Model to Inhibit Contraction in Third-Degree Burns Employing Split-Thickness Skin Graft and Administered Bone Marrow-Derived Stem Cells.

Third-degree burns typically result in pronounced scarring and contraction in superficial and deep tissues. Established techniques such as debridement and grafting provide benefit in the acute phase of burn therapy, nevertheless, scar and contraction remain a challenge in deep burns management. Our ambition is to evaluate the effectiveness of novel cell-based therapies, which can be implemented into the standard of care debridement and grafting procedures. Twenty-seven third-degree burn wounds were created on the dorsal area of Red Duroc pig. After 72 h, burns are surgically debrided using a Weck knife. Split-thickness skin grafts (STSGs) were then taken after debridement and placed on burn scars combined with bone marrow stem cells (BM-MSCs). Biopsy samples were taken on days 17, 21, and 45 posttreatment for evaluation. Histological analysis revealed that untreated control scars at 17 days are more raised than burns treated with STSGs alone and/or STSGs with BM-MSCs. Wounds treated with skin grafts plus BM-MSCs appeared thinner and longer, indicative of reduced contraction. qPCR revealed some elevation of α-SMA expression at day 21 and Collagen Iα2 in cells derived from wounds treated with skin grafts alone compared to wounds treated with STSGs + BM-MSCs. We observed a reduction level of TGFß-1 expression at days 17, 21, and 45 in cells derived from wounds treated compared to controls. These results, where the combined use of stem cells and skin grafts stimulate healing and reduce contraction following third-degree burn injury, have a potential as a novel therapy in the clinic.

Application of Low-Dose CT and MRI in the Evaluation of Soft Tissue Injury in Tibial Plateau Fractures.

Objective: To explore the application value of low-dose CT and MRI in the evaluation of soft tissue injury in tibial plateau fractures. Methods: This study included 89 patients with high suspicion of TPF and KI admitted to our hospital from July 2015 to May 2021. After arthroscopy, 81 patients were diagnosed with FTP combined with KI. The Schatzker classification based on X-ray and CT plain scan combined with three-dimensional reconstruction was recorded, and the soft tissue injury was recorded according to the MRI examination of the affected knee joint. Results: With the results of pathological examination and arthroscopic surgery as the gold standard, the results of MRI and pathological examination and arthroscopic examination were in good agreement (Kappa = 0.857, 0.844), and CT was moderately in agreement (Kappa = 0.697, 0.694). In KI examination, CT and MRI had no difference in the evaluation of ligament injury and bone injury (P > 0.05), but MRI had better diagnostic effect on meniscus injury (P < 0.05). Finally, the satisfaction survey showed that patients in the CT group were more satisfied with clinical services (P < 0.05). Conclusion: Both CT and MRI have certain diagnostic value for occult tibial plateau fractures, among which CT examination is more advantageous for trabecular bone fractures, MRI examination is more advantageous for cortical bone fractures, and MRI examination can improve occult tibial plateau fracture inspection accuracy.

A novel model of traumatic femoral head necrosis in rats developed by microsurgical technique.

BACKGROUND: Clinical angiography and vascular microperfusion confirmed that the femoral head retains blood supply after a collum femur fracture. However, no animal model accurately mimics this clinical situation. This study was performed to establish a rat model with retained viability of the femoral head and partial vasculature deprivation-induced traumatic caput femoris necrosis by surgery. METHODS: Thirty rats were randomly divided into three groups (n = 10 per group): normal group, sham-operated group (Control), and ischemic osteonecrosis group. The femoral head of the normal group of rats underwent a gross anatomy study and microangiography to identify femoral head blood supply. Microsurgical techniques were used to cauterize the anterior-superior retinacular vessels to induce osteonecrosis. Hematoxylin and Eosin (H&E) staining were used for femoral head histologic assessment. Morphologic assessments of the deformity in and trabecular bone parameters of the femoral head epiphysis were performed using micro-CT. RESULTS: The blood supply of the femoral head in rats primarily came from the anterior-superior, inferior, and posterior retinacular arteries. However, anterior-superior retinacular vasculature deprivation alone was sufficient in inducing femoral head osteonecrosis. H&E showed bone cell loss in nuclear staining, disorganized marrow, and trabecular structure. The bone volume (BV) decreased by 13% and 22% in the ischemic group after 5 and 10 weeks, respectively. The mean trabecular thickness (Tb.Th) decreased from 0.09 to 0.06 mm after 10 weeks. The trabecular spacing (Tb.Sp) increased from 0.03 to 0.05 mm after 5 weeks, and the epiphyseal height-to-diameter (H/D) ratio decreased. CONCLUSIONS: We developed an original and highly selective rat model that embodied femoral head traumatic osteonecrosis induced by surgical anterior-superior retinacular vasculature deprivation.

