Sirolimus-Induced Severe Hypertriglyceridemia in a Lung Transplant Recipient

Sirolimus-induced Hypertriglyceridemia Leads to Acute Pancreatitis and Diabetic Ketoacidosis Post Stem Cell Transplant for Sickle Cell Disease

Sirolimus (mammalian target of rapamycin inhibitor) is a potent immunosuppressive agent, used in patients receiving hematopoietic stem cell transplant (HSCT) for Graft vs Host disease prophylaxis. Compared to calcineurin inhibitors, sirolimus has no neurotoxicity or nephrotoxicity, but sirolimus causes dose-dependent thrombocytopenia, leukopenia, delayed wound healing, hyperlipidemia, and hypertriglyceridemia. Here we report a case of acute pancreatitis and diabetic ketoacidosis in a patient with sickle cell disease post haploidentical family donor HSCT which was managed conservatively without plasmapheresis. Based on our review of the literature, this is the first reported case of developing acute pancreatitis as an adverse effect of sirolimus-induced hypertriglyceridemia leading to diabetic ketoacidosis in a recipient of HSCT.

Case report: Severe asymptomatic hypertriglyceridemia associated with long-term low-dose rapamycin administration in a healthy middle-aged Labrador retriever

Rapamycin is an mTOR inhibitor that has been shown to extend the lifespan of laboratory model organisms. In humans, rapamycin is used at higher doses as an immunosuppressive medication to prevent organ rejection. Numerous adverse effects are seen with rapamycin treatment in humans, with one of the most common being dysregulation of lipid metabolism. In humans, this often manifests as mild to moderate serum lipid elevations, with a small subset developing extreme triglyceride elevations. This case report describes an eight-year-old, castrated male, clinically healthy Labrador retriever who developed severe hypertriglyceridemia associated with low-dose rapamycin administration over a six-month period. During this time, the dog was asymptomatic and displayed no other clinical abnormalities, aside from a progressive lipemia. Within 15 days of discontinuing rapamycin treatment, and with no targeted lipemic intervention, the dog's lipemia and hypertriglyceridemia completely resolved.

New Approaches to Cardiovascular Disease and Its Management in Kidney Transplant Recipients

Cardiovascular events, including ischemic heart disease, heart failure, and arrhythmia, are common complications after kidney transplantation and continue to be leading causes of graft loss. Kidney transplant recipients have both traditional and transplant-specific risk factors for cardiovascular disease. In the general population, modification of cardiovascular risk factors is the best strategy to reduce cardiovascular events; however, studies evaluating the impact of risk modification strategies on cardiovascular outcomes among kidney transplant recipients are limited. Furthermore, there is only minimal guidance on appropriate cardiovascular screening and monitoring in this unique patient population. This review focuses on the limited scientific evidence that addresses cardiovascular events in kidney transplant recipients. Additionally, we focus on clinical management of specific cardiovascular entities that are more prevalent among kidney transplant recipients (ie, pulmonary hypertension, valvular diseases, diastolic dysfunction) and the use of newer evolving drug classes for treatment of heart failure within this cohort of patients. We note that there are no consensus documents describing optimal diagnostic, monitoring, or management strategies to reduce cardiovascular events after kidney transplantation; however, we outline quality initiatives and research recommendations for the assessment and management of cardiovascular-specific risk factors that could improve outcomes.

Severe Hypertriglyceridemia Induced by Sirolimus Treated With Medical Management Without Plasmapheresis: A Case Report

Hypertriglyceridemia and hyperlipidemia are the most remarkable metabolic complications seen with long-term sirolimus therapy. We report the case of a 36-year-old woman status post bilateral lung transplantation on a maintenance immunosuppression regimen of sirolimus, tacrolimus, and prednisone who presented with status migrainosus, chest pain, abdominal discomfort, and triglyceride levels greater than 4425 mg/dL. In previously reported cases of severe hypertriglyceridemia that developed on maintenance sirolimus therapy, plasmapheresis has been utilized as an early strategy to rapidly lower triglycerides in order to minimize the risk of acute complications such as pancreatitis, but our case was managed medically without plasmapheresis. The most recent triglyceride was down to 520 mg/dL 2 months after discontinuation of sirolimus. We estimate the probability of this reaction to sirolimus as probable based on a score of 5 points on the Naranjo scale. This is the first case report to our knowledge that highlights the sole use of oral lipid-lowering drug agents to treat severe hypertriglyceridemia secondary to sirolimus without the use of plasmapheresis.

