The Relationship between Proliferative Scars and Endothelial Function in Surgically Revascularized Patients

Association of Cutaneous Keloids, Hypertrophic Scarring, and Fibrosis with Risk of Postoperative Proliferative Vitreoretinopathy

PURPOSE

To assess an association between cutaneous keloids, hypertrophic scarring, and fibrosis (KHF) and risk of postoperative proliferative vitreoretinopathy (PVR) after rhegmatogenous retinal detachment (RRD) repair.

DESIGN

Retrospective, population-based cohort study.

PARTICIPANTS

Patients aged ≥ 18 years who underwent initial retinal detachment (RD) repair with pars plana vitrectomy with or without scleral buckle (SB) (Current Procedural Terminology [CPT] 67108), pneumatic retinopexy (67110), and primary SB (67107) from January 1, 2003, to March 1, 2023.

METHODS

A de-identified electronic health record database through TriNetX, a global health research network, was used to analyze patients. Patients were queried for International Classification of Diseases, 10th Revision (ICD-10) codes L91.0 (hypertrophic scar) and L90.5 (scar conditions and fibrosis of skin). Frequency of subsequent diagnosis of PVR (H35.2) and CPT codes for secondary surgery including complex RD repair (67113) were determined. Patients with proliferative diabetic retinopathy (PDR) (ICD-10 H10.35/H11.35) were excluded. Descriptive statistics (Z-test) and propensity score matching (PSM) were used to match for age, sex, and race.

MAIN OUTCOME MEASURES

Prevalence of H35.2 and CPT 67113 within 180 days after RRD repair in the KHF cohort versus the non-KHF cohort.

RESULTS

Among patients with CPT 67108, 1061 in each cohort (KHF and non-KHF) were analyzed after PSM. The mean (standard deviation) age was 60.7 (15.2) years. Within 180 days, 10.1% of patients in the KHF cohort and 3.4% in the non-KHF cohort had a diagnosis of PVR (H35.2) (P < 0.001, odds ratio [OR], 3.2; 95% confidence interval [CI], 2.13-4.71). A total of 8.3% of patients in the KHF cohort and 5.4% of patients in the non-KHF cohort underwent complex RD repair (CPT 67113) (P = 0.008; OR, 3.2; 95% CI, 1.13-2.25). When including all RD repair types (CPT 67108, 67110, 67107), the rate of PVR diagnosis was still significantly greater in the KHF cohort than in the non-KHF cohort (9.0% vs 4.2%, P < 0.01; OR, 2.28; 95% CI, 1.64-3.16).

CONCLUSIONS

A dermatologic history of KHF may be a risk factor for PVR after RD repair.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Angiogenic gene characterization and vessel permeability of dermal microvascular endothelial cells isolated from burn hypertrophic scar

Hypertrophic scar (HTS) formation is a common challenge for patients after burn injury. Dermal microvascular endothelial cells (DMVECs) are an understudied cell type in HTS. An increase in angiogenesis and microvessel density can be observed in HTS. Endothelial dysfunction may play a role in scar development. This study aims to generate a functional and expression profile of HTS DMVECs. We hypothesize that transcript and protein-level responses in HTS DMVECs differ from those in normal skin (NS). HTSs were created in red Duroc pigs. DMVECs were isolated using magnetic-activated cell sorting with ulex europaeus agglutinin 1 (UEA-1) lectin. Separate transwell inserts were used to form monolayers of HTS DMVECs and NS DMVECs. Cell injury was induced and permeability was assessed. Gene expression in HTS DMVECS versus NS DMVECs was measured. Select differentially expressed genes were further investigated. HTS had an increased area density of dermal microvasculature compared to NS. HTS DMVECs were 17.59% less permeable than normal DMVECs (p < 0.05). After injury, NS DMVECs were 28.4% and HTS DMVECs were 18.8% more permeable than uninjured controls (28.4 ± 4.8 vs 18.8 ± 2.8; p = 0.11). PCR array identified 31 differentially expressed genes between HTS and NS DMVECs, of which 10 were upregulated and 21 were downregulated. qRT-PCR and ELISA studies were in accordance with the array. DMVECs expressed a mixed profile of factors that can contribute to and inhibit scar formation. HTS DMVECs have both a discordant response to cellular insults and baseline differences in function, supporting their proposed role in scar pathology. Further investigation of DMVECs is warranted to elucidate their contribution to HTS pathogenesis.

