PEG hydrogel degradation and the role of the surrounding tissue environment

Poly(ethylene glycol) (PEG)‐based hydrogels are extensively used in a variety of biomedical applications, due to ease of synthesis and tissue‐like properties. Recently there have been varied reports regarding PEG hydrogel's degradation kinetics and in vivo host response. In particular, these studies suggest that the surrounding tissue environment could play a critical role in defining the inflammatory response and degradation kinetics of PEG implants. In the present study we demonstrated a potential mechanism of PEG hydrogel degradation, and in addition we show potential evidence of the role of the surrounding tissue environment on producing variable inflammatory responses. Copyright © 2013 John Wiley & Sons, Ltd.     

Rapid‐onset clinical and mechanistic effects of anti‐C5aR treatment in the mouse collagen‐induced arthritis model

Preclinical evidence supports targeting the C5a receptor (C5aR) in rheumatoid arthritis (RA). To support ongoing clinical development of an anti‐C5aR monoclonal antibody, we have investigated for the first time the mechanism of action and the pharmacodynamics of a blocking anti‐murine C5aR (anti‐mC5aR) surrogate antibody in mouse collagen‐induced arthritis (CIA). First, efficacy was demonstrated in a multiple‐dose treatment study. Almost complete inhibition of clinical disease progression was obtained, including reduced bone and cartilage destruction in anti‐mC5aR‐treated mice. Then, the mechanism of action was examined by looking for early effects of anti‐mC5aR treatment in single‐dose treatment studies. We found that 48 h after single‐dose treatment with anti‐mC5aR, the neutrophil and macrophage infiltration into the paws was already reduced. In addition, several inflammatory markers, including tumour necrosis factor (TNF)‐α, interleukin (IL)‐6 and IL‐17A were reduced locally in the paws, indicating reduction of local inflammation. Furthermore, dose‐setting experiments supported a beneficial clinical effect of dosing above the C5aR saturation level. In conclusion, these preclinical data demonstrated rapid onset effects of antibody blockade of C5aR. The data have translational value in supporting the Novo Nordisk clinical trials of an anti‐C5aR antibody in rheumatoid arthritis patients, by identifying potential biomarkers of treatment effects as well as by providing information on pharmacodynamics and novel insights into the mechanism of action of monoclonal antibody blockade of C5aR.     

T-cell receptor and carbamazepine-induced Stevens–Johnson syndrome and toxic epidermal necrolysis: understanding a hypersensitivity reaction

Ample evidence exists to support the view that drug hypersensitivity is mediated by adaptive immunity, which involves MHC-restricted drug presentation, activation and clonal expansion of T cells. The specific MHC molecules implicated in hypersensitivity have been identified; for example, HLA-B*5701 in abacavir-induced drug hypersensitivity and HLA-B*1502 in carbamazepine-induced Stevens–Johnson syndrome. However, little is known about the role of drug-specific T cells and their T-cell receptors (TCRs) in the pathogenesis of drug hypersensitivity. Using the combination of a strong HLA-B*1502 predisposition in carbamazepine-induced Stevens–Johnson syndrome and applying global analysis of the TCR repertoire, restricted and common TCR usage in the development of severe drug hypersensitivity have recently been documented. This article reviews recent advances in the understanding of the pathogenic role of drug-specific T cells and their TCRs in the development of drug hypersensitivity and provides an analysis of their potential clinical implications.     

Garlic Extract Ameliorates Renal and Cardiopulmonary Injury in the Rats with Chronic Renal Failure

Abstract

Chronic renal failure (CRF) is associated with oxidative stress that promotes production of reactive oxygen species and cytokine release. We aimed to investigate the possible protective and antioxidant effects of aqueous garlic extract (AGE) in a rat model of CRF. Male Sprague-Dawley rats were randomly assigned as either CRF group with 5/6 reduction in the renal mass or sham-operated control group. CRF group received either saline or AGE (250 mg/kg/day/1 mL) orally for 3 weeks. At the end of the 3 weeks, rats were decapitated and trunk blood was collected. Creatinine, blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) activity, and TNF-α and IL-1β levels were measured in the serum samples, while malondialdehyde (MDA), glutathione (GSH) levels, and myeloperoxidase (MPO) activity were determined in the kidney, lung, and heart samples. CRF caused significant decreases in tissue GSH, which were accompanied with significant increases in MDA levels and MPO activities, while the circulating levels of the LDH activity, creatinine, BUN, TNF-α, and IL-1β were elevated. AGE treatment alleviated CRF-induced oxidative changes in the injured tissues, while CRF-induced elevations in the blood levels of the pro-inflammatory cytokines and LDH were reduced. In conclusion, CRF-induced oxidative tissue injury occurs via the activation of pro-inflammatory mediators and by neutrophil infiltration into tissues and that the protective effects of garlic on CRF-induced injury can be attributed to its ability to inhibit neutrophil infiltration and pro-inflammatory mediators. These findings suggest that garlic, as a supplementary to diet, may have a potential therapeutic use in delimitating the systemic oxidant effects of CRF on remote organs.     

