Inflammation as a therapeutic target: a unique role for abciximab

Network Proximity-Based Drug Repurposing Strategy for Early and Late Stages of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic, cholestatic, immune-mediated, and progressive liver disorder. Treatment to preventing the disease from advancing into later and irreversible stages is still an unmet clinical need. Accordingly, we set up a drug repurposing framework to find potential therapeutic agents targeting relevant pathways derived from an expanded pool of genes involved in different stages of PBC. Starting with updated human protein-protein interaction data and genes specifically involved in the early and late stages of PBC, a network medicine approach was used to provide a PBC "proximity" or "involvement" gene ranking using network diffusion algorithms and machine learning models. The top genes in the proximity ranking, when combined with the original PBC-related genes, resulted in a final dataset of the genes most involved in PBC disease. Finally, a drug repurposing strategy was implemented by mining and utilizing dedicated drug-gene interaction and druggable genome information knowledge bases (e.g., the DrugBank repository). We identified several potential drug candidates interacting with PBC pathways after performing an over-representation analysis on our initial 1121-seed gene list and the resulting disease-associated (algorithm-obtained) genes. The mechanism and potential therapeutic applications of such drugs were then thoroughly discussed, with a particular emphasis on different stages of PBC disease. We found that interleukin/EGFR/TNF-alpha inhibitors, branched-chain amino acids, geldanamycin, tauroursodeoxycholic acid, genistein, antioestrogens, curcumin, antineovascularisation agents, enzyme/protease inhibitors, and antirheumatic agents are promising drugs targeting distinct stages of PBC. We developed robust and transparent selection mechanisms for prioritizing already approved medicinal products or investigational products for repurposing based on recognized unmet medical needs in PBC, as well as solid preliminary data to achieve this goal.

Homocysteine, Vitamins B6 and Folic Acid in Experimental Models of Myocardial Infarction and Heart Failure—How Strong Is That Link?

Cardiovascular diseases are the leading cause of death and the main cause of disability. In the last decade, homocysteine has been found to be a risk factor or a marker for cardiovascular diseases, including myocardial infarction (MI) and heart failure (HF). There are indications that vitamin B6 plays a significant role in the process of transsulfuration in homocysteine metabolism, specifically, in a part of the reaction in which homocysteine transfers a sulfhydryl group to serine to form α-ketobutyrate and cysteine. Therefore, an elevated homocysteine concentration (hyperhomocysteinemia) could be a consequence of vitamin B6 and/or folate deficiency. Hyperhomocysteinemia in turn could damage the endothelium and the blood vessel wall and induce worsening of atherosclerotic process, having a negative impact on the mechanisms underlying MI and HF, such as oxidative stress, inflammation, and altered function of gasotransmitters. Given the importance of the vitamin B6 in homocysteine metabolism, in this paper, we review its role in reducing oxidative stress and inflammation, influencing the functions of gasotransmitters, and improving vasodilatation and coronary flow in animal models of MI and HF.

Influence of integrins on thrombus formation: a road leading to the unravelling of DVT

Integrins are a group of transmembrane glycoprotein receptors that are responsible for platelet activation through bidirectional signalling. These receptors have left their footprints in various cellular events and have intrigued many groups of scientists that have led to some significant discoveries. A lot of the recent understanding of haemostasis has been possible due to the integrins filling the gaps in between several cellular mechanism. Apart from this, other important functions carried out by integrins are growth and maturation of cardiomyocytes, mechano-transduction, and interaction with actin cytoskeleton. The signalling cascade for integrin activation involves certain intracellular interacting proteins, which initiates the step-by-step activation procedure through 'inside-out' signalling. The signalling cascade gets activated through 'outside-in' signalling with the involvement of agonists such as ADP, Fibronectin, Vitronectin, and so on. This is a crucial step for the downstream processes of platelet spreading, followed by aggregation, clot progression and finally thrombus formation. Researchers throughout the world have shown direct relation of integrins with CVD and cardiac remodelling. The present review aims to summarize the information available so far on the involvement of integrins in thrombosis and its relationship to DVT. This information could be a bedrock of hidden answers to several questions on pathogenesis of deep vein thrombosis.

