mycophenolic-acid and Necrosis

Necrotising myopathy is an autoimmune disease that commonly affects muscles. Here we examine a case of a middle-aged women presenting with a chief report of shortness of breath, who subsequently developed muscle weakness. Her clinical course was complicated by respiratory failure and pulmonary hypertension likely due to the underlying pathology of signal recognition particle-positive necrotising myopathy. After further evaluation, her shortness of breath was thought to be secondary to muscle pathology rather than cardiopulmonary pathology. She was transferred to our institution for workup by rheumatology. At the time of admission, 6 months after initial presentation, her weakness progressed, so that she was unable to lift her arms and legs against gravity. Furthermore, neurological examination revealed mild facial and nuchal weakness, severe proximal weakness, more moderate distal weakness and global areflexia.

Topics: Autoimmune Diseases; Electromyography; Enzyme Inhibitors; Female; Glucocorticoids; Humans; Immunoglobulins, Intravenous; Immunologic Factors; Middle Aged; Muscular Diseases; Mycophenolic Acid; Necrosis; Prednisone; Signal Recognition Particle

1. Gastrointestinal (GI) intolerability is a concern for drugs such as mycophenolic acid (MPA) and drug metabolism may play a role. Few in vitro models exist that allow for the preclinical evaluation of a potential role of drug metabolism in intestinal drug toxicity. Thus, we sought to develop an in vitro model based on the human colon adenocarcinoma cell line LS180 to investigate MPA's negative effects on intestinal cells. 2. Stability of expression of key enzymes of MPA metabolism (UGT1A7, UGT1A9, UGT1A10, UGT2B7, CYP3A4 and CYP3A5), transporters (OATP1B1, OATP1B3, OATP2B1, MRP1, MRP2 and MDR1) and the nuclear receptor PXR over 12 passages in combination with guanosine supplementation to counter MPA's antiproliferative effects (determined by western blot analysis and proliferation assays, respectively) was established. 3. Expression of LS180 key enzymes remained stable over passages 47-59 and MPA-induced growth inhibition was circumvented by exogenous guanosine over a period of three days. MPA was not cytotoxic at concentrations up to 250 μM, a concentration that intestinal cells adjacent to the dissolving capsule or tablet are exposed to. 4. We concluded that LS180 cells are suitable to study the potential association between MPA metabolism and its negative effects on intestinal cells.

Topics: Apoptosis; Caspase 3; Cell Line, Tumor; Cell Proliferation; Enzyme Stability; Female; Gastrointestinal Tract; Guanosine; Humans; L-Lactate Dehydrogenase; Middle Aged; Models, Biological; Mycophenolic Acid; Necrosis; Reproducibility of Results; Toxicity Tests

Immune-mediated necrotising myopathy (IMNM) is a type of inflammatory myopathy characterised by acute or subacute severe proximal muscle weakness, significantly elevated creatine kinase levels, and prominent myofibre necrosis and regeneration with little or no inflammation. A subtype of IMNM identified by anti-HMG-CoA reductase (HMGCR)antibodies has been shown to be associated with statin exposure. Treatment of IMNM consists of immunosuppression with steroids, steroid-sparing agents, intravenous immune globulin and/or biologics. We present here a case of anti-HMCGR-associated IMNM and review the pathophysiology, diagnosis and treatment to increase physician awareness of this rare and debilitating condition.

Topics: Administration, Intravenous; Aged; Autoimmune Diseases; Biopsy; Creatine Kinase; Diagnosis, Differential; Enzyme Inhibitors; Glucocorticoids; Humans; Hydroxymethylglutaryl CoA Reductases; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Immunoglobulins, Intravenous; Male; Methylprednisolone; Muscle Weakness; Muscular Diseases; Mycophenolic Acid; Myositis; Necrosis; Treatment Outcome

