Current Pharmaceutical Design - Volume 18, Issue 28, 2012

In many ways, atherosclerosis is a chronic inflammatory disorder and this issue is confirmed by recent investigations of that have focused on inflammation, providing new insight into mechanisms of disease. Several recent studies have addressed the role of chemokines in leukocyte accumulation in atherosclerosis, extending our knowledge and understanding of the complex and cell typespecific functions of chemokines in atherosclerosis. Activated T-lymphocytes within the atherosclerotic vessel wall express the CD40 ligand surface molecule, known to play a major role in several immunological pathways. In addition to activated T-lymphocytes, functional CD40 and CD40L are coexpressed by human vascular endothelial cells, smooth muscle cells and human macrophages in vitro as well as in situ in human atherosclerotic lesions. Recent studies indicate that CD40L activates atheroma-associated cells by promoting the expression of molecules thought to be involved in atherosclerosis, such as adhesion molecules, cytokines, matrix metalloproteinases, and tissue factor. Atherosclerosis starts with an innate immune response involving the recruitment and activation of monocytes macrophages that respond to an excessive accumulation of modified lipids within the arterial wall, followed by an adaptive immune response involving antigen-specific T lymphocytes. Effector T cells recognize modified auto-antigens such as oxidized LDL and heat shock proteins (i.e. HSP-60) that are presented by antigen-presenting cells such as macrophages or dendritic cells. The accumulation of inflammatory cells within the arterial wall leads to local production of chemokines, interleukins and proteases that enhance the influx of monocytes and lymphocytes, thereby promoting the progression of atherosclerotic lesions Recent reports have helped explain some of these questions by pointing to a role of contact dependent interaction between CD40 and CD40 ligand (CD40L, renamed CD154) as a stimulus for atheroma-associated cells. Also Macrophages play important roles in the progression of atherosclerosis by exhibiting unique characteristics under the various stimuli, evolving the plaque instability, thrombus formation and remodeling. Macrophage recruitment by abnormal endothelium over developing atherosclerotic plaques, is aided by endothelial expression of adhesion molecules (ICAM-1, VCAM, ELAM). The knowledge of atherosclerosis as an inflammatory disease offers the opportunity to develop novel therapeutic strategies targeting the inflammatory component of the disease.

Determining the cause of stroke does influence choices for management. categorization of subtypes of ischemic stroke has had considerable study, but definitions are hard to formulate and their application for diagnosis in an individual patient is often problematic. Cerebral ischemia initiates a complex cascade of events at genomic, molecular, and cellular levels, and inflammation is important in this cascade. In 1993 for For the Trial of Org 10172 in Acute Stroke Treatment (TOAST), Adams et al] conducted a placebo-controlled, randomized, blinded study of the low-molecular-weight heparinoid given to patients within 24 hours after stroke and developed a system for diagnosis of subtype of ischemic stroke that uses components of existing diagnostic schemes. The type of acute ischemic stroke was classified according to the TOAST classification: 1) Large Artery AtheroSclerosis (LAAS); 2) CardioEmbolic Infarct (CEI); 3) LACunar infarct (LAC); 4) stroke of Other Determined Etiology (ODE); 5) stroke of UnDetermined Etiology (UDE) (see Fig. (1)). On the basis of pathophysiologic differences of each stroke subtype it's possible to hypothesize a different pattern of immuno-inflammatory activation in relation of ischemic stroke subtype. A nonspecific systemic inflammatory response occurs after both ischemic and hemorrhagic stroke, either as part of the process of brain damage or in response to complications such as deep venous thrombosis. Several studies have reported that higher levels of inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) are associated with worse outcome after ischemic stroke. Our group reported that patients with cardioembolic subtype showed significantly higher median plasma levels of TNF-α, IL-6, IL-1β whereas the lacunar subtype showed significantly lower median plasma levels of TNF-α, IL-6 and IL-1β. Our findings underlined the significant association was noted between the severity of neurological deficit at admission, the diagnostic subtype and some inflammatory variables.

