Cytokine Gene Expression in Human LPS- and IFNγ-stimulated Mononuclear Cells Is Inhibited by Heparin

The rationale for using low-molecular weight heparin in the therapy of symptomatic COVID-19 patients

Accumulated evidence suggest that the adverse outcome of severe coronavirus disease 2019 (COVID-19) is closely related to prothrombotic microvascular pathology with a high risk of venous thromboembolism. Furthermore, the first observational studies indicated that adjunct therapy with low-molecular weight heparin (LMWH) was associated with lower mortality in this cohort of patients. However, the timing of starting LMWH and the dose remain controversial in COVID-19 patients. Considering the above, the aim of this study was to reveal the rationale for using LMWH in the therapy of symptomatic COVID-19 patients based on experimental and clinical studies on LMWH in inflammatory settings with special consideration given to randomized trials.

Low-molecular-weight-heparin increases Th1- and Th17-associated chemokine levels during pregnancy in women with unexplained recurrent pregnancy loss: a randomised controlled trial

Low-molecular-weight heparin (LMWH) is widely used to treat recurrent pregnancy loss (RPL) because of its anti-coagulant effects. Although in vitro studies have suggested additional immunological effects, these are debated. We therefore investigated whether LMWH could modulate immune responses in vivo during pregnancy of women with unexplained RPL. A Swedish open multi-centre randomised controlled trial included 45 women treated with tinzaparin and 42 untreated women. Longitudinally collected plasma samples were obtained at gestational weeks (gw) 6, 18, 28 and 34 and analysed by multiplex bead technology for levels of 11 cytokines and chemokines, chosen to represent inflammation and T-helper subset-associated immunity. Mixed linear models test on LMWH-treated and untreated women showed differences during pregnancy of the Th1-associated chemokines CXCL10 (p = 0.01), CXCL11 (p < 0.001) and the Th17-associated chemokine CCL20 (p = 0.04), while CCL2, CCL17, CCL22, CXCL1, CXCL8, CXCL12, CXCL13 and IL-6 did not differ. Subsequent Student's t-test showed significantly higher plasma levels of CXCL10 and CXCL11 in treated than untreated women at gw 28 and 34. The consistent increase in the two Th1-associated chemokines suggests a potential proinflammatory and unfavourable effect of LMWH treatment during later stages of pregnancy, when Th1 immunity is known to disrupt immunological tolerance.

Insights of efferocytosis in normal and pathological pregnancy

Efferocytosis, which is known as the phagocytic clearance of dying cells by professional as well as non-professional phagocytes, including a great number of intracellular/extracellular factors and signals, is interrelated with the immune system, contributing to local and systemic homeostasis, especially in tissues with high constitutive rates of apoptosis. Accumulating studies have indicated that immune dysregulation is associated with the pathogenesis of the female reproductive system, which causes preeclampsia (PE), recurrent spontaneous abortion (RSA), ruptured ectopic pregnancy, and so on. And some studies have revealed the pleiotropic and essential role of efferocytosis in these obstetrical disorders. More specifically, the occurrence and development of these diseases were in connection with some efferocytosis-related factors and signals, such as C1q, MBL, and IL-33/ST2. In this review, we systematically review the diverse impacts of efferocytosis in immune system and discuss its relevance to normal and pathological pregnancy. These findings may instruct future basic researches as well as clinical applications of efferocytosis-related factors and signals as latent predictors or therapeutic targets on the obstetrical disorders.

Heparin inhibits intracellular Mycobacterium tuberculosis bacterial replication by reducing iron levels in human macrophages

Iron is a crucial micronutrient for both mammals and their associated pathogens, and extensive literature has shown that Mycobacterium tuberculosis (Mtb) bacilli inhibited from acquiring iron from the host are severely attenuated. In contrast, increased dietary iron concentrations or patients with hemochromatosis have long been associated with a more severe tuberculosis (TB) disease outcome. We have observed that upon macrophage infection, Mtb bacilli strongly promote intracellular iron sequestration, both through increased expression of hepcidin, a key mammalian iron regulatory protein, and downregulation of the iron exporter protein, ferroportin. Heparin is a highly sulfated glycosaminoglycan released by mast cells and basophils at sites of tissue injury. During Mtb infection, heparin alters intracellular trafficking in alveolar epithelial cells and decreases extrapulmonary dissemination but recently, heparin also has been reported to inhibit hepcidin expression in hepatocytes, decreasing intracellular iron availability. In this report, we demonstrate that heparin significantly reduces hepcidin expression in macrophages infected with Mtb bacilli. Heparin-treated macrophages have higher ferroportin expression compared to untreated macrophages, promoting iron export and decreasing iron availability to intracellular bacilli. Thus, here we describe a novel immunomodulatory effect and potential therapeutic role for heparin against mycobacterial infection in human macrophages.

Effects of low molecular weight heparin on the polarization and cytokine profile of macrophages and T helper cells in vitro

Low molecular weight heparin (LMWH) is widely used in recurrent miscarriage treatment. The anti-coagulant effects are established, while immunological effects are not fully known. Our aim was to assess LMWH effects on activation and polarization of central regulatory immune cells from healthy women, and on placenta tissues from women undergoing elective abortions. Isolated blood monocytes and T helper (Th) cells under different activation and polarizing conditions were cultured with or without LMWH. Flow cytometry showed that LMWH exposure induced increased expression of HLA-DR and CD206 in macrophages. This phenotype was associated with increased secretion of Th17-associated CCL20, and decreased secretion of CCL2 (M2-associated) and CCL22 (Th2), as measured by multiplex bead array. In accordance, LMWH exposure to Th cells reduced the proportion of CD25highFoxp3+ regulatory T-cells, intensified IFN-γ secretion and showed a tendency to increase the lymphoblast proportions. Collectively, a mainly pro-inflammatory effect was noted on two essential tolerance-promoting cells. Although the biological significancies of these in vitro findings are uncertain and need to be confirmed in vivo, they suggest the possibility that immunological effects of LMWH may be beneficial mainly at an earlier gestational age to provide an appropriate implantation process in women with recurrent miscarriage.

Low-dose intravenous heparin infusion in patients with aneurysmal subarachnoid hemorrhage: a preliminary assessment

OBJECT

Aneurysmal subarachnoid hemorrhage (aSAH) predisposes to delayed neurological deficits, including stroke and cognitive and neuropsychological abnormalities. Heparin is a pleiotropic drug that antagonizes many of the pathophysiological mechanisms implicated in secondary brain injury after aSAH.

