Ryan D. Sullivan

A bioengineered version of recombinant tissue plasminogen activator, i.e., tenecteplase (TNK-tPA), was designed to have a longer half-life, resistance to plasminogen activator inhibitor-1, and fibrin-targeted plasminogen activation. By comparison to tPA, clinical trials suggest that TNK-tPA may be less susceptible to the effects of alpha2-antiplasmin (α2AP), the primary inhibitor of thrombus dissolution. However, preclinical studies are limited, and whether α2AP affects TNK-tPA’s fibrinolytic activity or efficacy in experimental ischemic stroke is unknown. We examined the effects of TNK-tPA and α2AP on the dissolution of human plasma clots (in vitro) and experimental ischemic brain injury from stroke induced by transient middle cerebral artery ischemia. TNK-tPA induced a dose-dependent increase in plasma clot dissolution; inhibition of α2AP with a specific monoclonal antibody caused a synergistic increase in TNK-tPA-mediated clot dissolution. In experimental ischemic stroke with ischemia and reperfusion, TNK-tPA treatment of α2AP^−/− mice significantly reduced ischemic infarct volume, brain swelling, brain hemorrhage, and neurobehavioral disability vs. TNK-tPA-treated α2AP^+/+ (C57BL/6 background) mice with normal α2AP levels (p < 0.05 to p < 0.0001). α2AP impairs the dissolution of human clots in vitro by TNK-tPA and significantly exacerbates ischemic brain injury, swelling, hemorrhage, and neurobehavioral disability after experimental stroke, even with reperfusion. Targeting α2AP may improve the efficacy of TNK-tPA and reduce hemorrhagic complications.

BACKGROUND: Recent randomized trials showed no benefit of mechanical thrombectomy (MT) for ischemic stroke due to distal medium vessel occlusion (DMVO). We sought to understand the use of MT for DMVO stroke treatment before and after the publication of these trials. METHODS: We conducted an email survey of 47 comprehensive stroke centers across the United States, which are participating in a National Institutes of Health–funded randomized controlled trial (RCT; Unique identifier: NCT05948566). The questionnaire was developed and modified with expert feedback. Site principal investigators were asked to discuss the DMVO RCT results with their local clinical teams and to subsequently respond to survey questions in a manner that reflected team-based decision-making regarding MT for DMVO before and after the publication of the RCTs, considering the location of the vessel occlusion (nondominant M2 versus M3/M4/A1/A2). If the site principal investigator was responsible for >1 site with the same stroke team, only 1 survey response was tallied. RESULTS: Of the 43 site principal investigators surveyed representing 47 unique sites, 40 (93%) representing 44 unique sites completed the survey. Before the DMVO RCTs, 95% of respondents were treating nondominant M2 occlusions with MT. Only 15% will continue to be treated with MT, while 57.5% said that treatment was dependent on at least ≥1 variable following presentation of the DMVO RCTs. For all other anterior circulation DMVOs, 50% were treating DMVOs with MT before RCT results’ presentation. Only 7.5% will continue to treat with MT, while 32.5% said that treatment was dependent on at least 1 other variable following presentation of the DMVO RCTs. The most common variable named by survey respondents as important to treatment decision was symptom severity. CONCLUSIONS: In this survey of comprehensive stroke centers, the DMVO RCT results created a significant practice change in how stroke teams approach anterior circulation DMVO stroke with MT.

According to the statistical updates from the Centers for Disease Control and Prevention and American Heart Association in conjunction with the National Institutes of Health

Matrix metalloproteinases (MMPs) such as MMP-9, 3, and 2 degrade the cellular matrix and are believed to play a crucial role in ischemic stroke. We examined how the duration of ischemia (up to 4 h) and treatment with recombinant tissue plasminogen activator altered the comparative expression of these MMPs in experimental ischemic stroke with reperfusion. Both prolonged ischemia and r-tPA treatment markedly increased MMP-9 expression in the ischemic hemisphere (all p < 0.0001). The duration of ischemia and r-tPA treatment also significantly increased MMP-2 expression (p < 0.01–0.001) in the ischemic hemisphere (p < 0.01) but to a lesser degree than MMP-9. In contrast, MMP-3 expression significantly decreased in the ischemic hemisphere (p < 0.001) with increasing duration of ischemia and r-tPA treatment (p < 0.05–0001). MMP-9 expression was prominent in the vascular compartment and leukocytes. MMP-2 expression was evident in the vascular compartment and MMP-3 in NeuN+ neurons. Prolonging the duration of ischemia (up to 4 h) before reperfusion increased brain hemorrhage, infarction, swelling, and neurologic disability in both saline-treated (control) and r-tPA-treated mice. MMP-9 and MMP-2 expression were significantly positively correlated with, and MMP-3 was significantly negatively correlated with, infarct volume, swelling, and brain hemorrhage. We conclude that in experimental ischemic stroke with reperfusion, the duration of ischemia and r-tPA treatment significantly altered MMP-9, 3, and 2 expression, ischemic brain injury, and neurological disability. Each MMP showed unique patterns of expression that are strongly correlated with the severity of brain infarction, swelling, and hemorrhage. In summary, in experimental ischemic stroke in male mice with reperfusion, the duration of ischemia, and r-tPA treatment significantly altered the immunofluorescent expression of MMP-9, 3, and 2, ischemic brain injury, and neurological disability. In this model, each MMP showed unique patterns of expression that were strongly correlated with the severity of brain infarction, swelling, and hemorrhage.