Atherosclerosis is considered an inflammatory disease. T-cells, macrophages, and mast cells infiltrate atherosclerotic plaques and platelets play an essential role releasing inflammatory mediators that stimulate plaque progression. This is important in acute coronary syndromes but it is also the mechanism involved in plaque progresion and endothelial dysfunction. Antiplatelet drugs exert their effects not only by inhibition of platelet aggregation but also through their antiinflammatory effect. Aspirin, thyenopiridines and GPIIb/IIIa inhibitors have antiinflammatory properties that involve different mechanisms of action, especially related to the blockade of platelet activation and platelet-leukocyte interactions. Testing platelet function in addition to assessing levels of inflammatory markers, and not only the risk of bleeding, could help in decision-making to balance the risk-benefit of anti-thrombotic treatment. Different clinical settings are associated with variable inflammatory states, and this could be, in part, responsible for variable response to treatment.

It is well established that physically fit individuals have a reduced risk of developing CVD (cardiovascular disease) and other age-related chronic disorders. Regular exercise is an established therapeutic intervention with an enormous range of benefits. Chronic low-grade systemic inflammation may be involved in atherosclerosis, diabetes and in pathogenesis of several chronic pathological conditions; recent findings confirm that physical activity induces an increase in the systemic levels of a number of cytokines and chemokines with anti-inflammatory properties. The possibility that regular physical exercise exerts anti-inflammation activity, being the interaction between contracting muscle and the other tissues and the circulating cells mediated through signals transmitted by “myokines” produced with muscle contractions. To date the list of myokines includes IL-6, IL-8, and IL-15. During muscle contractions are also released IL- 1receptor antagonis and sTNF-R, molecules that contribute to provide anti-inflammatory actions. Nevertheless discrepancies, analysis of available researches seem to confirm the efficacy of regular physical training as a nonpharmacological therapy having target chronic low-grade inflammation. Given this, physical exercise could be considerate a useful weapon against local vascular and systemic inflammation in atherosclerosis. Several mechanisms explain the positive effect of chronic exercise, nevertheless, these mechanisms do not fully enlighten all pathways by which exercise can decrease inflammation and endothelial dysfunction, and hence modulate the progression of the underlying disease progress.

Peripheral arterial disease (PAD) affects a large number of individuals over the age of 55 years old, and data from studies has shown a relationship between inflammation, and PAD. Many researchers have not only focused on the role played by inflammatory biomarkers and the progression of PAD, but also on the efficiency of biomarkers in monitoring medical, surgical and interventional strategies in PAD patients. In this review, Authors aim to demonstrate that biomarkers play a key role in the pathophysiology of PAD, and consequently they could be screened to highlight individuals showing these crucial pathophysiological signs. Based on a large debate about phlogosis, it is now considered to be a relevant objective in reducing the prevalence and consequences of atherosclerotic diseases such as PAD. Finally, efforts must be made towards addressing this very important objective, and consequently a greater number of studies need to be made in combatting phlogosis, especially among PAD patients.

Acute myocardial infarction (AMI) constitutes the major cause of death in most nations and death rates and morbidity remain substantial in the years thereafter. Inflammation is a hallmark throughout the distinct stages of atherosclerotic lesion formation preceding AMI as well as at the time of plaque rupture and during the post-infarct repair phase. Epidemiological, genetic, clinical and experimental evidence converges on inflammation as a pivotal factor in disease progression and exacerbation. Harnessing its harmful consequences constitutes an attractive therapeutic approach to address this unmet medical need. Components of the innate and adaptive immune system with the characteristic cytokines interleukin-1 and tumor necrosis factor-α, respectively exert prominent functions in atherogenesis and post-infarct remodeling. Leukocyte subsets of the monocyte/macrophage and CD4+ T lymphocyte cell lineage interacting with a vast array of cells comprising platelets, neutrophils, dendritic cells, mast cells, vascular smooth muscle cells and fibroblasts orchestrate the inflammatory pathophysiology underlying plaque progression in the vasculature and fibrotic repair of the infarct. This pathophysiology is amenable to modification by drugs targeting cell proliferation, cell migration, osteogenic/fibrous turnover of the extracellular matrix ranging from antimetabolites, glucocorticoids, specific cytokine and leukotriene antagonists to classic immunosuppressive agents and vaccines directed specifically at certain disease-relevant antigens. Based on published data on clinical safety and clinical/experimental efficacy in inhibiting disease progression this review covers recent advances in this field and aims to propose candidate drugs for future clinical trials.

