Recurrent thrombosis rescued by fondaparinux in high-risk patients: A case series.

Background: Recurrent thrombosis treatment options are limited when anticoagulation with dose escalation of low molecular weight heparin or unfractionated heparin fail. Fondaparinux is a pure, synthetic pentasaccharide that consists of heparin's essential five-sugar chain that binds antithrombin to inactivate factor Xa. There is scarce data regarding fondaparinux's use in recurrent thrombosis. Key Clinical Question: We aim to explore fondaparinux's role in recurrent thrombosis when other standard anticoagulation treatments fail. Clinical Approach: We report a case series of six high thrombotic risk patients successfully treated with fondaparinux after thrombosis progression while on supratherapeutic low molecular weight heparin or unfractionated heparin. Of our six patients, two were previously diagnosed with a high-risk thrombophilia: triple positive antiphospholipid syndrome, and homozygous factor V Leiden. The other four had an underlying malignancy. Conclusion: With fondaparinux, no thrombosis progression was observed, and no bleeding complications occurred.

In-situ follicular neoplasia: a clinicopathological spectrum.

AIMS: In-situ follicular neoplasia (ISFN) occurs in approximately 2-3% of reactive lymph nodes, and is currently set apart from 'partial involvement by follicular lymphoma' (PFL). ISFN can progress to overt lymphoma, but precise parameters with which to assess this risk and its association with related diseases remain incompletely understood. The aim of this study was to explore these parameters. METHODS AND RESULTS: We reviewed 11 cases of ISFN and one of PFL between 2003 and 2018. Ten patients had ISFN in the lymph nodes, and one had ISFN in the spleen. Haematoxylin and eosin and immunohistochemical stains were reviewed. Involvement of follicles by ISFN was scored with a three-tier scheme. Of five patients with low ISFN scores, one had chronic myelomonocytic leukaemia, one had mycosis fungoides, and three were free of haematopoietic disease. Among them, four are alive and one was lost to follow-up. Of the six ISFN patients with high scores, two had concurrent marginal zone lymphomas, one had concurrent diffuse large B-cell lymphoma (DLBCL), one had Castleman-like disease, one had progressive transformation of germinal centres with IgG4-related disease, and one had no haematopoietic disease; all are alive except for one who died of concurrent DLBCL. The patient with PFL developed DLBCL 7 years after diagnosis. CONCLUSIONS: On the basis of this limited series, we conclude that only cases with high scores are associated with an overt lymphoma or an abnormal lymphoid process, and that scoring may be a useful parameter with which to assess the risk of associated lymphoma, and deserves further study. We also performed a comprehensive review of the literature.

Antithrombotic agents and traumatic brain injury in the elderly population: hemorrhage patterns and outcomes.

OBJECTIVE: Among the elderly, use of antithrombotics (ATs), antiplatelets (APs; aspirin, clopidogrel), and/or anticoagulants (ACs; warfarin, direct oral ACs [DOACs; dabigatran, rivaroxaban, apixaban]) to prevent thromboembolic events must be carefully weighed against the risk of intracranial hemorrhage (ICH) with trauma. The goal of this study was to assess the risk of sustaining a traumatic brain injury (TBI), ICH, and poorer outcomes in relation to AT use among all patients 65 years or older presenting to a single institution with head trauma. METHODS: Data were collected from all head trauma patients 65 years or older presenting to the authors' supraregional tertiary trauma center over a 24-month period and included age, sex, injury mechanism, medical history, international normalized ratio, Glasgow Coma Scale (GCS) score, ICH presence and type, hospital admission, reversal therapy, surgery, discharge destination, Extended Glasgow Outcome Scale (GOSE) score at discharge, and mortality. RESULTS: A total of 1365 head trauma patients 65 years or older were included; 724 were on AT therapy (413 on APs, 151 on ACs, 59 on DOACs, 48 on 2 APs, 38 on AP+AC, and 15 on AP+DOAC) and 641 were not. Among all head trauma patients, the risk of sustaining a TBI was associated with AP use after adjusting for covariates. Of the 731 TBI patients, those using ATs had higher rates of ICH (p <0.0001), functional dependency at discharge (GOSE score ≤ 4; p < 0.0001), and mortality (p < 0.0001). Elevated rates of ICH progression on follow-up CT scanning were observed in patients in the warfarin monotherapy (OR 5.30, p < 0.0001) and warfarin + AP (OR 6.15, p = 0.0011). Risk of mortality was not associated with single antiplatelet use but was notably high with 2 APs (OR 4.66, p = 0.0056), warfarin (OR 5.18, p = 0.0003), and DOAC use (OR 5.09, p = 0.0149). CONCLUSIONS: Elderly trauma patients on ATs, especially combination therapy, are at elevated risk of ICH and poor outcomes compared with those not on AT therapy. While both AP and warfarin use alone and in combination were associated with significantly elevated odds of sustaining an ICH among TBI patients, only warfarin use was a predictor of hemorrhage progression on follow-up scans. The use of a single AP was not associated with mortality; however, the combination of both aspirin and clopidogrel was. Warfarin and DOAC users had comparable mortality rates; however, DOAC users had lower rates of ICH progression, and fewer survivors were functionally dependent at discharge than were warfarin users. DOACs are an overall safer alternative to warfarin for patients at high risk of falls.

