The relative importance of thrombin inhibition and factor Xa inhibition to the antithrombotic effects of heparin

The relative importance of antithrombin and anti-factor Xa activities of heparin fractions required to achieve optimal antithrombotic effects is unknown. To study this, we measured the effects of standard heparin, an octasaccharide heparin fraction (anti-factor Xa activity only), and dermatan sulfate (antithrombin activity only) on the prevention of thrombosis and related this to their anticoagulant effects in vivo in rabbits. Thrombosis was measured as the incorporation of 125I- fibrinogen into tissue thromboplastin-induced thrombi using a Wessler- type model. Ex vivo changes in thrombin clotting time (TCT) were used as an index of antithrombin activity, and a chromogenic anti-factor Xa assay was used to measure anti-factor Xa activity. In addition, the ability of the three sulfated polysaccharides to simultaneously inhibit the generation of thrombin activity and to enhance the inactivation of the factor Xa added to initiate thrombin generation in plasma was determined. Standard heparin, in a dose of 10 anti-factor Xa U/kg, inhibited thrombus formation by 90%, prolonged the TCT by two seconds, and resulted in an anti-factor Xa level of 0.32 U/mL. The octasaccharide heparin fraction, in a dose of 10 anti-factor Xa U/kg, inhibited thrombus formation by 41%, had no effect on the TCT, and resulted in an anti-factor Xa level of 0.28 U/mL. Higher doses of the octasaccharide resulted in a further increase in the anti-factor Xa levels but had no further effect on thrombus formation. Dermatan sulfate, in a dose of 500 micrograms/kg, inhibited thrombus formation by 95%, but had no affect on the TCT. These results indicate that the antithrombotic effect achieved by inhibiting factor Xa is limited and that better antithrombotic effects are achieved by heparin or heparin- like substances capable of influencing the inactivation and/or the generation of thrombin.     

Interleukin-21 combined with ART reduces inflammation and viral reservoir in SIV-infected macaques

Despite successful control of viremia, many HIV-infected individuals given antiretroviral therapy (ART) exhibit residual inflammation, which is associated with non–AIDS-related morbidity and mortality and may contribute to virus persistence during ART. Here, we investigated the effects of IL-21 administration on both inflammation and virus persistence in ART-treated, SIV-infected rhesus macaques (RMs). Compared with SIV-infected animals only given ART, SIV-infected RMs given both ART and IL-21 showed improved restoration of intestinal Th17 and Th22 cells and a more effective reduction of immune activation in blood and intestinal mucosa, with the latter maintained through 8 months after ART interruption. Additionally, IL-21, in combination with ART, was associated with reduced levels of SIV RNA in plasma and decreased CD4⁺ T cell levels harboring replication-competent virus during ART. At the latest experimental time points, which were up to 8 months after ART interruption, plasma viremia and cell-associated SIV DNA levels remained substantially lower than those before ART initiation in IL-21–treated animals but not in controls. Together, these data suggest that IL-21 supplementation of ART reduces residual inflammation and virus persistence in a relevant model of lentiviral disease and warrants further investigation as a potential intervention for HIV infection.     

Gene expression profiles in granuloma tissue reveal novel diagnostic markers in sarcoidosis

Sarcoidosis is an immune-mediated multisystem disease characterized by the formation of non-caseating granulomas. The pathogenesis of sarcoidosis is unclear, with proposed infectious or environmental antigens triggering an aberrant immune response in susceptible hosts. Multiple pro-inflammatory signaling pathways have been implicated in mediating macrophage activation and granuloma formation in sarcoidosis, including IFN-γ/STAT-1, IL-6/STAT-3, and NF-κB. It is difficult to distinguish sarcoidosis from other granulomatous diseases or assess disease severity and treatment response with histopathology alone. Therefore, development of improved diagnostic tools is imperative. Herein, we describe an efficient and reliable technique to classify granulomatous disease through selected gene expression and identify novel genes and cytokine pathways contributing to the pathogenesis of sarcoidosis. We quantified the expression of twenty selected mRNAs extracted from formalin-fixed paraffin embedded (FFPE) tissue (n = 38) of normal lung, suture granulomas, sarcoid granulomas, and fungal granulomas. Utilizing quantitative real-time RT-PCR we analyzed the expression of several genes, including IL-6, COX-2, MCP-1, IFN-γ, T-bet, IRF-1, Nox2, IL-33, and eotaxin-1 and revealed differential regulation between suture, sarcoidosis, and fungal granulomas. This is the first study demonstrating that quantification of target gene expression in FFPE tissue biopsies is a potentially effective diagnostic and research tool in sarcoidosis.     