Open total dislocation of ankle joint without fractures: A case report.

RATIONALE: Open total dislocation of ankle joint is rare and often caused by high-energy injury. The present study describes a patient with open total lateral dislocation of ankle joint without fractures and obtained a satisfactory clinical result following early debridement and irrigation, one-stage repairment of ligaments, and plaster external fixation. PATIENT CONCERNS: The patient, a 45-year-old male, complained of right foot pain with bleeding and limited motion. Physical examination showed a 15-cm open wound at the medial ankle region, with soft tissues impaired and ankle bones exposed. The 3 dimensional reconstruction computed tomography (CT) examination showed an open total dislocation of ankle joint without concomitant fractures. DIAGNOSES: open total lateral dislocation of ankle joint without fractures. INTERVENTIONS: Early modern wound care including thorough debridement and irrigation on the wound was performed to remove contaminated soft tissues. Subsequently, the dislocated ankle joint was reduced by hand and the medial and lateral collateral ligaments were repaired using wire anchors. OUTCOMES: The medial wound healed at 2 weeks after surgery, and several common complications such as infection and skin necrosis did not occur. The last follow-up showed a good range of metatarsal flexion and extension of the injured foot, and obvious signs of traumatic arthritis were not observed. According to Kaikkonen ankle function score, the patient was assessed with 90 points. LESSONS: For open total dislocation of ankle joint, early treatment should focus on debridement and irrigation, reduction and fixation of the dislocated ankle, protection of the weak soft tissues, and stable external fixation to promote wound healing and reduce the incidence of related complications.

Autologous thrombin preparations: Biocompatibility and growth factor release.

Platelet-rich plasma (PRP) has been investigated to promote wound healing in a variety of tissues. Thrombin, another essential component of wound healing, is sometimes combined with PRP to generate a fibrin clot in order to retain the sample at the delivery site and to stimulate growth factor release. Using a fully autologous approach, autologous serum (AS) with thrombin activity can be prepared using a one-step procedure by supplementing with ethanol (E+ AS) to prolong room temperature stability or prepared ethanol free (E- AS) by utilizing a two-step procedure to prolong stability. The objective of this study was to evaluate potential wound healing mechanisms of these two preparations using commercially available devices. A variety of tests were conducted to assess biocompatibility and growth factor release from PRP at various ratios. It was found that E- AS contained greater leukocyte viability in the product (97.1 ± 2.0% compared to 41.8 ± 11.5%), supported greater bone marrow mesenchymal stem cell proliferation (3.7× vs 0.8× at a 1:4 ratio and 3.6× vs 1.6× at a 1:10 ratio), and stimulated release of growth factors and cytokines from PRP to a greater extent than E+ AS. Of the 36 growth factors and cytokines evaluated, release of 27 of them were significantly reduced by the presence of ethanol in at least one of the tested configurations. It is concluded that the high concentrations of ethanol needed to stabilize point of care autologous thrombin preparations could be detrimental to normal wound healing processes.

Individualized design of double skin paddle anterolateral thigh perforator flaps to repair complex soft tissue defects of the extremities: An anatomical study and retrospective cohort study.

This study describes our experience using individually designed double skin paddle anterolateral thigh perforator (ALTP) flaps to reconstruct complex soft tissue defects. An anatomical study of double skin paddle ALTP flaps was conducted in six fresh cadavers (12 thighs). We also performed a retrospective cohort study of 36 patients who underwent reconstruction using double skin paddle ALTP flaps from January 2009 to June 2019. The soft tissue defects were large or non-adjacent defects that could not be repaired by a single flap. Three types of double skin paddle ALTP flaps were designed. In type I, separate perforators supplied each flap: one perforator from the transverse branch of the lateral circumflex femoral artery (LCFA) and one from the descending branch of the LCFA (d-LCFA). In type II, both perforators were from the d-LCFA. In type III, a single perforator from the d-LCFA had two branches that each supplied one flap. In the cadaver study, type I was observed in 11 thighs, type II in 10, and type III in six. All patients were successfully treated using double skin paddle ALTP flaps. Four patients received type I flaps, 23 received type II, and nine received type III. Vascular compromise occurred in one patient, and the flap was saved by emergency revascularization. Most patients had satisfactory contours and functional recovery during follow-up. Individually designed double skin paddle ALTP flaps is a reliable option for reconstructing complex soft tissue defects. Moreover, we created an algorithm for microvascular reconstruction of complex soft tissue defects.