To evaluate whether xenografts derived from hysterectomized patients would implant successfully and lead to uterine leiomyoma in Wistar rats.. This experimental study examined six female Wistar rats implanted with uterine leiomyoma obtained from patients who underwent hysterectomies at the gynecological surgery service of the HUUFMA. The rats were divided into two groups. Group I consisted of three rats in which the uterine leiomyoma had been implanted in the parietal peritoneum, and group II consisted of three rats in which the uterine leiomyoma was implanted in the subcutaneous tissue. The immunosuppressant mycophenolate mofetil (MMF) was administered orally by gavage (at a dose of 40 mg/kg of body weight) to prevent transplant rejection starting 15 days before the transplant and continuing throughout the entire experiment. After four weeks, necrosis and neovascularization were evaluated histologically in both groups and were classified as either absent or present. Lymphocytic inflammatory infiltration was also examined and classified as mild, moderate or intense (by hematoxylin and eosin staining), and fibrosis was classified as grade I-III (by Masson's trichrome staining).. Necrosis was absent from all three rats in group I and was observed in only one rat from group II. Neovascularization was present in two rats from group I and in only one rat from group II. The lymphocytic inflammatory infiltrate was mild in two rats and moderate in one rat from group I, and it was moderate in two rats and intense in one rat from group II. Two rats from group 1 exhibited grade III fibrosis, and one rat presented grade I fibrosis. In group II, two rats presented grade I fibrosis and one rat had grade II fibrosis. When necrosis and neovascularization were evaluated as variables, group I demonstrated greater evidence of successful implantation when compared to group II, indicating that the peritoneal implantation technique produces better results than the subcutaneous approach (p=0.039).. This study demonstrates that the xenotransplantation of uterine leiomyoma into the parietal peritoneum is more effective than the xenotransplantation of uterine leiomyoma into the subcutaneous tissue, and it describes a promising new model for the study of leiomyoma in vivo.

Topics: Animals; Disease Models, Animal; Female; Fibrosis; Graft Rejection; Humans; Immunosuppressive Agents; Leiomyoma; Mycophenolic Acid; Necrosis; Neoplasm Transplantation; Neovascularization, Pathologic; Peritoneum; Pilot Projects; Rats; Rats, Wistar; Subcutaneous Tissue; Transplantation, Heterologous; Uterine Neoplasms

A case of drug-induced hepatitis mediated by troxis necrosis, a form of autoimmune hepatitis, is described.. Clinical data, light and electron microscopy of an ultrasound-guided core needle liver biopsy specimen, were examined to investigate the cause of transaminitis in a 26year old male patient on Cellcept and Plaquenil for the treatment of lupus erythematosus. A systematic PUBMED review of troxis necrosis as the underlying mechanism for drug-induced hepatitis was performed.. Liver function tests (LFTs) were significant for elevated AST (305) and ALT (174); the autoimmune workup was significant for anti-ANA positivity and α-SMA negativity. On light microscopy, the liver biopsy shows focal areas of lymphocytic infiltrates surrounding and forming immunologic synapses with lobular hepatocytes, indicating lobular hepatitis of autoimmune nature. Electron microscopy confirmed the presence of immunologic synapses. Upon cessation of the offending medications, the LFTs returned to baseline with no further intervention. Literature search yielded 7 previously reported cases of drug-induced hepatitis mediated by troxis necrosis.. Troxis necrosis is a novel mechanism for drug-induced hepatitis, including immunomodulatory medications including a monoclonal anti-TWEAK antibody and Cellcept and Plaquenil, two widely used immunosuppression/anti-rejection medications.

