Immature Scars Research Articles

Exclusive expression of KANK4 promotes myofibroblast mobility in keloid tissues

Keloids are characterized by abnormal wound healing with excessive accumulation of extracellular matrix. Myofibroblasts are the primary contributor to extracellular matrix secretion, playing an essential role in the wound healing process. However, the differences between myofibroblasts involved in keloid formation and normal wound healing remain unclear. To identify the specific characteristics of keloid myofibroblasts, we initially assessed the expression levels of well-established myofibroblast markers, α-smooth muscle actin (α-SMA) and transgelin (TAGLN), in scar and keloid tissues (n = 63 and 51, respectively). Although myofibroblasts were present in significant quantities in keloids and immature scars, they were absent in mature scars. Next, we conducted RNA sequencing using myofibroblast-rich areas from keloids and immature scars to investigate the difference in RNA expression profiles among myofibroblasts. Among significantly upregulated 112 genes, KN motif and ankyrin repeat domains 4 (KANK4) was identified as a specifically upregulated gene in keloids. Immunohistochemical analysis showed that KANK4 protein was expressed in myofibroblasts in keloid tissues; however, it was not expressed in any myofibroblasts in immature scar tissues. Overexpression of KANK4 enhanced cell mobility in keloid myofibroblasts. Our results suggest that the KANK4-mediated increase in myofibroblast mobility contributes to keloid pathogenesis.

Development of a Novel Scar Screening System with Machine Learning.

Hypertrophic scars and keloids tend to cause serious functional and cosmetic impediments to patients. As these scars are not life threatening, many patients do not seek proper treatment. Thus, educating physicians and patients regarding these scars is important. The authors aimed to develop an algorithm for a scar screening system and compare the accuracy of the system with that of physicians. This algorithm was designed to involve health care providers and patients. Digital images were obtained from Google Images (Google LLC, Mountain View, Calif.), open access repositories, and patients in the authors' hospital. After preprocessing, 3768 images were uploaded to the Google Cloud AutoML Vision platform and labeled with one of the four diagnoses: immature scars, mature scars, hypertrophic scars, and keloid. A consensus label for each image was compared with the label provided by physicians. For all diagnoses, the average precision (positive predictive value) of the algorithm was 80.7 percent, the average recall (sensitivity) was 71 percent, and the area under the curve was 0.846. The algorithm afforded 77 correct diagnoses with an accuracy of 77 percent. Conversely, the average physician accuracy was 68.7 percent. The Cohen kappa coefficient of the algorithm was 0.69, while that of the physicians was 0.59. The authors developed a computer vision algorithm that can diagnose four scar types using automated machine learning. Future iterations of this algorithm, with more comprehensive accuracy, can be embedded in telehealth and digital imaging platforms used by patients and primary doctors. The scar screening system with machine learning may be a valuable support tool for physicians and patients. Diagnostic, II.

Early Intervention with Autologous Fat Grafting to Reduce Hypertrophic Scar Formation: A Prelimilary Study.

Once an early-stage immature scar develops into a hypertrophic scar, it is difficult to achieve satisfactory improvement with existing treatments. Therefore, the prevention of hypertrophic scar formation should be given priority. Fat grafting was previously proven to be an effective treatment for mature scars, but it has not been used in the early-stages of (less than three months) scar formation. We present our experience with the use of combined grafting of macro fat and emulsified fat for prevention of hypertrophic scar formation in patients. Thirty-five patients who received fat grafting for facial scar repair were included as a treatment group and another 35 patients without particular interventions were classified as the control group. Patients in both groups were followed up every three months during one year, and the Vancouver Scar Scale (VSS) was used for evaluation of the clinical outcomes at baseline (within one to three months after trauma, burn or surgery) and after 12 months of follow-up. All patients in the treatment group achieved a marked improvement after their first fat grafting procedure. Thirteen patients (37.1%) underwent the second procedure and seven (20%) underwent the third procedure. Statistical analysis of average VSS score also showed significant differences between the treatment and control groups. The results of this retrospective study suggest that treatment of immature scars with combined grafting of macro fat and emulsified fat can successfully prevent the formation of hypertrophic scars. This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A study looking at the differences between hypertrophic scars and keloid scars

