Low Molecular Weight Glycosaminoglycans Research Articles

Prophylaxis of placental insufficiency and other complications of gestation in women with diseases associated with endothelial dysfunction

The pathogenesis of placental insufficiency and other complications of gestation is associated with vascular endothelial dysfunction. Glycocalyx covering the endothelium plays a fundamental role in coagulation and fibrinolysis. The presence of low molecular weight glycosaminoglycans in glycocalyx has a protective effect. The proven clinical efficacy of sulodexide to correct vascular endothelial dysfunction, prevent placental insufficiency and other pregnancy complications makes it a promising tool for use in obstetric practice among patients with chronic diseases (arterial hypertension, diabetes, obesity, etc.), autoimmune pathology, thrombophilia and related pregnancy complications (gestational diabetes, hypertension in pregnant women, pre-eclampsia, recurrent miscarriage, fetal growth retardation).

Prophylaxis and Treatment Strategy for Endothelial Cell Damages after Hematopoietic Cell Transplantation in Children

Introduction Sinusoidal obstruction syndrome (hSOS) and thrombotic microangiopathy (TMA) are life-threatening complications caused by endothelial cell damage (ECD) associated with hematopoietic cell transplantation (HCT). Danaparoid sodium (DS) is a heparinoid comprising a mixture of low molecular weight glycosaminoglycans with anti-Xa and anti-IIa effects, which prevent fibrin formation. Recombinant thrombomodulin (rTM) comprises the active extracellular domain of thrombomodulin and inactivates coagulation by binding to thrombin. Both of them were expected to play crucial roles in the management of disseminated intravascular coagulation (DIC) and ECD after HCT. Objectives We aimed to evaluate the efficacy and feasibility of DS for prophylaxis and rTM for the treatment of hSOS and TMA after HCT in children. Methods Between January 2011 and December 2017, 91 children (median age 7.6 years, range 0.6–18.2; with hematologic malignancies [n = 54], solid tumors [n = 9], or benign diseases [n = 28]) underwent 118 consecutive HCTs (9 autologous and 109 allogeneic settings; busulfan-based myeloablative conditioning [n = 23], total body irradiation-based myeloablative conditioning [n = 35], or reduced intensity [n = 60]) at our institution. All of them were treated prophylactically with DS (intravenously injection, 30 international units [IU] per kg of body weight, twice a day from the initiation of the conditioning regimen to day 50 after HCT) to prevent ECD. Any patient who developed ECD despite prophylaxis were treated with rTM (intravenous drip infusion, 380 IU per kg, once a day). We reviewed their clinical records and evaluated the efficacy and feasibility of rTM for these children. Results Nine patients developed SOS (severe 5, moderate 1, and mild 3) at a median of 19 days after HCT (range, 6–173), and 6 patients developed TMA at median day 38 (range, 27–106). The cumulative incidences of SOS and TMA at 100 days were 6.8% and 4.4%, respectively. A total of 17 patients received 18 courses of rTM for complications after HCT. The median dose and duration of rTM treatments were 367 IU/kg/day (range, 189–404) and 7 days (range, 3–22), repectively. rTM treatments initiated at a median of 30 days after HCT (range, 6–173). The cause of rTM administration included SOS (n = 9), infection with DIC (n = 4), TMA (n = 3), or engraftment syndrome with DIC (n = 2). All these complications were resolved or improved by rTM treatment along with supportive care. Among the 17 patients receiving rTM treatment, no hemorrhagic events or deaths due to HCT-related toxicity were observed; however, 7 died of their underlying disease. Multivariate analysis revealed that neither SOS nor TMA had a negative impact for transplant outcome. Conclusion DS and rTM are effective and safe for the management of ECD after HCT in children. A larger multicenter prospective study is warranted to confirm these findings.