Topics: Adult; Chemical and Drug Induced Liver Injury; Enzyme Inhibitors; Humans; Hydroxychloroquine; Immunomodulation; Lupus Erythematosus, Systemic; Lymphocytes; Male; Mycophenolic Acid; Necrosis

Topics: Adrenal Cortex Hormones; Dermatomyositis; Drug Therapy, Combination; Female; Hand; Humans; Immunoglobulins, Intravenous; Immunosuppressive Agents; Middle Aged; Mycophenolic Acid; Necrosis; Skin; Treatment Outcome

Immunosuppressive drugs are used in clinical medicine for a variety of disorders, but their effects on the reparative capacity of the dental pulp are unknown. This study evaluated the influence of selected immunosuppressive drugs on pulpal tissue healing after direct pulp capping of mechanically exposed dog's teeth with mineral trioxide aggregate (MTA).. Ten healthy male dogs were assigned into 5 experimental groups: a control group in which no drug was received and 4 experimental groups in which the immunosuppressive drugs prednisone, mycophenolate mofetil, sirolimus, and cyclosporine A were administered 45 days before the operative procedures and until the dogs were killed. Class V cavities were prepared on the buccal surfaces of 12 teeth in each dog. In each cavity, the pulp was exposed and capped with MTA. The pulpal tissue responses to capping material were assessed 65 days postoperatively.. Compared with the control group, variable responses was recorded in the groups treated with mycophenolate mofetil, sirolimus, and cyclosporine A, which were characterized by moderate to severe inflammatory reactions, tissue necrosis, and total absence of hard tissue bridging. Pulpal tissue responses in the group treated with prednisone were characterized by inflammatory cell infiltration, limited tissue necrosis, as well as partial to complete hard tissue bridging.. From these findings, it seemed evident that acceptable repair of the dentin-pulp complex, eg, wound healing with hard tissue formation after capping with MTA, is unlikely with mycophenolate mofetil, sirolimus, or cyclosporine A immunosuppressive drug therapy.

Topics: Aluminum Compounds; Animals; Calcium Compounds; Cyclosporine; Dental Pulp; Dental Pulp Capping; Dental Pulp Exposure; Dentin, Secondary; Dogs; Drug Combinations; Immunosuppressive Agents; Male; Mycophenolic Acid; Necrosis; Oxides; Prednisone; Pulpitis; Silicates; Sirolimus; Wound Healing

We recently demonstrated that the anti-viral agent ribavirin and the immunosuppressor mycophenolic acid (MPA) are both potent inducers of a necrotic signal. These two chemicals deplete the intracellular pool of guanosine triphosphate through the inhibition of inosine monophosphate dehydrogenase (IMPDH) activity. The cellular stress resulting from the GTP/GDP depletion leads to the activation of the small GTPase Cdc42 and the remodeling of actin, which are crucial events in the transmission of the MPA-mediated necrotic signal. Nevertheless, we observe for each tested cell (leukemic T and B-cell lines, activated PBLs) that a minor part of the cell population is killed through a caspase-dependent apoptotic signal. Blockade of the caspase activity eliminates the apoptotic cells, which are replaced by cells exhibiting autophagic features. In light of our findings, we assume that the newly characterized atypical cell death induced by MPA may account for the decreased risk of cancer occurrence observed in transplant recipients treated with mycophenolate mofetil (MMF) versus a non-MMF regimen.

Topics: Actins; Antiviral Agents; Apoptosis; Autophagy; cdc42 GTP-Binding Protein; Cell Line; GTP Phosphohydrolases; Humans; Immunosuppressive Agents; IMP Dehydrogenase; Kidney Transplantation; Models, Biological; Mycophenolic Acid; Necrosis; Risk

Topics: Acyclovir; Antiphospholipid Syndrome; Antiviral Agents; Drug Therapy, Combination; Female; Herpes Zoster; Humans; Immunosuppressive Agents; Infusions, Intravenous; Lupus Erythematosus, Systemic; Middle Aged; Mycophenolic Acid; Necrosis; Prednisone; Skin