Osteonecrosis of the femoral head: genetic basis.

PURPOSE: Genetic factors and hereditary forms of osteonecrosis of the femoral head (ONFH) have been elucidated through genetic association studies. The significance of these cases is that they suggest an alternative hypothesis to the development of the disease. This review presents a summary of single nucleotide polymorphisms (SNPs) and other genetic mutation variations found in association with ONFH, including our recent identification of a novel mutation in the transient receptor potential vanilloid 4 (TRPV4) gene in association with inherited ONFH. The purpose of this review is to consolidate and categorize genetic linkages according to physiological pathways. METHODS: A systematic review of literature from PubMed and Google Scholar was undertaken with a focus on genetic linkages and hereditary case studies of the disease. Recent genetic analysis studies published after 2007 were the focus of genetic linkages in non-hereditary cases. RESULTS: The summary of these genetic findings identifies biological processes believed to be involved in the development of ONFH, which include circulation, steroid metabolism, immunity, and the regulation of bone formation. CONCLUSION: Taken together, these associations may lead to new pathways of bone repair and remodeling while opening new avenues for therapeutic targets. Knowledge of genetic variations could help identify individuals considered to be at higher risk of developing ONFH and prevent the multiple hit effect.

Substrain-specific differences in bone parameters, alpha-2-macroglobulin circulating levels, and osteonecrosis incidence in a rat model.

Osteonecrosis of the femoral head (ONFH) is a potentially devastating complication that occurs in up to 40% of young adults receiving chronic glucocorticoid (GC) therapy. Through a validated GC therapy rat model, we have previously shown that Wistar Kyoto (WK) rats exhibit a genetic susceptibility to GC-induced ONFH compared to Sasco Fischer (F344) rats. We have undertaken this study in order to investigate differences between these two strains for their bone parameters, alpha-2-macroglobulin (A2M) circulating levels and incidence of GC-induced osteonecrosis of the femoral head. WK and F344 rats were treated either with 1.5 mg/kg/day of prednisone or placebo for 6 months. Blood was taken every month. The femoral heads were harvested for histological examination to detect ONFH and analyzed with micro-computed tomography. After 3 months of GC-therapy, plasma A2M was elevated in treated rats only. GC-treated WK rats exhibited histological evidence of early ONFH through higher rates of cellular apoptosis and empty osteocyte lacunae in the subchondral bone compared to placebos and to F344 rats. Furthermore, micro-CT analysis exhibited femoral head collapse only in GC-treated WK rats. Interestingly, GC-treated F344 rats exhibited significant micro-CT changes, but such changes were less concentrated in the articular region and were accompanied histologically with increased marrow fat. These µCT and histological findings suggest that elevated A2M serum level is not predictive and suitable as an indicative biomarker for early GC-induced ONFH in rodents. Elevated A2M levels observed during GC treatment suggests that it plays role in the host reparative response to GC-associated effects. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1183-1194, 2017.

The PETALE study: Late adverse effects and biomarkers in childhood acute lymphoblastic leukemia survivors.

