Chronic Knee and Ankle Pain Treatment through Selective Microsurgical Approaches: A Minimally Invasive Option in the Treatment Algorithm for Refractory Lower Limb Pain.

BACKGROUND: Injury or compression of a sensory nerve is an under-reported source of disabling pain in the lower limb. It is known that peripheral nerve microsurgeons can reconstruct and rewire injured nerves to relieve chronic pain but this option remains not completely understood and ignored by most orthopaedic surgeons, neurologists, and pain therapists. In this paper, we describe our experience with knee and ankle peripheral nerve surgery to improve the condition of patients suffering from chronic, posttraumatic lower limb pain. PATIENTS AND METHODS: Between 2015 and 2018, a retrospective investigation was performed including patients who underwent ankle and knee nerve surgery for posttraumatic chronic pain with at least 1 year of follow-up. Previous surgeries or type of trauma, pain location and characteristics, type of operation (reconstruction, decompression, or denervation), and number of nerves operated were listed. Selective neuropathy was confirmed by ultrasound-guided nerve blocks. Outcome was assessed combining the visual analogue scale (VAS) score at rest and during movement, functional indexes, drug use, and ability to work. RESULTS: A total of 34 patients (14 knee and 20 ankle) were included in this study. A statistically significant difference (p < 0.05%) in postoperative pain at rest and during activity was seen in both groups of patients. Good to excellent outcomes were recorded in 92 and 80% of patients treated, respectively, at the knee and the ankle levels. No major complications occurred, while a secondary procedure due to neuroma recurrence was necessary in seven patients (three knees and four ankles). CONCLUSION: Peripheral nerve microsurgery is a useful and minimally invasive tool to be added in the algorithm of treatment of chronic knee and ankle pain. Physicians should be trained to suspect a neuropathic origin of pain in absence of musculoskeletal signs of pathology, especially following trauma or surgeries.

Selective denervation of the corrugator supercilii muscle for the treatment of idiopatic trigeminal neuralgia purely paroxysmal distributed in the supraorbital and suprathrochlear dermatomes.

INTRODUCTION: Idiopatic trigeminal neuralgia purely paroxysmal (ITNp) distributed in the supraorbital and suprathrochlear dermatomes (SSd), refractory to conventional treatments have been linked to the hyperactivity of the corrugator supercilii muscle (CSM). In these patients, the inactivation of the CSM via botulinum toxin type A (BTA) injections has been proven to be safe and effective in reducing migraine burden. The main limitation of BTA is the need of repetitive injections and relative high costs. Based on the study of the motor innervation of the CSM, we describe here an alternative approach to improve these type of migraines, based on a minimally invasive denervation of the CSM. MATERIALS AND METHODS: Motor innervation and feasibility of selective CSM denervation was first studied on fresh frozen cadavers. Once the technique was safely established, 15 patients were enrolled. To be considered eligible, patients had to meet the following criteria: positive response to BTA treatment, migraine disability assessment score > 24, > 15 migraine days/month, no occipital/temporal trigger points and plausible reasons to discontinue BTA treatment. Pre- and post- operative migraine headache index (MHI) were compared, and complications were classified following the Clavien-Dindo classification (CDC). RESULTS: Fifteen patients (9 females and 6 males) underwent the described surgical procedure. The mean age was 41 ± 10 years. Migraine headache episodes decreased from 24 ± 4 day/month to 2 ± 2 (p < 0.001) The MHI decreased from 208 ± 35 to 10 ± 11 (p < 0.001). One patient (7%) had a grade I complication according to the CDC. No patient needed a second operative procedure. CONCLUSIONS: Our findings suggest that the selective CSM denervation represents a safe and minimally invasive approach to improve ITNp distributed in the SSd associated with CSM hyperactivation. TRIAL REGISTRATION: The data collection was conducted as a retrospective quality assessment study and all procedures were performed in accordance with the ethical standards of the national research committee and the 1964 Helsinki Declaration and its later amendments.

