Decellularization and preservation of human skin: A platform for tissue engineering and reconstructive surgery.

A matrix derived from natural tissue functions as a highly biocompatible and versatile scaffold for tissue engineering applications. It can act as a supportive construct that provides a niche for colonization by host cells. In this work, we describe a cost-effective, reliable and reproducible protocol for decellularization and preservation of human skin as a potential soft tissue replacement. The decellularized human skin is achieved using purely chemical agents without any enzymatic steps. The suitability of the proposed method for the preservation of the extracellular matrix (ECM) structure and its main components and integrity were evaluated using histological and immunohistochemical analysis. Cryopreservation and final sterility were conducted using programmable freeze-drying and gamma irradiation. The architecture, basement membrane and 3D structure of ECM can be successfully preserved after decellularization. Our protocol was found to be appropriate to maintain key proteins such as collagen type I, III, IV and laminin in the structure of final scaffold. This protocol offers a novel platform for the preparation of a dermal substitute for potential clinical applications. STATEMENT OF SIGNIFICANCE: Clinical application of naturally-based scaffolds for verity of health problems obliges development of a reproducible and effective technology that does not change structural and compositional material properties during scaffold preparation and preservation. Lack of an effective protocol for the production of biological products using decellularization method is still remaining. This effort is directing to solve this challenge in order to accomplish the off-the -shelf availability of decellularized dermal scaffold in market for clinical application.

Unilateral Buccinator Flap for Lengthening of Short Palate.

BACKGROUND: Velopharyngeal insufficiency is one of the most frequent complications after cleft palate repair. PURPOSE: To evaluate the results and complications of unilateral Buccinator flap (BMF) in velopharyngeal insufficiency. MATERIALS AND METHODS: During 4 years the authors performed unilateral BMF in all short palates. Age, sex, demographic data, length of palate, cause of short palate, nasopharyngoscopy and videofluroscopy results, hyper nasality, nasal escape, nasal emission, nasal fluid leak, speech evaluation and results, outcome and complications of the treatment were surveyed before surgery and in 1, 3, 6 months after treatment. RESULTS: The authors had 43 patients, 29 below 8 years old and 14 adults. Velopharyngeal gap was between 10 and 27 mm, mean 21 mm. Buccinator flap were measuring 15 to 19 mm in width and 32 to 56 mm in length. The operation time was 80 to 100 minutes, mean 86 minutes.Nasal emission, nasal escape, and nasal leak were treated in all patients.Hyper nasality was completely improved in all of the patients below 8 years old (29 patients) and in 10 patients of the adults (totally 39 patients, 90.6%). And it was improved significantly in other 4 patients (9.4%). The speech evaluation reported between 70% and 86% improvements.The lengthening of the palate was between 12 and 19 mm, mean 17 mm.The satisfaction of the patients was as 0% poor, 2.3% fair, 72.1% good, and 25.6% excellent. CONCLUSION: Unilateral BMF is reliable, promising, and safe flap for lengthening of short palate and it can lengthen the palate up to 19 mm. The time of surgery is very short compared with other methods. It is an anatomical treatment versus pharyngeal flap which is not an anatomical one. Speech improvement will achieve in 70% to 86% patients.

Comparison of the Results of Delayed Repair of Flexor Pollicis Longus (FPL) Tendon with Tendon Transfer or with Tendon Graft.

Background: In Flexor Pollicis Longus (FPL) injuries, primary repair with end-to-end suture is the treatment of choice. In cases where primary repair is not possible, tendon transfer or tendon grafting is used, each of which has its strengths and weaknesses. We aimed to investigate the effectiveness of each of the above two methods in patients. Methods: Patients with FPL injury who referred to Hazrat Fatemeh Hospital, Tehran, Iran late in 2020 to 2021, if primary tendon repair was not possible, were randomly repaired with tendon transfer or tendon graft. After the appropriate time, the splint was opened and physiotherapy was performed for the patients. Then, at least three months after the repair, the range of motion of the IP and MP joints of the patients thumb was measured and compared in two groups. Results: Ten patients in the tendon transfer group and 10 patients in the tendon graft group were studied. In the secondary repair of FPL with tendon grafting, the range of motion of both IP and MP joints of the thumb was not significantly different compared to repair with tendon transfer. Conclusion: The findings of this research confirm controversies in this field. In order to obtain more accurate results, it is suggested to carry out a research with a larger number of patients and with strict control over the surgical technique and post-operative care, as well as taking into account the morbidities caused by donor tendon removal and examining the overall satisfaction of the patients.

Oxidized carboxymethyl cellulose/gelatin in situ gelling hydrogel for accelerated diabetic wound healing: Synthesis, characterization, and in vivo investigations.