BACKGROUND: Childhood cancer survivorship issues represent an established public health challenge. Most late adverse effects (LAEs) have been demonstrated to be time and treatment dependent. The PETALE study is a multidisciplinary research project aiming to comprehensively characterize LAEs and identify associated predictive biomarkers in childhood acute lymphoblastic leukemia (cALL) survivors. METHODS: cALL survivors treated at Sainte-Justine University Health Center with Dana-Farber Cancer Institution-ALL protocols 87-01 through 2005-01 were eligible. During Phase I of the study, the participants underwent comprehensive clinical, biologic, and psychosocial investigation targeting metabolic syndrome, cardiotoxicity, bone morbidity, neurocognitive problems, and quality of life issues. Whole-exome sequencing was performed for all participants. Subjects identified with an extreme phenotype during Phase I were recalled for additional testing (Phase II). RESULTS: Phase I included 246 survivors (recall rate 71.9%). Of those, 85 participants completed Phase II (recall rate 88.5%). Survivors agreeing to participate in Phase I (n = 251) were similar to those who refused (n = 31) in terms of relapse risk profile, radiotherapy exposure, and age at the time of study. Participants, however, tended to be slightly older at diagnosis (6.1 vs. 4.7 years old, P = 0.08), with a higher proportion of female agreeing to participate compared with males (93.2 vs. 86.5%, P = 0.07). CONCLUSION: The PETALE study will contribute to comprehensively characterize clinical, psychosocial, biologic, and genomic features of cALL survivors using an integrated approach. Expected outcomes include LAE early detection biomarkers, long-term follow-up guidelines, and recommendations for physicians and health professionals.

Gain-of-function mutation in TRPV4 identified in patients with osteonecrosis of the femoral head.

BACKGROUND: Osteonecrosis of the femoral head is a debilitating disease that involves impaired blood supply to the femoral head and leads to femoral head collapse. METHODS: We use whole-exome sequencing and Sanger sequencing to analyse a family with inherited osteonecrosis of the femoral head and fluorescent Ca(2+) imaging to functionally characterise the variant protein. RESULTS: We report a family with four siblings affected with inherited osteonecrosis of the femoral head and the identification of a c.2480_2483delCCCG frameshift deletion followed by a c.2486T>A substitution in one allele of the transient receptor potential vanilloid 4 (TRPV4) gene. TRPV4 encodes a Ca(2+)-permeable cation channel known to play a role in vasoregulation and osteoclast differentiation. While pathogenic TRPV4 mutations affect the skeletal or nervous systems, association with osteonecrosis of the femoral head is novel. Functional measurements of Ca(2+) influx through mutant TRPV4 channels in HEK293 cells and patient-derived dermal fibroblasts identified a TRPV4 gain of function. Analysis of channel open times, determined indirectly from measurement of TRPV4 activity within a cluster of TRPV4 channels, revealed that the TRPV4 gain of function was caused by longer channel openings. CONCLUSIONS: These findings identify a novel TRPV4 mutation implicating TRPV4 and altered calcium homeostasis in the pathogenesis of osteonecrosis while reinforcing the importance of TRPV4 in bone diseases and vascular endothelium.

Screening for thrombophilia does not identify patients at risk of portal or splenic vein thrombosis following laparoscopic splenectomy.

BACKGROUND: Portal and/or splenic vein thrombosis (PSVT) is a potentially lethal complication of splenectomy for hematologic disease. Known risk factors for PSVT include malignancy and splenomegaly. While these patients are believed to be hypercoagulable, the specific mechanism is unclear. The aim of this study is to evaluate whether specific acquired prothrombotic risk factors contribute to the development of PSVT following laparoscopic splenectomy (LS). METHODS: Consecutive patients undergoing LS were prospectively studied between 2005 and 2013. Preoperatively, patients were screened for prothrombotic states and surveillance duplex ultrasonography was performed between 1 week and 1 month postoperatively to assess for PSVT. The association between baseline prothrombotic disorders and PSVT was explored using descriptive statistics. RESULTS: Sixty-eight patients were included in the analysis, and 17 (25 %) of these developed PSVT. There were no differences in patients with and without PSVT with respect to age, body mass index, gender or surgical time. Preoperative spleen size, as determined by diagnostic imaging, and intraoperative blood transfusion were associated with PSVT. Seven of 9 patients (78 %) with massive splenomegaly (>20 cm) developed PSVT compared with 4 of 13 patients (31 %) with moderate splenomegaly (15-20 cm) and 6 of 45 patients (13 %) without (p < 0.001). Abnormalities in baseline prothrombotic screening tests were common, with 52 patients (75 %) demonstrating at least one; however, none were associated with the development of PSVT. CONCLUSION: In patients scheduled for LS, screening for prothrombotic states is not useful to identify patients at risk of development of PSVT. Preoperative spleen size and blood transfusion were predictive of PSVT formation.