Hypertrophic and keloid scars are two types of raised, abnormal scars. Hypertrophic scars grow within the borders of the original wound and eventually grow smaller, but keloids grow beyond the original wound borders, do not grow smaller on their own, and are difficult to treat. Keloids usually occur in people with darker skin colour. Sometimes it is still difficult to determine if a raised scar is a hypertrophic scar or a keloid. This study from the Netherlands aimed to find out if both these abnormal scars form because they retain characteristics of the young, immature scars, rather than maturing in a normal way. The authors examined the types of cells present in the outer (epidermis) and the inner (dermis) layer of the skin and found that the hypertrophic and keloid scars closely resembled immature scars, rather than normal healthy scars in two important ways: the outer layer cells did not mature properly (increased involucrin expression); the inner layer cells of normal skin express a protein called CD34 and do not have cells that function to contract tissue (α‐SMA), but in the abnormal scars this is reversed ‐ CD34 is missing and the (α‐SMA) contracting cells are present. Unlike abnormal scars, the cells of the inner and outer layer of immature scars showed increased cell growth (Ki67). The outer layer of the abnormal scars was much thicker and the inner layer had many cells (vimentin), but these cells had stopped growing (known as p16). It was difficult to separate the hypertrophic scars from the keloids based on what the inner layer looks like, but hypertrophic scars have more cells that contract and keloids have very thick bands of connective tissue in their inner layer. In conclusion, the results of this study suggest that hypertrophic and keloid scars maintain characteristics of immature scars and do not mature like normal scars do. This is a summary of the study: Hypertrophic and keloid scars fail to progress from the CD34−α‐smooth muscle actin (SMA)+immature scar phenotype and show gradient differences in α‐SMA and p16 expression

Effect of Age on Outcome of Low Level Laser Therapy (Lllt) Treated Post Burn Immature Scars

Effect of Age on Outcome of Low Level Laser Therapy (Lllt) Treated Post Burn Immature Scars

Hypertrophic and keloid scars fail to progress from the CD34- /α-smooth muscle actin (α-SMA)+ immature scar phenotype and show gradient differences in α-SMA and p16 expression.

Our understanding of the pathogenesis underlying keloid scar formation is still very limited, and the morphological distinction between hypertrophic and keloid scars remains difficult. To test whether hypertrophic and keloid scars may reflect an inability to progress from immaturity to the desired mature normotrophic scar phenotype. Using whole-biopsy imaging and an objectively quantifiable way to analyse immunoreactivity, we have compared the immunohistopathological profiles of young immature scars with mature normotrophic scars, hypertrophic scars, and keloids with their surrounding-normal-skin. Abnormal scars (hypertrophic scars and keloids) maintain the immature scar phenotype, characterized by a CD34- (tumour biomarker) and α-smooth muscle actin (α-SMA)+ (myofibroblast) dermal region. This is in contrast to normal skin, surrounding-normal-skin and mature normotrophic scars that were CD34+ / α-SMA- . Immature, hypertrophic and keloid scars showed abnormal epidermal differentiation (involucrin), but only hypertrophic scars and keloids showed increased epidermal thickness. Immature scars did show increased epidermal and dermal proliferation (Ki67), which was absent from abnormal scars, where mesenchymal hypercellularity (vimentin) and senescence (p16) were predominant. Keloidal collagen and α-SMA were previously considered to distinguish between hypertrophic scars and keloids. However, α-SMA staining was present in both abnormal scar types, while keloidal collagen was present mostly in keloids. There were no obvious signs of heterogeneity within keloid scars, and the surrounding-normal-skin resembled normal skin. Both abnormal scar types showed a unique CD34- /α-SMA+ /p16+ scar phenotype, but the differences between hypertrophic scars and keloids observed in this study were of a gradient rather than absolute nature. This suggests that scar progression to the mature normal scar phenotype is, for as yet unknown reasons, hindered in hypertrophic and keloid scars. What's already known about this topic? Hypertrophic and keloid scars both have sustained epidermal barrier dysfunction, suggesting the persistence of an immature scar phenotype. Morphological distinction between hypertrophic and keloid scars remains a topic of debate, although α-smooth muscle actin (α-SMA) and keloidal collagen have been considered distinguishing features of hypertrophic and keloid scars, respectively. It has been suggested that keloids are not simply homogeneous growths, as heterogeneity within keloid scars and possible involvement of the surrounding-normal-skin have been reported. What does this study add? An extensive whole-biopsy imaging and quantifiable immunohistochemical assessment of immature, mature normal, hypertrophic and keloid scars, including normal skin surrounding keloids. Hypertrophic and keloid scars maintain dermal characteristics of immature scars, rather than transitioning into the normal mature phenotype. Differences between hypertrophic and keloid scars were of a gradient rather than absolute nature, with keloids showing the more extreme phenotype. There was no obvious heterogeneity within keloids, and the normal skin surrounding keloids resembled normal skin. What is the translational message? Keloids remain primarily a clinical diagnosis. A raised scar with the CD34- /α-SMA+ /p16+ phenotype with strong immunoreactivity for p16 and significant amounts of keloidal collagen, together with a thickened and strongly abnormal involucrin-stained epidermis, would sway the diagnosis towards keloid scars. A hypertrophic scar seems more likely when the CD34- /α-SMA+ /p16+ phenotype shows very strong presence of α-SMA+ in large dermal nodules, with lesser p16 staining and absent or negligible keloidal collagen.

