Regulation of valve endothelial cell vasculogenic network architectures with ROCK and Rac inhibitors.

OBJECTIVE: The age- and disease-dependent presence of microvessels within heart valves is an understudied characteristic of these tissues. Neovascularization involves endothelial cell (EC) migration and cytoskeletal reorientation, which are heavily regulated by the Rho family of GTPases. Given that valve ECs demonstrate unique mesenchymal transdifferentiation and cytoskeletal mechanoresponsiveness, compared to vascular ECs, this study quantified the effect of inhibiting two members of the Rho family on vasculogenic network formation by valve ECs. APPROACH AND RESULTS: A tubule-like structure vasculogenesis assay (assessing lacunarity, junction density, and vessel density) was performed with porcine aortic valve ECs treated with small molecule inhibitors of Rho-associated serine-threonine protein kinase (ROCK), Y-27632, or the Rac1 inhibitor, NSC-23766. Actin coordination, cell number, and cell migration were assessed through immunocytochemistry, MTT assay, and scratch wound healing assay. ROCK inhibition reduced network lacunarity and interrupted proper cell-cell adhesion and actin coordination. Rac1 inhibition increased lacunarity and delayed actin-mediated network formation. ROCK inhibition alone significantly inhibited migration, whereas both ROCK and Rac1 inhibition significantly reduced cell number over time compared to controls. Compared to a vascular EC line, the valve ECs generated a network with larger total vessel length, but a less smooth appearance. CONCLUSIONS: Both ROCK and Rac1 inhibition interfered with key processes in vascular network formation by valve ECs. This is the first report of manipulation of valve EC vasculogenic organization in response to small molecule inhibitors. Further study is warranted to comprehend this facet of valvular cell biology and pathology and how it differs from vascular biology.

The gut microbiome regulates the clinical efficacy of sulfasalazine therapy for IBD-associated spondyloarthritis.

Sulfasalazine is a prodrug known to be effective for the treatment of inflammatory bowel disease (IBD)-associated peripheral spondyloarthritis (pSpA), but the mechanistic role for the gut microbiome in regulating its clinical efficacy is not well understood. Here, treatment of 22 IBD-pSpA subjects with sulfasalazine identifies clinical responders with a gut microbiome enriched in Faecalibacterium prausnitzii and the capacity for butyrate production. Sulfapyridine promotes butyrate production and transcription of the butyrate synthesis gene but in F. prausnitzii in vitro, which is suppressed by excess folate. Sulfasalazine therapy enhances fecal butyrate production and limits colitis in wild-type and gnotobiotic mice colonized with responder, but not non-responder, microbiomes. F. prausnitzii is sufficient to restore sulfasalazine protection from colitis in gnotobiotic mice colonized with non-responder microbiomes. These findings reveal a mechanistic link between the efficacy of sulfasalazine therapy and the gut microbiome with the potential to guide diagnostic and therapeutic approaches for IBD-pSpA.

Factors associated with delayed enteral nutrition in the intensive care unit: a propensity score-matched retrospective cohort study.

BACKGROUND: Guidelines recommend enteral nutrition (EN) within 48 h of admission to the medical intensive care unit (ICU) in appropriate patients. However, delayed EN is still common. OBJECTIVES: This study sought to identify risk factors for delayed EN ordering in the ICU and to examine its association with patient outcomes. METHODS: This was a retrospective study from 2010-2018. Adult patients were included if they were admitted to the medical ICU for >48 h, were appropriate for EN, and had an order for EN placed within 30 d of admission. The primary outcome was ordering of EN, classified as early if ordered within 48 h of ICU admission and otherwise as delayed. Propensity score matching was used to examine the relation between delayed EN and ICU-free days, and outcomes such as length of ICU admission, length of hospitalization during 30 d of follow-up, and mortality. RESULTS: A total of 738 (79%) patients received early EN and 196 (21%) received delayed EN. The exposures most strongly associated with delayed EN were order placement by a Doctor of Medicine compared with a dietitian [adjusted OR (aOR): 2.58; 95% CI: 1.57, 4.24] and use of vasopressors within 48 h of ICU admission (aOR: 1.78; 95% CI: 1.22, 2.59). After propensity score matching to balance baseline characteristics, delayed EN ordering was significantly associated with fewer ICU-free days, longer ICU admissions, and longer hospitalizations, but not mortality, compared with early EN. CONCLUSIONS: Provider-level factors were associated with delayed ordering of EN which itself was associated with worse outcomes. Interventions directed at providers may increase timely EN in the ICU and improve outcomes.

Premedication Use in Preventing Acute Infliximab Infusion Reactions in Patients with Inflammatory Bowel Disease: A Single Center Cohort Study.

BACKGROUND: Infliximab (IFX) is commonly used in patients with inflammatory bowel disease. One common side effect of IFX is an acute infusion reaction. Despite the lack of evidence supporting their use, clinicians use various premedications to prevent acute reactions. We evaluated the effectiveness of premedications in the prevention of acute IFX infusion reactions. METHODS: A retrospective cohort study was performed identifying patients with a diagnosis of inflammatory bowel disease who received IFX at our institution. Information about each IFX infusion was recorded, including the dose, infusion rate, use of premedications, and any reactions. Infusions were stratified into low and high risk. In the high- and low-risk groups, the relative risk was calculated for each premedication combination used in our institution. RESULTS: Seven hundred seventy-three patients were identified; 578 patients (7090 infusions) met inclusion criteria and were included for analysis. Nine hundred eighty-six high-risk infusions were isolated; 620 (62.8%) of these infusions were administered with premedications (diphenhydramine and/or hydrocortisone) and 53 (5.4%) reactions occurred. Six thousand one hundred four low-risk infusions were identified; 2253 (36.9%) of these infusions had premedications and 61 (1.0%) reactions occurred. In both groups, none of the premedications used resulted in a significantly lower reaction rate compared with no premedication use. CONCLUSIONS: In both the high- and low-risk cohorts in this study, premedication use was not effective in reducing the rate of acute IFX reactions. Given this, routine premedication use is not recommended without future randomized control trials to demonstrate efficacy.