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Background and Aims: Preclinical data suggest that activation of the adaptive immune system is critical for myocardial repair processes in acute myocardial infarction. The aim of the present study was to determine the clinical value of baseline effector T cell chemokine IP-10 blood levels in the acute phase of ST-segment elevation myocardial infarction (STEMI) for the prediction of the left ventricular function changes and cardiovascular outcomes after STEMI., Methods: Serum IP-10 levels were retrospectively quantified in two independent cohorts of STEMI patients undergoing primary percutaneous coronary intervention., Results: We report a biphasic response of the effector T cell trafficking chemokine IP-10 characterized by an initial increase of its serum levels in the acute phase of STEMI followed by a rapid reduction at 90min post reperfusion. Patients at the highest IP-10 tertile presented also with more CD4 effector memory T cells (CD4 T EM cells), but not other T cell subtypes, in blood. In the Newcastle cohort (n=47), patients in the highest IP-10 tertile or CD4 T EM cells at admission exhibited an improved cardiac systolic function 12 weeks after STEMI compared to patients in the lowest IP-10 tertile. In the Heidelberg cohort (n=331), STEMI patients were followed for a median of 540 days for major adverse cardiovascular events (MACE). Patients presenting with higher serum IP-10 levels at admission had a lower risk for MACE after adjustment for traditional risk factors, CRP and high-sensitivity troponin-T levels (highest vs. rest quarters: HR [95% CI]=0.420 [0.218-0.808])., Conclusion: Increased serum levels of IP-10 in the acute phase of STEMI predict a better recovery in cardiac systolic function and less adverse events in patients after STEMI., Competing Interests: MM-H. reports consulting fees for Zoll CMS GmbH, research funding from Roche Diagnostics and BRAHMS Thermo Scientific. NF has received lecture fees from AstraZeneca, Boehringer Ingelheim, Bayer Vital and consulting fees for Boehringer Ingelheim, all of which not related to the subject in this manuscript. DD reports consulting and speaker fees from Bayer Healthcare, Boston Scientific, Daiichi Sankyo, AstraZeneca, and research grants from DFG, DZHK. EG has received honoraria for lectures from AstraZeneca, Daiichi Sankyo and Roche Diagnostics, consulting fees for BRAHMS Deutschland, Roche Diagnostics, AstraZeneca, Daiichi and Novo Nordisk, research funding from Daiichi and Roche Diagnostics. IS receives research grants from Kancera AB and Astra Zaneca. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Sopova, Tual-Chalot, Mueller-Hennessen, Vlachogiannis, Georgiopoulos, Biener, Sachse, Turchinovich, Polycarpou-Schwarz, Spray, Maneta, Bennaceur, Mohammad, Richardson, Gatsiou, Langer, Frey, Stamatelopoulos, Heineke, Duerschmied, Giannitsis, Spyridopoulos and Stellos.)

The brain and spinal cord are immune-privileged organs, but in the disease state protection mechanisms such as the blood brain barrier (BBB) are ineffective or overcome by pathological processes. In neuroinflammatory diseases, microglia cells and other resident immune cells contribute to local vascular inflammation and potentially a systemic inflammatory response taking place in parallel. Microglia cells interact with other cells impacting on the integrity of the BBB and propagate the inflammatory response through the release of inflammatory signals. Here, we discuss the activation and response mechanisms of innate and adaptive immune processes in response to neuroinflammation. Furthermore, the clinical importance of neuroinflammatory mediators and a potential translational relevance of involved mechanisms are addressed also with focus on non-classical immune cells including microglia cells or platelets. As illustrative examples, novel agents such as Anfibatide or Revacept, which result in reduced recruitment and activation of platelets, a subsequently blunted activation of the coagulation cascade and further inflammatory process, demonstrating that mechanisms of neuroinflammation and thrombosis are interconnected and should be further subject to in depth clinical and basic research., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sun and Langer.)

Beyond platelets function in hemostasis, there is emerging evidence to suggest that platelets contribute crucially to inflammation and immune responses. Therefore, considering the detrimental role of inflammatory conditions in severe neurological disorders such as multiple sclerosis or stroke, this review outlines platelets involvement in neuroinflammation. For this, distinct mechanisms of platelet-mediated thrombosis and inflammation are portrayed, focusing on the interaction of platelet receptors with other immune cells as well as brain endothelial cells. Furthermore, we draw attention to the intimate interplay between platelets and the complement system as well as between platelets and plasmatic coagulation factors in the course of neuroinflammation. Following the thorough exposition of preclinical approaches which aim at ameliorating disease severity after inducing experimental autoimmune encephalomyelitis (a counterpart of multiple sclerosis in mice) or brain ischemia-reperfusion injury, the clinical relevance of platelet-mediated neuroinflammation is addressed. Thus, current as well as future propitious translational and clinical strategies for the treatment of neuro-inflammatory diseases by affecting platelet function are illustrated, emphasizing that targeting platelet-mediated neuroinflammation could become an efficient adjunct therapy to mitigate disease severity of multiple sclerosis or stroke associated brain injury., (Copyright © 2020 Rawish, Nording, Münte and Langer.)

Besides mediating hemostatic functions, platelets are increasingly recognized as important players of inflammation. Data from experiments in mice and men revealed various intersection points between thrombosis, hemostasis, and inflammation, which are addressed and discussed in this review in detail. One such example is the intrinsic coagulation cascade that is initiated after platelet activation thereby further propagating and re-enforcing wound healing or thrombus formation but also contributing to the pathophysiology of severe diseases. FXII of the intrinsic pathway connects platelet activation with the coagulation cascade during immune reactions. It can activate the contact system thereby either creating an inflammatory state or accelerating inflammation. Recent insights into platelet biology could show that platelets are equipped with complement receptors. Platelets are important for tissue remodeling after injury has been inflicted to the endothelial barrier and to the subendothelial tissue. Thus, platelets are increasingly recognized as more than just cells relevant for bleeding arrest. Future insights into platelet biology are to be expected. This research will potentially offer novel opportunities for therapeutic intervention in diseases featuring platelet abundance.

Platelets contribute to processes beyond thrombus formation and may play a so far underestimated role as an immune cell in various circumstances. This review outlines immune functions of platelets in host defense, but also how they may contribute to mechanisms of infectious diseases. A particular emphasis is placed on the interaction of platelets with other immune cells. Furthermore, this article outlines the features of atherosclerosis as an inflammatory vascular disease highlighting the role of platelet crosstalk with cellular and soluble factors involved in atheroprogression. Understanding, how platelets influence these processes of vascular remodeling will shed light on their role for tissue homeostasis beyond intravascular thrombosis. Finally, translational implications of platelet-mediated inflammation in atherosclerosis are discussed.