METHODS

The authors performed a retrospective analysis in 86 consecutive patients with Fisher Grade 3 aSAH due to rupture of a supratentorial aneurysm who presented within 36 hours and were treated by surgical clipping within 48 hours of their ictus. Forty-three patients were managed postoperatively with a low-dose intravenous heparin infusion (Maryland low-dose intravenous heparin infusion protocol: 8 U/kg/hr progressing over 36 hours to 10 U/kg/hr) beginning 12 hours after surgery and continuing until Day 14 after the ictus. Forty-three control patients received conventional subcutaneous heparin twice daily as deep vein thrombosis prophylaxis.

RESULTS

Patients in the 2 groups were balanced in terms of baseline characteristics. In the heparin group, activated partial thromboplastin times were normal to mildly elevated; no clinically significant hemorrhages or instances of heparin-induced thrombocytopenia or deep vein thrombosis were encountered. In the control group, the incidence of clinical vasospasm requiring rescue therapy (induced hypertension, selective intraarterial verapamil, and angioplasty) was 20 (47%) of 43 patients, and 9 (21%) of 43 patients experienced a delayed infarct on CT scanning. In the heparin group, the incidence of clinical vasospasm requiring rescue therapy was 9% (4 of 43, p = 0.0002), and no patient suffered a delayed infarct (p = 0.003).

CONCLUSIONS

In patients with Fisher Grade 3 aSAH whose aneurysm is secured, postprocedure use of a low-dose intravenous heparin infusion may be safe and beneficial.

Evaluation of the blood compatibility of materials, cells, and tissues: basic concepts, test models, and practical guidelines

Medicine today uses a wide range of biomaterials, most of which make contact with blood permanently or transiently upon implantation. Contact between blood and nonbiological materials or cells or tissue of nonhematologic origin initiates activation of the cascade systems (complement, contact activation/coagulation) of the blood, which induces platelet and leukocyte activation. Although substantial progress regarding biocompatibility has been made, many materials and medical treatment procedures are still associated with severe side effects. Therefore, there is a great need for adequate models and guidelines for evaluating the blood compatibility of biomaterials. Due to the substantial amount of cross talk between the different cascade systems and cell populations in the blood, it is advisable to use an intact system for evaluation. Here, we describe three such in vitro models for the evaluation of the biocompatibility of materials and therapeutic cells and tissues. The use of different anticoagulants and specific inhibitors in order to be able to dissect interactions between the different cascade systems and cells of the blood is discussed. In addition, we describe two clinically relevant medical treatment modalities, the integration of titanium implants and transplantation of islets of Langerhans to patients with type 1 diabetes, whose mechanisms of action we have addressed using these in vitro models.

Effect of anticoagulation regimens on handling of interleukin-6 and -8 during continuous venovenous hemofiltration in critically ill patients with acute kidney injury

OBJECTIVE

During continuous venovenous hemofiltration (CVVH) to replace renal function in acute kidney injury (AKI), anticoagulation of the filter is routinely required. A survival benefit for citrate has been reported, possibly due to reduced proinflammatory effects of the filter (bioincompatibility). We hypothesized that the type of anticoagulation modulates the immune response to, and clearance by CVVH of interleukin-6 (IL-6) and -8 (IL-8).

METHODS

Three anticoagulation regimens were compared: trisodium citrate (n=17), unfractionated heparin (n=8) and no anticoagulation in case of bleeding tendency (n=13). Immediately before initiation of CVVH (cellulose triacetate membrane) pre-filter blood was drawn. Thereafter, at 10, 60, 180 and 720 min, samples were collected from the pre- and postfilter blood and from ultrafiltrate. IL-6 and IL-8 were determined by ELISA.

RESULTS

High inlet levels of IL-6 and IL-8, particularly in the no anticoagulation group, were associated with non-survival. The inlet concentrations and mass rates of IL-6 and IL-8 decreased during CVVH. The course of fluxes across the filter were similar for the groups, however. Although increasing in time for IL-6 in the no anticoagulation group, mass removal and adsorption of IL-6 and IL-8 were low and did not differ among the anticoagulation groups.

CONCLUSIONS

Blood to membrane contact, adsorption/clearance and anticoagulation do not increase nor attenuate high circulating levels of IL-6 and IL-8 during CVVH for AKI. This renders the hypothesis that the reported survival benefit for citrate anticoagulation is based on a reduction of bioincompatibility unlikely.

Semi-synthetic heparinoids

New chemical-enzymatic technology based on the modification of the bacterial polysaccharide K5 from Escherichia coli leads to the synthesis of a number of heparin/heparan sulfate-like molecules with different biological activities. With this technology, two families of sulfated compounds were synthesized, which differ in their uronic acid content. The first group contains only glucuronic acid, whereas the second group contains about 50% iduronic acid following epimerization by immobilized recombinant C5 epimerase. This has led to the development of various anticoagulant and nonanticoagulant K5 derivatives endowed with different - and sometimes highly specific - antitumor, antiviral, and/or anti-inflammatory activities.

Low molecular weight heparin downregulates tissue factor expression and activity by modulating growth factor receptor-mediated induction of nuclear factor-κB

Treatment of cancer patients with low molecular weight heparin (LMWH) appears to have beneficial effects. In this study, the influence of low molecular weight heparin (LMWH) on tissue factor (TF) expression and activity in five cell lines from various tissues was analysed and explored. Incubation of cells with LMWH (0-2000μg/ml) resulted in the downregulation of TF mRNA expression which was both LMWH concentration-dependent and time-dependent. Downregulation of TF was also measured as decreased cellular TF antigen and activity. Consistently, incubation of cells with LMWH suppressed the nuclear localisation and the transcriptional activity of NFκB. Decreased TF mRNA was largely achievable by incubating the cells with an NFκB inhibitor alone whilst incubation with betulinic acid to activate NFκB reversed the inhibitory influence of LMWH. Cells were also incubated with a range of concentrations of EGF (0-10ng/ml), bFGF (0-20ng/ml) or VEGF (0-4ng/ml) in the presence or absence of LMWH (200μg/ml) for 24h and TF antigen measured. Inclusion of LMWH reduced TF expression in response to EGF, bFGF or VEGF but TF expression was partially restored by increasing concentrations of the growth factors. We conclude that LMWH downregulates TF expression in vitro through a mechanism that involves interference with the function of growth factors which in turn is mediated through the downregulation of the transcriptional activity of NFκB. This mechanism may also explain some of the beneficial influences attributed to LMWH therapy in the treatment of cancer patients.

Treatment with unfractionated heparin attenuates coagulation and inflammation in endotoxemic mice

INTRODUCTION

In the pathogenesis of sepsis, inflammation and coagulation play a pivotal role. In addition to the anticoagulant activity, unfractionated heparin (UFH) has important immunomodulatory properties. However, different studies have reported conflicting effects on sepsis in association with heparin. The objective of this study is to determine whether UFH is able to reduce endotoxin-induced inflammation and coagulation in mice or produce improved outcome.