High-level production of ChSase ABC I by co-expressing molecular chaperones in Escherichia coli

Chondroitinase ABC I (ChSase ABC I), as a polysaccharide lyase, can catalyze high molecular weight chondroitin sulfate (CS) to low molecular weight glycosaminoglycan which are easier to be absorbed and utilized by organisms. In this study, to enhance the production of ChSase ABC I and avoid the negative influence of tags on its catalytic efficiency, we employed molecular chaperones to co-express with ChSase ABC I. Firstly, different molecular chaperones and their combinations were screened and GroES exhibited the best positive effect. Consecutively, fermentation conditions were optimized to further improve the production. As a result, the production of ChSase ABC I was increased to 4640.44 ± 896.26 IU/g wet weight, a 2.15-fold higher value when compared with that of control in the same fermentation conditions. After that, to testify the influence of GroES on characterization of ChSase ABC I, the optimal pH and temperature, and kinetic parameters were confirmed. The affinity to substrate of ChSase ABC I with GroES assist was increased 7 folds as compared to the native ChSase ABC I, and ChSase ABC I with GroES co-expression still has high catalytic activity. This work not only presents to date the first achievement of ChSase ABC I high-level production with molecular chaperone co-expression, but also serves as a potential basis for its industrial application.

Effects of BioCell Collagen® on connective tissue protection and functional recovery from exercise in healthy adults: a pilot study

Background The extracellular matrix (ECM) of muscle, tendon, and ligament is sensitive to exercise-induced mechanical stimuli. Exercise-induced muscle damage is associated with not only myofibrillar injury, but also the involvement of connective tissue elements such as collagen, proteoglycans (PG), tendon and ligament. However, little is known about the impact of nutritional agents and metabolic optimization for enhancing adaptation and recovery of the connective tissue elements that support musculoskeletal function. BioCell Collagen (BCC) is a patented hydrolyzed chicken sternal cartilage extract that contains a naturally-occurring matrix of hydrolyzed collagen type II, and low molecular weight glycosaminoglycans such as chondroitin sulfate and hyaluronic acid. The purpose of this pilot study was to determine the potential impact of daily supplementation with BCC on functional indices and molecular biomarkers of recovery from intense exercise, and identify effect sizes on various outcome measures.

Preventive effect of glycosaminoglycans from Amussium pleuronectus (Linne) on biomolecules, lactate dehydrogenase-isoenzyme and electrocardiographic patterns in isoproterenol-induced myocardial infarction in Wistar rats

Objectives:This study was aimed to assess the cardioprotective role of low molecular weight glycosaminoglycans (LMW-GAG) in isoproterenol (ISO)-induced myocardial infarction (MI) in male Wistar rats. Effect of LMW-GAG on biomolecules, lactate dehydrogenase (LDH)-isoenzyme, and electrocardiographic (ECG)-patterns was studied as evidence of cardioprotection.Materials and Methods:Male Wistar rats (140 ± 10 g) were divided into four groups; untreated control (group I), LMW-GAG treated (300 μg/day s. c. for 2 weeks—group II), ISO (85 mg s.c. injected on 13th and 14th days—group III), and LMW-GAG plus ISO (300 μg/day s. c. for 12 days followed by 85 mg/kg ISO on the end of 13th and 14th days—group IV). At the end of the experimental period, all animals were terminated.Results:Rats treated with LMW-GAG (300 μg/kg) for 12 days showed significant increasing levels of triglyceride (TG) (both serum and heart tissue), low density lipoprotein (LDL), very low density lipoprotein (VLDL), total cholesterol, uric acid, creatinine, and glucose. However, it significantly decreased the levels of high density lipoprotein (HDL) (serum), plasma total protein, and albumin/globulin (A/G) ratio. ISO also adversely affected the LDH-isoenzymes and caused marked elevation in ST segment. Pretreatment with LMW-GAG (300 μg/kg) daily for a period of 2 weeks prevented the ISO-treated changes.Conclusions:The results indicate that LMW-GAG exhibits a cardioprotective effect in ISO-induced MI in rats, by maintaining the biomolecules and LDH-isoenzymes.