Mesenchymal stem cells derived-exosomes as a new therapeutic strategy for acute soft tissue injury.

The study aimed to investigate the role of exosomes derived from rat bone marrow mesenchymal stem cells (rBMSCs) in acute soft tissue injury and its related mechanisms. Exosomes were isolated from rBMSCs and characterized by Nanosight NS300 particle size analyser (NTA), transmission electron microscopy (TEM), and western blot. Twenty four rats were randomly divided into four groups (n = 6): control group, strike group, rBMSCs group, and rBMSCs-exo group. Haematoxylin-eosin (HE) staining was used to observe the morphology. Real-time quantification PCR (RT-qPCR) and western blot were used to analyse the expression of IL-1A, IL-12A, COL11A1, COL4A4, and Wnt4. NTA, TEM and western blot results showed that exosomes isolated from rBMSCs were cup-shaped morphology with a size of about 100 nm. HE staining showed that there was severe soft tissue inflammation in strike group, and the symptoms were alleviated after rBMSCs and rBMSCs-exo treatment. RT-qPCR and western blot indicated that in the strike group, the expression levels of IL-1A and IL-12A were significantly increased, and their expressions were decreased markedly by exosomes treatment. In addition, after treatment, the expression levels of COL11A1 and Wnt4 were up-regulated, while the expression of COL4A4 was down-regulated. Exosomes isolated from rBMSCs could improve acute soft tissue injury, and may be used as a new therapeutic strategy acute soft tissue injury. SIGNIFICANCE OF THE STUDY: Acute soft tissue injury is a common clinical exercise injury, which has a significant impact on people's health and work ability. Exosomes have been attracting increasing attention as a media of cell-to-cell communication. This study showed that exosomes isolated from rBMSCs could improve acute soft tissue injury by inhibiting inflammatory response, regulating the levels of COL11A1 and COL4A4, and up-regulating the expression of Wnt4. These will provide a new therapy strategy of acute soft tissue injury, and improve our understanding of the occurrence and development in acute soft tissue injury.

Quantification of axonal ingrowth and functional recovery in a myocutaneous flap model in rats with strong clinical implications.

The process of reinnervation, an important component of functional restoration after flap transfer, is understudied, making it necessary to carry out a further investigation for delineation of the exact timeline. Seventy-six Sprague-Dawley rats were used as the experimental animals. An anatomic study was first conducted to clarify the pattern of nerve distribution in the dorsal skin of 16 rats. Afterward, a myocutaneous flap was harvested on the right flanks of 40 rats, which were then assigned into seven time points. At each time point, skin samples were harvested and immunofluorescent staining was performed using α-Bungarotoxin, and antibodies against NF-200, p75, α-SMA, and TH. One-way analysis of variance was adopted for comparison of nerve density after surgery. For evaluation of functional return, cutaneous trunci muscle reflex (CTMr) test was performed on 10 additional rats, and the Chi-square test was used for comparison of reflex intensity among six time points after surgery. The outcomes revealed that the cutaneous branches from the intercostal nerves and the dorsothoracic nerve from the brachial plexus could be found entering the dorsal skin, distributed in the skin proper and the panniculus carnosus, respectively. After flap surgery, full spontaneous reinnervation of the skin proper and vessels within the flaps could be achieved at day 180. However, if the stumps of cutaneous branches of the intercostal nerves were damaged, the nerve density in the skin proper underwent a 2/3 decline. The panniculus carnosus in the cranial part had a much better reinnervation than that in the caudal part. The CTMr test showed that the flap could regain most of its sensate and motor activity. Our study shows that strong spontaneous reinnervation could be expected after flap surgery. The pattern of the original nerve distribution in both the recipient and donor sites may have a big impact on the reinnervation of the flap.

Annexin A1-derived peptide Ac2-26 facilitates wound healing in diabetic mice.

