Project description:Mitral valve prolapse (MVP) is often benign but can progress to mitral regurgitation, requiring invasive treatment. In mgR mice with hypomorphic Fbn1 mutations?mimicking Marfan syndrome?myxomatous mitral degeneration and regurgitation develop by 12 weeks. TGF-? and mTOR signaling activation, along with macrophage infiltration, appear by 4 weeks, before histological changes. Short-term rapamycin treatment blocks early TGF-? activation and inflammation, while long-term mTOR or TGF-? inhibition rescues valve degeneration. Transcriptomics revealed integrins as upstream regulators of mTOR. Blocking integrin signaling or altering its pathway prevented mTOR activation. These findings are conserved in human MVP, suggesting that mTOR activation via abnormal integrin-matrix signaling drives disease and that mTOR inhibition may be a potential therapy.
Project description:Evaluation of global expression patterns provides a molecular portrait of mitral valve disease, yields insight into the pathophysiologic aspects of DMVD, and identifies intriguing genes and pathways for further study. (Am J Vet Res 2006;67:1307–1318) Keywords: control vs diseased 4 controls( beagle crosses) and 4 affected (1 Daschund, 1 Lhasa apso, 2 miniature poodles)
Project description:Abstract Cardiac myxomas are the most common primary cardiac tumors in adults, with the left atrium being the most frequently affected. Echocardiography is the diagnostic modality of choice. The most effective treatment for cardiac myxomas is surgical excision. We present a clinical video of a large left atrial myxoma causing mitral valve obstruction, highlighting the importance of echocardiography as a diagnostic modality to facilitate referral to a tertiary center.
Project description:Aim: Test the hypothesis that 5HT receptors (5HTRs) signaling contributes to MVP pathophysiology. Methods and results: MV RNA was used for microarray analysis of MVP patients versus control, highlighting genes that indicate the involvement of 5HTR pathways and extracellular matrix remodeling in MVP. These canine MVP leaflets (N=5/group) showed 5HTR2B upregulation. Conclusion: In humans, MVP is associated with an upregulation in 5HTR2B expression and increased 5HT receptor signaling in the leaflets. 5HTR signaling is involved not only in previously reported 5HTrelated valvulopathies, but it is also involved in the pathological remodeling of MVP.
Project description:Evaluation of global expression patterns provides a molecular portrait of mitral valve disease, yields insight into the pathophysiologic aspects of DMVD, and identifies intriguing genes and pathways for further study. (Am J Vet Res 2006;67:1307–1318) Keywords: control vs diseased
Project description:Mitral valve prolapse (MVP) is often benign but can progress to mitral regurgitation, requiring invasive treatment. In mgR mice with hypomorphic Fbn1 mutations—mimicking Marfan syndrome—myxomatous mitral degeneration and regurgitation develop by 12 weeks. TGF-β and mTOR signaling activation, along with macrophage infiltration, appear by 4 weeks, before histological changes. Short-term rapamycin treatment blocks early TGF-β activation and inflammation, while long-term mTOR or TGF-β inhibition rescues valve degeneration. Transcriptomics revealed integrins as upstream regulators of mTOR. Blocking integrin signaling or altering its pathway prevented mTOR activation. These findings are conserved in human MVP, suggesting that mTOR activation via abnormal integrin-matrix signaling drives disease and that mTOR inhibition may be a potential therapy.
Project description:The generality of operational species definitions is limited by problematic definitions of between-species divergence. A recent phylogenetic species concept based on a simple objective measure of statistically significant genetic differentiation uses between-species application of statistical parsimony networks that are typically used for population genetic analysis within species. Here we review recent phylogeographic studies and reanalyse several mtDNA barcoding studies using this method. We found that (i) alignments of DNA sequences typically fall apart into a separate subnetwork for each Linnean species (but with a higher rate of true positives for mtDNA data) and (ii) DNA sequences from single species typically stick together in a single haplotype network. Departures from these patterns are usually consistent with hybridization or cryptic species diversity.
Project description:ObjectiveIntraoperative predictors of functional mitral valve (MV) stenosis after surgical repair of mitral regurgitation (MR) caused by prolapse remain poorly characterised. This study evaluated the effect of annuloplasty size on postoperative MV haemodynamics during exercise and evaluated predictors of MV hemodynamics.Methods104 patients were randomly assigned to leaflet resection or preservation for surgical repair of MR in the Canadian Mitral Research Alliance CardioLink-2 study. In this post hoc analysis, we compared MV haemodynamics between the two surgical groups and examined the relationship between annuloplasty size and MV haemodynamics 1 year after repair in the combined groups. Echocardiograms were performed at baseline and intraoperatively. Exercise transthoracic echocardiography was performed 1 year postoperatively. Multivariable linear regression analysis was used to identify predictors of exercise MV gradients at follow-up.ResultsMean age of participants was 65±10 years, and 83% were male. Median annuloplasty size was 34 (IQR 32-36). Dividing by the median, 48 (46%) had annuloplasty size of <34 mm and 56 (54%) had ≥34 mm. Mean and peak exercise gradients at 1 year were 11±5 mm Hg and 22±9 mm Hg in <34, and 6±3 mm Hg and 14±5 mm Hg in ≥34 (p<0.001). Rate of residual MR was similar in both groups. In multivariable analyses, annuloplasty size of ≥34 mm was associated with lower mean and peak exercise gradients at 12 months, after adjustment for repair type, age, sex, heart rate and body surface area (β -4.1, 95% CI -6 to -3, p<0.001, and β -7 95% CI -10 to -4, p<0.001, respectively). Intraoperative mean and peak MV gradients by transesophageal echocardiography independently predicted mean and peak resting and exercise gradients at follow-up (p<0.001). Similar results were obtained in both leaflet resection and preservation.ConclusionAnnuloplasty size of ≥34 mm is associated with a 4 and 7 mm Hg reduction in mean and peak exercise MV gradients, respectively, 1 year post MV repair regardless of the repair strategy used. Intraoperative TEE MV gradients predict exercise MV gradients 1 year post repair.Trial registration numberNCT02552771.