Teruyuki Dohi

siRNA Knockdown of Tissue Inhibitor of Metalloproteinase-1 in Keloid Fibroblasts Leads to Degradation of Collagen Type I

Keloids are defined as overgrowths of scar tissue resulting from abnormal wound healing. They are characterized by excessive dermal deposition of thick, hyalinized collagen bundles resulting from an imbalance between the production and degradation of extracellular matrix (ECM) components. Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are two important regulators of ECM degradation and remodeling. To evaluate the role played by knockdown of TIMPs in keloid formation, we transduced human keloid-derived fibroblasts (KFs) with small interfering RNAs targeting TIMP-1 or -2 (siTIMP-1 or siTIMP-2) using a lentiviral vector and assessed the biological effects. We found that MMP-1/TIMP-1 and MMP-1/TIMP-2 complexes were suppressed and that MMP-2 activity was upregulated in KFs expressing siTIMP-1 or siTIMP-2. In addition, increased degradation of collagen type I was observed in the supernatant of KFs expressing siTIMP-1, but not siTIMP-2, with the suppression of cell viability and induction of apoptosis. These results suggest that targeting TIMP-1 using small interfering RNA has significant therapeutic potential as an approach to treating keloids through degradation of their thick collagen bundles.

Nd:YAG Laser Treatment for Keloids and Hypertrophic Scars: An Analysis of 102 Cases

Background: The present retrospective cohort study was performed to determine the efficacy of contact-mode 1064 nm neodymium-yttrium-aluminum-garnet (Nd:YAG) laser laser for keloids and hypertrophic scars. The indication and limitations of this modality are discussed. Methods: The cohort consisted of 102 consecutive Japanese patients (23 males and 79 females) with keloids and hypertrophic scars for more than 1 year. They were treated every 3–4 weeks for 1 year with a long-pulsed 1064 nm Nd:YAG laser (Cutera, Brisbane, Calif.) in contact mode. Thirty-eight patients had hypertrophic scars and 64 had keloids. The scars were evaluated before the treatment commenced and 1 month after the last session by using the Japan Scar Workshop Scar Scale 2011. Recurrence was assessed at 6 months after the termination of treatment. Results: The average total Japan Scar Workshop score of the keloid and hypertrophic scar region groups dropped significantly after 1 year of treatment compared with before treatment (all P < 0.05). None of the hypertrophic scars or keloids deteriorated. However, 3 of the 34 anterior chest keloids (8.8%) did not respond. The following recurrence rates were observed 6 months after stopping laser treatment: 1 of the abdomen hypertrophic scars (4%), 18 of the anterior chest keloids (52.9%), 5 of the upper arm keloids (35.7%), and 4 of the scapula keloids (25%). Conclusions: Hypertrophic scars responded significantly better to 1064 nm Nd:YAG laser treatment than keloids. However, keloid recurrence occurred when there was remaining redness and induration, even if only a small part of the scar was affected.

Reply: Analysis of the Surgical Treatments of 63 Keloids on the Cartilaginous Part of the Auricle: Effectiveness of the Core Excision Method.

Background: Treatments for keloids on the cartilaginous part of the auricle (i.e., the upper part of the ear excluding the earlobe) include surgical excision, cryosurgery, postoperative radiation therapy, steroid injection, taping stabilization, and pressure therapy. However, to date, there is no universally accepted treatment strategy for auricle keloids. Methods: In this retrospective cohort study, the 63 primary auricle keloids in all 57 patients who underwent surgery from 2006 to 2012 were included. Mild scars such as hypertrophic scars were excluded. All 63 scars were treated with surgery, namely, total excision or intralesional excision (core excision method), and postoperative adjuvant radiation therapy and self-managed scar stabilization with surgical tape. The postsurgical radiation therapy consisted of 15 Gy administered in three fractions over 3 days. The recurrence rates associated with the two surgical methods over 18 months of follow-up were recorded. Results: Of the 57 patients, 91.2 percent were women. Of the 63 lesions, 95.2 percent and 4.8 percent were caused by piercing and trauma, respectively. All were primary keloids. Before 2009, all lesions (n = 37) were treated by total excision. After 2009, all lesions (n = 26) were treated by core excision. These methods were associated with recurrence rates of 8.1 percent and 0 percent, respectively, although this difference did not achieve statistical significance (p > 0.05). The overall recurrence rate was 4.8 percent. Complications such as wound dehiscence and pigmentation during the 18-month follow-up period were not observed. Conclusion: Auricle keloids can be treated by customized plans consisting of appropriate surgical modalities, postoperative radiotherapy, and self-management. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Tissue Inhibitor of Metalloproteinase-2 Suppresses Collagen Synthesis in Cultured Keloid Fibroblasts