Minimal Undermining Suspension Technique (MUST): Combined Eyebrow and Mid-face Lift via Temporal Access.

BACKGROUND: Less downtime following esthetic interventions leads to the popularity of injectable solutions for facial rejuvenation treatments. Surgical interventions for esthetic purposes are usually associated with higher complication rates and longer recovery times when compared to less invasive treatments. Here we present for the first time a minimally invasive surgical technique for a simultaneous mid-face and eyebrow lift using one small temporal incision. MATERIALS AND METHODS: We prospectively studied patients who underwent facial rejuvenation using a minimal undermining suspension technique (MUST) in an outpatient setting. Postoperatively, surgical complications were classified according to the Clavien-Dindo classification. Preoperatively and at 12-month post-intervention, patient-reported outcomes were described using the FACE-Q questionnaire. Pre- and postoperative pictures were compared using MERZ Aesthetic Scales. RESULTS: Fifty-five patients (50 females and 5 males) with a mean age of 47 years were studied. The overall complication rate was 19%, whereas 18 patients (15%) developed an ecchymosis of the orbicular temporal region and two patients (4%) developed a dimple caused by the anchor of the suture. No displacements of the palpebral rim or injuries to the facial nerve were observed. Recovery time was in average 7 days and no long-term complications were seen. Both, the FACE-Q and the MERZ Aesthetic Scales showed significant improvements at 12-month post-surgery (p < 0.01). CONCLUSIONS: The MUST can be used as a minimal invasive procedure for facial rejuvenation with a short downtime and low complication rate. The discreet temporal access and the MUST dissector allowed a safe dissection of anatomical tissue planes to perform safely a mid-face and eyebrow lift. Further studies are warranted to prove long-term outcomes. LEVEL OF EVIDENCE IV: 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 A3 online Instructions to Authors. www.springer.com/00266 .

The Outcome of Primary Subglandular Breast Augmentation Using Tumescent Local Anesthesia.

BACKGROUND: Tumescent local anesthesia (TLA) technique to obtain regional anesthesia and vasoconstriction of the skin and subcutaneous tissues is routinely adopted for several plastic surgery procedures. Here, we describe the use of TLA in primary subglandular breast augmentation. This series evaluates advantages and disadvantages of TLA in elective augmentation breast surgery as well as patients' response to this procedure. METHODS: Between December 2008 and November 2011, 150 patients underwent bilateral primary subglandular breast augmentation under TLA and conscious sedation in the presence of a board-certified anesthesiologist. Midazolam 0.05 mg/kg IV and ranitidine 100 mg IV were given as premedication. Tumescent local anesthesia was composed of 25 mL of lidocaine 2%, 8 mEq of sodium bicarbonate, and 1 mL of epinephrine (1 mg/1 mL) in 1000 mL of 0.9% NS. The solution was delivered between the pectoral fascia and the mammary gland via a spinal needle. After infiltration, 45 minutes were allowed before surgery for local anesthetic effects to take place. RESULTS: The mean age of the patients was 34.3 years. The average amount of tumescent solution infiltrated was 1150 mL, with a maximal dose of 17 mg/kg of lidocaine used. Operating time was 45 minutes and recovery room time averaged 125 minutes. Minor complications were found in a total of 9 (5.3%) patients, with no main surgery-related complications such as hematoma or seroma formation. CONCLUSIONS: Breast augmentation under TLA and conscious sedation proved to be safe in the presence of a board-certified anesthesiologist and when performed with meticulous surgical technique.

Minimally invasive nerve and artery sparing surgical approach for temporal migraines.