Treatment with acetylsalicylic acid prevents short to mid-term radiographic progression of nontraumatic osteonecrosis of the femoral head: a pilot study.

BACKGROUND: Nontraumatic osteonecrosis of the femoral head (ONFH) is a progressive disease in young adults producing substantial morbidity and frequently resulting in total hip arthroplasty. Although hip-preserving surgical procedures represent the current mainstay of treatment for early disease, medical therapies targeting specific pathways in the ONFH pathogenesis could help prevent disease progression while producing less morbidity. Acetylsalicylic acid (ASA) is a promising alternative to other therapies for ONFH owing to its anti-inflammatory and antithrombotic mechanisms of action and its relatively benign side effect profile. METHODS: We followed a prospective cohort of 10 patients (12 hips) with precollapse ONFH who were given ASA to prevent disease progression. Their outcomes were compared with those of a historic control group taken from the literature. RESULTS: Progression occurred in 1 of 12 (8%) patients taking ASA compared with 30 of 45 (66.6%) controls (p = 0.002) at a mean follow-up of 3.7 years. Patients taking ASA also tended to exhibit decreased femoral head involvement at the end of therapy. CONCLUSION: This hypothesis-generating study leads us to believe that ASA may be a simple and effective treatment option for delaying disease progression in patients with early-stage ONFH.

CONTEXTE: L'ostéonécrose non traumatique de la tête fémorale (ONTF) est une maladie progressive qui affecte les adultes jeunes, s'accompagne d'une morbidité substantielle et mène souvent à une arthroplastie totale de la hanche. Même si les interventions chirurgicales visant à préserver la hanche représentent la pierre angulaire actuelle du traitement pour la maladie au stade précoce, les traitements médicamenteux qui ciblent les voies spécifiques de la pathogenèse de l'ONTF pourraient contribuer à prévenir la progression de la maladie tout en atténuant la morbidité. L'acide acétylsalicylique (AAS) est une solution de rechange prometteuse aux autres traitements indiqués pour l'ONTF en raison de ses propriétés anti-inflammatoires et antithrombotiques et de son profil d'innocuité relativement bénin. MÉTHODES: Nous avons suivi une cohorte prospective de 10 patients (12 hanches) présentant une ONTF au stade précollapsus qui ont reçu de l'AAS pour prévenir la progression de la maladie. Leurs résultats ont été comparés à ceux d'un groupe témoin historique de patients décrits dans la littérature. RÉSULTANTS: La progression a affecté 1 patient sur 12 (8 %) traités par AAS, contre 30 témoins sur 45 (66,6 %) (p = 0,002) après un suivi moyen de 3,7 ans. Les patients sous AAS avaient tendance à présenter une atteinte moins prononcée de la tête fémorale à la fin du traitement. CONCLUSION: Cette étude exploratoire nous amène à croire que l'AAS pourrait être une option thérapeutique simple et efficace pour retarder la progression de la maladie chez les patients au stade précoce d'une ONTF.

Refractory autoimmune hemolytic anemia in a patient with DiGeorge syndrome treated successfully with plasma exchange: a case report and review of the literature.