Impaired wound healing is a common complication of diabetes. In diabetic wounds, macrophages present dysfunctional efferocytosis and abnormal phenotypes, which could result in excessive neutrophil accumulation and prolonged inflammation, thereby eventually hindering wound repair. ANXA1 N-terminal peptide Ac2-26 exhibits a high potential in mitigating inflammation and improving repair; however, its efficacy in diabetic wound repair remains unclear. In this study, a cutaneous excisional wound model was built in genetically diabetic mice. Ac2-26 or a vehicle solution was employed locally in wound sites. Subsequently, wound zones were measured and sampled at different time intervals post-wounding. Using hematoxylin-eosin and Masson's trichrome staining, we observed the histopathological variations and collagen deposition in wound samples. Based on immunohistochemistry and immunofluorescence, the numbers of neutrophils, macrophages, and CD206-positive macrophages in the wound samples were determined. Cytokine expression in wound samples was studied by immunoblot assay. Results showed that Ac2-26 treatment could facilitate diabetic wound closure, down-regulate the number of neutrophils, and improve angiogenesis and collagen deposition. In addition, Ac2-26 application expedited macrophage recruitment and up-regulated the percentage of macrophages expressing CD206, which is a marker for M2 macrophages. Moreover, Ac2-26 inhibited the expressions of TNF-α and IL-6 and up-regulated the expressions of IL-10, TGF-ß, and VEGFA during diabetic wound healing. Hence, based on the aforementioned findings, Ac2-26 application in diabetic wounds could exert anti-inflammatory and pro-repair effects by reducing neutrophil accumulation and facilitating M2 macrophage development.

Histopathological Comparison of 2-Octyl Cyanoacrylate and Primary Suturing for Tongue Lacerations.

OBJECTIVE: To enable tongue incisions to be repaired more easily, rapidly, and practically, particularly in pediatric patients by using 2-octyl cyanoacrylate (OCA) tissue adhesive. METHODS: A single linear incision was made on the midline dorsal part of the tongue. Twenty-four rats were randomly divided into the four groups: Group 1 (n = 6), OCA healing at day 5; group 2 (n = 6), OCA healing at day 21; group 3 (n = 6), Vicryl healing at day 5; group 4 (n = 6), Vicryl healing at day 21. In groups 1 and 2, OCA was applied to the incision site. The incisions of the rats in groups 3 and 4 were closed using Vicryl sutures. Histopathological examination was compared between and within the groups at day 5 and 21. RESULTS: The operation duration was significantly shorter with OCA than with Vicryl sutures(P < 0.001). Regarding the histopathological results, there were no differences between group 1 and group 3 in epithelial regeneration, inflammation, fibroblastic activity, edema, presence of giant cells, fibrin deposition, ulceration, abscess formation, and granulation tissue. However, moderate infiltration of acute inflammatory cells was significantly more frequent in group 1 than in group 3. At day 5, the incidence of moderate foreign body residue was significantly higher in group 1 than in group 3. No difference was observed between group 2 and group 4 at day 21 (P > 0.05). CONCLUSION: OCA is a practical, rapid, and effective method for repairing tongue lacerations. Although infiltration by inflammatory cells and foreign bodies increased in the early period, the long-term results of OCA were indistinguishable from those of suturing.

A minimally invasive incision and loop drainage technique for the treatment of lower limb Morel-Lavallée lesions: Nose ring drainage technique.

Morel-Lavallée lesions (MLLs) are shearing injuries resulting in separation of the skin and subcutaneous tissue from the underlying fascia. They are closed internal degloving injuries. Classical sites of the lesions are around the greater trochanter, pelvis, thigh, knee joint, and on the head, in decreasing order of frequency. This injury is often delayed or misdiagnosed when patients present with soft tissue injury alone or when more obvious injuries distract from its presence in polytrauma patients. There is currently no universally accepted treatment for these lesions. Conservative management often fails and requires surgical intervention. The purpose of this manuscript is to show that nose ring drainage, a minimally invasive incision and loop drainage technique for the treatment of lower limb Morel-Lavallée lesions, is effective and economical.

Wound-Healing Following Negative-Pressure Wound Therapy with Use of a Locally Developed AquaVac System as Compared with the Vacuum-Assisted Closure (VAC) System.