The amount of inosine monophosphate dehydrogenase (IMPDH), a pivotal enzyme for the biosynthesis of the guanosine tri-phosphate (GTP), is frequently increased in tumor cells. The anti-viral agent ribavirin and the immunosuppressant mycophenolic acid (MPA) are potent inhibitors of IMPDH. We recently showed that IMPDH inhibition led to a necrotic signal requiring the activation of Cdc42.. Herein, we strengthened the essential role played by this small GTPase in the necrotic signal by silencing Cdc42 and by the ectopic expression of a constitutive active mutant of Cdc42. Since resistance to apoptosis is an essential step for the tumorigenesis process, we next examined the effect of the MPA-mediated necrotic signal on different tumor cells demonstrating various mechanisms of resistance to apoptosis (Bcl2-, HSP70-, Lyn-, BCR-ABL-overexpressing cells). All tested cells remained sensitive to MPA-mediated necrotic signal. Furthermore, inhibition of IMPDH activity in Chronic Lymphocytic Leukemia cells was significantly more efficient at eliminating malignant cells than apoptotic inducers.. These findings indicate that necrosis and apoptosis are split signals that share few if any common hub of signaling. In addition, the necrotic signaling pathway induced by depletion of the cellular amount of GTP/GDP would be of great interest to eliminate apoptotic-resistant tumor cells.

Topics: Apoptosis; Blotting, Western; cdc42 GTP-Binding Protein; Cell Line; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Green Fluorescent Proteins; Guanosine Diphosphate; Guanosine Triphosphate; Humans; IMP Dehydrogenase; Jurkat Cells; K562 Cells; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphocytes; Microscopy, Electron; Mutation; Mycophenolic Acid; Necrosis; RNA, Small Interfering; Signal Transduction; Transfection; Tumor Cells, Cultured

Mycophenolate mofetil (MMF) is an immunosuppressive agent used in transplantation. Over the last decade, MMF has also emerged as an alternative therapeutic regimen for autoimmune diseases, mainly for patients refractory to other therapies. The active compound of MMF, mycophenolic acid (MPA), depletes the intracellular pool of guanosine tri-phosphate through inosine monophosphate dehydrogenase blockade. The molecular mechanism involved in the elimination of T and B lymphocytes upon inhibition of inosine monophosphate dehydrogenase remains elusive. In this study, we showed that in contrast to the immunosuppressors azathioprine, cyclosporin A, and tacrolimus, MPA killed lymphocytes through the activation of a caspase-independent necrotic signal. Furthermore, the MPA-mediated necrotic signal relied on the transmission of a novel intracellular signal involving Rho-GTPase Cdc42 activity and actin polymerization. In addition to its medical interest, this study sheds light on a novel and atypical molecular mechanism leading to necrotic cell death.

Topics: Actins; Adenosine Triphosphatases; B-Lymphocytes; cdc42 GTP-Binding Protein; Enzyme Inhibitors; Guanosine Triphosphate; Humans; Immunosuppressive Agents; IMP Dehydrogenase; Jurkat Cells; Lymphocyte Activation; Mycophenolic Acid; Necrosis; Organ Transplantation; Signal Transduction; T-Lymphocytes

A single-center cohort study of kidney and kidney-pancreas recipients was conducted to evaluate the association between new immunosuppressive regimens and risk of thrombotic microangiopathy (TMA). From January 1st,1996 to December 31, 2002, 368 patients received a kidney or kidney-pancreas transplant at our center. Four immunosuppressive regimens were evaluated as potential risk factors of TMA: cyclosporin + mycophenolate mofetil (CsA + MMF), cyclosporin + sirolimus (CsA + SRL), tacrolimus + myophenolate mofetil (FK + MMF), and tacrolimus + sirolimus (FK + SRL). Thirteen patients developed biopsy-proven TMA in the absence of vascular rejection. The incidence of TMA was significantly different in the four immunosuppressive regimens studied (p < 0.001). The incidence of TMA was highest in the CsA + SRL group (20.7%). The relative risk of TMA was 16.1 [95% confidence interval (CI): 4.3-60.8] for patients in the CsA + SRL group as compared with those in the FK + MMF group. We also investigated in vitro the pathophysiological basis of this association. The CsA-SRL combination was found to be the only regimen that concomitantly displayed pro-necrotic and anti-angiogenic activities on arterial endothelial cells. We propose that this combination concurs to development of TMA through dual activities on endothelial cell death and repair.