Detection of native chondroitin sulfate impurities in heparin sodium with a colorimetric micro-plate based assay

We have recently described a 96-well plate format assay for visually detecting oversulfated chondroitin sulfate A (OSCS) in heparin that uses a water soluble cationic polythiophene polymer (3-(2-(N-(N′-methylimidazole))ethoxy)-4-methylthiophene (LPTP)) and heparinase digestion. Because dermatan sulfate (DS, a.k.a. chondroitin sulfate B (CSB)) and, to a lesser degree, chondroitin sulfate A (CSA) are the most common native impurities of heparin active pharmaceutical ingredients (APIs) we adapted the previously established micro-plate assay for the visual detection of DS and CSA in heparin sodium. We describe a naked-eye detection test of these common heparin impurities with sensitivity appropriate for the United States Pharmacopeia (USP) 1% percent galactosamine in total hexosamine specification. For example, the test detects DS ≥ 1.0% w/w visually and 0.5% using a plate reader, or CSA ≥ 1.0 to 2.0% w/w visually and at ≥1.0% with a plate reader. In contrast to the test developed for oversulfated glycosaminoglycans such as OSCS, the LPTP–chondroitinase test developed here utilizes chondroitinase ABC instead of heparinases and requires a centrifugal filtration step to remove un-digested heparin. The test takes advantage of the sensitivity of the LPTP chemosensor to low molecular weight glycosaminoglycan (GAG) fragments formed by digesting DS or CSA. Importantly, the LPTP–chondroitinase method detects DS and CSA in heparin sodium in a format potentially amenable to high throughput screening.

Preventive Effect of Low Molecular Weight Glycosaminoglycan from Amussium pleuronectus (Linne) on Oxidative Injury and Cellular Abnormalities in Isoproterenol-Induced Cardiotoxicity in Wistar Rats

The present work explores suspicious consequence of low molecular weight glycosaminoglycan (LMW-GAG) on oxidative stress and cellular abnormalities in isoproterenol (ISO)-induced myocardial infarction in an experimental model. Group-III male Wistar rats (140 +/- 10 g) were administrated by ISO (85 mg ISO/ml subcutaneously (SC) injected at the last two days of a 2-week period). Group-IV rats were treated LMW-GAG plus ISO (300 microg/day per rat SC for 1 week followed by 85 mg/kg ISO on the end last two days of the 2 - weeks). Untreated control (Group-I) and LMW-GAG drug control (Group-II) were also included. Serum and tissue lactate dehydrogenase, aminotransferases, and creatine kinase activities were increased in ISO group, which were normalized by LMW-GAG pretreatment rats. Antioxidant enzymes - superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities and non-enzymatic enzyme reduced glutathione (GSH) were decreased in the ISO induced rats, and this was increased by LMW-GAG pretreatment. Increased level of thiobarbituric acid reactive substances (TBARS) in plasma and the heart of ISO treated rats; pre s.c. injected with LMW-GAG to ISO-induced rats decreased the levels of TBARS. Histological examination revealed that the ISO-induced deleterious changes in the heart tissues were offset by LMW-GAG treatment. LMW-GAG affords considerable protection to the tissues challenged by cardiotoxicity, evidenced by its correction and restoration of serum and tissue indices of injury, to normalcy.

The Role of Sulodexide in the Treatment of Diabetic Nephropathy

Diabetic nephropathy is an important cause of morbidity and mortality in patients with either type 1 or type 2 diabetes mellitus. The pathogenesis and natural history of diabetic nephropathy, characterised by a progressive decline in glomerular function, were initially described in patients with type 1 diabetes. Reports that describe the glomerulopathy and progression of renal disease in patients with type 2 diabetes suggest that the disease process is similar to that observed in patients with type 1 diabetes with diabetic nephropathy. An emerging body of evidence supports the notion that glomerular capillary wall and mesangial alterations in diabetic nephropathy involve pathobiochemical alterations of glycoproteins in these structures. Evidence in experimental animals rendered diabetic, reveal that the administration of heparin and other anionic glycoproteins can effectively prevent the biochemical alterations that promote albuminuria. Clinical reports of the use of sulodexide, a preparation of low molecular weight glycosaminoglycan polysaccharides, have shown that proteinuria is significantly diminished in patients with diabetic nephropathy, even when these patients are receiving either an ACE inhibitor or angiotensin receptor antagonist.