BACKGROUND: Negative-pressure wound therapy (NPWT) gained widespread clinical use after its introduction in the 1990s because of its many beneficial effects on the wound environment. However, high treatment costs have limited its use in third-world countries. The present study compares a low-cost, locally developed NPWT system with a commercially available system in terms of efficacy, reliability, ease of application, and safety. METHODS: This prospective, randomized controlled trial involved 36 patients who were managed with NPWT with either a low-cost, locally developed system (AquaVac) or a commercially available Vacuum-Assisted Closure Advanced Therapy System (VAC ATS; KCI). The low-cost NPWT system described consists of a converted aquarium pump as a reusable vacuum source and a dressing system that can be found in the hospital supply room: food plastic wrap as an occlusive drape, surgical gauze as wound filler, nasogastric tubes as tubing, and used intravenous (IV) bottles as effluent canisters. The purpose of the study was to compare the 2 systems in terms of (1) time to apply the dressing, (2) exudate levels, (3) amount of granulation tissue, (4) wound size reduction, (5) average cost of treatment, (6) visual analog scale (VAS) pain scores, and (7) complications. RESULTS: The experimental low-cost system had a small but statistically insignificant advantage over the commercially available system in terms of application time, pain during dressing changes, and wound contraction percentage. The 2 systems were comparable in terms of the amount of exudate, granulation tissue coverage, and VAS scores during the course of treatment. No wound or periwound complications were observed. The systems were significantly different in terms of cost, with the AquaVac system being 7 times less expensive than the VAC ATS system ($63.75 compared with $491.38 USD). CONCLUSIONS: The low-cost AquaVac system was shown to be comparable with the commercial VAC ATS system, suggesting that it is an effective and safe alternative method for NPWT in resource-challenged settings. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

[Coverage in the management of loss of skin substances on the lower third of the leg: about 9 cases]. / La couverture des pertes de substances cutanées du tiers inférieur de la jambe: à propos de 09 cas.

Coverage of loss of skin substances on the lower third of the leg is a challenging problem. This is due to adjacent soft tissues impairment, shortage of local vascularization and bone exposure. We conducted a retrospective study of a series of 9 cases of skin coverage of the lower third of the leg treated at the University Hospital Hassan II of Fez from 2016 to 2018. This study aims to highlight the characteristic of the loss of skin substances on the lower third of the leg, while emphasizing the difficulty of management.

Reconstruction of radiation-induced ulcers with free flaps using the perforating vessel as a recipient vessel.

BACKGROUND: Free flaps can be options for coverage of radiation ulcers. However, due to radiation damage, it may be hard to find and dissect a reliable recipient vessel for microsurgical anastomosis. When the radiation fields are targeted for deep tissues, superficial tissues may be less affected by radiation. Therefore, damage to perforator vessels near the skin may be lesser than that to the major vessels in deeper structures. We would like to introduce our experiences of using these less injured perforating vessels within or near the wound as recipient vessels for free flap coverage. PATIENTS AND METHODS: From 2013 to 2015, 11 patients underwent free flap coverage for the treatment of radiation-induced ulceration. The location of ulcers were three cases of thigh, two cases of inguinal area, axilla, trochanteric area, chest wall, lower leg, perineal area, and back. Eleven cases were reconstructed using the anterolateral thigh (ALT) perforator flap, and in one case, the thoracodorsal artery perforator (TDAP) flap was used for inguinal area defect. With preoperative computed tomography, we found perforating vessels around the radiation ulcer. The perforating vessels that were identified before the operation were detected by hand-held Doppler during the operation and meticulous dissection was performed. In all-cases, the perforating vessels were accompanied by vena commitantes. A reliable perforator is one with visible pulsation, strong sound detected on Doppler, and sufficient diameter, preferably larger than 0.6 mm. Anastomosis was performed after confirming that the blood vessel was reliable. RESULTS: The flap sizes ranged from 7 × 6 cm to 24 × 10 cm. No flap total necrosis developed. Patients were followed in the outpatient clinic for 21 to 31 months postoperatively. No patients experienced recurrence of ulceration during the follow-up. CONCLUSIONS: In free flap reconstruction of radiation ulcers, using perforating vessels within or outside the ulcer as recipient vessels provided less damaged vessels and healthier flaps for the defects with minimal wound complications. These perforating vessels can be a good option as recipient vessel for free flap coverage of radiation ulcers.

Post-Traumatic Sarcomas: Do They Exist?