Warm antibody autoimmune hemolytic anemia (AIHA) results from targeted antibodies towards the red blood cells (RBCs) and can be either idiopathic or secondary to certain diseases, such as autoimmune disorders or malignancy, drugs, or infection. Patients with DiGeorge syndrome are particularly vulnerable to autoimmune conditions secondary to thymic hypoplasia and dysfunction of the immune system. First-line therapy for AIHA consists of corticosteroids, with most patients showing signs of response. Relapses are not uncommon and are treated with splenectomy or rituximab. There is a paucity of reports in the literature regarding treatment options beyond this stage. Herein, we describe an unusual case of a 20-year-old female affected by DiGeorge syndrome with a history of immune thrombocytopenia (ITP), who presented with life-threatening AIHA. Standard first- and second-line therapeutic modalities were ineffective in controlling her disease and she ultimately underwent plasma exchange therapy with successful resolution of hemolysis. At her last follow-up, one year after her initial presentation, she remains clinically well without signs of hemolysis. We conclude that in refractory cases of warm AIHA, plasma exchange therapy can be a valuable tool in the therapeutic armamentarium.

A rat model of early stage osteonecrosis induced by glucocorticoids.

BACKGROUND: Glucocorticoid (GC)-induced osteonecrosis (ON) is an important complication of medical therapy. The exact pathomechanisms of ON has not been clearly elucidated. There is a need for a reproducible animal model that better approximates the clinical scenario. METHODS: To determine the genetic susceptibility of rats to develop GC-induced femoral head ON, we evaluated 5 different inbred strains of rats (Spontaneous Hypertensive Rat, Wistar Kyoto, Wistar Furth, SASCO Fisher and Lewis). Prednisone pellets (dosage of 1.82-2.56 mg/kg/day) were implanted subcutaneously for 90. After 90 days, the femurs were resected and examined histologically and radiographically. Pathological and histological examination was performed. Hematoxylin and eosin (H & E) staining was used to delineate the femoral head osteonecrosis lesions as well as abnormalities of articular cartilage and growth plate. RESULTS: The greatest differences in H & E staining were seen in the Wistar Kyoto and Wistar Furth groups. In these groups 4 out of 5 and 3 out of 5, respectively, steroid-induced rats revealed growth plate disruption with acellular areas. The TUNEL apoptosis staining assay for apoptosis revealed that 4 out of 5 of Wistar Kyoto rats, 5 out of 5 of Wistar Furth, 2 out of 4 of surviving Lewis and 2 out of 2 of the surviving spontaneous hypertensive rats had apoptotic osteocytes in trabeculae, whereas none of the Fisher rats showed apoptotic osteocytes. CONCLUSIONS: We postulate that Wistar Kyoto, Wistar Furth and spontaneous hypertensive rats may be strains of rats more susceptible to develop ON of the femoral head while Fisher rats were the most resistant.

New insights into the pathogenesis of glucocorticoid-induced avascular necrosis: microarray analysis of gene expression in a rat model.

INTRODUCTION: Avascular necrosis of the femoral head (ANFH) occurs variably after exposure to corticosteroids. Microvascular thrombosis is a common pathological finding. Since systemic thrombophilia is only weakly linked with ANFH, we propose that microvascular vessel pathology may be more related to local endothelial dysfunction and femoral head apoptosis. Corticosteroid effects on the endothelium and resultant apoptosis have been reported. We hypothesize that corticosteroids contribute to a differential gene expression in the femoral head in rats with early ANFH. METHODS: Besides bone marrow necrosis, which is a common sign in ANFH and reported in the early stages, we include the presence of apoptosis in this study as a criterion for diagnosing early disease. Forty Wistar Kyoto (WKY) rats were randomized to either a corticosteroid-treated group or an age-matched control group for six months. After sacrifice, the femoral heads were examined for ANFH. Total mRNA was extracted from femoral heads. Affymetrix exon array (Santa Clara, CA, USA) was performed on 15 selected RNA samples. Validation methods included RT-PCR and immunohistochemistry (IHC). RESULTS: Although rat exon array demonstrated a significant upregulation of 51 genes (corticosteroid(+)/ANFH(+) VS control), alpha-2-macroglobulin (A2M) gene was particularly over-expressed. Results were validated by RT-PCR and IHC. Importantly, A2M is known to share vascular, osteogenic and cartilage functions relevant for ANFH. CONCLUSIONS: The findings suggest that corticosteroid-induced ANFH in rats might be mediated by A2M. Investigation of A2M as a potential marker, and a treatment target, for early ANFH should be carried out.

Recommended timing for surveillance ultrasonography to diagnose portal splenic vein thrombosis after laparoscopic splenectomy.