Microneedling of Immature Scars Is Safe and Improves Scar Esthetics

PURPOSE: 1. Dispelling previous myths that immature scars could not be treated with microneedling. 2. Microneedling scars as early as 6 weeks following wound closure is safe. 3. Microneedling improves scars esthetics. Scar formation involves the remodeling of extracellular matrix proteins. Wound contraction and hyperproliferation can result in hypertrophic or keloid scars with features linked to poor cosmetic results. Currently early intervention with microneedling in immature scars is not the standard of care and some recommend waiting upward of 1 year before microneedling treatment. Our hypothesis is that mechanical stimulation of the myofibroblasts at the early tissue formation stage can positively influence the extracellular matrix to influence cell activity to produce collagen, matrix metalloproteinases, and cytokines which lead to flat scars with minimal discoloration as a result of small parallel collagen bundles METHODS AND MATERIALS: Subjects were enrolled between 6 weeks and 4 months following closure of their wounds. Once enrolled, the patients were treated with 3 microneedling treatments 1 month apart and a final evaluation at 2 months following the last treatment. The treatment areas included facelift, breast mastopexy, and tummy tuck scars. The patients consented to participate in the Institutional Review Board–approved study. Twenty-five patients were enrolled, and data were analyzed using analysis of variance and post hoc testing. RESULTS: The Vancouver Scar Scale demonstrated a statistically significant improvement when compared from the initial evaluation to the final evaluation at the 2-month follow-up following the 3 treatments (7.00 versus 3.08; P < 0.001). The Patient and Observer Scar Assessment Scale showed statistically significant improvement when initial evaluation was compared to the 2-month follow-up (23.72 versus 11.76; P < 0.001). CONCLUSIONS: Early microneedling on immature scars is safe and has demonstrated improvement in both Vancouver Scar Scale and Patient and Observer Scar Assessment Scale scores when initial evaluation is compared to 2-month follow-up.

52 SCAR-Q, A Patient-Reported Outcome Measure for Scars, Field-Test of Individuals with Burn Scars

As mortality rates of burn survivors continues to decrease, burn surgeons are facing more complex reconstructive challenges and need a systematic way to elicit patient input about their scars. Burn scars are especially difficult to treat as the vast majority will develop hypertrophic scars, which are more symptomatic and lead to increased functional and cosmetic disabilities. A comprehensive scar-specific PROM for the burn, surgical, and traumatic scar populations was field-tested worldwide. Our aim is to describe the field-test findings specific for the burn population and the overall Rasch Measurement Theory (RMT) analysis. A preliminary PROM, the SCAR-Q, was developed from a secondary analysis of 244 qualitative interviews, 45 cognitive interviews, and feedback from 27 clinical experts worldwide to encompass three scales: Appearance, Symptoms, and Psychosocial Impact. SCAR-Q was field-tested in 4 burn-specific clinics worldwide. RMT was used to analyze its psychometric properties and to further refine it of the overall sample. Of the 731 participants who filled out the SCAR-Q booklet, a total of 184 burn survivors completed the SCAR-Q study booklet. The majority were adults(87,47%), individuals with flame burns(97,53%), immature scars(92,50%), normal scar type(96,52%), spanning multiple anatomic locations(average 3.1+/12.9). The RMT findings are on the overall sample. RMT analysis decreased the number of items from 48 to 29 due to poor item fit, disordered thresholds, and/or redundancy. No DIF was found based on scar etiology suggesting items worked the same across all scar etiologies. Person separation indexes were above 0.80 (with extremes) and 0.79 (without extremes). Cronbach’s alpha values were 0.91 and higher, and the intraclass correlation coefficients were 0.88 and above. Lower mean scores were associated with burn scars on all three SCAR-Q scales. With surgical evaluations becoming more person-centered, a PROM specific to scars is essential to adequately capture patient concerns and the impact of interventions on their lives. The SCAR-Q can be used in the burn scar population. We anticipate that SCAR-Q will be used to determine the crucial timing for scar modulation, evaluate outcomes in scar therapies, aid in clinical trials, and be part of quality improvement initiatives.