Background: Keloids are defined as a kind of dermal fibroproliferative disorder resulting from the accumulation of collagen. In the remodeling of extracellular matrix, the balance between matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) is as critical as the proper production of extracellular matrix. We investigate the role of TIMPs and MMPs in the pathogenesis of keloids and examine the therapeutic potential of TIMP-2. Methods: The expression of TIMPs and MMPs in most inflamed parts of cultured keloid fibroblasts (KFs) and peripheral normal skin fibroblasts (PNFs) in the same individuals and the reactivity of KFs to cyclic mechanical stretch were analyzed by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay (n = 7). To evaluate the effect of treating KFs with TIMP-2, collagen synthesis was investigated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, and microscopic analysis was used to examine the treatment effects of TIMP-2 on ex vivo cultures of keloid tissue (n = 6). Results: TIMP-2 was downregulated in cultured KFs compared with PNFs in the same individuals, and the reduction in TIMP-2 was exacerbated by cyclic mechanical stretch. Administration of TIMP-2 (200 or 300 ng/mL) significantly suppressed expression of Col1A2 and Col3A1 mRNA and collagen type I protein in KFs. TIMP-2 also significantly reduced the skin dermal and collagen bundle thickness in ex vivo cultures of keloid tissue. Conclusion: These results indicated that downregulation of TIMP-2 in KFs is a crucial event in the pathogenesis of keloids, and the TIMP-2 would be a promising candidate for the treatment of keloids.

Reconstruction after Anterior Chest Wall Keloid Resection Using Internal Mammary Artery Perforator Propeller Flaps.

Background: It is difficult to completely resect huge anterior chest wall keloids and then close the wound directly. We report here our retrospective analysis of our case series of patients with such keloids who underwent reconstruction with internal mammary artery perforator (IMAP) pedicled propeller flaps and then received postoperative high-dose-rate superficial brachytherapy. Methods: All consecutive patients with large/severe keloids on the anterior chest wall who underwent keloid resection followed by reconstruction with IMAP-pedicled propeller flaps and then high-dose-rate superficial brachytherapy in our academic hospital were identified. All cases were followed for >18 months. Donor site position, perforator pedicle, flap size, angle of flap rotation, complications, and recurrence were documented. Results: There were nine men and one woman. The average age was 37.9 years. The average follow-up duration was 28.7 months. The largest flap was 16 × 4 cm. The dominant perforators of the internal mammary artery were located in the sixth (n = 2), seventh (n = 5), eighth (n = 1), and ninth (n = 2) intercostal spaces. Twelve months after surgery, patients reported marked relief from keloid-associated pain and itching, except in two patients who underwent partial keloid resection; their remaining keloids were still troublesome but after conservative therapies, including steroid ointments/plasters, the keloids gradually ameliorated. Eighteen months after surgery, there was no keloid recurrence or new development of keloids on the donor site. Conclusions: IMAP-pedicled propeller flaps transfer skin tension from the anterior chest wall to the abdomen. Our series suggests that this approach combined with radiation therapy can control keloid recurrence.

Objective Spectrometric Measurement of Keloid Color in the East Asian Population: Pitfalls of Subjective Color Measurements

BACKGROUND Keloids are characterized by the formation of excessive scar tissue that extends beyond the area of the initial wound. Keloid redness is due to angiogenesis and chronic inflammation and is an important indicator of the severity of the lesion and the effectiveness of treatment. METHODS The color of 33 untreated keloids from 30 patients was measured with a narrow-band reflectance colorimeter. The erythema and melanin levels in the keloids (Ek and Mk, respectively) were recorded with control data obtained from the flexor aspect of the forearm (Ec and Mc, respectively). The keloid color was also evaluated subjectively. RESULTS The Ek or Mk values did not vary significantly according to symptom intensity, scar region, patient age, and patient sex. Younger patients (<40 years) and female patients had significantly higher Ek/Ec ratios than did older patients and male patients, respectively. Subjective keloid redness evaluations distinguished keloids with high Ek/Ec ratios from keloids with low Ek/Ec ratios (P<0.0001) but could not distinguish keloids with high Ek from keloids with low Ek. CONCLUSIONS Subjective evaluations of keloids in Japanese subjects reflected Ek/Ec ratios, which were strongly affected by variation in background skin color. The subjective assessment of the color of keloids or other skin disorders should be performed with caution in Asian populations.