The pivotal role of inflammation in scar/keloid formation after acne

The effects of systemic diseases, genetic disorders and lifestyle on keloids

Keloid are a fibroproliferative disorder caused by abnormal healing of skin, specifically reticular dermis, when subjected to pathological or inflammatory scars demonstrating redness, elevation above the skin surface, extension beyond the original wound margins and resulting in an unappealing cosmetic appearance. The severity of keloids and risk of developing keloids scars are subjected to elevation by other contributing factors such as systemic diseases, general health conditions, genetic disorders, lifestyle and natural environment. In particular, recently, daily physical work interpreted into mechanical force as well as the interplay between mechanical factors such as stress, strain and stiffness have been reported to strongly modulate the cellular behaviour of keloid formation, affect their location and shape in keloids. Herein, we review the extensive literature on the effects of these factors on keloids and the contributing predisposing mechanisms. Early understanding of these participating factors and their effects in developing keloids may raise the patient awareness in preventing keloids incidence and controlling its severity. Moreover, further studies into their association with keloids as well as considering strategies to control such factors may help clinicians to prevent keloids and widen the therapeutic options.

Association Between Sebum, Total Cholesterol, and Low-Density Lipoprotein (LDL) Cholesterol Levels With Post-acne Keloids

Background Prolonged acne inflammation causes scar formation, one of which is post-acne keloids. Sebum, total cholesterol, and low-density lipoprotein (LDL) level can influence post-acne keloids. This study aims to determine the association between sebum, total cholesterol, and LDL levels with post-acne keloids to better define the predisposing factors for this condition. Methods This study used primary data involving sociodemographics, clinical features, keloid classification, sebum levels, total cholesterol levels, and LDL levels in post-acne keloid patients at the Dermatology, Venereology, and Aesthetics Outpatient Clinics of Dr. Mohammad Hoesin General Hospital Palembang, Indonesia. Study samples were patients who fulfilled the inclusion and exclusion criteria by consecutive sampling. The data then underwent univariate and bivariate analyses to show the association between variables. Result A total of 22 patients with post-acne keloids participated. The subjects presented mostly with major keloids based on the classification (59.1%). The patients were predominantly 21-30 years old (50%) and male (90.9%). The keloids had onsets >six months to one year (45.5%), durations of one to five years (77.3%), and multiple presentations (68.2%). Vancouver Scar Scale (VSS) assessment showed mainly red vascularity (40.9%), mixed pigmentation (68.2%), >5 mm keloid height (59.1%), and firm pliability (40.9%). Most patients presented with pruritus (86.4%) but without pain (54.5%). Most had low levels of sebum (50%), normal total cholesterol (90.9%), and near-optimal LDL level (40.9%). There were no significant association between sebum (p = 1.000), total cholesterol (p = 1.000), and LDL (p = 0.376) levels with post-acne keloids. However, LDL levels above normal were most found in this study (68.2%). Conclusions There is no association between sebum, total cholesterol, and LDL levels with post-acne keloids. Despite the fact that LDL level was not statistically significant, there has been a rise in LDL level in the research subjects. Further research with a larger number of subjects and consideration of multicenter study through retrospective/prospective methods and complete lipid profile examinations is still required to provide a more representative study.

Surgical Treatment for Chest "Lock" Keloid Using Autologous Split-Thickness Skin Grafting and Postoperative Radiotherapy

BACKGROUND

The treatment of chest "lock" keloids is challenging due to skin defects and a high recurrence rate.

OBJECTIVE

Evaluation of the effectiveness of autologous split-thickness skin graft with local radiotherapy for treating chest "lock" keloids.

METHODSAND MATERIALS

Fifty-seven patients with chest "lock" keloids were treated from July 2018 to September 2020. The skin defects were closed with an autologous split-thickness skin graft (STSG) and vacuum sealing drainage. The donor and the recipient sites received the first session of radiotherapy 72 hours postoperation for 3 consecutive days. Patients underwent follow-up examinations 12 months after surgery. The Patient and Observer Scar Assessment Scale (POSAS) was used to assess the treatment outcome.