Asporin inhibits collagen matrix-mediated intercellular mechanocommunications between fibroblasts during keloid progression

Keloids are fibrotic lesions that grow unceasingly and invasively and are driven by local mechanical stimuli. Unlike other fibrotic diseases and normal wound healing, keloids exhibit little transformation of dermal fibroblasts into α-SMA⁺ myofibroblasts. This study showed that asporin is the most strongly expressed gene in keloids and its gene-ontology terms relate strongly to ECM metabolism/organization. Experiments with human dermal cells (HDFs) showed that asporin overexpression/treatment abrogated the HDF ability to adopt a perpendicular orientation when subjected to stretching tension. It also induced calcification of the surrounding 3D collagen matrix. Asporin overexpression/treatment also prevented the HDFs from remodeling the surrounding 3D collagen matrix, leading to a disorganized network of thick, wavy collagen fibers that resembled keloid collagen architecture. This in turn impaired the ability of the HDFs to contract the collagen matrix. Asporin treatment also made the fibroblasts impervious to the fibrous collagen contraction of α-SMA⁺ myofibroblasts, which normally activates fibroblasts. Thus, by calcifying collagen, asporin prevents fibroblasts from linearly rearranging the surrounding collagen; this reduces both their mechanosensitivity and mechanosignaling to each other through the collagen network. This blocks fibroblast activation and differentiation into the mature myofibroblasts that efficiently remodel the extracellular matrix. Consequently, the fibroblasts remain immature, highly proliferative, and continue laying down abundant extracellular matrix, causing keloid growth and invasion. Notably, dermal injection of asporin-overexpressing HDFs into murine wounds recapitulated keloid collagen histopathological characteristics. Thus, disrupted interfibroblast mechanocommunication may promote keloid progression. Asporin may be a new diagnostic biomarker and therapeutic target for keloids.

Keloidal pathophysiology: Current notions

INTRODUCTION

Keloids are pathological scars that are notorious for their chronic and relentless invasion into adjacent healthy skin, with commonly seen post-therapeutic recurrence after monotherapies.

METHODS

An English literature review on keloid pathophysiology was performed by searching the PubMed, Embase and Web of Science databases, to find out the up-to-date relevant articles. The level of evidence was evaluated based on the included studies with the highest level of evidence first.

RESULTS

Keloid morphology, signs, symptoms and the histopathological changes that occur in the local cells and extracellular matrix components are described. The theories on the pathophysiology of keloidogenesis that have been proposed to date are also covered; these include endocrinological, nutritional, vascular, and autoimmunological factors. In addition, we describe the local mechanical forces (and the mechanosignalling pathways by which these forces shape keloid cell activities) that promote keloid formation and determine the direction of invasion of keloids and the body sites that are prone to them.

CONCLUSION

A better understanding of this pathological entity, particularly its mechanobiology, will aid the development of new diagnostic and therapeutic strategies for use in the clinic to prevent, reduce or even reverse the growth of this pathological scar.

LAY SUMMARY

Keloids are skin scars that are famous for their chronic invasion into healthy skin, with commonly seen recurrence after surgeries. Cells such as lymphocytes, macrophages, mast cells and endothelial cells are involved in keloid growth. Particularly, endocrinological, nutritional, vascular, autoimmunological and mechanical factors actively take part in keloid progression.

Can proliferative hypertrophic scars of the median sternotomy incision predict the occurrence and characteristics of urethral stricture?

Objectives:

To investigate the correlation between the characteristics of urethral stricture and incision scars in patients with urethral stricture and median sternotomy incision.

Methods:

We identified 368 patients who had undergone internal urethrotomy between January 2014 and December 2017. A total of 49 male patients with a median sternotomy scar and diagnosed with urethral stricture were retrospectively evaluated. The median sternotomy incision scars were assessed using the Vancouver Scar Scale (VSS) and the patients were divided into 2 groups. Group I consisted of patients with a VSS score of <4 points, and those with ≥4 points constituted group II. The groups were compared in terms of age, smoking habit, body mass index, diabetes mellitus, hypertension, urethral stricture etiology, length and localization, and stricture relapse after intervention.

Results:

The mean total VSS score was 2.0 points in group I and 7.46 points in group II. There was a significant correlation between the VSS total score and the urethral stricture length among the whole study population (correlation coefficient value=0.481; p<0.001). The urethral stricture was longer as the VSS score increased.

Conclusion:

A poorly healed median sternotomy incision scar can predict a poor wound healing in the urethra tissue. Further large scale, multi-center and prospective studies are needed to clarify this relationship.