P4-248: Neuroparin (C3), an orally administered low molecular weight glycosaminoglycan, improves behavior and ameliorates amyloid-beta pathology in a double transgenic mouse model of Alzheimer’s disease (APPSwe, PSEN1dE9)

P4-248: Neuroparin (C3), an orally administered low molecular weight glycosaminoglycan, improves behavior and ameliorates amyloid-beta pathology in a double transgenic mouse model of Alzheimer’s disease (APPSwe, PSEN1dE9)

Low molecular weight glycosaminoglycan C3 attenuates AF64A-stimulated, low-affinity nerve growth factor receptor-immunoreactive axonal varicosities in the rat septum

Glycosaminoglycans (GAGs) play a pivotal role in the pathogenesis of Alzheimer's disease (AD). Although, as we have shown earlier, a low molecular weight GAG, C3, protects against ethylcholine aziridinium (AF64A)-induced cholinergic damage, and against Aβ-induced tau-2-immunoreactivity (IR), the mechanism of the neuroprotective effect of GAGs is not yet known. Several clues exist. Previous studies in rats revealed that continuous NGF infusion (icv) after AF64A injection increases septal ChAT and AChE activities. Moreover, C3 increases axonal outgrowth in the rat hippocampus, raising the possibility of a NGF-receptor mediated neuroprotection. Furthermore, it has been reported that NGF expression is increased in the septum following AF64A administration. To study the question regarding the mechanism of neuroprotective action of GAGs, AF64A, a selective cholinotoxin, was administered stereotaxically, bilaterally, into the lateral ventricles of Fischer albino male rats (1 nmol/2 μl/side). In order to establish the effect of C3 on the expression of the NGF receptor-IR elements, C3 was administered orally (25 mg/kg, once a day), by gavage, 7 days before, and 7 days after the AF64A injection. NGF receptor immunohistochemistry revealed that AF64A induced the appearance of NGF-receptor-IR axonal varicosities in the rat medial septum. These varicose fibers were attenuated by 14 days' administration of C3. The possible explanation of our data may be that C3 increases NGF synthesis in the lateral septum. The increased level of NGF could suppress the increased, AF64A-induced NGF receptor expression in the medial septal nucleus. These results further accentuate our earlier observations that C3 may have potential as a therapeutic agent in AD and other neurodegenerative disorders.

Characterization of Sugar Binding by Osteoclast Inhibitory Lectin

Osteoclast inhibitory lectin (OCIL) is a membrane-bound C-type lectin that blocks osteoclast differentiation and, via binding to its cognate receptor NKRP1D, inhibits natural killer cell-mediated cytotoxicity. OCIL is a member of the natural killer cell receptor C-type lectin group that includes CD69 and NKRP1D. We investigated carbohydrate binding of soluble recombinant human and mouse OCIL in enzyme-linked immunosorbent assay-based assays. OCIL bound immobilized high molecular weight sulfated glycosaminoglycans, including fucoidan, lambda-carrageenan, and dextran sulfate, but not unsulfated dextran or sialated hyaluronic acid. Carbohydrate binding was Ca(2+)-independent. Binding of immobilized low molecular weight glycosaminoglycans, including chondroitin sulfate (A, B, and C forms) and heparin, was not observed. However, the soluble forms of these low molecular weight glycosaminoglycans competed for OCIL binding of immobilized fucoidan (as did soluble fucoidan, dextran sulfate, and lambda-carrageenan), indicating that OCIL does recognize these carbohydrates. Inhibition constants for chondroitin sulfate A and heparin binding were 380 and 5 nm, respectively. Immobilized and soluble monosaccharides did not bind OCIL. The presence of saturating levels of fucoidan, dextran sulfate, and lambda-carrageenan did not affect OCIL inhibition of osteoclast formation. The fucoidan-binding lectins Ulex europaeus agglutinin I and Anguilla anguilla agglutinin did not block osteoclast formation or affect the inhibitory action of OCIL. Although the osteoclast inhibitory action of OCIL is independent of sugar recognition, we have found that OCIL, a lectin widely distributed, but notably localized in bone, skin, and other connective tissues, binds a range of physiologically important glycosaminoglycans, and this property may modulate OCIL actions upon other cells.