BACKGROUND: Symptomatic portal or splenic vein thrombosis (PSVT) is a rare but potentially lethal complication of laparoscopic splenectomy (LS). While routine postoperative duplex ultrasound surveillance can be used for early detection, the optimal timing is unknown. The aim of this study is to investigate the incidence and progression of asymptomatic PSVT 1 week and 1 month after LS. METHODS: Consecutive patients scheduled for LS for hematologic disease participated in this study. Patients underwent surveillance for PSVT using duplex ultrasonography 1 week and 1 month postoperatively. RESULTS: 43 of 48 patients planning to undergo LS in the study period were enrolled, with 3 subsequently excluded, leaving 40 for further analysis. The indications for LS were benign disease in 31 [19 had immune thrombocytopenia purpura (ITP)] and malignant disease in 9. A hand-assisted technique was used in 12 cases. PSVT was diagnosed in 9/40 patients (22.5%). Seven (77.8%) were diagnosed by 1 week with ultrasound, of whom one had mild symptoms (fever and diarrhea). After anticoagulation, subsequent ultrasounds showed resolution or improvement in all seven patients. Thirty-three patients had a normal ultrasound result at 1 week. One of these patients also had a computed tomography (CT) scan that found a PSVT not seen on ultrasound. Twenty-seven patients returned for follow-up after normal 1-week imaging: 26 patients had an ultrasound at 1 month, with no new PSVT found. One additional patient did not return for subsequent ultrasound until 2 months later, when a new distal SVT was found; ultrasound at 6 months showed complete resolution without treatment. CONCLUSION: The 1-week incidence of PSVT after LS was 8/40 (20%). The high incidence justifies ultrasonographic screening on postoperative day 7. If asymptomatic PSVT has not developed at this time, it is unlikely to develop by 1 month, and subsequent screening ultrasound at 1 month is not required.

Glucocorticoids in osteonecrosis of the femoral head: a new understanding of the mechanisms of action.

Glucocorticoid (GC) usage is the most common non-traumatic cause of osteonecrosis of the femoral head (ON). Despite the strong association of GC with ON, the underlying mechanisms have been unclear. Investigators have proposed both direct and indirect effects of GC on cells. Indirect and direct mechanisms remain intimately related and often result in positive feedback loops to potentiate the disease processes. However, the direct effects, in particular apoptosis, have recently been shown to be increasingly important. Suppression of osteoblast and osteoclast precursor production, increased apoptosis of osteoblasts and osteocytes, prolongation of the lifespan of osteoclasts and apoptosis of endothelial cells (EC) are all direct effects of GC usage. Elevated blood pressure through several pathways may raise the risk of clot formation. High-dose GC also decreases tissue plasminogen activator activity (t-PA) and increases plasma plasminogen activator inhibitor-1 (PAI-1) antigen levels increasing the procoagulant potential of GC. Inhibited angiogenesis, altered bone repair and nitric oxide metabolism can also result. Also, GC treatment modulates other vasoactive mediators such as endothelin-1, noradrenalin and bradykinin. Thus, GCs act as a regulator of local blood flow by modulating vascular responsiveness to vasoactive substances. Vasoconstriction induced in intraosseous femoral head arteries causes femoral head ischemia. GCs also cause ischemia through increased intraosseous pressure, which subsequently decreases the blood flow to the femoral head by apoptosis of ECs as well as elevating the level of adipogenesis and fat hypertrophy in the bone marrow. It is difficult to predict which patients receiving a specific dose of GC will develop ON, indicating individual differences in steroid sensitivity and the potential of additional mechanisms. The textbook model of ON is a multiple hit theory in which, with a greater number of risk factors, the risk of ON increases. While more effort is needed to better comprehend the role of GC in ON, newer data on GC action upon the endothelial cell and the regional endothelial bed dysfunction theory sheds new light on particular GC mechanisms. Better understanding of GC pathomechanisms can lead to better treatment options.

Effect of high-dose dexamethasone on endothelial haemostatic gene expression and neutrophil adhesion.