Carbon dioxide laser treatment in burn-related scarring: A prospective randomised controlled trial

To investigate the effect of ablative fractional CO2 laser (AFCO2L)on burns scar appearance and dermal architecture at 6 weeks and up to 3-years post-treatment. Twenty adult patients with a burn-related scar were recruited. Inclusion criteria were a minimum scar area of 10 × 10 cm and Vancouver scar scale (VSS) score of >5 and ≥6 months since the time of injury. The region of scar was randomised to treatment/control zones. Treatment zones received 3 standardised laser treatments at 4- to 6-week intervals. All areas of scar received standard scar care. Outcome measures were recorded at baseline, 6-weeks post final treatment and up to 3 years post-treatment. Measures included blinded assessor VSS, Patient Scar Assessment Scale and histological tissue analysis. Nineteen and nine patients completed the short- and long-term studies, respectively. Clinical results revealed improvement in all scar areas over time. There was a statistically significant improvement in pain and itch in the treatment zone compared to the control zone at 6 weeks. Histological data revealed a significant increase in medium-sized collagen fibres at 6 weeks relative to the control site. Sub-group analysis according to scar age revealed greater histological improvement following laser treatment in immature scars relative to more mature scar. Results demonstrate that 3 treatments of AFCO2L significantly improve scar pain, itch and dermal architecture at 6 weeks post-treatment. Histological results suggest greater potential in treating immature scar. Further investigation into the timing of laser treatment could help assist treatment protocols.

The role of CO2-laser in scarring management

To assess the role of CO2-laser in treatment of various scars and to determine the indications for its application. It has been carried out a prospective analysis of treatment of 218 patients with scars of different duration, locations and anatomic areas with the use of CO2-laser for the period 2011-2017. POSAS scale and sonography were used for analysis. 1. Laser therapy is not effective for scarring-related functional defects (contractures, ectropion, microstomia), when surgery is indicated. 2. The outcomes of treatment (both surgical and laser) depend on the time of existence of the scars rather their cause and anatomical region. 3. Laser therapy is not effective enough for formed scars existing over 12 months. 4. Laser therapy is effective for immature scars, especially indicated for cicatricial deformation when the aesthetics cannot be repaired with traditional surgery. Application of CO2-laser in scars treatment with regard to its real efficiency determines the effectiveness of therapy.

Combination laser treatment for immediate post-surgical scars: a retrospective analysis of 33 immature scars.

The application of laser treatments beginning on the day of stitch removal has been demonstrated to improve scar quality. However, there are few guidelines for the treatment of immature scars (ISs), which are defined as "scars whose features are not yet expressed." The purpose of this study was to extract information about early combination laser treatment (CLT) beyond what is currently known by analyzing 33 pairs of pre-treatment and post-treatment photographs of ISs. Two hundred fifty medical records of patients with scars were reviewed, and 33 scars were included in the study. The included scars were treated with vascular lasers (585 or 532nm) followed by 1550-nm fractional lasers from May 2014 to July 2015 (fewer than 52days after stitch removal, Fitzpatrick's skin types III-IV, mean age=16.0years). Blinded evaluators (one plastic surgeon and two dermatologists) evaluated the pre-treatment and post-treatment photographs. The pre-treatment photographs were scored on a spectrum from "0," when no difference with the surrounding unaffected skin was observed, to "100," when the worst scarring was present. The pre-treatment and post-treatment photographs were compared, and the results were graded on a spectrum from 0, when no difference between the pre-treatment and post-treatment photographs was observed, to 100, when no difference was observed between the post-treatment skin and the surrounding unaffected skin. Statistical analyses were performed with PASW 17.0, SPSS Korea, Seoul, Korea (p<0.05). The improvement scores (ImS) and weighted scores (Wtd: i.e., weighted according to the pre-treatment scores) were used as dependent variables. The average improvement score was 87.98 (median=90). Seventeen cases were scored as 100-point improvements. The facial and non-facial scars exhibited differences in the ImS and Wtd scores. The Wtd scores were negatively correlated with the temporal gap (in days) between stitch removal and the beginning of CLT. No significant difference in the Wtd scores was demonstrated between the two vascular laser groups. Patient age and Wtd score were negatively correlated, and a significant difference was observed in the Wtd scores between the age groups (≥15 and <15years old). CLT for ISs results in excellent outcomes. Better results are achieved with earlier CLT initiation following stitch removal. Better outcomes can be expected for younger patients and for facial scars. We found that 532 and 585-nm lasers are equally effective for CLT of ISs.