Low molecular weight glycosaminoglycan blockade of β-amyloid induced neuropathology

Previous studies have shown different roles for proteoglycans and glycosaminoglycans (GAGs) in Alzheimer's disease (AD) neuropathology. Using a rat model of β-amyloid induced neuropathology, we tested whether low molecular weight glycosaminoglycans (Certoparin and C6) could be useful as preventative agents and/or as a potential therapeutic treatment for AD. Chronic subcutaneous low molecular weight glycosaminoglycan injections beginning either before or after an intra-amygdaloid β-amyloid-(25–35) injection blocked abnormal intracellular tau changes and reactive astrocytosis but did not affect β-amyloid's aggregation state. Also, low molecular weight glycosaminoglycan injections beginning 1 day prior to sacrifice did not block the effects of β-amyloid nor did injections of a disaccharide, suggesting chronic low molecular weight glycosaminoglycan treatment is needed to block the effects of β-amyloid. Furthermore, these data indicate that there is a molecular weight range of active low molecular weight glycosaminoglycans in this model; and supports the investigation of low molecular weight glycosaminoglycans as a preventative and/or therapeutic treatment of β-amyloid induced neuropathology.

Glycosaminoglycans: use in treatment of diabetic nephropathy.

Glycosaminoglycans: use in treatment of diabetic nephropathy.

Pharmacokinetics of Low Molecular Weight Dermatan Sulphate (Desmin) in Different Cohorts of Patients

Dermatan sulphate (DS) is a natural glycosaminoglycan which enhances the inactivation of thrombin by heparin cofactor II and inhibits thrombin generation in plasma [1–3]. DS enhances the fibrinolytic activity in rats, exhibits antithrombotic properties in different animal models of venous thrombosis without increasing the risk of hemorrhage. Thus, this glycosaminoglycan could present a significant therapeutic advantage, particularly in terms of safety when compared to heparins [4–8]. Desmin is a new low molecular weight dermatan sulphate (LMW-DS) endowed with high antithrombotic effect and a negligible anticoagulant activity as measured by a global clotting test such as activated partial thromboplastin time (aPTT). It presents a lower hemorrhagic risk/better antithrombotic properties ratio than standard heparin [5,8] and it is able to reduce the size of preformed thrombi, probably because of the profibrinolytic properties mentioned above [9–12]. After subcutaneous (SC) administration, desmin, like other low molecular weight glycosaminoglycans, showed a higher bioavailability than the natural compound [13–16], and no accumulation phenomenon was observed after once daily consecutive administration of 100 and 200 mg [14]. Previous studies in elderly patients and in patients suffering from myocardial infarction did not show any pharmacodynamic modification when compared to younger healthy volunteers [17,18]. Due to the low degree of sulfation, DS has no or a low affinity towards endothelium, and Desmin is essentially eliminated by the kidneys [19].