Construction of an miRNA-regulated drug-pathway network reveals drug repurposing candidates for myasthenia gravis

Myasthenia gravis (MG) is a rare debilitating autoimmune neuromuscular disorder. Many studies have focused on the mechanism and treatment strategies of MG. However, the exact pathogenesis of MG and effective treatment strategies remain unclear. Recent studies have indicated that microRNAs (miRNAs or miRs) can regulate the pathological pathways of MG, suggesting their potential role in novel treatments. In the present study, we created a comprehensive catalog of experimentally confirmed MG risk genes and miRNAs by manually mining published literature and public databases. Based on these genes and miRNAs, we identified 41 MG risk pathways and 105 approved drugs that can affect these pathways. Some important MG-related pathways, such as hsa04060 (cytokine-cytokine receptor interaction) and hsa05200 (pathway in cancer), were found to be regulated by MG risk miRNAs and drugs. Furthermore, we constructed an miRNA-regulated drug-pathway network and identified miRNAs and drugs that synergistically regulate key MG pathways and biological processes. We developed a drug repurposing strategy to identify 25 drug repurposing candidates for MG; several of these drugs, such as rituximab, adalimumab, sunitinib, and muromonab, have the potential to be novel MG treatment drugs. This study provides novel insight into the pathogenesis of MG and potential drug candidates for MG were identified.

Trans-system mechanisms against ischemic myocardial injury

A mammalian organism possesses a hierarchy of naturally evolved protective mechanisms against ischemic myocardial injury at the molecular, cellular, and organ levels. These mechanisms comprise regional protective processes, including upregulation and secretion of paracrine cell-survival factors, inflammation, angiogenesis, fibrosis, and resident stem cell-based cardiomyocyte regeneration. There are also interactive protective processes between the injured heart, circulation, and selected remote organs, defined as trans-system protective mechanisms, including upregulation and secretion of endocrine cell-survival factors from the liver and adipose tissue as well as mobilization of bone marrow, splenic, and hepatic cells to the injury site to mediate myocardial protection and repair. The injured heart and activated remote organs exploit molecular and cellular processes, including signal transduction, gene expression, cell proliferation, differentiation, migration, mobilization, and/or extracellular matrix production, to establish protective mechanisms. Both regional and trans-system cardioprotective mechanisms are mediated by paracrine and endocrine messengers and act in coordination and synergy to maximize the protective effect, minimize myocardial infarction, and improve myocardial function, ensuring the survival and timely repair of the injured heart. The concept of the trans-system protective mechanisms may be generalized to other organ systems-injury in one organ may initiate regional as well as trans-system protective responses, thereby minimizing injury and ensuring the survival of the entire organism. Selected trans-system processes may serve as core protective mechanisms that can be exploited by selected organs in injury. These naturally evolved protective mechanisms are the foundation for developing protective strategies for myocardial infarction and injury-induced disorders in other organ systems.

Osteoarthritis: From Palliation to Prevention: AOA Critical Issues

Osteoarthritis is a leading cause of disability. The traditional focus on late-stage osteoarthritis has not yielded effective disease-modifying treatments. Consequently, current clinical care focuses on palliation until joint replacement is indicated. A symposium format was used to examine emerging strategies that support the transformation of the clinical approach to osteoarthritis from palliation to prevention. Central to this discussion are concepts for diagnosis and treatment of pre-osteoarthritis, meaning joint conditions that increase the risk of accelerated development of osteoarthritis. The presentation of translational and clinical research on three common orthopaedic conditions-anterior cruciate ligament tear, intra-articular fracture, and hip dysplasia-were used to illustrate these ideas. New information regarding the use of novel quantitative magnetic resonance imaging (MRI) in the form of ultrashort echo time enhanced T2* (UTE-T2*) mapping to evaluate the potential for articular cartilage to heal subsurface damage in a mechanically sound environment was presented. These data indicate that improved diagnostics can both identify cartilage at risk and evaluate the effectiveness of early treatment strategies. With use of a new mouse model for intra-articular fracture, it was shown that inflammation correlated to fracture severity and that super-healer mice avoided early posttraumatic osteoarthritis in part through an enhanced ability to dampen inflammation. These findings suggest that there is a role for acute and sustained anti-inflammatory treatment in the prevention of osteoarthritis. For long-term treatment, contemporary gene-therapy approaches may offer an effective means for sustained intra-articular delivery of anti-inflammatory and other bioactive agents to restore joint homeostasis. To illustrate the potential of early treatment to prevent or delay the onset of disabling osteoarthritis, the positive clinical effects on articular cartilage and in long-term clinical follow-up after operative correction of structural abnormalities about the hip highlight the role for targeting mechanical factors in delaying the onset of osteoarthritis. Given that orthopaedic surgeons treat the full spectrum of joint problems, ranging from joint trauma to pre-osteoarthritic conditions and end-stage osteoarthritis, an awareness of the paradigm shift toward the prevention of osteoarthritis is critical to the promotion of improved clinical care and participation in clinical research involving new treatment strategies.