Background: Temporal migraines (TM) present with throbbing, pulsating headaches in the temporal area. Different surgical techniques ranging from resecting the auriculotemporal nerve (ATN) and or ligating the superficial temporal artery (STA) have shown similar good results to decrease TM symptoms. No conclusive data supports a specific disease of the STA in TM patients. A minimally invasive technique is proposed to preserve both vascular and nerve structures. Methods: Patients with drug resistant TM were selected and treated with two techniques: nerve sparing and nerve and artery sparing. The study included 57 patients with TM, with an average age of 47.5 years. TM improvement was quantified after at least one year of follow up time. STA biopsies were sent for histological analysis. Results: Forty-two patients underwent nerve-sparing decompression, with a therapeutic success rate of 78.6%, corresponding to 22.1 days with migraine per month decreasing to 6.2. Histological analysis of the STA showed varying degrees of endofibrosis in 75% of the samples. Histological results do not correlate with the intensity of symptoms before or after surgery. Fifteen patients underwent nerve and artery sparing arteriolysis, with an overall therapeutic success rate of 86.6% of which 80% had >90% improvement. The average migraine days dropped from 24 to 2.5 days per month in this group. Conclusion: Minimally invasive nerve sparing approaches are an effective and safe treatment to improve drug resistant TM symptoms. Endofibrosis of the STA was present in 75% of the cases, but it was found to be unrelated to pre-operative symptoms and outcome. Results are promising, but the limited numbers of patients treated with artery and nerve sparing technique needs further investigations.

Minimally invasive scar release by autologous adipose tissue transfer for post-traumatic neuropathic pain.

Introduction: Addressing post traumatic lower limb neuropathic pain is challenging across medical specialties. To address this potentially devastating condition, several invasive and non-invasive approaches have been proposed with inconsistent results. Adipose fat transfer (AFT), also known as fat grafting, is a regenerative medicine technique in which a patient's own fat is harvested from one area of the body (usually through liposuction) and then injected into another area for various purposes, such as aesthetic contour enhancement or reconstruction and regeneration of scarred tissues. Methods: We analyze the effects of fat grafting for neuropathic pain combined with neuroma excision (hybrid technique, hAFT) or alone (AFT). A retrospective review was conducted on 22 patients with neuropathic lower limb pain, after trauma or orthopedic surgery treated with hAFT (n = 9) or AFT (n = 13). Results: Reduction in VAS scale more than 50 % was observed in 6 patients (66 %) treated with hybrid technique and in eleven patients (85 %) treated with AFT alone. Among these, complete pain reduction (>91 %) was achieved in 33.3 % of hAFT and 54 % of AFT technique. A 3.2 points reduction in VAS was found in the hAFT group versus 5.8 points in the AFT group (p = 0.035). Conclusion: This pioneering use of AFT emerges as a minimally invasive breakthrough, promising significant improvement in reconstructing scarred subcutaneous tissue and managing neuropathic pain.

Minimally Invasive Nerve- and Muscle-Sparing Surgical Decompression for Occipital Neuralgia.

BACKGROUND: Occipital neuralgia is a well-defined type of headache, and its treatment algorithm is still debated across medical specialties. From the analysis of the literature, it appears that surgical decompression of the occipital nerves is the most effective invasive approach to improve the quality of life of patients with occipital neuralgia refractory to medications. The authors describe here a minimally invasive nerve- and muscle-sparing technique to decompress the occipital nerves. METHODS: The results in terms of reduction of migraine days per month, use of medications, pain evaluation, and decrease in Migraine Headache Index were analyzed by means of a retrospective chart review of 87 patients who underwent nerve- and muscle-sparing surgical decompression of the greater and lesser monolateral or bilateral occipital nerves in their institution and were followed up for at least 12 months. The surgical technique is described in detail. RESULTS: Surgical decompression significantly reduced occipital neuralgia burden (at least 50% improvement) in 91% of patients, with 45% reporting a complete remission of occipital pain. Days with pain per month decreased by 80%, chronic background pain intensity decreased by 81%, and pain intensity during crisis decreased by 76%. Accordingly, drug use dropped by approximately 70%. Only minor complications were reported in four patients. CONCLUSIONS: The described technique could contribute to and further support surgical decompression as the first option among the invasive approaches to treat occipital neuralgia. Results corroborate previous findings, adding a less-invasive, nerve- and muscle-sparing approach. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

A review of the role of mechanical forces in cutaneous wound healing.