Topics: Adult; Angiogenesis Inhibitors; Apoptosis; Cells, Cultured; Cohort Studies; Cyclosporine; Drug Therapy, Combination; Endothelium, Vascular; Graft Rejection; Humans; Immunosuppressive Agents; Kidney; Kidney Transplantation; Middle Aged; Mycophenolic Acid; Necrosis; Neovascularization, Pathologic; Pancreas Transplantation; Risk Factors; Sirolimus; Thrombosis

Historically, late steroid withdrawal after kidney transplants has been associated with an increased rejection rate. Recently, low rejection rates have been reported for recipients treated with complete avoidance or rapid elimination of steroids. However, follow-up has been short. We herein report on 3-year outcome in recipients whose prednisone was rapidly eliminated and who were maintained on a steroid-free regimen. From 10/1/1999 through 5/1/2003, 349 recipients (254 LD, 95 CAD; 319 in first 30 s) were immunosuppressed with polyclonal antibody (Thymoglobulin), a calcineurin inhibitor, either mycophenolate mofetil or sirolimus, and rapid discontinuation of prednisone. Actuarial 3-year patient survival was 95%; graft survival, 93%. Acute rejection-free graft survival at 1 year was 94%; at 3 years, 92%. There was no difference between LD and CAD. At 2 years, the mean (+/- SE) serum creatinine level for LDs was 1.6 +/- 0.5 mg/dL; for CAD, 1.6 +/- 0.4 mg/dL. We have no new cases of PTLD or avascular necrosis; 22 recipients (6%) developed CMV. Currently, 84% of recipients remain prednisone-free. We conclude that excellent 3-year patient and graft survival can be achieved without maintenance prednisone. With such a protocol, steroid-related side-effects are minimal.

Topics: Antilymphocyte Serum; Case-Control Studies; Creatinine; Female; Graft Rejection; Graft Survival; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Mycophenolic Acid; Necrosis; Prednisone; Sirolimus; Time Factors

Topics: Adult; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Drug Therapy, Combination; Female; Humans; Immunosuppressive Agents; Kidney Failure, Chronic; Kidney Transplantation; Mycophenolic Acid; Necrosis; Sirolimus; Skin; Treatment Outcome; Vasculitis, Leukocytoclastic, Cutaneous

Intracellular ATP depletion is a hallmark event in ischemic injury. It has been extensively characterized in models of chemical anoxia in vitro. In contrast, the fate of GTP during ischemia remains unknown. We used LLC-PK proximal tubular cells to measure GTP and ATP changes during anoxia. In 45 min, antimycin A decreased ATP and GTP to 8% and 2% of controls, respectively. Ischemia in vivo resulted in comparable reductions in GTP and ATP. After 2 h of recovery, GTP levels in LLC-PK cells increased to 65% while ATP increased to 29%. We also investigated steady-state models of selective ATP or GTP depletion. Combinations of antimycin A and mycophenolic acid selectively reduced GTP to 51% or 25% of control. Similarly, alanosine selectively reduced ATP to 61% or 26% of control. Selective GTP depletion resulted in significant apoptosis. Selective ATP depletion caused mostly necrosis. These models of ATP or GTP depletion can prove useful in dissecting the relative contribution of the two nucleotides to the ischemic phenotype.

Topics: Adenosine Triphosphate; Alanine; Animals; Antibiotics, Antineoplastic; Antimycin A; Apoptosis; Cell Hypoxia; Cells, Cultured; Deoxyglucose; Enzyme Inhibitors; Guanosine; Guanosine Triphosphate; Ischemia; Kidney Cortex; Kidney Tubules, Proximal; LLC-PK1 Cells; Male; Models, Biological; Mycophenolic Acid; Necrosis; Oxidative Phosphorylation; Rats; Rats, Sprague-Dawley; Swine