Neointimal hyperplasia persists at six months after sirolimus-eluting stent implantation in diabetic porcine

Background

Observational clinical studies have shown that patients with diabetes have less favorable results after percutaneous coronary intervention compared with the non-diabetic counterparts, but its mechanism remains unclear. The aim of this study was to examine the changes of neointimal hyperplasia after sirolimus-eluting stent (SES) implantation in a diabetic porcine model, and to evaluate the impact of aortic inflammation on this proliferative process.

Methods

Diabetic porcine model was created with an intravenous administration of a single dose of streptozotocin in 15 Chinese Guizhou minipigs (diabetic group); each of them received 2 SES (Firebird, Microport Co, China) implanted into 2 separated major epicardial coronary arteries. Fifteen non-diabetic minipigs with SES implantation served as controls (control group). At 6 months, the degree of neointimal hyperplasia was determined by repeat coronary angiography, intravascular ultrasound (IVUS) and histological examination. Tumor necrosis factor (TNF)-α protein level in the aortic intima was evaluated by Western blotting, and TNF-α, interleukin (IL)-1β and IL-6 mRNA levels were assayed by reverse transcription and polymerase chain reaction.

Results

The distribution of stented vessels, diameter of reference vessels, and post-procedural minimal lumen diameter were comparable between the two groups. At 6-month follow-up, the degree of in-stent restenosis (40.4 ± 24.0% vs. 20.2 ± 17.7%, p < 0.05), late lumen loss (0.33 ± 0.19 mm vs. 0.10 ± 0.09 mm, p < 0.001) by quantitative angiography, percentage of intimal hyperplasia in the stented area (26.7 ± 19.2% vs. 7.3 ± 6.1%, p < 0.001) by IVUS, and neointimal area (1.59 ± 0.76 mm² vs. 0.41 ± 0.18 mm², p < 0.05) by histological examination were significantly exacerbated in the diabetic group than those in the controls. Significant increases in TNF-α protein and TNF-α, IL-1β and IL-6 mRNA levels were observed in aortic intima in the diabetic group.

Conclusion

Neointimal hyperplasia persisted at least up to 6 months after SES implantation in diabetic porcine, which may be partly related to an exaggerated inflammatory response within the blood vessel wall. Our results provide theoretical support for potential direct beneficial effects of anti-diabetic and anti-inflammation medications in reducing the risk of restenosis after stenting.

Concentration-dependent effect of abciximab on platelets and neutrophils in a model of cardiopulmonary bypass

Abciximab is a GPIIb/IIIa antagonist used in percutaneous coronary interventions to avoid platelet activation, thrombosis and inflammation. We investigated whether abciximab influenced platelet activation and platelet interaction with neutrophils and polyvinyl chloride (PVC) in a cardiopulmonary bypass (CPB) model. Isolated platelets, preincubated with and without 0.1-20 μg/mL of abciximab, were resuspended with neutrophils in plasma and recirculated by a roller pump. Platelet, but not neutrophil adhesion to PVC was inhibited by abciximab. Only high doses of abciximab reduced platelet aggregation size, but simultaneously increased platelet-neutrophil aggregation. Abciximab had no effect on platelet CD62P expression or degranulation, but platelet activation on platelet-neutrophil aggregates increased with high doses. Only low doses inhibited neutrophil degranulation. The concentration-dependent effect of abciximab on platelet-neutrophil interaction reduces its usefulness and stresses the dependency on experimental design in the evaluation of abciximab. Our study does not support the use of abciximab alone in CPB. However, incorporation of surface-coating the biomaterial with abciximab may be an interesting option.