CONCLUSION

Sirolimus-induced severe hypertriglyceridemia can be managed with oral lipid-lowering agents without plasmapheresis. Clinician needs to be aware of the importance of baseline and regular triglyceride monitoring in patients on sirolimus.

Unexplained hemolysis in patients undergoing ECMO: beware of hypertriglyceridemia

Hemolysis is a common complication of extracorporeal membrane oxygenation (ECMO) support and is associated with increased mortality. Frequent monitoring of markers of hemolysis is performed at ECMO centers. We report two cases of spurious hemolysis caused by hypertriglyceridemia in patients undergoing ECMO support. Critically ill patients, including those receiving ECMO, may be at risk of developing medication-induced hypertriglyceridemia. The interference of lipids with the measurement of plasma free hemoglobin, a marker of hemolysis, should be recognized. Our cases highlight the importance of investigating hypertriglyceridemia as part of the assessment of unexplained hemolysis in patients supported with ECMO.

PPARγ activation attenuates glucose intolerance induced by mTOR inhibition with rapamycin in rats

mTOR inhibition with rapamycin induces a diabetes-like syndrome characterized by severe glucose intolerance, hyperinsulinemia, and hypertriglyceridemia, which is due to increased hepatic glucose production as well as reduced skeletal muscle glucose uptake and adipose tissue PPARγ activity. Herein, we tested the hypothesis that pharmacological PPARγ activation attenuates the diabetes-like syndrome associated with chronic mTOR inhibition. Rats treated with the mTOR inhibitor rapamycin (2 mg·kg(-1)·day(-1)) in combination or not with the PPARγ ligand rosiglitazone (15 mg·kg(-1)·day(-1)) for 15 days were evaluated for insulin secretion, glucose, insulin, and pyruvate tolerance, skeletal muscle and adipose tissue glucose uptake, and insulin signaling. Rosiglitazone corrected fasting hyperglycemia, attenuated the glucose and insulin intolerances, and abolished the increase in fasting plasma insulin and C-peptide levels induced by rapamycin. Surprisingly, rosiglitazone markedly increased the plasma insulin and C-peptide responses to refeeding in rapamycin-treated rats. Furthermore, rosiglitazone partially attenuated rapamycin-induced gluconeogenesis, as evidenced by the improved pyruvate tolerance and reduced mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase. Rosiglitazone also restored insulin's ability to stimulate glucose uptake and its incorporation into glycogen in skeletal muscle of rapamycin-treated rats, which was associated with normalization of Akt Ser(473) phosphorylation. However, the rapamycin-mediated impairments of adipose tissue glucose uptake and incorporation into triacylglycerol were unaffected by rosiglitazone. Our findings indicate that PPARγ activation ameliorates some of the disturbances in glucose homeostasis and insulin action associated with chronic rapamycin treatment by reducing gluconeogenesis and insulin secretion and restoring muscle insulin signaling and glucose uptake.

Major involvement of mTOR in the PPARγ-induced stimulation of adipose tissue lipid uptake and fat accretion

Evidence points to a role of the mammalian target of rapamycin (mTOR) signaling pathway as a regulator of adiposity, yet its involvement as a mediator of the positive actions of peroxisome proliferator-activated receptor (PPAR)γ agonism on lipemia, fat accretion, lipid uptake, and its major determinant lipoprotein lipase (LPL) remains to be elucidated. Herein we evaluated the plasma lipid profile, triacylglycerol (TAG) secretion rates, and adipose tissue LPL-dependent lipid uptake, LPL expression/activity, and expression profile of other lipid metabolism genes in rats treated with the PPARγ agonist rosiglitazone (15 mg/kg/day) in combination or not with the mTOR inhibitor rapamycin (2 mg/kg/day) for 15 days. Rosiglitazone stimulated adipose tissue mTOR complex 1 and AMPK and induced TAG-derived lipid uptake (136%), LPL mRNA/activity (2- to 6-fold), and fat accretion in subcutaneous (but not visceral) white adipose tissue (WAT; 50%) and in brown adipose tissue (BAT; 266%). Chronic mTOR inhibition attenuated the upregulation of lipid uptake, LPL expression/activity, and fat accretion induced by PPARγ activation in both subcutaneous WAT and BAT, which resulted in hyperlipidemia. In contrast, rapamycin did not affect most of the other WAT lipogenic genes upregulated by rosiglitazone. Together these findings demonstrate that mTOR is a major regulator of adipose tissue LPL-mediated lipid uptake and a critical mediator of the hypolipidemic and lipogenic actions of PPARγ activation.