METHODS

C57BL/6J mice were randomly divided into two groups. Experimental mice were given intravenous injection of 8 units/20 g body weight UFH (heparin sodium) diluted in 20 μl sterile saline while the control mice received vehicle sterile saline only. They were injected with LPS (30 mg/kg, i.p.) 0.5h later. Blood was collected and Livers were harvested at 3 and 6h for analysis. In survival studies, a separate group of mice were treated with 8 units/20 g UFH (n=20) or sterile saline (n=20) given intravenously at 1, 12, 24 and 36 hours after LPS injection. Mice were monitored every 12 hours for a maximum of 72 hrs.

RESULTS

1) Pretreatment of mice with UFH strongly reduced the levels of TNF-α, IL-1β and TAT in plasma at 3 and 6h; 2) Pretreatment of mice with UFH inhibited the expression of TNF-α, IL-1β and tissue factor genes in blood cells at 3h; 3) UFH pretreatment dramatically diminished LPS-induced neutrophil sequestration (at 3 and 6h) , thrombi formation and fibrin(ogen) deposition in the liver (at 6h). 4) The UFH-pretreated group exhibited significantly lower levels of ALT and CRE at 6h. 5) Treatment with UFH could prevent mortality associated with endotoxin challenge.

CONCLUSION

These data suggest that UFH attenuates inflammation and coagulation and prevents lethality in endotoxemic mice.

Anti-inflammatory effects of low molecular weight heparin derivative in a rat model of carrageenan-induced pleurisy

Low molecular weight heparin derivatives are characterized by low anti-coagulant activity and marked anti-inflammatory effects that allow for these molecules to be viewed as a new class of non-steroidal anti-inflammatory drugs (NSAIDs). We show here that K5NOSepiLMW, an O-sulphated heparin-like semi-synthetic polymer of the D-glucuronic acid-N-acetyleparoson disaccharide unit with low molecular weight, has marked anti-inflammatory effects in a rat model of acute inflammation, the carrageenan-induced pleurisy, commonly used to test NSAID efficacy. A 30-min. pre-treatment with K5NOSepiLMW (0.1, 0.5 and 1 mg/kg b.wt., given intrapleurally) attenuated the recruitment of leucocytes in the lung tissue and the pleural exudate, inhibited the induction of inducible nitric oxide synthase and cyclooxygenase-2 (COX-2), thereby abating the generation of nitric oxide and pro-inflammatory prostaglandins such as PgE(2) and PGF(1alpha), reduced the inflammation-induced nitroxidative lung tissue injury, as shown by tissue thiobarbituric acid-reactive substances and nitrotyrosine, and blunted the local generation of cytokines such as interleukin-1beta and tumour necrosis factor-alpha. All these parameters were markedly increased by intrapleural carrageenan in the absence of any pre-treatment. The anti-inflammatory action of K5NOSepiLMW is specific, as judged by the lack of therapeutic effects of B4/110, a biologically inactive cognate polysaccharide, given in the place of the authentic molecule. Moreover, K5NOSepiLMW showed similar effects as celecoxib (1 mg/kg b.wt), a COX-2 inhibitor and well-known NSAID. This study provides further insight into the mechanisms underlying the beneficial effects of heparin derivatives in inflammation and identifies K5NOSepiLMW as a novel, promising anti-inflammatory drug.

Heparin and low-molecular weight heparins in thrombosis and beyond

Heparin and its improved version, low-molecular weight heparin (LMWH), are known to exert polypharmacological effects at various levels. Early studies focused on the plasma anti-Xa and anti-IIa pharmacodynamics of different LMWHs. Other important pharmacodynamic parameters for heparin and LMWH, including effects on vascular tissue factor pathway inhibitor (TFPI) release, inhibition of inflammation through NFkappaB, inhibition of key matrix-degrading enzymes, selectin modulation, inhibition of platelet-cancer cell interactions, and inflammatory cell adhesion, help explain the diverse clinical impact of this class of agents in thrombosis and beyond.

Sulodexide suppresses inflammation in human endothelial cells and prevents glucose cytotoxicity

Sulodexide is a mixture of heparin and dermatan sulfate with antithrombotic and profibrynolytic activity. Individual reports suggest the anti-inflammatory action of sulodexin. The goal of this study was to evaluate the effect of sulodexide on the release of the inflammatory mediators from endothelium in normal conditions and in cells chronically exposed to glucose. The experiments were performed on in vitro cultured human umbilical endothelial cells kept for 7 days in standard medium or in the same medium but supplemented with glucose 30 mmol/L. Sulodexide was added to the culture medium in concentrations of 0.125 lipase releasing unit (LRU)/mL, 0.25 LRU/mL, and 0.5 LRU/mL Spontaneous generation of oxygen-derived free radicals and the release of monocyte chemotactic protein-1 (MCP-1) and interleukin-6 (IL-6) from the studied cells was evaluated. Additionally, the healing of the injured mesothelium was studied in the presence of sulodexide and glucose. Sulodexide caused the inhibition of the intracellular generation of free radicals in a dose-dependent manner (maximally by 32%, P < 0.01), as well as the inhibition of MCP-1 (maximally by 60%, P < 0.001) and IL-6 (maximally by 69%, P < 0.01). Cells cultured in a medium with glucose 30 mmol/L generated more free radicals (+20%, P < 0.05) and released more MCP-1 (+113%, P < 0.001) and IL-6 (+26%, P < 0.05). Cell monolayers treated with glucose had a decreased ability to heal after mechanical injury (-28%, P < 0.001). All these glucose effects were reversed when cells were exposed to sulodexide simultaneously. The results of our study demonstrate a significant anti-inflammatory action of sulodexide in the endothelial cells and a protective effect of that drug against glucose cytotoxicity.

Production of monoclonal antibodies against the 8 kDa subunit of Echinococcus granulosus Antigen B (EgAgB8/2) using DNA immunization

Cystic echinococcosis (CE), an endemic cosmopolitan zoonotic helminthic disease caused by the larval stage of Echinococcus granulosus, lacks reliable diagnostic tools that fulfill the criteria of high sensitivity and specificity. Antigen B (AgB), a thermostable lipoprotein that constitutes a considerable fraction of the cystic hydatid fluid (HF), is being considered as a suitable source for vaccination and immunodiagnosis of CE due to its high specificity. Genetic immunization was used to immunize BALB/c mice with the second subunit of antigen B (EgAgB8/2) for the production of monoclonal antibodies (MAb). Fusion products between the spleen cells and myeloma cells produced six MAbs of the following isotypes: IgG2a (two clones), IgG2b (three clones), and IgM (one clone). The MAbs were tested for their specificity to crude sheep hydatid fluid (CSHF) versus other antigens prepared from other helminthic parasites including Toxocara canis, Acanthocheilonema viteae, Fasciola hepatica, Schistosoma mansoni, and Taenia. Five MAbs reacted with E. granulosus antigens, one showed cross reactivity with S. mansonia antigens, and one showed a high reactivity with E. granulosus but was cross reactive with all helminthic antigens tested. Using SDS-PAGE and immunoblotting under reducing conditions, all MAbs identified the four AgB subunits with molecular weights of 8, 16, 24, and 36 kDa. Further work on the specificity and sensitivity of these MAbs as well as their use in detecting circulating parasite antigens and in antigen purification will be assessed in future studies.