Diabetic wounds are chronic wounds that are currently affecting many patient's quality of life. These wounds are challenging because of the impaired healing cycle and harsh environment. In this study in situ gelling hydrogels based on oxidized carboxymethyl cellulose (OCMC) and gelatin (Gel) were used to hasten the healing rate due to their ease of application. The suggested system in this work is synthesized from entirely natural renewable biomaterials to not only achieve the best biocompatibility and biodegradability but also to develop a sustainable product. The rheological studies showed that the hydrogel is turned into a gel after about 30 s of the mixing process. Moreover, the hydrogel can absorb about ten times its weight, keeping the wound hydrated. In vitro biological investigations indicated optimal biocompatibility, antibacterial, and antioxidant activity for faster tissue regeneration. This product was tested in vivo on normal rats and diabetic mice models to treat full-thickness incisional wounds. Results showed that the OCMC-Gel hydrogel is able to hasten the healing rate in both non-diabetic and diabetic wounds. Pathological examinations of the regenerated skin tissue revealed that the OCMC-Gel treated groups developed much more than the control group.

The Effect of Rainbow Trout (Oncorhynchus mykiss) Collagen Incorporated with Exo-Polysaccharides Derived from Rhodotorula mucilaginosa sp. on Burn Healing.

Burn is one of the physically debilitating injuries that can be potentially fatal; therefore, providing appropriate coverage in order to reduce possible mortality risk and accelerate wound healing is mandatory. In this study, collagen/exo-polysaccharide (Col/EPS 1-3%) scaffolds are synthesized from rainbow trout (Oncorhynchus mykiss) skins incorporated with Rhodotorula mucilaginosa sp. GUMS16, respectively, for promoting Grade 3 burn wound healing. Physicochemical characterizations and, consequently, biological properties of the Col/EPS scaffolds are tested. The results show that the presence of EPS does not affect the minimum porosity dimensions, while raising the EPS amount significantly reduces the maximum porosity dimensions. Thermogravimetric analysis (TGA), FTIR, and tensile property results confirm the successful incorporation of the EPS into Col scaffolds. Furthermore,the biological results show that the increasing EPS does not affect Col biodegradability and cell viability, and the use of Col/EPS 1% on rat models displays a faster healing rate. Finally, histopathological examination reveals that the Col/EPS 1% treatment accelerates wound healing, through greater re-epithelialization and dermal remodeling, more abundant fibroblast cells and Col accumulation. These findings suggest that Col/EPS 1% promotes dermal wound healing via antioxidant and anti-inflammatory activities, which can be a potential medical process in the treatment of burn wounds.

Investigating the effect of poly (ɛ-caprolactone) nanofibers scaffolds with random, unidirectionally, and radially aligned morphologies on the Fibroblast cell's attachment and growth behavior.

In the last decade, significant progress in tissue engineering, repairing, and replacing organs has been achieved. The design and production of scaffolds for tissue engineering are one of the main areas which have attracted the researcher's interest. In this regard, electrospinning is one of the most popular methods of nanoscale scaffold similar to extracellular matrix production. This paper reports the fabrication of scaffolds consisting of radially aligned PCL nanofibers by utilizing a collector composed of a central point electrode and a peripheral ring electrode. The chemical and physical properties were compared using SEM, FTIR, XRD, and DSC experiments, as well as biological performance using the MTT method and cell morphology with nanofibers with random and unidirectionally morphology. Results of this study showed greater physical and biological properties for radially aligned nanofibers which make them an excellent candidate for wound healing applications due to the guided cell growth on this type of nanofiber.

Histopathological Changes of Organs (Lungs, Liver, Kidney, and Brain) After Using Two Types of AgiCoat and Acticoat Nanosilver Dressings on Deep Second-Degree Burn in Rat.

Prevention of infections is a very important issue in treating the burn wounds. The nanosilver dressings have many promising advantages, but absorption of silver ions and its adverse effects to the body were always a question. The aim of this study was to compare Silver serum levels and acute toxic effects of nanosilver on histopathology of organs (lungs, liver, kidney, spleen, and brain) in two types of AgiCoat and Acticoat (nanosilver) dressings on second-degree deep burn in rat. This is an experimental study conducted in our animal laboratory. We divided 24 Sprague-Dawley male rats weighing 300 to 350 randomly into two groups. After anesthesia, a second deep-degree burn was made over dorsal skins of rats by standard method. For group A, Agicoat and, for group B, Acticoat dressings were used. The dressings were changed every 3 days with AgiCoat and Acticoat, respectively. After 14 days, we got blood samples and tissue samples taken from heart, liver, kidneys, spleen, lungs, and brain and a sample from dorsal skin of the rat for histopathological examinations. The results showed that the levels of serum silver in both groups were significantly higher than the standard level (1.22 part per million (PM); AgiCoat, P = .017; Acticoat, P = .000), but there was no significant difference between the groups (P = .551). Examination of the relationship between the level of serum silver and histopathological changes in liver showed that hepatotoxicity of AgiCoat was higher compared with Acticoat and the difference was significant (P = .002). There were no pathological changes in brain, kidneys, spleen, heart, and lungs. Wound healing was faster in Acticoat group. The nanosilver dressings can cause toxicity in liver but not in kidney, brain, spleen, heart, and lungs. Liver pathology and hepatotoxicity were more prominent in AgiCoat group. Wound healing was faster in Acticoat group.