The effect of moisturizers or creams on scars: a systematic review protocol.

The objectives of the review are to identify the effect of any moisturizers or creams (medicated or unmedicated) on immature scars (linear, keloid or hypertrophic) on any persons of any age. Effects will be assessed by changes in scar activity, changes in the final appearance/cosmesis of the scar, improvements in patient reported features of scars (e.g. itch, tightness, range of movement) and/or by altering measurable features of the scar such as vascularity, color, height, length, pliability and/or transepidermal water loss.Specifically the review question is: are moisturizers or creams effective in modifying immature scars?

Investigation of optical attenuation imaging using optical coherence tomography for monitoring of scars undergoing fractional laser treatment.

We demonstrate the use of the near-infrared attenuation coefficient, measured using optical coherence tomography (OCT), in longitudinal assessment of hypertrophic burn scars undergoing fractional laser treatment. The measurement method incorporates blood vessel detection by speckle decorrelation and masking, and a robust regression estimator to produce 2D en face parametric images of the attenuation coefficient of the dermis. Through reliable co-location of the field of view across pre- and post-treatment imaging sessions, the study was able to quantify changes in the attenuation coefficient of the dermis over a period of ∼20weeks in seven patients. Minimal variation was observed in the mean attenuation coefficient of normal skin and control (untreated) mature scars, as expected. However, a significant decrease (13±5%, mean ± standard deviation) was observed in the treated mature scars, resulting in a greater distinction from normal skin in response to localized damage from the laser treatment. By contrast, we observed an increase in the mean attenuation coefficient of treated (31±27%) and control (27±20%) immature scars, with numerical values incrementally approaching normal skin as the healing progressed. This pilot study supports conducting a more extensive investigation of OCT attenuation imaging for quantitative longitudinal monitoring of scars. En face 2D OCT attenuation coefficient map of a treated immature scar derived from the pre-treatment (top) and the post-treatment (bottom) scans. (Vasculature (black) is masked out.) The scale bars are 0.5mm.

Current options for the treatment of pathological scarring.

Scarring is the consequence of surgery, trauma or different skin diseases. Apart from fresh, immature scars,that transform into mature scars over the course of would healing and that do not require further treatment,linear hypertrophic scars, widespread hypertrophic scars, keloids and atrophic scars exist. Symptoms like pruritusand pain, stigmatization as well as functional and aesthetic impairments that are very disturbing for the affected patients can bethe basis for the desire for treatment. Today, a multitude of options for the treatment and prevention of scars exists. Topical agents based on silicone or onion extract, intralesional injections of cristalline glucocorticoids (oftentimes in combinationwith cryotherapy) or 5-Fluorouracil as well as ablative and nonablative laser treatment are used. Current guidelines summarize the multitude of available treatment options and the currently available datafor the treating physicians, allowing them to make clear therapy recommendations for every single scar type. Relieving patients of their discomfort and doing their aesthetic demands justice is thus possible. Apart from scar prevention becoming more and more important, the increased use of modernlaser treatment options constitutes a key point in clinical scar treatment. At the same time the attention is turned to evaluating current therapeutic options with the help of contemporary study designs so as to graduallyimprove the level of evidence in scar treatment.

Photoletter to the editor: Topical 0.5% brimonidine gel to camouflage redness of immature scars.