Heparin and EDTA as anticoagulant differentially affect cytokine mRNA level of cultured porcine blood cells

Cytokine mRNA expression profiles serve to characterize immune cell activation in different test systems. Both, diluted whole blood and isolated PBMC are widely applied for these studies. Comprehensive data regarding the suitability of different anticoagulants for profiling cytokine expression are not available for the pig. Therefore the aim of this study was to compare the effect of two commonly used anticoagulants (heparin and EDTA) on the cytokine expression pattern of porcine blood cells. IL-1alpha, IL-2, IL-4, IL-6, IL-10 and IFN-gamma mRNA levels were detected ex-vivo and upon in-vitro stimulation in diluted porcine whole blood and isolated PBMC by real-time PCR. The cells were stimulated with ConA or LPS, known to act on different target cells and implying different signalling pathways. Additionally the integrity of the isolated RNA was investigated. Ex-vivo cytokine expression pattern of fresh whole blood were not affected by the investigated anticoagulants. In contrast, stimulation of cultured diluted whole blood or PBMC resulted in significant differences depending on the applied anticoagulant. Using EDTA we found a significantly decreased capacity of whole blood to express cytokines. However, isolated PBMC from EDTA anticoagulated blood showed a higher cytokine expression capacity than PBMC from heparinized blood. Comparing diluted whole blood and PBMC we found that cultured porcine whole blood responded better to bacterial products than isolated PBMC, probably because sufficient auxiliary plasma derived factors such as LPS-binding protein, are present. However, isolated PBMC showed a higher T-cell response than diluted whole blood. In conclusion, our findings underline that each application demands a specific assay system.

The effects of high-dose heparin on inflammatory and coagulation parameters following cardiopulmonary bypass

Systemic inflammation and the activation of the coagulation system following cardiopulmonary bypass (CPB) may contribute to postoperative complications. In vitro studies have demonstrated that heparin possesses anti-inflammatory properties. To ascertain the relative benefits of high versus low heparin doses, we studied the impact of varying heparin doses on the inflammatory response and coagulation system during and following CPB. Forty patients scheduled for elective coronary artery bypass surgery requiring CPB were randomized to either a low dose (300 U/kg) (Group L) or a high dose of unfractionated heparin (600 U/kg) (Group H). To evaluate the inflammatory response, proinflammatory cytokines [tumor necrosis factor-alpha and interleukin-6 (IL-6)] were measured at four different times: before CPB (T0), 30 min after the institution of CPB (T1), 30 min after cross-clamp release (T2), and 4 h after the end of CPB (T3). Thrombin-antithrombin complex, platelet factor 4 and anti-activated factor X heparin concentrations were also measured. Patients in Group H received greater heparin (44.934 U versus 27.741 U, P<0.001) and protamine (P=0.003) doses. Postoperative blood loss and blood products transfusions were not significantly different in the groups. At T1, mean heparin plasma concentration was higher in Group H (P<0.001). IL-6 was significantly lower in Group H compared with Group L (P=0.01) only at T1. Using a mixed-effects statistical model, tumor necrosis factor-alpha and IL-6 levels were comparable regardless of the heparin dose. Thrombin-antithrombin complex levels were lower in Group H (P=0.04) and platelet factor 4 levels were significantly lower in Group H at T2 (P=0.04). Higher heparin doses were associated with higher heparin concentrations during CPB. A high heparin dose achieved a better preservation of the coagulation system with less thrombin formation and platelet activation. The heparin dose had small influence on proinflammatory cytokines release.

Low-molecular weight and unfractionated heparins induce a downregulation of inflammation: decreased levels of proinflammatory cytokines and nuclear factor-kappaB in LPS-stimulated human monocytes

Unfractionated heparin (UFH) and low-molecular weight heparin (LMWH) are well defined anticoagulant agents. Recent data suggest that both LMWH and UFH may also have potent anti-inflammatory properties; however, their mechanism of action responsible for the anti-inflammatory effect is not yet fully elucidated. This study was designed to assess the effect of LMWH and UFH on human monocytes production of inflammatory markers and nuclear translocation of nuclear factor (NF)-kappaB. Cultured monocytes were pretreated for 15 min with LMWH or UFH (10 microg and 1 microg/million cells) before stimulation with lipopolysaccharide (LPS) at a dose of 1 ng/million cells. Proinflammatory cytokines tumour necrosis factor (TNF)-alpha, interleukin (IL)-8, IL-6 and IL-1beta release were subsequently measured by enzyme-linked immunosorbent assay at 6 h, and nuclear translocation of the proinflammatory NF-kappaB was assessed at 2 h. Treatment with pharmacological doses of LMWH and UFH significantly attenuated LPS-induced production of TNF-alpha, IL-8, IL-6 and IL-1beta as well as NF-kappaB translocation. These results indicate equivalent and significant heparin anti-inflammatory properties at low doses on monocyte-mediated immune response. The inhibition of NF-kappaB activation certainly represents one of the mechanisms by which heparin exerts its anti-inflammatory effect. LMWH and UFH therefore appear as potential therapeutic inhibitors of inflammation.

Haptoglobin dampens endotoxin-induced inflammatory effects both in vitro and in vivo

We report that haptoglobin, an acute-phase protein produced by liver cells in response to interleukin-6 (IL-6), can modulate the inflammatory response induced by endotoxins. We provide evidence that haptoglobin has the ability to selectively antagonize lipopolysaccharide (LPS) effects in vitro by suppressing monocyte production of tumour necrosis factor-alpha, IL-10 and IL-12, while it fails to inhibit the production of IL-6, IL-8 and IL-1 receptor antagonist. In two animal models of LPS-induced bronchopulmonary hyperreactivity and endotoxic shock, haptoglobin knockout mice were more sensitive to LPS effects compared to their wild-type counterparts. The present data suggest that haptoglobin regulates monocyte activation following LPS stimulation. The increase in haptoglobin levels during an acute-phase reaction may generate a feedback effect which dampens the severity of cytokine release and protects against endotoxin-induced effects.

