Cerebral microvascular matrix metalloproteinase-3 (MMP3) contributes to vascular injury after stroke in female diabetic rats

Extracellular(Serum) Levels of Matrix Metalloproteinases in Pediatric Type 1 Diabetes Mellitus and Association with Diabetic Ketoacidosis and Cerebral Edema

Background

Type 1 diabetes mellitus (T1DM) in children is associated with acute complications such as diabetic ketoacidosis (DKA) and the severe risk of diabetic ketoacidosis-related cerebral edema (DKACE). Matrix metalloproteinases (MMPs) are implicated in inflammation and tissue remodeling, potentially contributing to these complications. This study explores the role of MMPs as biomarkers in pediatric T1DM patients with DKA and DKACE.

Methods

We conducted a systematic cross-sectional study at Jiangxi Children's Hospital, enrolling 56 pediatric patients with T1DM, categorized into three groups: T1DM without complications, DKA, and DKACE. Serum levels of MMP-2, MMP-3, and MMP-9 were measured through ELISA. Statistical analyses assessed correlations between MMPs, glucose metabolism, and inflammatory markers, evaluating potential biomarker utility in disease characterization.

Results

MMP-3 and MMP-9 levels were significantly elevated in the DKACE group compared to the T1DM and DKA groups, exhibiting strong correlations with decreased pH and bicarbonate levels (both p < 0.001). MMP-2 levels were reduced in DKACE, correlating positively with pH and bicarbonate levels. Post-clinical improvement analyses demonstrated no significant differences in MMP levels between DKA and DKACE groups, suggesting stabilization post-treatment regardless of initial acidosis severity.

Conclusion

The distinct patterns of MMP-3 and MMP-9 elevations in DKACE highlight their potential as biomarkers for identifying and monitoring severe DKA complications. The findings suggest these enzymes play a significant role in cerebral edema pathophysiology, making them viable targets for future therapeutic interventions.

MMP-3 Knockout Induces Global Transcriptional Changes and Reduces Cerebral Infarction in Both Male and Female Models of Ischemic Stroke

Ischemic stroke followed by reperfusion (IR) leads to extensive cerebrovascular injury characterized by neuroinflammation and brain cell death. Inhibition of matrix metalloproteinase-3 (MMP-3) emerges as a promising therapeutic approach to mitigate IR-induced stroke injury. We employed middle cerebral artery occlusion with subsequent reperfusion (MCAO/R) to model ischemic stroke in adult mice. Specifically, we investigated the impact of MMP-3 knockout (KO) on stroke pathophysiology using RNA sequencing (RNA-seq) of stroke brains harvested 48 h post-MCAO. MMP-3 KO significantly reduced brain infarct size following stroke. Notably, RNA-seq analysis showed that MMP-3 KO altered expression of 333 genes (252 downregulated) in male stroke brains and 3768 genes (889 downregulated) in female stroke brains. Functional pathway analysis revealed that inflammation, integrin cell surface signaling, endothelial- and epithelial-mesenchymal transition (EndMT/EMT), and apoptosis gene signatures were decreased in MMP-3 KO stroke brains. Intriguingly, MMP-3 KO downregulated gene signatures more profoundly in females than in males, as indicated by greater negative enrichment scores. Our study underscores MMP-3 inhibition as a promising therapeutic strategy, impacting multiple cellular pathways following stroke.

Single-cell transcriptome analysis of cavernous tissues reveals the key roles of pericytes in diabetic erectile dysfunction

Erectile dysfunction (ED) affects a significant proportion of men aged 40-70 and is caused by cavernous tissue dysfunction. Presently, the most common treatment for ED is phosphodiesterase 5 inhibitors; however, this is less effective in patients with severe vascular disease such as diabetic ED. Therefore, there is a need for development of new treatment, which requires a better understanding of the cavernous microenvironment and cell-cell communications under diabetic condition. Pericytes are vital in penile erection; however, their dysfunction due to diabetes remains unclear. In this study, we performed single-cell RNA sequencing to understand the cellular landscape of cavernous tissues and cell type-specific transcriptional changes in diabetic ED. We found a decreased expression of genes associated with collagen or extracellular matrix organization and angiogenesis in diabetic fibroblasts, chondrocytes, myofibroblasts, valve-related lymphatic endothelial cells, and pericytes. Moreover, the newly identified pericyte-specific marker, Limb Bud-Heart (Lbh), in mouse and human cavernous tissues, clearly distinguishing pericytes from smooth muscle cells. Cell-cell interaction analysis revealed that pericytes are involved in angiogenesis, adhesion, and migration by communicating with other cell types in the corpus cavernosum; however, these interactions were highly reduced under diabetic conditions. Lbh expression is low in diabetic pericytes, and overexpression of LBH prevents erectile function by regulating neurovascular regeneration. Furthermore, the LBH-interacting proteins (Crystallin Alpha B and Vimentin) were identified in mouse cavernous pericytes through LC-MS/MS analysis, indicating that their interactions were critical for maintaining pericyte function. Thus, our study reveals novel targets and insights into the pathogenesis of ED in patients with diabetes.

Advancing stroke therapy: A deep dive into early phase of ischemic stroke and recanalization

Ischemic stroke, accounting for the majority of stroke events, significantly contributes to global morbidity and mortality. Vascular recanalization therapies, namely intravenous thrombolysis and mechanical thrombectomy, have emerged as critical interventions, yet their success hinges on timely application and patient-specific factors. This review focuses on the early phase pathophysiological mechanisms of ischemic stroke and the nuances of recanalization. It highlights the dual role of neutrophils in tissue damage and repair, and the critical involvement of the blood-brain barrier (BBB) in stroke outcomes. Special emphasis is placed on ischemia-reperfusion injury, characterized by oxidative stress, inflammation, and endothelial dysfunction, which paradoxically exacerbates cerebral damage post-revascularization. The review also explores the potential of targeting molecular pathways involved in BBB integrity and inflammation to enhance the efficacy of recanalization therapies. By synthesizing current research, this paper aims to provide insights into optimizing treatment protocols and developing adjuvant neuroprotective strategies, thereby advancing stroke therapy and improving patient outcomes.