Influence of Low Molecular Weight Heparin and Low Molecular Weight Dextran Sulfate on the Inhibition of Coagulation Factor XIa by Serpins

We investigated the influence of low molecular weight dextran sulfate (LMWdxs) and low molecular weight heparins (LMWH: dalteparin, enoxaparin and nadroparin) on the inhibition of FXIa by C1-inhibitor, alpha1-antitrypsin, alpha2-antiplasmin and antithrombin in a purified system and in plasma. The second order rate constant for inactivation of FXIa by C1-inhibitor, alpha1-antitrypsin, alpha2-antiplasmin, and antithrombin was 1.23, 0.056, 0.33 and 0.59 x 10(3) M(-1) s(-1), respectively. LMWdxs and LMWH dose-dependently increased the second order rate constant of the inactivation of FXIa by C1-inhibitor up to 39-fold. The second order rate constant of the inactivation of FXIa by antithrombin was increased up to 6-fold by LMWH, whereas LMWdxs had no effect. In plasma, FXIa was inactivated to about 50% by C1-inhibitor, while the other serpins contributed together to the remaining 50% of plasma's inhibitory capacity towards FXIa. In the presence of LMWdxs or LMWH, FXIa was inactivated in plasma to more than 90% by C1-inhibitor. LMWH at maximal therapeutic plasma levels enhanced the contribution of antithrombin to the inactivation of FXIa in plasma up to 5-fold. In conclusion, we found that the tested low molecular weight glycosaminoglycans dalteparin, enoxaparin and nadroparin and LMWdxs stimulate inactivation of FXIa by C1-inhibitor in a system using purified proteins as well as in plasma. Furthermore, LMWH but not LMWdxs slightly enhanced FXIa inhibition by antithrombin.

Reperfusion-induced arrhythmias and lethality are reduced by a 2KDa heparin fragment

The influence of a low molecular weight heparin (Oligo-H, m.w. 2KDa) on ventricular arrhythmias and lethality induced by heart reperfusion following a 5 min coronary occlusion was studied in anesthetized rats. Both intravenous (i.v.) and subcutaneous (s.c.) injection of the compound doseand time-dependently prevented the reperfusion syndrome: in all salinepretreated animals post-ischemic reperfusion induced ventricular tachycardia (VT), which degenerated into ventricular fibrillation (VF) in 25 out of 30 rats, with a mortality rate of 73%; on the other hand, in rats I.V. Or s.c. pretreated with Oligo-H (20 mg/kg, 30 and 90 min, respectively, before coronary occlusion), VT occurred in 4 out of 10–11 animals and degenerated into VF in 2–3 out of 10–11 animals, with a mortality rate of 18–20%. Even more effective was a low molecular weight dermatan sulfate (Oligo-Ds, M.w. 2.1KDa). In rats treated with lidocaine, used as reference compound, at the dose of 5 mg/kg i.v. 10 min before coronary occlusion, VT occurred in 2 out of 10 animals and degenerated into VF in 1 out of 10 animals, with a mortality rate of 10%. It is concluded that low molecular weight glycosaminoglycans significantly reduce the consequences of heart reperfusion.

Thrombopénie à l'héparine sous hémodialyse en réanimation : utilisation d'un héparinoïde de bas poids moléculaire, l'ORG 10 172 (Orgaran ®)

A 48-yr-old patient was admitted to the ICU for cardiogenic shock and acute renal failure after coronary artery bypass graft surgery. A heparin-induced thrombocytopenia (HIT) occurred during haemodialysis with unfractioned heparin (UFH) as the anticoagulant. The dialysers, the circuits and the catheters were recurrently thrombosing and the platelet count decreased to 9 G · L −1 on postoperative day 7. UFH was discontinued. Attempts to substitute UFH with a low molecular weight heparin (LMWH) failed, due to the presence of a high cross-reactivity rate of LMWH with the heparin-dependent antibody. Intermittent haemodialysis without anti-coagulation using a predilution of the dialysers failed also and resulted in recurrent clotting. After informed consent of the patient, a new natural heparinoid Orgaran ® (Org 10172, Organon, Oss Holland) was administered. This agent is a mixture of several non heparin low molecular weight glycosaminoglycans, with proven anti-coagulant efficacy, low cross-reactivity with the HIT antibody, and a half-time prolonged over 18–25 hours. The treatment regimen consisted in a i.v. bolus of 40–45 IU · kg −1 prior to each dialysis procedure, performed every two days. The platelet count increased to 200 G · L −1, seven days after discontinuing heparin injection, and remained stable during the administration of Orgaran ®. No other thrombosis occurred again. Each procedure of four hours duration was monitored with the plasma anti-Xa activity and APTT test. The mean anti-Xa plasma concentrations (0.44 ± 0.55 IU · mL −1, 30 min after injection of Orgaran ®) were well correlated with APTT test (r = 0.73, p < 0.01). As the drug tends to accumulate in plasma in case of renal failure, the dose should be titrated according to the pre-dialysis plasma anti-Xa activity.