Cutaneous wound healing is a complex process with many types of mechanical forces regulating the quality and speed of healing. The role of mechanical forces in regulating tissue growth, repair and remodelling was recognised more than a century ago. Such forces influence gene expression, the synthesis of growth factors and inflammatory mediators and cellular processes like proliferation of many load-sensitive cells. However, the exact mechanisms by which these forces interact with cells and ways to use them to stimulate tissues are still active research fronts. This article sets to review the literature on mechanical forces and their role in cutaneous wound healing.

Poly-N-acetyl glucosamine fibers induce angiogenesis in ADP inhibitor-treated diabetic mice.

BACKGROUND: It has been previously demonstrated that short-fiber poly-N-acetyl-glucosamine (sNAG) nanofibers specifically interact with platelets, are hemostatic, and stimulate diabetic wound healing by activating angiogenesis, cell proliferation, and reepithelialization. Platelets play a significant physiologic role in wound healing. The influence of altered platelet function by treatment with the ADP inhibitor Clopidogrel (CL) on wound healing and the ability of sNAG to repair wounds in diabetic mice treated with CL were studied. METHODS: Dorsal 1 cm2 skin wounds were excised on genetically diabetic 8-week to 12-week-old, Lep/r-db/db male mice, and wound healing kinetics were determined. Microscopic analysis was performed for angiogenesis (PECAM-1) and cell proliferation (Ki67). Mice were either treated with CL (P2Y12 ADP receptor antagonist, CL) or saline solution (NT). CL wounds were also treated with either a single application of topical sNAG (CL-sNAG) or were left untreated (CL-NT). RESULTS: CL treatment did not alter wound healing kinetics, while sNAG induced faster wound closure in CL-treated mice compared with controls. CL treatment of diabetic mice caused an augmentation of cell proliferation and reduced angiogenesis compared with nontreated wounds. However, sNAG reversed the effects of CL on angiogenesis and partially reversed the effect on cell proliferation in the wound beds. The sNAG-treated wounds in CL-treated mice showed higher levels of cell proliferation and not did inhibit angiogenesis. CONCLUSIONS: CL treatment of diabetic mice decreased angiogenesis and increased cell proliferation in wounds but did not influence macroscopic wound healing kinetics. sNAG treatment did not inhibit angiogenesis in CL-treated mice and induced faster wound closure; sNAG technology is a promising strategy to facilitate the healing of complex bleeding wounds in CL-treated diabetic patients.

Portable bioluminescent platform for in vivo monitoring of biological processes in non-transgenic animals.

Bioluminescent imaging (BLI) is one of the most powerful and widely used preclinical imaging modalities. However, the current technology relies on the use of transgenic luciferase-expressing cells and animals and therefore can only be applied to a limited number of existing animal models of human disease. Here, we report the development of a "portable bioluminescent" (PBL) technology that overcomes most of the major limitations of traditional BLI. We demonstrate that the PBL method is capable of noninvasive measuring the activity of both extracellular (e.g., dipeptidyl peptidase 4) and intracellular (e.g., cytochrome P450) enzymes in vivo in non-luciferase-expressing mice. Moreover, we successfully utilize PBL technology in dogs and human cadaver, paving the way for the translation of functional BLI to the noninvasive quantification of biological processes in large animals. The PBL methodology can be easily adapted for the noninvasive monitoring of a plethora of diseases across multiple species.

Quiescent platelets stimulate angiogenesis and diabetic wound repair.