Pathogenic factors in vascular dementia and Alzheimer's disease. Multiple actions of heparin that probably are beneficial

The following areas are discussed in this review: atherogenesis; cerebrovascular factors; hypoperfusion; beta-amyloid production; beta-amyloid fibril formation; beta-sheets; metal cations; reactive oxygen species/free radicals; chronic inflammatory factors; endogenous plasma heparin; lipoprotein lipase; polyamines; protein kinase C; casein kinases; phospholipase A2; serine proteases; myeloperoxidase; cyclooxygenase 2; cysteine proteases; caspases; proprotein convertases; aspartic proteases; cyclin proteinases; thrombin; tau hyperphosphorylation; advanced glycosylation end products; activator protein 1; calcium; apolipoprotein E epsilon4; histamine; blood-brain barrier; glutamate; transglutaminase; insulin-like growth factor 1.

Cytokine gene expression and production by human LPS-stimulated mononuclear cells are inhibited by sulfated heparin-like semi-synthetic derivatives

BACKGROUND

The K5 polysaccharide obtained from Escherichia coli strain 010:K5:H4 is a polymer of the disaccharidic unit formed by D-glucuronic acid and N-acetylglucosamine. This structure is akin to N-acetylheparosan, the precursory polymer of heparin and of heparan sulfate. This structural affinity with N-acetylated heparin and with de-sulfated heparin makes the K5 polysaccharide extremely useful for the preparation of sulfated heparin-like semi-synthetic derivatives. It has been demonstrated that heparins are able to inhibit tissue factor and cytokine production and expression by human monocytes.

OBJECTIVE

The aim of this study was to evaluate the effects of four different heparin-like semi-synthetic derivatives on inflammatory cytokine production and expression by human mononuclear cells.

RESULTS

The simultaneous addition of lipopolysaccharide (LPS; 0.2 and 10 micro g mL(-1)) and the K5 polysaccharide did not inhibit interleukin (IL)-1beta, IL-6 or tumor necrosis factor (TNF)-alpha production by stimulated mononuclear cells. IL-1beta, IL-6 and TNF-alpha concentrations in supernatants of LPS-stimulated mononuclear cells were not influenced by the addition of N,O-sulfated K5 polysaccharide (K5-N, OS) and epimerized N-sulfated K5 polysaccharide (K5 NS epi) at 5 and 10 microg mL(-1), whereas the addition of epimerized N,O-sulfated K5 polysaccharide (K5-N, OS epi) (5 and 10 microg mL(-1)) and O-sulfated K5 polysaccharide (K5-OS) (5 and 10 microg mL(-1)) to LPS-stimulated cells caused a significant dose-dependent inhibition of IL-1beta, IL-6 and TNF-alpha. All sulfated heparin-like semi-synthetic derivatives did not influence the IL-10 production by LPS-stimulated mononuclear cells. In LPS-stimulated cells (0.2 and 10 microg mL(-1)), K5-OS or K5-N, OS epi at 5 and 10 microg mL(-1) markedly decreased TNF-alpha mRNA expression.

CONCLUSIONS

These results indicate that the sulfated heparin-like semi-synthetic derivatives K5-OS and K5-N, OS epi are able to inhibit both expression and production of inflammatory cytokines, whereas they do not influence the anti-inflammatory cytokine IL-10, suggesting a potential role for these products as modulators of inflammatory reactions.

Heparin inhibits lipopolysaccharide (LPS) binding to leukocytes and LPS-induced cytokine production

The glycosaminoglycan heparin is known to exhibit anti-inflammatory properties unrelated to its anticoagulant activity. However, in a generalized inflammatory response with implanted or extracorporeal devices, the beneficial effect of heparin coating and/or systemic administration is still unclear as well as the precise mechanisms of action. In the present study, we have first studied the effect of heparin on lipopolysaccharide (LPS)-induced cytokine production by human blood monocytes. Our results indicated that the production of interleukin-1alpha, tumor necrosis factor-alpha, and interleukin-8 was significantly decreased when heparin was simultaneously incubated with Escherichia coli LPS. Because the modulation of heparin on monocyte activation could be mediated by its binding via CD14, the main LPS receptor on monocytes, we then studied the binding of LPS and heparin to leukocytes from human blood and to Chinese hamster ovary cells transfected with the human CD14 gene. The data by flow cytometry showed the binding of biotinylated heparin to leukocytes. Moreover, the experiments performed on leukocytes and on CD14-positive Chinese hamster ovary cells indicated that heparin inhibited LPS binding. From our results, we conclude that: 1. heparin is an effective inhibitor of LPS-induced monocyte activation, and 2. heparin inhibits the binding of LPS to cells via a CD14-independent pathway. This study suggests a potentially important therapeutic application for heparin or heparin analogs to prevent inflammation with biomaterials.

Dalteparin sodium prevents liver injury due to lipopolysaccharide in rat through suppression of tumor necrosis factor-alpha production by Kupffer cells

BACKGROUND

Sensitization of Kupffer cells (KC) to lipopolysaccharide (LPS) and overproduction of tumor necrosis factor (TNF)-alpha play important roles in the pathogenesis of alcoholic liver damage and sepsis-associated organ injury. Therefore, suppression of TNF-alpha should prove useful for treatment of LPS-induced liver injury. Recently, heparin has been reported to diminish TNF-alpha production from macrophages in response to LPS. Dalteparin sodium (DS) is a low-molecular-weight heparin with a mean molecular weight of 5,000. DS elicits an antithrombotic effect through a mechanism depending on anti-factor Xa activity but not on the antithrombin activity. DS is thus suitable for treatment of disseminated intravascular coagulation because it has a much smaller prohemorrhagic property. In this study, we evaluated whether DS could prevent LPS-induced liver injury.

METHODS

Female Wistar rats were administered DS (50 IU/kg intraperitoneally) followed by challenge with LPS (5 mg/kg intravenously) 2 hr later. Livers and sera were collected 24 hr later. KC from rats were isolated and cultured in RPMI 1640 supplemented with 10% fetal bovine serum. After the addition of LPS (10 microg/ml) to the culture media, intracellular Ca2+ was measured by using a fluorescent indicator, fura-2.

RESULTS

LPS (5 mg/kg intravenously) caused focal necrosis and neutrophil infiltration in the control liver. The histological changes and increased alanine aminotransferase levels caused by LPS injection were diminished by treatment with DS. LPS increased intracellular Ca2+ of KC in control rats from the basal level (26 +/- 6 nmol/liter) to 280 +/- 18 nmol/liter. This increase was blunted by DS (126 +/- 28 nmol/liter). The DS treatment decreased the LPS-induced TNF-alpha production by KC from 911 +/- 78 pg/ml to 309 +/- 45 pg/ml (p < 0.05).

CONCLUSIONS

These results indicate that DS reduces the LPS-induced liver injury through suppression of TNF-alpha production.