Patients often cite a history of trauma prior to the diagnosis of a sarcoma. Sparse literature suggests that there may be a link between sarcoma development and trauma. A 10-year review of academic tertiary-referral sarcoma center database was examined to identify patients who developed a sarcoma after having a history of a significant musculoskeletal trauma. A total of 501 patients were treated for a sarcoma during this time period. Six patients were identified as previously having a significant musculoskeletal trauma at the site of sarcoma development. Half of the sarcomas arose in bone and the other half in soft tissue. Five (83%) patients had multiple operations for the injury with 3 (50%) patients having a postoperative wound infection. The average time from injury to development of the sarcoma was 19.8 years. Survival after diagnosis was poor, and 4 (67%) of the patients died due to their metastatic disease within 3 years of diagnosis. Our findings suggest the possibility of post-traumatic sarcomas.

Effects of depression on healing and inflammatory responses of acute wounds in rats.

This study aimed to elucidate the effect of depression on the healing of acute wounds in rats. We hypothesized that depression would have negative effects on inflammation and wound healing and that antidepressant therapy would reverse these effects. This study included 100 rats randomly allocated into five groups: control group (CG), depression group (DG), pre-depression group (PDG), antidepressant group (AG), and pre-antidepressant group (PAG). Acute wounds were created on the rats' backs. The groups were subjected to no interventions (CG), aversive stimuli before (PDG) and after (DG) wound creation, and antidepressant treatment before (PAG) and after (AG) wound creation. On the day of wound creation and on days 3, 6, 9, and 12 after wound creation, observations of the wound area and degree of depression (evaluated using the sucrose preference test, open-field test, and weight change) were recorded. On days 6 and 12 after wound creation, venous serum and wound tissues were collected. Tumor necrosis factor alpha (TNF-α), interleukin (IL)-1ß, IL-6, and IL-10 levels were measured using the enzyme-linked immunosorbent assay. Results showed an initial increase followed by a decrease in the degree of depression in all groups except DG (continuous decline). The wound-healing rate was significantly lower in PDG and DG than in CG; it was higher in AG and PAG than in CG. DG and PDG had higher concentrations of inflammatory cytokines than CG, and AG and PAG had lower concentrations than CG. This indicates that the onset of depression delays the healing of acute wounds and aggravates the inflammatory response in rats. Antidepressant treatment counteracts both of these negative effects.

Results of Achilles Tendon Excision for Purpose of Wound Closure: Case Series.

The loss of Achilles tendon results in reduced plantar flexion strength; however, in patients who are not fit for major reconstructive surgery, with soft-tissue defects overlying the tendon, Achilles tendon excision is a useful adjunct procedure for wound closure. We report 3 patients with infections around the Achilles tendons needing debridement procedures who underwent Achilles tendon excision for the purpose of wound closure. Local healing was achieved in all patients; all returned to their premorbid ambulatory status, and 2 could perform heel raise. Our series showed that Achilles tendon excision eases soft-tissue reconstruction around it and that the primary aim of wound closure was met with a reasonable functional outcome. As such, it is a viable option for selected patients with infections around the Achilles tendon who are poor candidates for flaps.

Novel Biodegradable Polymeric Microparticles Facilitate Scarless Wound Healing by Promoting Re-epithelialization and Inhibiting Fibrosis.

Despite decades of research, the goal of achieving scarless wound healing remains elusive. One of the approaches, treatment with polymeric microcarriers, was shown to promote tissue regeneration in various in vitro models of wound healing. The in vivo effects of such an approach are attributed to transferred cells with polymeric microparticles functioning merely as inert scaffolds. We aimed to establish a bioactive biopolymer carrier that would promote would healing and inhibit scar formation in the murine model of deep skin wounds. Here we characterize two candidate types of microparticles based on fibroin/gelatin or spidroin and show that both types increase re-epithelialization rate and inhibit scar formation during skin wound healing. Interestingly, the effects of these microparticles on inflammatory gene expression and cytokine production by macrophages, fibroblasts, and keratinocytes are distinct. Both types of microparticles, as well as their soluble derivatives, fibroin and spidroin, significantly reduced the expression of profibrotic factors Fgf2 and Ctgf in mouse embryonic fibroblasts. However, only fibroin/gelatin microparticles induced transient inflammatory gene expression and cytokine production leading to an influx of inflammatory Ly6C+ myeloid cells to the injection site. The ability of microparticle carriers of equal proregenerative potential to induce inflammatory response may allow their subsequent adaptation to treatment of wounds with different bioburden and fibrotic content.