INTRODUCTION: Platelets partake in hemostasis, wound healing, and tumor growth. Although platelet-rich-plasma (PRP) has been used in surgery for several years, its mechanism of action and application methods are still poorly characterized. MATERIALS AND METHODS: A single unit of human platelets obtained by plateletpheresis was diluted in plasma and divided into three equal volumes. One volume was stored at room temperature as fresh platelets (RT), another volume was frozen by storage at -80 degrees C (FZ), and the third volume was frozen at -80 degrees C with 6% DMSO (FZ6). Plasma (PL) was used as control. Using flow cytometry, platelets were tested for platelet glycoprotein GPIb and annexin V binding, as survival and activation markers, respectively. Hemostatic function was assessed by thromboelastometry. In vivo, platelets were topically applied on 1 cm,(2) full-thickness wounds on db/db mice (n = 10/group) and healing was staged microscopically and macroscopically. RESULTS: All platelet preparations showed hemostatic ability. RT platelets were GPIb positive (nonactivated-quiescent platelets) and stimulated angiogenesis by threefold, and cell proliferation by fourfold in vivo. FZ platelets were positive for annexin V, indicating activated platelets and, in vivo, increased only wound granulation. FZ6 platelets contained 30% nonactivated-quiescent and 50% activated platelets and stimulated granulation, angiogenesis, cell proliferation, and promoted re-epithelialization in vivo. CONCLUSIONS: Platelets showed distinct mechanisms to induce hemostasis and wound healing. Quiescent platelets are required to induce angiogenesis in vivo. Platelets stored at room temperature and frozen with 6% DMSO and stored at -80 degrees C achieved optimal wound healing in diabetic mice.

Use of the parabiotic model in studies of cutaneous wound healing to define the participation of circulating cells.

Previous experimental studies to assess the contribution of blood-borne circulating (BBC) cells to cutaneous wound healing have relied on discontinuous pulsing of labeled BBC elements or bone marrow transplant protocols. Such approaches do not allow the examination of stable BBC cells that have matured in a physiologically normal host. We have used a parabiotic murine model for cutaneous wound healing to evaluate the relative contribution of stable populations of peripheral blood cells expressing the green fluorescent protein (GFP) transgene in otherwise normal animals. Circulating cells (mature and immature) expressing the GFP transgene were easily detected and quantified in wounds of GFP- parabiotic twins during all evaluated stages of the healing response. Using multiple antibody probes, the relative contribution of various subsets of BBC cells could be comparatively assessed. In early wounds, some cells expressing mesenchymal epitopes were documented to be of hematopoietic origin, indicating the utility of this model in assessing cell plasticity in the context of tissue regeneration and repair. Application of this approach enables further investigation into the contribution of peripheral blood in normal and abnormal healing responses.

Embryonic stem cell extracts improve wound healing in diabetic mice.

AIMS/HYPOTHESIS: Impaired wound healing significantly impacts morbidity and mortality in diabetic patients, necessitating the development of novel treatments to improve the wound healing process. We here investigated the topical use of acellular embryonic stem cell extracts (EXTs) in wound healing in diabetic db/db mice. METHODS: Wounds were induced in diabetic db/db mice, which were subsequently treated with EXTs, with 3T3 fibroblast cell line protein extracts (3T3XTs) or with saline as a control. Pathology and mechanistic assays were then performed. RESULTS: The in vivo topical administration of EXTs facilitates wound closure, contraction and re-epithelialization. Moreover, EXTs reduced the number of wound-infiltrating CD45+ inflammatory cells and increased the rate of repair and of angiogenesis as compared to controls. Interestingly, the EXT effect was partly enhanced by the use of a collagen-based biocompatible scaffold. In vivo, topical administration of EXTs increased the percentage of regulatory T cells in the wounded tissue, while in vitro EXT treatment reduced T cell-mediated IFN-γ production. Proteomic screening revealed 82 proteins differentially segregating in EXTs as compared to 3T3 extracts, with APEX1 identified as a key player for the observed immunomodulatory effect of EXTs. CONCLUSIONS: EXTs are endowed with immunoregulatory and anti-inflammatory properties; their use improves wound healing in diabetic preclinical models.

Poly-N-acetyl glucosamine nanofibers: a new bioactive material to enhance diabetic wound healing by cell migration and angiogenesis.