Plasma TFPI activity after intravenous injection of pentasaccharide (PS) and unfractionated heparin in rabbits

Tissue Factor Pathway Inhibitor (TFPI), is known, to be released in plasma after injection of intravenous or subcutaneous injection of heparin or low molecular weight heparin (1,2). Addition of protamine or polybrene in plasma can neutralize anticoagulant effects of heparin in vitro but not completely ex vivo in patients treated with heparin (3). It was believed for many years that this post-heparin anticoagulant effect was due to another activity released by heparin. More recently it has been shown that post-heparin anticoagulant effect could be inhibited by anti-TFPI antibodies (4). Since we have shown in a previous work (5), that in healthy volunteers, pharmacokinetics of TFPI were more closely related to anti IIa activity than anti Xa activity we hypothesized that fragments with anti-IIa activity may be required for this release, possibly from vascular wall. In order to determine if a very low molecular weight glycosaminoglycan can release TFPI in plasma, in the present study, we compared plasma TFPI amidolytic activity after intravenous injection in rabbits of pentasaccharide (PS), a synthetic fragment of very low molecular weight and with a strong and exclusive anti Xa activity, and unfractionated heparin (UFH).

Parenteral Anticoagulation with the Heparinoid Lomoparan (Org 10172) in Patients with Heparin Induced Thrombocytopenia and Thrombosis

Progressive thrombocytopenia may develop in as many as 5% of patients receiving heparin anticoagulation. In these patients, the risk of thromboembolic complications as well as continued thrombocytopenia necessitates discontinuation of heparin and initiation of an alternative anticoagulant when indicated. The heparinoid Lomoparan (Org 10172) is a mixture of several non-heparin low molecular weight glycosaminoglycans with proven anticoagulant efficacy that is generally non-reactive with platelets in the presence of plasma from patients with heparin induced thrombocytopenia, whereas standard heparin will induce platelet aggregation. We evaluated the role of heparinoid as a potential alternative anticoagulant in patients with heparin induced thrombocytopenia. During a 6 month period, we identified six patients with heparin induced thrombocytopenia who required an alternative parenteral anticoagulant, four as primary treatment for specific medical problem, and two as anticoagulation during a necessary surgical procedure. Heparinoid was used successfully in both medical and surgical patients requiring parenteral anticoagulation. In no case was there an exacerbation of the thrombocytopenia nor thromboembolic complications while on heparinoid therapy. Three of our patients sustained hemorrhagic complications, predominantly in the post-surgical setting in association with elevated anti-factor Xa levels and additional anticoagulant agents. We feel that these results confirm the utility of heparinoid anticoagulation in a select subset of patients with heparin induced thrombocytopenia who require continued parenteral anticoagulation.

DELAYED HYPERSENSITIVITY REACTION TO SUBCUTANEOUS HEPARIN

Two women developed well-demarcated eczematous and erythematous plaques localized to the injection sites of subcutaneous preservative-free heparin 72-96 h after heparin administration. The plaques resolved within a week of discontinuing the therapy. Neither epicutaneous testing with preservative-free heparin nor in vitro proliferation assays to heparin and two low molecular weight glycosaminoglycans could elicit a response in either patient. In contrast, both patients developed localized eczematous plaques 48-96 h after re-challenge with intradermal and/or subcutaneous heparin. Delayed hypersensitivity reactions to subcutaneous heparin are uncommon and have not been reported in the Australasian medical literature. Given the frequency with which heparin preparations are used, it is important for physicians and surgeons to be aware of this potential adverse reaction.