Browsing by Subject "Connective tissues"

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    An Emergent Nexus between Striae and Thoracic Aortic Dissection
    (MDPI, 2021) Landis, Benjamin J.; Vujakovich, Courtney E.; Elmore, Lindsey R.; Pillai, Saila T.; Lee, Lawrence S.; Everett, Jeffrey E.; Markham, Larry W.; Brown, John W.; Hess, Phillip J.; Corvera, Joel S.; Pediatrics, School of Medicine
    Current approaches to stratify the risk for disease progression in thoracic aortic aneurysm (TAA) lack precision, which hinders clinical decision making. Connective tissue phenotyping of children with TAA previously identified the association between skin striae and increased rate of aortic dilation. The objective of this study was to analyze associations between connective tissue abnormalities and clinical endpoints in adults with aortopathy. Participants with TAA or aortic dissection (TAD) and trileaflet aortic valve were enrolled from 2016 to 2019 in the setting of cardiothoracic surgical care. Data were ascertained by structured interviews with participants. The mean age among 241 cases was 61 ± 13 years. Eighty (33%) had history of TAD. While most participants lacked a formal syndromic diagnosis clinically, connective tissue abnormalities were identified in 113 (47%). This included 20% with abdominal hernia and 13% with skin striae in atypical location. In multivariate analysis, striae and hypertension were significantly associated with TAD. Striae were associated with younger age of TAD or prophylactic aortic surgery. Striae were more frequent in TAD cases than age- and sex-matched controls. Thus, systemic features of connective tissue dysfunction were prevalent in adults with aortopathy. The emerging nexus between striae and aortopathy severity creates opportunities for clinical stratification and basic research.
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    The individual and combined effects of exercise and collagenase on the rodent Achilles tendon
    (2013-10) Dirks, Rachel Candace; Warden, Stuart J.; Allen, Matthew R.; Fuchs, Robyn K.; Robling, Alexander G.
    Tendinopathy is a common degenerative pathology that is characterized by activity related pain, focal tendon tenderness, intratendinous imaging changes, and typically results in changes in the histological, mechanical, and molecular properties of the tendon. Tendinopathy is difficult to study in humans, which has contributed to limited knowledge of the pathology, and thus a lack of appropriate treatment options. However, most believe that the pathology is degenerative as a result of a combination of both extrinsic and intrinsic factors. In order to gain understanding of this pathology, animal models are required. Because each tendon is naturally exposed to different conditions, a universal model is not feasible; therefore, an appropriate animal model must be established for each tendon susceptible to degenerative changes. While acceptable models have been developed for several tendons, a reliable model for the Achilles tendon remains elusive. The purpose of this dissertation was to develop an animal model of Achilles tendinopathy by investigating the individual and combined effects of an intrinsic and extrinsic factor on the rodent Achilles tendon. Rats selectively bred for high capacity running and Sprague Dawley rats underwent uphill treadmill running (an extrinsic factor) to mechanically overload the Achilles tendon or served as cage controls. Collagenase (intrinsic factor) was injected into one Achilles tendon in each animal to intrinsically break down the tendon. There were no interactions between uphill running and collagenase injection, indicating that the influence of the two factors was independent. Uphill treadmill running alone failed to produce any pathological changes in the histological or mechanical characteristics of the Achilles tendon, but did modify molecular activity. Intratendinous collagenase injection had negative effects on the histological, mechanical, and molecular properties of the tendon. The results of this dissertation demonstrated that the combined introduction of uphill treadmill running and collagenase injection did not lead to degenerative changes consistent with human Achilles tendinopathy. Intratendiouns collagenase injection negatively influenced the tendon; however, these changes were generally transient and not influenced by mechanical overload. Future studies should consider combinations of other intrinsic and extrinsic factors in an effort to develop an animal model that replicates human Achilles tendinopathy.