Tumor necrosis factor-alpha production in whole blood after cardiopulmonary bypass: downregulation caused by circulating cytokine-inhibitory activities

OBJECTIVES

Cardiopulmonary bypass is associated with the release of proinflammatory cytokines (tumor necrosis factor alpha, interleukin 1beta, interleukin 6, and interleukin 8) and anti-inflammatory cytokines (interleukin 10 and transforming growth factor beta(1)). On the one hand this cytokine release is related to the postoperative systemic inflammatory response syndrome, and on the other hand it is related to deterioration of the immune system, for example in monocyte or polymorphonuclear neutrophil function, leading to an increased susceptibility to infections. To gain further insight into the alterations of immune cell reactivity and possible regulatory mechanisms, we studied lipopolysaccharide-induced tumor necrosis factor alpha synthesis in whole blood from cardiac surgical patients.

METHODS

Fifteen patients undergoing elective heart surgery with cardiopulmonary bypass were included in the study. Ex vivo lipopolysaccharide-induced tumor necrosis factor alpha synthesis was measured in a whole blood assay before, during, and after bypass. Corresponding tumor necrosis factor alpha messenger RNA levels were determined by semiquantitative reverse transcriptase-polymerase chain reaction. In addition, the influence of patient serum on whole blood responsiveness and its relationship to anti-inflammatory cytokines were evaluated in vitro.

RESULTS

Tumor necrosis factor alpha synthesis was significantly reduced after 30 minutes of cardiopulmonary bypass and showed the lowest values at the end of bypass (mean +/- SD 0.109 +/- 0.105 ng/10(6) white blood cells after 30 minutes of bypass and 0.050 +/- 0.065 ng/10(6) white blood cells at the end of bypass, vs 0.450 +/- 0.159 ng/10(6) white blood cells preoperatively, P <.001). As a further indication of reduced cytokine biosynthesis, diminished messenger RNA levels for tumor necrosis factor alpha were detected. Serum withdrawn from patients at the end of cardiopulmonary bypass reduced tumor necrosis factor alpha synthesis in heterologous blood from healthy volunteers highly significantly to 39.93% +/- 23.18% relative to control serum (P =.005) and preoperatively drawn serum (P =.024). This effect was dose dependent and was not specific for lipopolysaccharide-induced tumor necrosis factor alpha synthesis. Anesthesia and heparin administration did not influence tumor necrosis factor alpha production significantly. Ex vivo tumor necrosis factor alpha synthesis was negatively related to interleukin 10 serum levels, positively but weakly related to interleukin 4, and was not related to transforming growth factor beta(1) (Spearman correlation coefficients -0.565, P <.001, 0.362, P <.001, and -0.062, P =.460, respectively). However, interleukin 10 levels in patient serum after cardiopulmonary bypass were 300-fold below the quantities needed for half-maximal inhibition of tumor necrosis factor alpha synthesis in vitro. Moreover, the inhibitory activity could not be removed by immune absorption of interleukin 10.

CONCLUSIONS

These results suggest that during cardiac operations cytokine-inhibitory serum activities are released or newly formed. These activities could not be explained by the actions of interleukins 4 and 10 or transforming growth factor beta(1). Although their exact nature remains undetermined, these substances may contribute to the diminished immune cell functions after cardiopulmonary bypass and thus need further characterization.

Heparin-like polymers modulate proinflammatory cytokine production by lipopolysaccharide-stimulated human monocytes

The search for heparin-like materials remains an intensive field of research. In this context, we studied the immunomodulatory properties of semisynthetic dextran derivatives and naturally occurring sulfated polysaccharides present in brown seaweed (fucans). In this study, we investigated the functional potencies of fucan and dextran derivatives by analyzing their effects on the release of proinflammatory cytokines by resting or lipopolysaccharide (LPS)-stimulated human monocytes and their interactions on monocyte surfaces. The results showed that fucan, dextran derivatives, and heparin differentially (1) triggered interleukin-1alpha, tumor necrosis factor alpha, interleukin-6, and interleukin-8 production by monocytes in a dose-dependent manner, (2) modulated cytokine production by LPS-stimulated monocytes, and (3) specifically inhibited the binding of biotinylated LPS to monocyte membranes. Taken together, these data indicated that fucan and dextran derivatives displayed interesting immunomodulatory effects on human blood cells that could be relevant as new drugs or biomaterial coatings. Indeed, such polysaccharides, by regulating monocyte activation, could contribute to the improved biocompatibility of implants.

Hypotension during septic shock does not correlate with exhaled nitric oxide in anesthetized rat

Sepsis is characterized by hypotension, acidosis, and increased nitric oxide (NO) production. The role of NO in the development of sepsis-related hypotension is still unclear. The relationship among exhaled nitric oxide (ENO), arterial blood pressure (BP), and pH after administration of lipopolysaccharide (LPS) and tumor necrosis factor alpha (TNFalpha) was investigated in anesthetized rats. Forty-three adult male Sprague-Dawley rats were randomized into five groups: group 1 (C, n = 8) received normal saline; group 2 (LPS-I, n = 8) received Escherichia coli (LPS) 10 mg/kg intravenously (i.v.); group 3 (LPS-h, n = 10) received 100 mg/kg LPS i.v.; group 4 (n = 9) was treated with 100 mg/kg i.v. aminoguanidine (AG) 1 h after receiving 100 mg/kg i.v. LPS; group 5 (TNFalpha, n = 8) received 1 microg recombinant rat TNFalpha i.v.. ENO, BP, and pH were measured every 30 min for 4 h whereas arterial blood gases and pH were measured every hour. LPS administration induced a dose-related increase in ENO and a dose-related decrease in BP and pH. AG blocked the increase in ENO after LPS but had minimal effect on BP and pH. TNFalpha administration increased ENO without changing BP and pH. In LPS-treated rats, no significant correlation was found between ENO and BP (r2 = 0.13, P= ns). However, there was a significant correlation between pH and BP (r2 = 0.7, P < 0.01). Our results suggest that, in this animal model, ENO may not be a key mediator in the development of systemic hypotension during sepsis, while acidosis may significantly contribute to it.

Novel COL6A1 splicing mutation in a family affected by mild Bethlem myopathy

Bethlem myopathy is an early-onset benign myopathy characterized by proximal muscular weakness and multiple flexion contractures. It is a dominantly inherited disorder associated with mutations in the three COL6 genes encoding type VI collagen. We detected a g-->a substitution at +1 position of COL6A1 intron 3 in a four-generation Italian family affected by a mild form of Bethlem myopathy. The mutation results in the activation of a cryptic splice donor site at the 3' end of exon 3, leading to the loss of 66 nucleotides and an "in-frame" deletion of 22 amino acids in the NH2-domain. Molecular analysis on fibroblasts of the propositus showed that the mutated mRNA was present and stable, but the mutated protein could not be detected. Western blot and immunofluorescence analyses showed a decreased level of collagen VI synthesis and deposition in fibroblasts of the propositus. Together, the results suggest that the mutated protein was highly unstable and rapidly degraded, and that the mild phenotype was caused by a reduced amount of normal collagen VI microfibrils. In addition, we demonstrated that lymphocytes can be used for the first mutation screening analysis of patients with Bethlem myopathy.