INTRODUCTION: In several fields of surgery, the treatment of complicated tissue defects is an unsolved clinical problem. In particular, the use of tissue scaffolds has been limited by poor revascularization and integration. In this study, we developed a polymer, poly-N-acetyl-glucosamine (sNAG), with bioactive properties that may be useful to overcome these limitations. OBJECTIVE: To develop a scaffold-like membrane with bioactive properties and test the biologic effects in vitro and in vivo in diabetic wound healing. METHODS: In vitro, cells-nanofibers interactions were tested by cell metabolism and migration assays. In vivo, full thickness wounds in diabetic mice (n = 15 per group) were treated either with sNAG scaffolds, with a cellulosic control material, or were left untreated. Wound healing kinetics, including wound reepithelialization and wound contraction as well as microscopic metrics such as tissue growth, cell proliferation (Ki67), angiogenesis (PECAM-1), cell migration (MAP-Kinase), and keratinocyte migration (p 63) were monitored over a period of 28 days. Messenger RNA levels related to migration (uPAR), angiogenesis (VEGF), inflammatory response (IL-1beta), and extracellular matrix remodeling (MMP3 and 9) were measured in wound tissues. RESULTS: sNAG fibers stimulated cell metabolism and the in vitro migratory activity of endothelial cells and fibroblasts. sNAG membranes profoundly accelerated wound closure mainly by reepithelialization and increased keratinocyte migration (7.5-fold), granulation tissue formation (2.8-fold), cell proliferation (4-fold), and vascularization (2.7-fold) compared with control wounds. Expression of markers of angiogenesis (VEGF), cell migration (uPAR) and ECM remodeling (MMP3, MMP9) were up-regulated in sNAG treated wounds compared with controls. CONCLUSIONS: The key mechanism of the bioactive membranes is the cell-nanofiber stimulatory interaction. Engineering of bioactive materials may represent the clinical solution for a number of complex tissue defects.

Tumors stimulate platelet delivery of angiogenic factors in vivo: an unexpected benefit.

The interaction between platelets and the tumor microenvironment results in the modulation of angiogenesis, although the mechanisms governing this regulation remain unclear. This study explores the differences in the communication between wounded tissues and healthy, tumor-conditioned, and frozen platelets. Platelet-rich plasma obtained from healthy (PRP) or tumor-bearing (TPRP) mice was applied to dorsal, full-thickness wounds on diabetic mice. Wound healing was evaluated using macroscopic criteria and a staging system based on angiogenesis and stromal cell proliferation. Proteomic analysis was used to compare the levels of angiogenic proteins contained in the platelet preparations. TPRP-treated wounds reached 90% wound closure 5.6 to 9.5 days earlier than PRP-treated and nontreated wounds, respectively. TPRP induced a fourfold increase in stromal cell proliferation compared with nontreated wounds, and a 2.5-fold increase compared with PRP-treated wounds. TPRP induced the highest stimulation of angiogenesis with a fourfold increase compared with nontreated controls. On day 21, wounds treated with TPRP showed a typical architecture with thick collagen bundles. Although the levels of angiogenesis regulators detected via SELDI-ToF were similar between the PRP and TPRP treatment regimens, the enhanced healing capacity of TPRP suggests improved platelet delivery as indicated by frozen TPRP preparations that had lost most of their pro-angiogenic drive. In conclusion, these results show that intact tumor-conditioned platelets display an improved ability to deliver angiogenesis regulators to wounded tissues.

The Greater Occipital Nerve and Obliquus Capitis Inferior Muscle: Anatomical Interactions and Implications for Occipital Pain Syndromes.