Glucocorticoid usage especially at high doses is complicated by adverse outcomes such as thrombotic events or acceleration of inflammatory response in conditions like myeloma and osteonecrosis. The mechanism(s) through which high-dose dexamethasone (HDDEXA) causes vascular injury remains unclear. We hypothesized that HDDEXA sensitizes endothelial cells (EC) to the effect of inflammatory mediators and modulates endothelial haemostatic gene expression and leukocyte adhesion. Human umbilical vein endothelial cells (HUVECs) were grown in the absence or presence of HDDEXA and were also tested in the presence or absence of tumor necrosis factor-alpha (TNF-alpha), lipopolysaccharide (LPS) or thrombin. mRNA and protein expression were measured and the functional consequences of HDDEXA preconditioning on cell adhesion molecules (CAM) were determined by agonist-mediated leukocyte adhesion assay. Treatment with HDDEXA resulted in an increased induction of CAM, tissue factor and von Willebrand factor, while down-regulating thrombomodulin and urokinase. HDDEXA alone had no effect on adhesion but resulted in enhanced TNF-alpha- and LPS-mediated adhesion of neutrophils. Together, these findings suggest that HDDEXA sensitizes HUVEC to the effect of inflammatory mediators and induces a pro-adhesive environment in primary EC. This finding is of importance when glucocorticoid usage is required at therapeutic high doses in patients with or without thrombotic risk factors.

Thrombin downregulates thrombomodulin expression and activity in primary human endothelial cells.

Thrombomodulin (TM) is a cell surface anticoagulant glycoprotein that plays a key role in the protein C pathway. TM expression in endothelial cells may be modulated by a variety of extracellular signals. Most notably, TM has been shown to be downregulated by inflammatory mediators, such as tumor necrosis factor-alpha and lipopolysaccharide. The objective of this study was to determine the effect of thrombin on TM expression and activity. Thrombin resulted in reduced TM in primary cultures of human endothelial cells by approximately 40% at the level of mRNA, protein, and activity. These effects were blocked by the thrombin inhibitor hirudin. These results suggest that activation of the coagulation cascade may result in a positive-feedback loop consisting of thrombin-mediated repression of TM-dependent protein C activation.

Priming effect of homocysteine on inducible vascular cell adhesion molecule-1 expression in endothelial cells.

Hyperhomocysteinemia is an independent risk factor for the development of atherosclerosis, as well as for arterial and venous thrombosis. However, the mechanisms through which elevated circulating levels of homocysteine cause vascular injury and promote thrombosis remain unclear. Here, we tested the hypothesis that homocysteine (Hcy) sensitizes endothelial cells to the effect of inflammatory mediators. Human umbilical vein endothelial cells (HUVEC) were incubated with Hcy 1.0 mM for varying time points, and then treated in the absence or presence of 1.5 U/ml thrombin or 10 mg/ml lipopolysaccharide (LPS). Hcy alone had no effect on the expression of vascular cell adhesion molecule (VCAM)-1. However, Hcy enhanced thrombin- and LPS-mediated induction of VCAM-1 mRNA and protein levels. Consistent with these results, pretreatment of HUVEC with Hcy resulted in a two-fold increase in LSP-mediated induction of leukocyte adhesion. The latter effect was significantly inhibited by anti-VCAM-1 antibodies. Together, these findings suggest that Hcy sensitizes HUVEC to the effect of inflammatory mediators thrombin and LPS, at least in part through VCAM-1 expression and function.

Multicentric Castleman's disease treated with combination chemotherapy and rituximab in four HIV-positive men: a case series.

Multicentric Castleman's disease (MDC) is a rare herpesvirus-8-related prelymphomatous condition that may develop in patients infected with human immunodeficiency virus (HIV). Therapy for MCD is not well established and most often includes: corticosteroids, single or combined chemotherapy, anti-CD20 monoclonal antibody and antiretroviral therapy. In order to obtain a rapid and long-lasting clinical response, we are reporting on a short course of anthracycline-based chemotherapy associated with rituximab in HIV-positive patients with MCD. Our study suggests that the combined immuno-chemotherapy approach may represent a valid strategy with acceptable toxicity in patients with severe and extensive MDC. Further studies will be needed to assess the efficacy and safety of such an approach, and to identify risk factors predictive of long-term tolerance in HIV patients with different degrees of immunosuppression.