Heparin in hypertriglyceridemia: friend or foe?

Lipoprotein Abnormalities in Chronic Kidney Disease and Renal Transplantation

Chronic kidney disease (CKD) is one of the most important risk factors for cardiovascular disease (CVD). Despite the kidney having no direct implications for lipoproteins metabolism, advanced CKD dyslipidemia is usually present in patients with CKD, and the frequent lipid and lipoprotein alterations occurring in these patients play a role of primary importance in the development of CVD. Although hypertriglyceridemia is the main disorder, a number of lipoprotein abnormalities occur in these patients. Different enzymes pathways and proteins involved in lipoprotein metabolism are impaired in CKD. In addition, treatment of uremia may modify the expression of lipoprotein pattern as well as determine acute changes. In renal transplantation recipients, the main lipid alteration is hypercholesterolemia, while hypertriglyceridemia is less pronounced. In this review we have analyzed lipid and lipoprotein disturbances in CKD and also their relationship with progression of renal disease. Hypolipidemic treatments may also change the natural history of CVD in CKD patients and may represent important strategies in the management of CKD patients.

Hypertriglyceridaemia-induced acute pancreatitis due to patient non-compliance

A 34-year-old woman presented with acute and progressive pain in the upper abdomen with worsening nausea, vomiting and diarrhoea. Her pain was described as severe, sharp and stabbing, with radiation to her chest and back. The patient's amylase and lipase levels were only mildly elevated. However, triglyceride levels (10,039 mg/dL) were markedly elevated upon presentation and no other causes of acute pancreatitis (e.g. obstruction, alcohol and medication) were identified. The patient was treated with opioids to control her pain and gemfibrozil was initiated to reduce her triglycerides. In addition, the patient received enoxaparin for deep vein thrombosis prevention and insulin for hyperglycaemia which also have been shown to decrease elevated triglycerides. The patient subsequently required antibiotic therapy with piperacillin-tazobactam after developing fever and an elevated white blood cell count. We review the role of adjunctive therapy with heparin and insulin in a patient with recurrent pancreatitis probably because of hypertriglyceridaemia and medication non-compliance.

Intravascular release and urinary excretion of tissue factor pathway inhibitor during heparin treatment

Tissue-factor-pathway inhibitor is the principal regulator of tissue factor-induced coagulation. Heparin treatment mobilizes TFPI into the circulation and contributes to the anticoagulant effects of heparins. Previous studies have demonstrated a selective depletion of intravascular TFPI by unfractionated heparin (UFH) but not by low-molecular-weight heparin (LMWH). In this study we sought to investigate the time- and dose-dependent relationships between release of TFPI and lipoprotein lipase (LPL) in respons to UFH and LMWH and to investigate whether the selective depletion of TFPI by UFH but not by LMWH is related to differential urinary excretion of TFPI. Eight healthy males participated in an open crossover study in which participants were assigned to receive (1) continuous infusion of unfractionated heparin (UFH, 450 IU/kg/24 hr); (2) subcutaneous dalteparin, 100 IU/kg given twice at a 12-hr interval; (3) subcutaneous dalteparin, 200 IU/kg given once; or (4) saline-solution infusion. Similar dose-dependent mobilization of TFPI and lipoprotein lipase (LPL), another glucosaminoglycan (GAG)-anchored protein of the endothelial membrane, was observed after both subcutaneous and intravenous administration of heparins. However, UFH induced a more efficient release of both TFPI and LPL into plasma than did LMWH at equivalent anti-Xa levels, indicating molecular-weight dependence of the release reactions. However, LPL reached peak levels faster and was more rapidly cleared from the circulation than was TFPI, regardless of the treatment modality. Only trace amounts of TFPI were detected in the urine in a native form (38 kD). UFH and LMWH treatment reduced renal clearance of TFPI compared with the control regimen. Our findings suggest that displacement of TFPI from the endothelial-surface GAG is the main mechanism for TFPI release during heparin treatment in vivo and that differential urinary excretion of TFPI is not the explanation for selective depletion of TFPI during UFH treatment.