Cutaneous scars develop as a result of a defective wound healing process. Scars are commonly visible as erythematous, sometimes disfiguring lesions which might be stigmatizing for the affected patient. Only a few therapies to improve the appearance of scars are available. Recently, brimonidine - a selective α2-receptor-agonist which causes vasoconstriction of small cutaneous vessels - was approved for the treatment of erythemato-telangiectatic rosacea. Topical brimonidine might also be helpful to improve redness of immature scars. Here we report on the effect of brimonidine 0.5% gel on a flat, erythematous scar in a 25-year-old female patient. Whitening of the scar could be observed immediately after application of brimonidine 0.5% gel and a good clinical result was observed within one hour. This effect lasted for up to three hours. We conclude that brimonidine 0.5% gel is a suitable topical therapy to reduce erythema in visible cutaneous scars.

Topical 0.5% brimonidine gel to camouflage redness of immature scars

Cutaneous scars develop as a result of a defective wound healing process. Scars are commonly visible as erythematous, sometimes disfiguring lesions which might be stigmatizing for the affected patient. Only a few therapies to improve the appearance of scars are available. Recently, brimonidine — a selective α2-receptor-agonist which causes vasoconstriction of small cutaneous vessels — was approved for the treatment of erythemato-telangiectatic rosacea. Topical brimonidine might also be helpful to improve redness of immature scars. Here we report on the effect of brimonidine 0.5% gel on a flat, erythematous scar in a 25-year-old female patient. Whitening of the scar could be observed immediately after application of brimonidine 0.5% gel and a good clinical result was observed within one hour. This effect lasted for up to three hours. We conclude that brimonidine 0.5% gel is a suitable topical therapy to reduce erythema in visible cutaneous scars. ( J Dermatol Case Rep . 2015; 9(3): 87-88)

Establishing a Reproducible Hypertrophic Scar following Thermal Injury: A Porcine Model.

Background:Our complete understanding of hypertrophic scarring is still deficient, as portrayed by the poor clinical outcomes when treating them. To address the need for alternative treatment strategies, we assess the swine animal burn model as an initial approach for immature scar evaluation and therapeutic application.Methods:Thermal contact burns were created on the dorsum of 3 domestic swine with the use of a branding iron at 170°F for 20 seconds. Deep partial-thickness burns were cared for with absorptive dressings over 10 weeks and wounds evaluated with laser and negative pressure transduction, histology, photographic analysis, and RNA isolation.Results:Overall average stiffness (mm Hg/mm) increased and elasticity (mm) decreased in the scars from the initial burn injury to 8 weeks when compared with normal skin (P < 0.01). Scars were thicker, more erythematous, and uniform in the caudal dorsum. The percent change of erythema in wounds increased from weeks 6 to 10. Histology demonstrated loss of dermal papillae, increased myofibroblast presence, vertically oriented vessels, epidermal and dermal hypercellularity, and parallel-layered collagen deposition. Immature scars remained elevated at 10 weeks, and minimal RNA was able to be isolated from the tissue.Conclusions:Deep partial-thickness thermal injury to the back of domestic swine produces an immature hypertrophic scar by 10 weeks following burn with thickness appearing to coincide with the location along the dorsal axis. With minimal pig to pig variation, we describe our technique to provide a testable immature scar model.

Adenosine A2A receptor (A2AR) is a fine-tune regulator of the collagen1:collagen3 balance

Adenosine is a potent endogenous anti-inflammatory and immunosuppressive metabolite that is a potent modulator of tissue repair. However, the adenosine A2A receptor (A2AR)-mediated promotion of collagen synthesis is detrimental in settings such as scarring and scleroderma. The signaling cascade from A2AR stimulation to increased collagen production is complex and obscure, not least because cAMP and its downstream molecules PKA and Epac1 have been reported to inhibit collagen production. We therefore examined A2AR-stimulated signaling for collagen production by normal human dermal fibroblasts (NHDF). Collagen1 (Col1) and collagen3 (Col3) content after A2AR activation by CGS21680 was studied by western blotting. Contribution of PKA and Epac was analyzed by the PKA inhibitor PKI and by knockdowns of the PKA-Cα, -Cβ, -Cγ, Epac1, and Epac2. CGS21680 stimulates Col1 expression at significantly lower concentrations than those required to stimulate Col3 expression. A2AR stimulates Col1 expression by a PKA-dependent mechanism since PKA inhibition or PKA-Cα and -Cβ knockdown prevents A2AR-mediated Col1 increase. In contrast, A2AR represses Col3 via PKA but stimulates both Col1 and Col3 via an Epac2-dependent mechanism. A2AR stimulation with CGS21680 at 0.1μM increased Col3 expression only upon PKA blockade. A2AR activation downstream signaling for Col1 and Col3 expression proceeds via two distinct pathways with varying sensitivity to cAMP activation; more highly cAMP-sensitive PKA activation stimulates Col1 expression, and less cAMP-sensitive Epac activation promotes both Col1 and Col3 expression. These observations may explain the dramatic change in Col1:Col3 ratio in hypertrophic and immature scars, where adenosine is present in higher concentrations than in normal skin.