Infections and neutrophils in the pathogenesis of bronchiolitis obliterans syndrome in children after allogeneic stem cell transplantation

It is plausible that infections post‐hematopoietic SCT play a role in the pathogenesis of BOS. A prospective study for children with history, questionnaire, examination, PFTs, and blood counts at one, three, six, nine, 12, 18, and 24 months post‐SCT was conducted. Between September 2009 and September 2011 (n = 39), six developed BOS at 200 days (range 94–282), three patients had probable clinical respiratory infection, and all six had higher neutrophil count compared to non‐BOS patients (4.7 vs. 2.4 at three months and 6.3 vs. 2.9 at six months ×10⁹/L, p = 0.03). Contribution of clinical and subclinical infection needs to be considered in the pathogenesis of BOS.     

The intriguing normal acute inflammatory response in mice lacking vimentin

Neutrophils express only two intermediate filament proteins, vimentin and, to a lesser extent, lamin B. Lamin B mutant mice die shortly after birth; however, mice lacking vimentin (vim(-/-)) develop and reproduce normally. Herein, we investigate for the first time the role of vimentin in general inflammation in vivo and in neutrophil functions ex vivo. Using the murine air pouch model, we show that the inflammatory response induced by lipopolysaccharide, interleukin-21 or carageenan is, intriguingly, uncompromised in vim(-/-) mice and that neutrophil functions are not altered ex vivo. Our results suggest that vimentin is dispensable for the establishment of an acute inflammatory response in vivo. In addition, based on several criteria presented in this study, one has to accept the existence of a very complex compensatory mechanism to explain the intriguing normal inflammatory response in absence of vimentin.     

Activation of granulocytes by direct interaction with dendritic cells

Granulocytes from human peripheral blood were co-cultured with conventional dendritic cells (cDC) or plasmacytoid DCs (pDC) to examine the effects of DCs on the activation or function of granulocytes. After co-culture of granulocytes with DCs, expression of the activation markers of granulocytes (CD63 and CD64) was up-regulated, and increased expression of CD50, the activation marker and ligand for CD209 (DC-SIGN) was also observed. The interaction of granulocytes with DCs was visualized as the cluster where DCs, especially cDCs, were surrounded by granulocytes to form a 'rosette'. After co-culture of granulocytes with cDCs, the secretion of elastase from granulocytes was enhanced significantly when examined cytohistochemically and by enzyme-linked immunosorbent assay. An increase in myeloperoxidase (another activation index of granulocytes) was also observed after co-culture with DCs. These findings suggest the functional and phenotypical activation of granulocytes by interaction with DCs. Furthermore, we examined the involvement of adhesion molecules in the granulocyte-DC interaction, and found that CD209 participates to some extent in this interaction.     

馥感啉口服液联合脾氨肽治疗小儿反复呼吸道感染的临床研究

目的探讨馥感啉口服液联合脾氨肽治疗小儿反复呼吸道感染的临床疗效。方法选取2015年9月—2016年3月在郑州市第三人民院治疗的反复呼吸道感染患儿98例,随机分为对照组(49例)和治疗组(49例)。对照组口服脾氨肽口服冻干粉,2 mg/次,1次/d;治疗组在对照组基础上口服馥感啉口服液,10 mL/次,1~3岁患儿3次/d,4~6岁4次/d,7~12岁5次/d。两组患儿均经过3个月治疗。观察两组患儿临床疗效,比较治疗前后两组患儿临床症状改善时间、血清学指标、白细胞分类和白三烯D4(LTD4)水平。结果治疗后,对照组临床总有效率为81.63%,显著低于治疗组的95.92%。两组比较差异具有统计学意义(P0.05)。治疗后,治疗组发热、咳嗽和肺部啰音消失时间均显著短于对照组(P0.05)。治疗后,两组血清IL-1β、IL-6、和肿瘤坏死因子-α(TNF-α)水平均显著降低,胰岛素1号增长因子(IGF-1)、干扰素-γ(IFN-γ)和25-OH维生素D_3[25-(OH)D_3]水平均显著升高,同组比较差异具有统计学意义(P0.05);且治疗组上述血清学指标改善程度明显好于对照组(P0.05)。治疗后,两组鼻咽分泌物中中性粒细胞、嗜酸性粒细胞和LTD4水平均显著降低,单核巨噬细胞显著升高,同组比较差异具有统计学意义(P0.05);且治疗组上述指标改善后水平显著优于对照组(P0.05)。结论馥感啉口服液联合脾氨肽治疗小儿反复呼吸道感染可有效改善临床症状,降低炎症水平,具有一定的临床推广应用价值。     

Proteolysis of the endothelial cell protein C receptor by neutrophil proteinase 3

BACKGROUND: The endothelial cell protein C receptor (EPCR) presents protein C to the thrombin:thrombomodulin complex on the endothelium of large vessels, and enhances the generation of activated protein C (APC) and activation of protease-activated receptor-1. A previous report has demonstrated binding of soluble (s) EPCR to activated neutrophils via surface proteinase 3 (PR3). METHODS: We now report further characterization of this interaction. Activated neutrophils and purified PR3 both decrease endothelial cell (EC) surface EPCR, suggestive of its proteolysis. RESULTS: When added to purified recombinant sEPCR, PR3 produced multiple cleavages, with early products including 20 kDa N-terminal and C-terminal (after Lys(176)) fragments. The binding of active site blocked PR3 to sEPCR was studied by surface plasmon resonance. Estimates of the K(D) of 18.5-102 nM were obtained with heterogeneous binding, suggestive of more than a single interaction site. CONCLUSIONS: This work demonstrates PR3 binding to and proteolysis of EPCR and suggests a mechanism by which anticoagulant and cell protective pathways can be down-regulated during inflammation.