Biology subjects

Gorressen, S.

Publications and source records attributed to Gorressen, S..

3 recordsLinked to original sources

bioRxiv2026

The heart-liver axis controls platelet turnover by hepatic STAT3 phosphorylation and TPO regulation after acute myocardial infarction

Background: Platelets play a critical role in thrombo-inflammation following acute myocardial infarction (AMI). Objectives: Their impact on hepatic thrombopoietin (TPO) regulation after AMI remains poorly understood to date. Methods: Wildtype, thrombocytopenic or GPVI deficient mice underwent ischemia/reperfusion (I/R) injury. Platelet activation and turnover, and hepatic expression of different receptors involved in TPO regulation were analyzed. Results: Here, we identify a heart-liver axis that dynamically regulates platelet production post AMI. An elevated platelet turnover with increased reticulated as well as desialylated platelets early after AMI was detected. This was accompanied by the upregulation of specific receptors such as Asgr1/2 and IL-6R and increased phosphorylation of STAT3 in the liver and elevated numbers of megakaryocytes in spleen tissue. Consequently, increased TPO plasma levels at 24h post AMI were detected and platelet counts were rapidly restored after AMI. Platelet depletion induces a compensatory increase in hepatic TPO expression and plasma TPO levels, accompanied by dysregulated STAT3 signaling. This response contrasts with GPVI-deficient (Gp6-/-) mice, which exhibit no major alterations in TPO regulation, suggesting distinct mechanisms between acute thrombocytopenia and chronic platelet receptor deficiency in platelet homeostasis after AMI. These findings provide the first evidence of a direct heart-liver axis regulating platelet homeostasis after AMI, driven by inflammatory and hepatic signaling pathways. Conclusions: Our study highlights a previously unrecognized role of the heart-liver axis in controlling platelet turnover, with hepatic STAT3 signaling as a key mediator. These insights enhance our understanding of post AMI platelet homeostasis and may be critical for future therapeutic strategies.

molecular biology↗

bioRxiv2025

Elevated IL-1 beta plasma levels, altered platelet activation and cardiac remodeling lead to moderately decreased LV function in Alzheimer transgenic mice after myocardial ischemia and reperfusion

IntroductionNeurodegeneration and dementia are key factors in Alzheimers disease (AD). The deposition of amyloid-{beta} into senile plaques in the brain parenchyma and in cerebral vessels known as cerebral amyloid angiopathy (CAA) are the main clinical parameters of AD. Acute myocardial infarction (AMI) and AD share a comparable pathophysiology. In detail, AMI survivors have a higher risk of vascular dementia and AD patients with AMI face a poor prognosis with a high rate of major adverse cardiovascular events. High blood levels of amyloid-{beta}40 are identified in patients with high risk for cardiovascular death. However, the underlying mechanisms and the consequences of AMI in AD patients are unclear to date. MethodsAD transgenic APP23 mice were analysed in an experimental AMI using the closed-chest model. ResultsAPP23 mice displayed significantly decreased left ventricular function as detected by FS/MPI (fractional shortening/myocardial performance index) after 24 h and 3 weeks after ligation of the LAD compared to WT controls. No differences have been observed in infarct and scar size. However, the analysis of cardiac remodeling after 3 weeks showed an altered composition of the collagen tissue of the scar with elevated tight but reduced fine collagen in APP23 mice. Altered scar formation was accompanied by elevated degranulation of platelets following activation of the collagen receptor GPVI. ConclusionThe here presented results suggest that AD patients are at higher risk for cardiac damage after AMI that might increase the risk for cardiovascular death. This implies the need of a personalized therapy of AMI in AD patients.

neuroscience↗

bioRxiv2024

Platelets induce cell apoptosis of cardiac cells via FasL after acute myocardial infarction

Acute myocardial infarction (AMI) is one of the leading causes of death worldwide. Cell apoptosis in the myocardium plays an important role in ischemia and reperfusion (I/R) injury, leading to cardiac damage and dysfunction. Platelets are major players of hemostasis and play a crucial role in vessel occlusion, inflammation and cardiac remodeling after I/R. Here, we studied the impact of platelets on cell apoptosis in the myocardium using a close-chest mouse model of AMI. We found caspase-3 positive resident cardiac cells while leukocytes were negative for caspase-3. Using two different mouse models of thrombocytopenia, we detected a significant reduction of caspase-3 positive cells in the infarct border zone after I/R injury. Further, we identified platelet FasL to induce cell apoptosis via the extrinsic pathway of Fas receptor activation of target cells. Mechanistically, hypoxia triggers platelet adhesion to FasR suggesting that platelet induced apoptosis is elevated after I/R. Platelet-specific FasL knock-out mice showed reduced Bax and BcL-2 expression suggesting that platelets modulate the intrinsic and the extrinsic pathway of apoptosis leading to reduced infarct size after myocardial I/R injury. Therefore, platelet induced cardiac damage needs to be taken into account while optimizing antithrombotic/antiplatelet strategies for patients with AMI.

molecular biology↗