Endogenous heparin activity deficiency: the 'missing link' in atherogenesis?

This paper reviews published studies since 1995 dealing with many atherogenic mechanisms where exogenous heparin was beneficial. In these areas endogenous heparin deficiency is likely to be harmful. Mechanisms included inflammatory factors, lower endogenous plasma heparin levels, lipoprotein lipase, chemokines, APOE e4, lipoprotein(a), among others. Demonstrated reduction of heparan sulfate proteoglycans (HSPG) and of endogenous plasma heparin was reviewed.

Treatment of chronic renal allograft rejection in rats with a low-molecular-weight heparin (reviparin)

BACKGROUND

Low-molecular-weight heparin (LMWH) has been shown to prolong survival of rat cardiac allografts independently from immunosuppressive treatment. Furthermore, long-term treatment reduces the development of chronic graft vascular disease after experimental heart transplantation. The aim of the present study was to determine whether treatment with the LMWH reviparin has a beneficial effect on chronic rejection in a rat renal allograft model.

METHODS

Kidneys of Fisher (F344) rats were transplanted into unilaterally nephrectomized Lewis (LEW) recipients. LEW-->LEW isografts served as controls. Animals were treated with cyclosporine (5 mg/kg/d) for the first 10 days. Nephrectomy of the remaining kidney was performed after 10 days. Allografted animals were treated either with reviparin (2 mg/kg/d subcutaneously) for 24 weeks (Allo-24), from week 12 to 24 (Allo-12), or with vehicle for 24 weeks. Proteinuria was determined at regular intervals. Kidneys were harvested after 24 weeks for histomorphological and immunohistochemical evaluation.

RESULTS

No major bleeding complications were observed in reviparin-treated animals. Proteinuria was significantly reduced in allografted animals both by early as well as by late-onset treatment with reviparin. Transplant glomerulopathy was diminished in Allo-24 and in Allo-12 groups compared to vehicle-treated animals, whereas tubulointerstitial inflammation was influenced only in animals immediately treated with reviparin. Immunohistochemical studies demonstrated a marked reduction of renal monocyte and T-cell infiltration as well as expression of MHC II by treatment with reviparin.

CONCLUSIONS

Treatment with the LMWH reviparin significantly improved chronic renal allograft rejection in the F344-to-LEW rat model, both after early and late start of therapy. Although the exact mechanisms of this beneficial effect remain unclear, our data offer a potential new therapeutical approach for prevention of chronic allograft nephropathy.

Gene monitoring of surface-activated monocytes in circulating whole blood using duplex RT-PCR

Previous studies have shown that blood-contacting materials activate blood monocytes. The aim of this study is to evaluate a highly sensitive technique for detecting changes at the mRNA level in circulating monocytes and to find suitable "gene markers" for assessing the hemocompatibility of biomaterials. Human blood was recirculated in a modified Chandler Loop formed of test tubes. Five groups of biomaterials were compared. Monocytes were separated by using magnetic beads, and gene expression analyses were performed using RT-PCR. We investigated the mRNA expression of stress proteins (hsp70) and inflammatory markers (IL-1alpha, IL-1beta, IL-6, TNF-alpha). mRNAs for cytokines were highly upregulated in LPS-stimulated monocytes. Hsp70 transcripts were upregulated after heat shock but were not influenced by treatment with LPS. The gene expression of the cytokines was affected by various biomaterials. The intensity of the inflammatory response increased in the following order: heparin coatings (PVC) < uncoated PVC < silicone, polypeptide-coated PVC. No change was seen in the expression of the hsp70 genes. An inhibitory effect of systemic heparin on surface-activated monocytes was observed for the mRNA expression of the cytokines. The recirculation of human blood in an in vitro model in combination with the immunomagnetic separation of monocytes and the Duplex RT-PCR method is a powerful tool for getting reliable results. Our data demonstrate that hsp70 genes cannot be recommended for short-term, biomaterial-induced mRNA expression studies. Conversely, mRNAs for IL-1alpha, IL-1beta, IL-6, and TNF-alpha were expressed in a material-dependent manner. Thus our model provides an effective tool for assessing the hemocompatibility of biomaterials before their clinical application and it also can serve as a safety control during the industrial manufacturing process. This method can be applied to various blood cell populations and numerous gene expression studies and may enable a more fundamental understanding of the biologic processes involved in blood-material interactions.

Differential effects of heparin on NO and tumor necrosis factor-alpha production in bovine blood mononuclear cells stimulated with Salmonella typhimurium lipopolisaccharide

We investigated the influence of heparin, one of the extracellular matrix (ECM) components, on nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) production by bovine peripheral blood mononuclear cells (PBMC) and monocytes left to adhere for 2 (freshly adherent monocytes) and 48 h (resting monocytes), activated with Salmonella typhimurium lipopolysaccharide (LPS). After 24-h stimulation with LPS, heparin (100 microg/ml) increased (by about 40%) NO production by peripheral blood mononuclear cells and by freshly adherent monocytes. However, it did not change NO synthesis by the resting monocytes. Unlike its influence on NO level, heparin diminished TNF-alpha production by PBMC and monocytes stimulated with LPS. Microscopical examination of PBMC stained with biotin-labeled heparin, showed that both lymphocytes and monocytes were able to bind this glycosaminoglycan. We suggest that heparin, as a component of ECM, modulates the early response of monocytes to exogenous stimuli.

Ullrich scleroatonic muscular dystrophy is caused by recessive mutations in collagen type VI

Ullrich syndrome is a recessive congenital muscular dystrophy affecting connective tissue and muscle. The molecular basis is unknown. Reverse transcription-PCR amplification performed on RNA extracted from fibroblasts or muscle of three Ullrich patients followed by heteroduplex analysis displayed heteroduplexes in one of the three genes coding for collagen type VI (COL6). In patient A, we detected a homozygous insertion of a C leading to a premature termination codon in the triple-helical domain of COL6A2 mRNA. Both healthy consanguineous parents were carriers. In patient B, we found a deletion of 28 nucleotides because of an A --> G substitution at nucleotide -2 of intron 17 causing the activation of a cryptic acceptor site inside exon 18. The second mutation was an exon skipping because of a G --> A substitution at nucleotide -1 of intron 23. Both mutations are present in an affected brother. The first mutation is also present in the healthy mother, whereas the second mutation is carried by their healthy father. In patient C, we found only one mutation so far-the same deletion of 28 nucleotides found in patient B. In this case, it was a de novo mutation, as it is absent in her parents. mRNA and protein analysis of patient B showed very low amounts of COL6A2 mRNA and of COL6. A near total absence of COL6 was demonstrated by immunofluorescence in fibroblasts and muscle. Our results demonstrate that Ullrich syndrome is caused by recessive mutations leading to a severe reduction of COL6.