FDC:TFH Interactions within Cervical Lymph Nodes of SIV-Infected Rhesus Macaques

Cerebrospinal fluid (CSF) drains via the lymphatic drainage pathway. This lymphatic pathway connects the central nervous system (CNS) to the cervical lymph node (CLN). As the CSF drains to CLN via the dural and nasal lymphatics, T cells and antigen presenting cells pass along the channels from the subarachnoid space through the cribriform plate. Human immunodeficiency virus (HIV) may also egress from the CNS along this pathway. As a result, HIV egressing from the CNS may accumulate within the CLN. Towards this objective, we analyzed CLNs isolated from rhesus macaques that were chronically-infected with simian immunodeficiency virus (SIV). We detected significant accumulation of SIV within the CLNs. SIV virion trapping was observed on follicular dendritic cells (FDCs) localized within the follicular regions of CLNs. In addition, SIV antigens formed immune complexes when FDCs interacted with B cells within the germinal centers. Subsequent interaction of these B cells with CD4+ T follicular helper cells (T_FHs) resulted in infection of the latter. Of note, 73% to 90% of the T_FHs cells within CLNs were positive for SIV p27 antigen. As such, it appears that not only do the FDCs retain SIV they also transmit them (via B cells) to T_FHs within these CLNs. This interaction results in infection of T_FHs in the CLNs. Based on these observations, we infer that FDCs within the CLNs have a novel role in SIV entrapment with implications for viral trafficking.     

Comparison of patient reported outcomes after Triathlon? and Kinemax Plus prostheses

INTRODUCTION

The Triathlon^® (Stryker, Kalamazoo, MI, US) total knee replacement was designed to improve patient function and survivorship. The aim of this study was to determine whether the Triathlon^® prosthesis produces better patient reported outcomes than a previous design by the same manufacturer, the Kinemax Plus.

METHODS

The outcome of 233 knees of patients with a mean age of 68 years (range: 40–80 years) who received the Kinemax Plus prosthesis were compared with the outcomes of 220 knees of patients with a mean age of 70 years (range: 42–90 years) who received the Triathlon^® prosthesis. Data were collected via postal questionnaire prior to surgery as well as at 8–12 weeks and at 1 year following surgery. Validated questionnaires were used including the WOMAC^® (Western Ontario and McMaster Universities) pain and function scales, the Knee injury and Osteoarthritis Outcome Score quality of life scale and the self-administered patient satisfaction scale.

RESULTS

This study found that patients who had the Triathlon^® prosthesis had significantly better pain relief (p<0.0001), function (p=0.028), knee related quality of life (p<0.0001) and satisfaction (p=0.0003) at three months after surgery than those who received the Kinemax Plus prosthesis. In addition, knee related quality of life (p=0.002) and satisfaction (p=0.021) were significantly higher at one year after surgery in Triathlon^® patients.

CONCLUSIONS

The findings suggest that return to function and reduction in pain may occur more quickly in patients with a Triathlon^® prosthesis than in those with the Kinemax Plus.     

Increasing access to renal transplantation in India through our single‐center kidney paired donation program: a model for the developing world to prevent commercial transplantation

Because access to transplantation with HLA‐desensitization protocols and ABO incompatible transplantation is very limited due to high costs and increased risk of infections from more intense immunosuppression, kidney paired donation (KPD) promises hope to a growing number of end‐stage renal disease (ESRD) patient in India. We present a government and institutional ethical review board approved study of 56 ESRD patients [25 two‐way and 2 three‐way pairs] who consented to participate in KPD transplantation at our center in 2013, performed to avoid blood group incompatibility (n = 52) or positive cross‐match (n = 4). All patients had anatomic, functional, and immunologically comparable donors. The waiting time in KPD was short as compared to deceased donor transplantation. Laparoscopic donor nephrectomy was performed in 54 donors. Donor relationships were spousal (n = 40), parental (n = 13), others (n = 3), with median HLA match of 1. Graft survival was 97.5%. Three patients died with functioning graft. 16% had biopsy‐proven acute rejection. Mean serum creatinine was 1.2 mg/dl at 0.73 ± 0.32 months follow‐up. KPD is a viable, legal, and rapidly growing modality for facilitating LDRT for patients who are incompatible with their healthy, willing living donor. To our knowledge, this is the largest single‐center report from India.