BACKGROUND: The compression/injury of the greater occipital nerve has been identified as a trigger of occipital headaches. Several compression points have been described, but the morphology of the myofascial unit between the greater occipital nerve and the obliquus capitis inferior muscle has not been studied yet. METHODS: Twenty fresh cadaveric heads were dissected, and the greater occipital nerve was tracked from its emergence to its passage around the obliquus capitis inferior. The intersection point between the greater occipital nerve and the obliquus capitis inferior, and the length and thickness of the obliquus capitis inferior, were measured. In addition, the nature of the interaction and whether the nerve passed through the muscle were also noted. RESULTS: All nerves passed either around the muscle loosely (type I), incorporated in the dense superficial muscle fascia (type II), or directly through a myofascial sleeve within the muscle (type III). The obliquus capitis inferior length was 5.60 ± 0.46 cm. The intersection point between the obliquus capitis inferior and the greater occipital nerve was 6.80 ± 0.68 cm caudal to the occiput and 3.56 ± 0.36 cm lateral to the midline. The thickness of the muscle at its intersection with the greater occipital nerve was 1.20 ± 0.25 cm. Loose, tight, and intramuscular connections were found in seven, 31, and two specimens, respectively. CONCLUSIONS: The obliquus capitis inferior remains relatively immobile during traumatic events, like whiplash injuries, placing strain as a tethering point on the greater occipital nerve. Better understanding of the anatomical relationship between the greater occipital nerve and the obliquus capitis inferior can be clinically useful in cases of posttraumatic occipital headaches for diagnostic and operative planning purposes.

Healing modulation induced by freeze-dried platelet-rich plasma and micronized allogenic dermis in a diabetic wound model.

The incidence and prevalence of chronic and diabetic wounds are increasing and clinical treatments to tackle these epidemics are still insufficient. In this study, we tested the ability of freeze-dried platelet-rich plasma (PRP) and an allogenic micronized acellular dermal matrix alone and in combination to modulate diabetic wound healing. Therapeutic materials were applied to 1.0 cm(2) excisional wounds on genetically diabetic (db/db) mice. Wound-healing kinetics and new tissue formation were studied at 9 and 21 days posttreatment. Quantitative immunohistochemistry was used to study vascularity and cellular proliferation (days 9 and 21), and collagen deposition was evaluated 21 days postwounding. In vitro, micronized allogenic dermis, when combined with PRP, absorbed nearly 50% of original platelet-derived growth factor, transforming growth factor-beta, vascular endothelial growth factor, and epidermal growth factor from platelets and stimulated fibroblast proliferation. In vivo, micronized dermis increased the formation of vascularized wound tissue by day 9. Freeze-dried PRP alone or in combination with micronized dermis increased wound tissue revascularization and proliferation compared with spontaneous healing. The increase in cell proliferation persisted until day 21 only when freeze-dried PRP was used in combination with micronized dermis. These results indicate that micronized allogenic dermis may be used to provide a dermal matrix to stimulate tissue formation and the combination with PRP may confer additional beneficial growth factors to chronic or diabetic wounds.

Effects of poly-N-acetyl glucosamine (pGlcNAc) patch on wound healing in db/db mouse.

BACKGROUND: Poly-N-acetyl glucosamine (pGlcNAc) nanofiber-based materials, produced by a marine microalga, have been characterized as effective hemostatic agents. In this study, we hypothesized that a pGlcNAc fiber patch may enhance wound healing in the db/db mouse. METHODS: pGlcNAc patches were applied on 1-cm, full-thickness, skin wounds in the db/db mouse model. Wounds (n = 15 per group) were dressed with a pGlcNAc nanofiber patch for 1 hour, 24 hours, or left untreated. After the application time, patches were removed and wounds were allowed to heal spontaneously. The rate of wound closure was evaluated by digital analysis of unclosed wound area as a function of time. At day 10, wounds (n = 7 per group) were harvested and quantified with immunohistochemical markers of proliferation (Ki-67) and vascularization (platelet endothelial cell adhesion molecule). RESULTS: Wounds dressed with pGlcNAc patches for 1 hour closed faster than control wounds, reaching 90% closure in 16.6 days, 9 days faster than untreated wounds. Granulation tissue showed higher levels of proliferation and vascularization after 1-hour treatment than the 24-hour and left-untreated groups. Foreign body reaction to the material was not noted in applications up to 24 hours. DISCUSSION: In addition to its hemostatic properties, the pGlcNAc material also appears to accelerate wound closure in healing-impaired genetically diabetic mice. This material, with its combination of hemostatic and wound healing properties, has the potential to be effective agent for the treatment of complicated wounds.