Immunohistochemical Expression of TGF-β1 in Keloids and Hypertrophic Scars

Aberrant wound healing of skin injury may lead to 2 pathologic entities, termed keloids and hypertrophic scars (HS). There has been growing evidence suggesting a role for transforming growth factor beta (TGF-β) family members in the pathogenesis of fibrosis. The aim of the present work was to investigate the role of TGF-β1 in the pathogenesis of keloids and HS. TGF-β1 was analyzed on skin biopsies of 30 patients presenting with keloids (16) or HS (14) and 10 normal surgical scar and 10 age- and sex-matched normal subjects (controls). TGF-β1 was expressed in dermal fibroblasts, inflammatory cells, and endothelial cells of normal surgical scar (60%) and aberrant scar (86.7%) with an absence of statistical difference. Although it is expressed in 90% of epidermis of aberrant scar (diffuse expression) compared with 60% of normal surgical scar (basal layer expression) and 20% of normal skin biopsies (basal layer expression) with highly significant differences. Dermal TGF-β1 expression in aberrant scar lesions was significantly associated with lesions of shorter duration (P = 0.01) and older age group (P = 0.02). The intense dermal expression was also associated with lesions of shorter duration (P = 0.0001) and immature scars (P = 0.002). TGF-β1 is involved in the pathogenesis of both keloids and HS with maximum effect at early stages. Keratinocytes are not passive partners but rather may have an active role in the induction of fibrosis. Targeting of TGF-β1 may be of benefit if applied early and if directed against keratinocytes as an unusual target of therapy.

Temporal differences in fibroblast proliferation and phenotype expression in response to chronic administration of angiotensin II or aldosterone

Chronic activation of the circulating renin-angiotensin-aldosterone system (RAAS), as can occur with unilateral renal ischemia (URI), is associated with an adverse structural remodeling of the right and left ventricles characterized by reparative (i.e., microscopic scars) and reactive (i.e., perivascular/interstitial) fibrosis. The time course and cells involved in fibroplastic and fibrogenic phases of these events are unclear. Hearts were examined over the course of 8 weeks in rats infused with either angiotensin II or aldosterone, and compared to rats with URI. Tissue sections from the same heart were stained with hematoxylin and eosin, collagen specific picrosirius red, or immunolabeled with PCNA or alpha smooth muscle actin antibody. With angiotensin II or renal ischemia, fibroblast proliferation, presenting as focal accumulations at both sites of myocyte necrosis and widespread perivascular locations, was present in each ventricle on days 2 and 4, but not thereafter, alpha-Smooth muscle actin containing cells (myofibroblasts) appeared at day 2 and persisted through week 2 with renal ischemia and week 6 with angiotensin II. Macrophages, neutrophils and lymphocytes were transiently found at sites of necrosis between day 2-4 of renal ischemia. AngII-induced necrotic sites were characterized by macrophages and lymphocytes from day 2 through week 6, and neutrophils at day 2-4. Increased collagen volume fraction, presenting as immature scars associated with fibroblast clusters and interstitial/perivascular fibrosis, was evident on day 14 in both ventricles. In contrast, fibroblast proliferation during aldosterone infusion did not appear in both ventricles until week 3 and was associated with a subsequent reparative and reactive fibrosis as early as 4 weeks. Myofibroblasts became evident between 3-6 weeks; macrophages and lymphocytes were seen between 3-8 weeks. Neutrophils were not seen at any time point with aldosterone. Thus, the temporal cellular response and appearance of myocardial fibrosis associated with chronic elevations in angiotensin II and/or aldosterone differ. We conclude that separate pathogenic mechanisms are operative with these effector hormones of the RAAS.