RESULTS

Except for the complaints of pain, which did not improve in the patients' assessments (p = .368), POSAS improved significantly after treatment (p < .0001). The cure rate (including cured and partially cured scars) was 100%. No keloid recurrence was observed during the follow-up period.

CONCLUSION

The procedure of treating chest "lock" keloid by keloid debulking and autologous STSG followed by postoperational radiotherapy is a novel combined methodology for treating keloids.

Interleukin-10-Modified Adipose-Derived Mesenchymal Stem Cells Prevent Hypertrophic Scar Formation via Regulating the Biological Characteristics of Fibroblasts and Inflammation

Hypertrophic scar causes serious functional and cosmetic problem, but no treatment method is known to achieve a satisfactory therapeutic effect. However, mesenchymal stem cells show a possible cure prospect. Here, we investigated the effect of interleukin-10-modified adipose-derived mesenchymal stem cells (IL-10-ADMSC) on the formation of hypertrophic scar. In vitro, IL-10-ADMSC could highly express IL-10 and exhibited stronger inhibition of hypertrophic scar fibroblasts (HSFs) proliferation, migration, and extracellular matrix synthesis (the expression of collagen I, collagen III, FN, and α-SMA protein) than ADMSC. In vivo, we found that IL-10-ADMSC speeded up wound healing time and reduced scar area and scar outstanding height. Same as in vitro, IL-10-ADMSC also exhibited stronger inhibition of extracellular matrix synthesis (the expression of collagen I, collagen III protein) in wound than ADMSC. In addition, we also found that IL-10-ADMSC is also a stronger inhibitory effect on inflammation in wound than ADMSC, and IL-10-ADMSC inhibited TGF-β/Smads and NF-κB pathway. In conclusion, IL-10-ADMSC demonstrated the ability to prevent hypertrophic scar formation. And its possible molecular mechanism might be related to IL-10-ADMSC inhibiting the proliferation and migration of the synthesis of extracellular matrix of HSFs, and IL-10-ADMSC inhibited the inflammation during the wound healing.

Correlation between elastic modulus and clinical severity of pathological scars: a cross-sectional study

Though widely used to assess pathological scars, the modified Vancouver Scar Scale (mVSS) is neither convenient nor objective. Shear wave elastography (SWE) is used to evaluate the stiffness of pathological scars. We aimed to determine the correlation between mVSS score and elastic modulus (EM) measured by SWE for pathological scars. Clinical information including ultrasound (US) results of the enrolled patients with pathological scars was analyzed. The clinical severity of the pathological scars was evaluated by mVSS. Skin stiffness, as represented by EM, was calculated using SWE. The average EM of the whole scar (EM_WHOLE), hardest part of the scar (EM_HARDEST), and normal appearance of the skin around the scar (EM_NORMAL) were also recorded. Enrolled in this study were 69 pathological scars, including 28 hypertrophic scars and 41 keloids. The univariable regression analyses showed that the EM of pathological scars was closely related to mVSS score, while the linear multivariable regression analyses showed no significantly correlation. Curve fitting and threshold effect analysis revealed that when EM_WHOLE was less than 166.6 kPa or EM_HARDEST was less than 133.07 kPa, EM was positively correlated with mVSS score. In stratified analysis, there was no significant linear correlation and threshold effect between EM_WHOLE and mVSS score in hypertrophic scars or keloids. However, the fully adjusted smooth curves presented a linear association between mVSS score and EM_HARDEST in keloids (the adjusted β [95% CI] was 0.010 [0.001, 0.018]), but a threshold and nonlinear association were found in hypertrophic scars. When EM_HARDEST was less than 156.13 kPa, the mVSS score increased along with the hardest scar part stiffness; the adjusted β (95% CI) was 0.024 (0.009, 0.038). In conclusion, EM of pathological scars measured by SWE were correlated with mVSS within a threshold range, and showed different association patterns in hypertrophic scars and keloids.

