Influence of pregnancy on gene expression in rabbit articular cartilage

AbstractObjective: Articular cartilage is known to be influenced by estrogen and the pregnancy-associated hormone, relaxin,in vitro. Such observations have raised the possibility that articular cartilage in females may be subjected to unique regulatory influences by such hormonesin vivo. The purpose of this study was to evaluate mRNA levels for several relevant molecules in the articular cartilage of pregnant and non-pregnant rabbits.Design: Total RNA was extracted from New Zealand White rabbit knee articular cartilage using the TRIspin method. The total RNA was reverse transcribed and analysed by the sensitive molecular technique of semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) using rabbit specific primer sets.Results: Total RNA yield from articular cartilage from primigravida rabbits was reduced to 65% of age-matched control values (P=0.0003); however the yield from multiparous animals was not significantly depressed. In both cases, DNA yields were not affected by pregnancy. There was a general tendency for depressed mRNA levels for most genes investigated in cartilage from pregnant animals. Articular cartilage from multiparous rabbits showed a significant decrease in mRNA levels for relevant molecules such as type II collagen, biglycan, collagenase and tissue inhibitors of metalloproteinases (TIMP)-1, as well as necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS) and cyclo-oxygenase 2 (COX-2). Transcripts for collagenase and lumican were significantly lower in cartilage from primigravida rabbits. Transforming growth factor β1 (TGF-β1) transcript levels were significantly decreased in both pregnant groups. In contrast, basic fibroblast growth factor (bFGF) and insulin-like growth factor-2 (IGF-2) mRNA levels were significantly decreased in cartilage from primigravida rabbits, whereas transcripts for these molecules were upregulated in the cartilage of multiparous rabbits.Conclusions: The present study demonstrates that regulation of RNA levels in articular cartilage during pregnancy is complex and is influenced by the parity and/or the skeletal maturity of the animals

Neuropeptides regulate expression of matrix molecule, growth factor and inflammatory mediator mRNA in explants of normal and healing medial collateral ligament

Abstract Denervation degrades normal ligament properties and impairs ligament healing. This suggests that secreted neuromediators, such as neuropeptides, could be modulating cell metabolism in ligament and scar tissue. To test this hypothesis we investigated the effect of exogenous substance P (SP), neuropeptide Y (NPY) or calcitonin gene-related peptide (CGRP) on the mRNA levels for proteins associated with inflammation, angiogenesis, and matrix production in tissue-cultured specimens of normal and injured medial collateral ligament. SP and NPY induced increased mRNA levels for several inflammatory mediators in the 2-week post-injury specimens. All three neuropeptides induced decreases in mRNA levels for healing-associated growth factors and matrix molecules, including basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF) and collagen types I and III. The results indicate that neuropeptides strongly influence the metabolic activity of cells in healing ligament, particularly at early time points after injury

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

PXL01 in sodium hyaluronate results in increased PRG4 expression: a potential mechanism for anti-adhesion

Purpose: To investigate the anti-adhesive mechanisms of PXL01 in sodium hyaluronate (HA) by using the rabbit lactoferrin peptide, rabPXL01 in HA, in a rabbit model of healing tendons and tendon sheaths. The mechanism of action for PXL01 in HA is interesting since a recent clinical study of the human lactoferrin peptide PXL01 in HA administered around repaired tendons in the hand showed improved digit mobility. Materials and methods: On days 1, 3, and 6 after tendon injury and surgical repair, reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) was used to assess mRNA expression levels for genes encoding the mucinous glycoprotein PRG4 (also called lubricin) and a subset of matrix proteins, cytokines, and growth factors involved in flexor tendon repair. RabPXL01 in HA was administered locally around the repaired tendons, and mRNA expression was compared with untreated repaired tendons and tendon sheaths. Results: We observed, at all time points, increased expression of PRG4 mRNA in tendons treated with rabPXL01 in HA, but not in tendon sheaths. In addition, treatment with rabPXL01 in HA led to repression of the mRNA levels for the pro-inflammatory mediators interleukin (IL)-1β, IL-6, and IL-8 in tendon sheaths. Conclusions: RabPXL01 in HA increased lubricin mRNA production while diminishing mRNA levels of inflammatory mediators, which in turn reduced the gliding resistance and inhibited the adhesion formation after flexor tendon repair

Diet-induced obesity leads to pro-inflammatory alterations to the vitreous humour of the eye in a rat model

The purpose of this study was to investigate if diet-induced obesity (DIO) and subsequent low-level systemic inflammation would result in local increases in pro-inflammatory mediators in the vitreous humour (VH) of the eyes of rats