Fibrillin-1 (FBN1) gene frameshift mutations in Marfan patients: genotype-phenotype correlation

Marfan syndrome (MFS) is a multisystemic disease associated with mutations in the fibrillin-1 gene. Most of the reported mutations are missense substitutions mainly affecting the epidermal growth factor (EGF)-like protein domain structure and the calcium-binding (cb) site. The aim of our study was to investigate the correlation between fibrillin-1 frameshift mutations and the clinical phenotype in patients affected by MFS. In 48 out of 66 Marfan patients a pathogenetic mutation was found. We detected novel mutations causing premature termination codon in exons 19, 37, 40 and 41 of four Italian patients. The first mutation in exon 19 (cbEGF #8 domain) results in a clinical phenotype involving mainly the skeletal and cardiovascular systems. Interestingly, we noticed that, while mutations in exons 37 and 41 (eight cysteine domains #4 and #5) are milder, the mutation in exon 40 (cbEGF #24 domain) is more severe and causes major cardiovascular involvement with thoracic and abdominal aortic aneurysms. It is noteworthy that the degree of the severity in the phenotype of one of our patients and another from the literature carrying a mutation in exon 41 could be explained with alterations in mRNA expression.

Heparin inhibits reactive oxygen species generation by polymorphonuclear and mononuclear leucocytes

To examine the hypothesis that heparin may affect leukocyte function and that it may have anti-inflammatory properties, we investigated the effect of heparin on reactive oxygen species (ROS) generation by leucocytes. Heparin was injected intravenously at a dose of 10000 units into eight normal subjects. Blood samples were collected from the antecubital vein sequentially, prior to and following heparin at 0, 0.5, 1, 2, and 4 hours. ROS generation was inhibited significantly by polymorphonuclear cells (PMNL) at 0.5, 1, and 2 hours and returned to baseline level at 4 hours. Similarly, ROS generation was inhibited markedly by mononuclear cells (MNC) at 0.5 hours, with a peak inhibition at 1 hour; it returned to baseline level by 4 hours. The maximum inhibition of ROS generation by PMNL was 57.3+/-19% of the basal, while that by MNC was 56.4+/-11% of the basal. Since ROS are proinflammatory and cause tissue damage, it is possible that heparin may have an anti-inflammatory effect in vivo, apart from its antithrombotic effect. Since ROS also bind to nitric oxide (NO) and reduce the bioavailability of NO, heparin may indirectly increase the bioavailability of NO and thus act as a vasodilator. This effect of heparin may be of particular relevance to its use in unstable angina and following thrombolysis in acute myocardial infarction in preventing reperfusion injury.

A novel de novo mutation in the triple helix of the COL6A3 gene in a two-generation Italian family affected by Bethlem myopathy. A diagnostic approach in the mutations' screening of type VI collagen

Bethlem myopathy is an autosomal dominant inherited disease producing a mild neuromuscular disorder, characterized mainly by muscular weakness and multiple joint contractures. Bethlem myopathy is caused by mutations in one of the three chains of collagen type VI. Here we report the clinical description and the molecular characterization of the defect in a two-generation Italian family in which a Gly-->Arg substitution disrupts the triple helix structure of the alpha 3 chain of collagen type VI, an ubiquitous glycoprotein of the extracellular matrix. In this family the identification of the mutation also allowed one to exclude the disease in the grandfather. It is noteworthy that the father of the proband carries a de novo mutation, the first described for Bethlem myopathy.

A heterozygous splice site mutation in COL6A1 leading to an in-frame deletion of the alpha1(VI) collagen chain in an italian family affected by bethlem myopathy

Bethlem myopathy is a mild neuromuscular disorder with proximal muscular weakness and early flexion contractures. It is an autosomal dominant disease due to mutations in type VI collagen genes. We found a T-->C substitution at the +2 position of COL6A1 intron 14 in a family, leading to skipping of exon 14 and an in-frame deletion of 18 amino acids in the triple-helical domain of the alpha1(VI) collagen chain. The deletion included a cysteine residue believed to be involved in the assembly of type VI collagen dimers intracellularly, prior to the protein secretion. Analysis of the affected fibroblasts showed that the shortened alpha1(VI) collagen chains were synthesized but not secreted by the cells and that the amount of type VI collagen microfibrils deposited by the cells was reduced. The results suggest that the clinical phenotype is due to a reduction in the level of type VI collagen in the extracellular matrix.

Effect of low-dose heparin on fibrinogen levels in patients with chronic ischemic heart disease

Several prospective studies have demonstrated that high plasma fibrinogen levels are associated with an increased risk of ischemic heart disease. Since in most patients an increased thrombin generation has been reported, we investigated whether the control of thrombin generation could affect plasma fibrinogen levels. Forty male outpatients (20 asymptomatic with previous myocardial infarction and 20 with stable effort angina) were enrolled in a randomized medium-term (6 months) cross-over study. Clottable fibrinogen, according to Clauss, prothrombin fragment 1 + 2, thrombin-antithrombin complex, and fibrinopeptide A were evaluated in relation to treatment with low-dose heparin. After a 15-day wash-out period, during which patients had been treated only with nitrates if needed, patients were allocated to two sequential periods of treatment with standard heparin (12,500 U, subcutaneously daily) plus antianginal treatment or antianginal treatment alone, separated by a second 15-day wash-out period. At the end of the treatment period with low-dose heparin significant decreases in the plasma fibrinogen (2.5 +/- 0.6 g/l vs. 3.3 +/- 0.5 g/l, P < 0.001), prothrombin fragment 1 + 2 (1.4 +/- 0.5 nmol/l vs. 1.9 +/- 0.7 nmol/l, P < 0.001), thrombinantithrombin (4.5 +/- 2.4 ng/ml vs. 9.7 +/- 3.6 ng/ml, P < 0.001), and fibrinopeptide A (2.1 +/- 1.1 ng/ml vs. 3.5 +/- 2.1 ng/ml, P < 0.001) were observed compared with the period without heparin. The present results indicate that low-dose heparin can effectively control the increased abnormal thrombin generation and elevated fibrinogen levels in patients with ischemic heart disease, possibly decreasing the risk of cardiovascular death.