Mycophenolate mofetil (MMF) is used for immunosuppression after renal transplantation because it reduces lymphocyte proliferation by inhibiting inosine monophosphate dehydrogenase (IMPDH) in lymphocytes and GTP biosynthesis. In the present study we asked if therapeutic concentrations of MMF might interfere with mesangial cell (MC) proliferation which is involved in inflammatory proliferative glomerular diseases.. Rat and human MCs were growth-arrested by withdrawal of fetal calf serum (FCS) and stimulated by addition of FCS, platelet-derived growth factor (PDGF) or lysophosphatidic acid (LPA). Different concentrations of MMF (0.019-10 microM) were added concomitantly in the presence or absence of guanosine. MC proliferation was determined by [3H]thymidine incorporation. Cell viability was assessed by trypan blue exclusion. Apoptotic nuclei were stained using the Hoechst dye H33258. Cytosolic free Ca2+ concentrations were determined with the fluorescent calcium chelator fura-2-AM.. MMF inhibited mitogen-induced rat MC proliferation with an IC50 of 0.45 +/- 0.13 microM. Human MCs proved to be even more sensitive (IC50 0.19 +/- 0.06 microM). Inhibition of MC proliferation was reversible and not accompanied by cellular necrosis or apoptosis. Addition of guanosine prevented the antiproliferative effect of MMF, indicating that inhibition of IMPDH is responsible for decreased MC proliferation. Early signalling events of GTP-binding-protein-coupled receptors, such as changes in intracellular Ca2+ levels were not affected by MMF.. The results show that MMF has a concentration-dependent antiproliferative effect on cultured MCs in the therapeutic range, which might be a rationale for the use of this drug in the treatment of mesangial proliferative glomerulonephritis.

Topics: Animals; Apoptosis; Calcium; Cell Division; Cells, Cultured; Culture Media, Serum-Free; Cytosol; Glomerular Mesangium; Guanosine; Humans; Iliac Artery; Immunosuppressive Agents; IMP Dehydrogenase; Lysophospholipids; Muscle, Smooth, Vascular; Mycophenolic Acid; Necrosis; Platelet-Derived Growth Factor; Rats

Topics: Animals; Digestive System; Dogs; Female; Heart; Hypertrophy; Immunosuppressive Agents; Kidney Transplantation; Mycophenolic Acid; Myocardium; Necrosis; Polyenes; Sirolimus; Tacrolimus; Transplantation, Homologous

Although technically possible, limb allotransplantation has not been applied clinically. The skin component is especially antigenic, requiring high immunosuppressant doses with an unacceptable toxicity profile. RS-61443, an experimental mycophenolic acid ester that inhibits lymphocyte proliferation without major systemic toxicity, was tested as an immunosuppressant to prevent rejection of rat hindlimb allotransplants. Utilizing Brown-Norway donors and F344 recipients to provide a major mismatch at the MHC, midfemur orthotopic limb transfer was performed with microsurgical repair of femoral vessels and sciatic nerve. Four primary groups were studied: autografts (n = 4); untreated allografts (n = 6); allografts receiving CsA 10 mg/kg for 20 days, then twice per week (n = 6); and allografts receiving RS-61443 30 mg/kg/day (n = 6). Skin and soft tissues were biopsied to assess rejection. Autografts had indefinite limb survival, while untreated allografts had complete acute rejection within 10-12 days. Five of the six CsA rats developed delayed mild-moderate acute rejection within 6 months. In contrast, 5 of the 6 RS-61443 rats had no rejection after at least 32 weeks, while the sixth rat developed only slight rejection on skin biopsy. All animals regained full sensation and partial functional return. RS-61443 is highly effective as a primary immunosuppressant for hindlimb allotransplantation. The disturbing moderate rejection observed in CsA animals, which was absent with RS-61443, may significantly hamper function of transplanted limbs.

Topics: Animals; Cyclosporine; Graft Rejection; Hindlimb; Immunosuppression Therapy; Immunosuppressive Agents; Major Histocompatibility Complex; Mycophenolic Acid; Necrosis; Rats; Rats, Inbred BN; Rats, Inbred F344; Skin Transplantation; Transplantation, Autologous; Transplantation, Homologous