In heart failure with reduced ejection fraction (HFrEF), cardiogenic edema develops from impaired cardiac function, pathological remodeling, chronic inflammation, endothelial dysfunction, neurohormonal activation, and altered nitric oxide-related pathways. Pre-clinical HFrEF studies have shown that treatment with sodium–glucose cotransporter-2 inhibitors (SGLT-2i) stimulates natriuretic and osmotic/diuretic effects, improves overall cardiac function, attenuates maladaptive cardiac remodeling, and reduces chronic inflammation, oxidative stress, and endothelial dysfunction. Here, we review the mechanisms and effects of SGLT-2i therapy on cardiogenic edema in various models of HFrEF. Overall, the data presented suggest a high translational importance of these studies, and pre-clinical studies show that SGLT-2i therapy has a marked effect on suppressing the progression of HFrEF through multiple mechanisms, including those that affect the development of cardiogenic edema.

Symptomatic heart failure with reduced ejection fraction (HFrEF) is characterized by edema and chronic pathological activation of the classical renin–angiotensin–aldosterone system (RAAS). The soluble (pro)renin receptor (s(P)RR) is released into circulation by proteolytic cleavage of tissue expressed (P)RR and is a candidate biomarker of RAAS activation. However, previous studies linked elevated levels of s(P)RR in patients with HFrEF to renal dysfunction. Utilizing prospectively enrolled patients with comparable rEF, we show that increased plasma levels of s(P)RR are associated with symptomatic HF (characterized by edema), independent of chronic renal dysfunction. We also found that s(P)RR levels were positively correlated with patient plasma renin activity (PRA). Normotensive mice with dilated cardiomyopathy (DCM) and HFrEF, without renal dysfunction, showed plasma s(P)RR and PRA patterns similar to human HFrEF patients. Plasma s(P)RR levels positively correlated with PRA and systemic edema, but not with EF, resembling findings in patients with HFrEF without chronic kidney dysfunction. In female DCM mice with elevated PRA levels and plasma s(P)RR levels, a randomized, blinded trial comparing the direct renin inhibitor, aliskiren vs. vehicle control, showed that direct renin inhibition normalized PRA, lowered s(P)RR, and prevented symptomatic HFrEF. Considered in light of previous findings, these data suggest that, in HFrEF, in the absence of renal dysfunction, elevation of plasma s(P)RR levels is caused by increased PRA and associated with the development of systemic edema.

The prevalence of heart failure (HF) with reduced (r) and preserved (p) ejection fraction (EF) continues to rise globally despite current advances in diagnostics and improvements to medical management

Pathological sodium-water retention or edema/congestion is a primary cause of heart failure (HF) decompensation, clinical symptoms, hospitalization, reduced quality of life, and premature mortality. Sodium-glucose cotransporter-2 inhibitors (SGLT-2i) based therapies reduce hospitalization due to HF, improve functional status, quality, and duration of life in patients with HF with reduced ejection fraction (HFrEF) independently of their glycemic status. The pathophysiologic mechanisms and molecular pathways responsible for the benefits of SGLT-2i in HFrEF remain inconclusive, but SGLT-2i may help HFrEF by normalizing salt-water homeostasis to prevent clinical edema/congestion. In HFrEF, edema and congestion are related to compromised cardiac function. Edema and congestion are further aggravated by renal and pulmonary abnormalities. Treatment of HFrEF patients with SGLT-2i enhances natriuresis/diuresis, improves cardiac function, and reduces natriuretic peptide plasma levels. In this review, we summarize current clinical research studies related to outcomes of SGLT-2i treatment in HFrEF with a specific focus on their contribution to relieving or preventing edema and congestion, slowing HF progression, and decreasing the rate of rehospitalization and cardiovascular mortality.

We report that the pathogenic role of ST2-mediated type 2 immunity and mechanisms contribute to RSV-associated pulmonary hypertension. Inhibiting ST2 signaling may be a novel therapeutic target for this condition.

Sodium restriction is often recommended in heart failure (HF) to block symptomatic edema, despite limited evidence for benefit. However, a low-sodium diet (LSD) activates the classical renin-angiotensin-aldosterone system (RAAS), which may adversely affect HF progression and mortality in patients with dilated cardiomyopathy (DCM). We performed a randomized, blinded pre-clinical trial to compare the effects of a normal (human-equivalent) sodium diet and a LSD on HF progression in a normotensive model of DCM in mice that has translational relevance to human HF. The LSD reduced HF progression by suppressing the development of pleural effusions (p < 0.01), blocking pathological increases in systemic extracellular water (p < 0.001) and prolonging median survival (15%, p < 0.01). The LSD activated the classical RAAS by increasing plasma renin activity, angiotensin II and aldosterone levels. However, the LSD also significantly up-elevated the counter-regulatory RAAS by boosting plasma angiotensin converting enzyme 2 (ACE2) and angiotensin (1–7) levels, promoting nitric oxide bioavailability and stimulating 3′-5′-cyclic guanosine monophosphate (cGMP) production. Plasma HF biomarkers associated with poor outcomes, such as B-type natriuretic peptide and neprilysin were decreased by a LSD. Cardiac systolic function, blood pressure and renal function were not affected. Although a LSD activates the classical RAAS system, we conclude that the LSD delayed HF progression and mortality in experimental DCM, in part through protective stimulation of the counter-regulatory RAAS to increase plasma ACE2 and angiotensin (1–7) levels, nitric oxide bioavailability and cGMP production.