Prognostic value of C-reactive protein and cardiac troponin I in primary percutaneous interventions for ST-elevation myocardial infarction

BACKGROUND

The rise in cardiac troponin I after ST-elevation myocardial infarction treated by primary percutaneous coronary interventions (PCIs) is predictive of infarct size and left ventricular ejection fraction (LVEF). However, the comparative value of C-reactive protein (CRP) and troponin I for infarct size evaluation and the respective relationships between these biomarkers and mortality have not been investigated.

METHODS

We studied 87 patients who underwent primary PCI for ST-elevation myocardial infarction. Concentrations of troponin I and CRP were measured before and for 72 hours after PCI. Infarct size was measured by the cumulative release of alpha-hydroxybutyrate deshydrogenase during the 72 hours after PCI (QHBDH72) and by delayed radionuclide LVEF (at 4.6 +/- 1.7 weeks).

RESULTS

Concentrations of CRP at peak and at 24, 48 and 72 hours, and of troponin I at 6 and 72 hours, correlated with QHBDH72 and LVEF. In single variable analysis, at a mean follow-up of 42 +/- 8 months, Killip score of 3 to 4, CRP at baseline and at 48 hours, and troponin I at 6 and 72 hours were related to mortality. By multiple variable analysis, Killip score (OR 9.9, CI 1.6-58.8) and troponin I at 72 hours (OR 9.43, CI 2.1-43.5) were the only independent predictors of mortality.

CONCLUSIONS

Plasma concentrations of CRP and troponin I after PCI were related to infarct size and mortality. However, Killip class and troponin I at 72 hours were the only independent predictors of mortality at long-term follow-up.

Effects of abciximab on key pattern of human coronary restenosis in vitro: impact of the SI/MPL-ratio

Background

The significant reduction of angiographic restenosis rates in the ISAR-SWEET study (intracoronary stenting and antithrombotic regimen: is abciximab a superior way to eliminate elevated thrombotic risk in diabetes) raises the question of whether abciximab acts on clopidogrel-independent mechanisms in suppressing neointimal hyperplasia. The current study investigates the direct effect of abciximab on ICAM-1 expression, migration and proliferation.

Methods

ICAM-1: Part I of the study investigates in cytoflow studies the effect of abciximab (0.0002, 0.002, 0.02, 0.2, 2.0, and 20.0 μg/ml) on TNF-α induced expression of intercellular adhesion molecule 1 (ICAM-1). Migration: Part II of the study explored the effect of abciximab (0.0002, 0.002, 0.02, 0.2, 2.0, and 20.0 μg/ml) on migration of HCMSMC over a period of 24 h. Proliferation: Part III of the study investigated the effect of abciximab (0.0002, 0.002, 0.02, 0.2, 2.0, and 20.0 μg/ml) on proliferation of HUVEC, HCAEC, and HCMSMC after an incubation period of 5 days.

Results

ICAM-1: In human venous endothelial cells (HUVEC), human coronary endothelial cells (HCAEC) and human coronary medial smooth muscle cells (HCMSMC) no inhibitory or stimulatory effect on expression of ICAM-1 was detected. Migration: After incubation of HCMSMC with abciximab in concentrations of 0.0002 – 2 μg/ml a stimulatory effect on cell migration was detected, statistical significance was achieved after incubation with 0.002 μg/ml (p < 0.05), 0.002 μg/ml (p < 0.001), and 0.2 μg/ml (p < 0.05). Proliferation: Small but statistically significant antiproliferative effects of abciximab were detected after incubation of HUVEC (0.02 and 2.0 μg/ml; p = 0.01 and p < 0.01), HCAEC (2.0 and 20.0 μg/ml; p < 0.05 and p < 0,01), and HCMSMC (2.0 and 20.0 μg/ml; p < 0.05 and p < 0.05). The significant inhibition (SI) of cell proliferation found in HCAEC and HCMSMC was achieved with drug concentrations more than 10 times beyond the maximal plasma level (MPL), resulting in a SI/MPL-ratio > 1.

Conclusion

Thus, the anti-restenotic effects of systemically administered abciximab reported in the ISAR-SWEET-study were not caused by a direct inhibitory effect on ICAM-1 expression, migration or proliferation.