Risk of cancer development in patients with keloids

Keloid is a skin disease characterized by exaggerated scar formation, excessive fibroblast proliferation, and excessive collagen deposition. Cancers commonly arise from a fibrotic microenvironment; e.g., hepatoma arises from liver cirrhosis, and oral cancers arise from submucosal fibrosis. As keloids are a prototypic fibroproliferative disease, this study investigated whether patients with keloids have an increased cancer risk. In a matched, population-based study, first 17,401 patients treated for keloids during 1998–2010 with 69,604 controls without keloids at a ratio of 1:4 were evaluated. The association between keloids and risk of cancer was estimated by logistic regression or Cox proportional hazard regression models after adjustment of covariates. In total, 893 first-time cases of cancer were identified in the 17,401 patients with keloids. The overall cancer risk was 1.49-fold higher in the keloids group compared to controls. Regarding specific cancers, the keloids group, had a significantly higher risk of skin cancer compared to controls (Relative risk = 1.73). The relative risk for skin cancer was even higher for males with keloids (Relative risk = 2.16). Further stratified analyses also revealed a significantly higher risk of developing pancreatic cancer in female patients with keloids compared to controls (Relative risk = 2.19) after adjustment for known pancreatic cancer risk factors. This study indicates that patients with keloids have a higher than normal risk for several cancer types, especially skin cancers (both genders) and pancreatic cancer (females). Therefore, patients with keloids should undergo regular skin examinations, and females with keloids should regularly undergo abdominal ultrasonography.

The association between keloid and osteoporosis: real-world evidence

Background

Keloids are characterized by disturbance of fibroblast proliferation and apoptosis, deposition of collagen, and upregulation of dermal inflammation cells. This benign dermal fibro-proliferative scarring condition is a recognized skin inflammation disorder. Chronic inflammation is a well-known contributor to bone loss and its sequelae, osteoporosis. They both shared a similar pathogenesis through chronic inflammation. We assessed whether keloids increase osteoporosis risk through using National Health Insurance Research Database.

Methods

The 42,985 enrolled patients included 8597 patients with keloids but no history of osteoporosis; 34,388 controls without keloids were identified from the general population and matched at a one-to-four ratio by age, gender. Kaplan-Meier method was applied to determine cumulative incidence of osteoporosis. Cox proportional hazard regression analysis was performed after adjustment of covariates to estimate the effect of keloids on osteoporosis risk.

Results

Of the 8597 patients with keloids, 178 (2.07%) patients were diagnosed with osteoporosis while in the 34,388 controls, 587 (1.71%) were diagnosed with osteoporosis. That is, the keloids patients had 2.64-fold higher risk of osteoporosis compared to controls after adjustment for age, gender, Charlson Comorbidity Index and related comorbidities. The association between keloids and osteoporosis was strongest in patients younger than 50 years (hazard ratio = 7.06%) and in patients without comorbidities (hazard ratio = 4.98%). In the keloids patients, a high incidence of osteoporosis was also associated with advanced age, high Charlson Comorbidity Index score, hyperlipidemia, chronic liver disease, stroke, and depression.

Conclusions

Osteoporosis risk was higher in patients with keloids compared to controls, especially in young subjects and subjects without comorbidities.

Keloid pathophysiology: fibroblast or inflammatory disorders?

Background

Keloids are defined as a benign dermal fibroproliferative disorder with no malignant potential. They tend to occur following trivial trauma or any form of trauma in genetically predisposed individuals. Keloids are known to grow beyond the margins of the wound and are common in certain body parts. The pathophysiology of keloid remains unclear, and fibroblasts have been presumed to be the main cells involved in keloid formation. Understanding the mechanism(s) of keloid formation could be critical in the identification of novel therapeutic regimen for the treatment of the keloids.

Objective

To review the pertinent literature and provide updated information on keloid pathophysiology.

Data Source

A Medline PubMed literature search was performed for relevant publications.

Results

A total of 66 publications were retrieved, with relevant publications on the etiology and pathogenesis as well as experimental studies on keloids. All articles were critically analyzed, and all the findings were edited and summarized.

Conclusion

There is still no consensus as on what is the main driving cell to keloid formation. One may, however, hypothesize that keloid formation could be a result of an abnormal response to tissue injury, hence resulting in an exaggerated inflammatory state characterized by entry of excessive inflammatory cells into the wound, including macrophages, lymphocytes, and mast cells. These cells seem to release cytokines including transforming growth factor β1 that stimulate fibroblasts to synthesize excess collagen, which is a hallmark of keloid disease.