the early studies have been mixed. In the next years further results of phase II- and phase Ill-studies may be expected, which should allow better assessment of the potential of those particular approaches. Some of these approaches could lead to the approval of new drugs to treat psoriasis and to enhance or replace already existing therapeutic options. Furthermore results of therapeutic experiments should contribute to a better understanding of the disease. As we learn which mechanisms are more or less important for the disease, we will be better able to plan intervention strategies.

Calcineurin inhibitors and sirolimus: mechanisms of action and applications in dermatology

Controlled trials and clinical experience indicate that systemic cyclosporin A and tacrolimus are effective treatments for psoriasis, and that cyclosporin A also improves atopic eczema. A variety of other inflammatory and non-inflammatory skin diseases are probably also responsive to these drugs. However, the widespread and longer-term use of cyclosporin A and tacrolimus are limited by side effects. The molecular mechanisms of action of cyclosporin A, tacrolimus and a related drug, sirolimus, have been well defined in T cells and involve inhibition of critical signalling pathways that regulate T cell activation. For example cyclosporin and tacrolimus inhibit calcineurin phosphatase activity and thereby inhibit activation of the transcription factor NFAT. The therapeutic efficacy of topical calcineurin inhibitors in atopic eczema have restimulated interest in the mechanism of action of these drugs in skin disease. Recently the expression pattern of calcineurin and NFAT has been defined in non-immune tissues including the akin. The relevance of this to the mechanism of action of systemic and topical calcineurin inhibitors and sirolimus in skin disorders is discussed.

Novel immunotherapies for psoriasis

New insights into the pathophysiology of psoriasis have suggested possibilities for targeted therapeutic intervention. Several novel, systemic immunomodulatory therapies are currently in clinical development and results of recent clinical trials are remarkable. These include approaches targeting antigen presentation and costimulation, T-cell activation and leukocyte adhesion, the action of proinflammatory mediators and the administration of anti-inflammatory cytokines. These trials contribute to our further understanding of the disease, indicating which mechanisms play a greater or lesser part in its development. Moreover, they will lead to new therapeutic options. If psoriasis is considered as a visible model disease for T-cell-mediated disorders characterized by a type-1 cytokine pattern these recent findings might have a more general impact on the treatment of autoimmune disorders.

Potent Reversible Inhibitors of the Protein Tyrosine Phosphatase CD45

The cytosolic portion of CD45, a major transmembrane glycoprotein found on nucleated hematopoietic cells, contains protein tyrosine phosphatase activity and is critical for T-cell receptor-mediated T-cell activation. CD45 inhibitors could have utility in the treatment of autoimmune disorders and organ graft rejection. A number of 9,10-phenanthrenediones were identified that reversibly inhibited CD45-mediated p-nitrophenyl phosphate (pNPP) hydrolysis. Chemistry efforts around the 9,10-phenanthrenedione core led to the most potent inhibitors known to date. In a functional assay, the compounds were also potent inhibitors of T-cell receptor-mediated proliferation, with activities in the low micromolar range paralleling their enzyme inhibition. It was also discovered that the nature of modification to the phenanthrenedione pharmacophore could affect selectivity for CD45 over PTP1B (protein tyrosine phosphatase 1B) or vice versa.