From the onset to the healing stage of acute coronary syndromes, an endless inflammation has been presented with complex, multiple cross-talk mechanisms at the molecular, cellular, and organ levels. Even though the early reperfusion treatment either by thrombolysis or percutaneous coronary intervention provides the excellent clinical benefits in patients with acute coronary syndromes, ischemia/ reperfusion injury may somewhat offset those great advantages. Inflammation, although potentially protective, has been deeply associated with those detrimental conditions. The hexagonal vascular inflammatory network which is composed of activated various leukocytes, vascular endothelial cells, vascular smooth muscle cells, platelets, excess reactive oxygen species, and cholesterol may contribute these vicious circles. To address these complex syndromes with more benefits regarding the prevention and treatment, this review comprehensively updates the pathogenesis of acute coronary syndromes from the view points of vascular inflammation.

The role of inflammation in cardiovascular disease and in hypertensive disease above all, is complex. Several studies confirm that activation of renin-angiotensin-aldosteron system (RAAS), through increase in the production of angiotensin II (Ang II), is closely related to local vascular inflammation. Over the BP lowering effects of anti-hypertensive treatments, several ancillary effects for every class may be found, distinguishing the various drugs from one another. Given the pro-inflammatory effects of Ang II and aldosterone, agents that interfere with the components of RAAS, such as ACE inhibitors, Angiotensin Recpetor Blockers (ARBs), and mineralocorticoid receptor antagonists (spironolactone or the more selective eplerenone), represent logical therapeutic tools to reduce vascular inflammation and cardiovascular risk, as suggested in large clinical trials in patients with hypertension and diabetes. Regarding ACE inhibitors, actually there is no convincing evidence indicating that ACEi’s reduce plasma levels of major inflammatory markers in hypertension models. Lack of evidence concerns especially these inflammation markers, such as fibrinogen of CRP, which are less closely related to atherosclerotic disease and vascular damage and conversely are affected by several more aspecific factors. Results obtained by trials accomplished using ARBs seem to be more univocal to confirm, although to great extent, these is an anti-inflmmatory effect of drugs bocking AT1 receptor. In order to strictly study the effects of blockage of RAAS on inflammation, future studies may explore different strategies by, for example, simultaneously acting on the ACE and the AT1 angiotensin receptors.

In the mouse postoperative ileus model, we have shown an increase in oxidative stress after intestinal manipulation occurring earlier in the mucosa than in the muscular layer, which might contribute to epithelial barrier dysfunction. To address these findings in vitro, we assessed TNF-α/cycloheximide (CHX)-induced oxidative stress and apoptosis in a mouse intestinal epithelial cell line, MODE-K. The influence of heme oxygenase (HO)-1-related products and agents known to reduce reactive oxygen species (ROS) production on TNF-α/CHX-induced oxidative stress and apoptosis were investigated. MODE-K cells were exposed to different concentrations of TNF- α/CHX in the absence/presence of the test agents. Cell viability, caspase-3/7 activity, apoptosis, reduced glutathione level (GSH) and intracellular ROS production were measured. TNF-α/CHX decreased cell viability, increased caspase-3/7 activity, induced apoptosis, reduced the GSH level and increased ROS production in a concentration-dependent manner in MODE-K cells. All these effects of TNF- α/CHX were partially prevented by pretreatment with a carbon monoxide-releasing agent (CORM-A1) and nitrite. The antioxidant resveratrol abolished TNF-α/CHX-induced increase in ROS production and caspase-3/7 activity, but apoptosis was only partially prevented. MODE-K cells are sensitive to TNF-α-induced apoptosis in the presence of CHX, which is associated with increased intracellular ROS production and caspase-3/7 activation. The effects were partially mitigated by CORM-A1, nitrite and resveratrol. Thus, these agents could be of potential use in protecting the epithelial barrier against oxidative stress during intestinal ischemia/reperfusion injury.

Cell replacement therapy with stem cells holds tremendous therapeutic potential for treating neurodegenerative diseases. Over the last decade, molecular imaging techniques have proven to be of great value in tracking transplanted cells and assessing the therapeutic efficacy. This current review summarizes the role and capabilities of different molecular imaging modalities including optical imaging, nuclear imaging and magnetic resonance imaging in the field of stem cell therapy for neurodegenerative disorders. We discuss current challenges and perspectives of these techniques and encompass updated information such as theranostic imaging and optogenetics in stem cell-based treatment of neurodegenerative diseases.