title: Hyaluronan turnover and hypoxic brown adipocytic differentiation are co-localized with ossification in calcified human aortic valves.
abstract: The calcification process in aortic stenosis has garnered considerable interest but only limited investigation into selected signaling pathways. This study investigated mechanisms related to hypoxia, hyaluronan homeostasis, brown adipocytic differentiation, and ossification within calcified valves. Surgically explanted calcified aortic valves (n=14) were immunostained for markers relevant to these mechanisms and evaluated in the center (NodCtr) and edge (NodEdge) of the calcified nodule (NodCtr), tissue directly surrounding nodule (NodSurr); center and tissue surrounding small "prenodules" (PreNod, PreNodSurr); and normal fibrosa layer (CollFibr). Pearson correlations were determined between staining intensities of markers within regions. Ossification markers primarily localized to NodCtr and NodEdge, along with markers related to hyaluronan turnover and hypoxia. Markers of brown adipocytic differentiation were frequently co-localized with markers of hypoxia. In NodCtr and NodSurr, brown fat and ossification markers correlated with hyaluronidase-1, whereas these markers, as well as hypoxia, correlated with hyaluronan synthases in NodEdge. The protein product of tumor necrosis factor-α stimulated gene-6 strongly correlated with ossification markers and hyaluronidase in the regions surrounding the nodules (NodSurr, PreNodSurr). In conclusion, this study suggests roles for hyaluronan homeostasis and the promotion of hypoxia by cells demonstrating brown fat markers in calcific aortic valve disease.
authors.affiliation: Department of Bioengineering, Rice University, Houston, TX 77005, United States.
authors.forename: Elizabeth H
authors.initials: EH
authors.lastname: Stephens
authors.forename: Jerome G
authors.initials: JG
authors.lastname: Saltarrelli
authors.forename: Liezl R
authors.initials: LR
authors.lastname: Balaoing
authors.forename: L Scott
authors.initials: LS
authors.lastname: Baggett
authors.forename: Indrajit
authors.initials: I
authors.lastname: Nandi
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Anderson
authors.forename: Joel D
authors.initials: JD
authors.lastname: Morrisett
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Reardon
authors.forename: Melanie A
authors.initials: MA
authors.lastname: Simpson
authors.forename: Paul H
authors.initials: PH
authors.lastname: Weigel
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Olmsted-Davis
authors.forename: Alan R
authors.initials: AR
authors.lastname: Davis
authors.forename: K Jane
authors.initials: KJ
authors.lastname: Grande-Allen
mesh_terms: D052437:Adipocytes, Brown / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D001021:Aortic Valve / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D001024:Aortic Valve Stenosis / Q000378:metabolism* / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D002114:Calcinosis / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002454:Cell Differentiation; D005260:Female; D014453:Glucuronosyltransferase / Q000378:metabolism; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000378:metabolism*; D006821:Hyaluronoglucosaminidase / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D009999:Ossification, Heterotopic / Q000378:metabolism / Q000473:pathology*
chemical_list: D015415:Biomarkers; D015815:Cell Adhesion Molecules; C072273:TNFAIP6 protein, human; D006820:Hyaluronic Acid; D014453:Glucuronosyltransferase; D000076002:Hyaluronan Synthases; D006821:Hyaluronoglucosaminidase