Pregnancy and burns: Guidelines for safe management.

BACKGROUND: IThe incidence of burns in pregnancy is very low, therefore little is confirmed in the specific management of pregnant women who are burned. PURPOSE: We conducted a study to survey the frequency of pregnancy in our patients and evaluate the risk factors of mortality for mother and foetus. Finally we provide recommendations about management of mother and child. MATERIALS AND METHODS: Retrospectively, we surveyed data of our pregnant patients for an 18 year period. All demographic data, gestational age, history of previous pregnancy or miscarriage, diabetes, suicide, number of operations, presence of inhalation injury, TBSA, percentage of burn in abdomen and lower extremity, early excision and outcome of mother and foetus were gathered in a special questionnaire. Uni-variate regression and multi-variate regression were done for mortality of mother and child. RESULTS: We treated 89 pregnant patients. Mean (SD) of mother's age and their pregnancy age were 24.08±5.56 years and 19.18±9.24 weeks, respectively. Mean TBSA (SD) was 36 (18%). Median of TBSA was 38 (IQR: 25, 70). Median of TBSA in Abdomen was 8 (IQR: 7, 9). Median of TBSA in lower extremities was 18 (IQR: 9, 34). Nine cases were due to attempted suicide. For 34 patients skin grafting was done. The main cause of death of the mothers was sepsis. The infections were due to Pseudomonas aeruginosa, Acinetobacter, E. coli, Klebsiella and Staphylococcus. In uni-variate regression model, TBSA, gestational week, and burns involving the abdomenwere related to maternal mortality. In multi-variate regression model, TBSA had high influence on maternal mortality, with every percent of burn surface area, the risk of mortality increased by 3.4% (p-value <0.005). In a uni-variate regression, TBSA and abdominal burn was associated with foetal mortality. However, in the multi-variate regression, only inhalation injury and TBSA had association with foetal mortality. Inhalation injury increased foetal mortality up to 16 times (p-value <0.05). CONCLUSION: TBSA burned is the only major risk factor of maternal mortality. TBSA burned and inhalation injury are the main risk factors of foetal mortality.

Tenocyte-imprinted substrate: a topography-based inducer for tenogenic differentiation in adipose tissue-derived mesenchymal stem cells.

Tendon tissue engineering based on stem cell differentiation has attracted a great deal of attention in recent years. Previous studies have examined the effect of cell-imprinted polydimethylsiloxane (PDMS) substrate on induction differentiation in stem cells. In this study, we used tenocyte morphology as a positive mold to create a tenocyte-imprinted substrate on PDMS. The morphology and topography of this tenocyte replica on PDMS was evaluated with scanning electron microscopy (SEM) and atomic force microscopy. The tenogenic differentiation induction capacity of the tenocyte replica in adipose tissue-derived mesenchymal stem cells (ADSCs) was then investigated and compared with other groups, including tissue replica (which was produced similarly to the tenocyte replica and was evaluated by SEM), decellularized tendon, and bone morphogenic protein (BMP)-12, as other potential inducers. This comparison gives us an estimate of the ability of tenocyte-imprinted PDMS (called cell replica in the present study) to induce differentiation compared to other inducers. For this reason, ADSCs were divided into five groups, including control, cell replica, tissue replica, decellularized tendon and BMP-12. ADSCs were seeded on each group separately and investigated by the real-time reverse transcription polymerase chain reaction (RT-PCR) technique after seven and 14 days. Our results showed that in spite of the higher effect of the growth factor on tenogenic differentiation, the cell replica can also induce tenocyte marker expression (scleraxis and tenomodulin) in ADSCs. Moreover, the tenogenic differentiation induction capacity of the cell replica was greater than tissue replica. Immunocytochemistry analysis revealed that ADSCs seeding on the cell replica for 14 days led to scleraxis and tenomodulin expression at the protein level. In addition, immunohistochemistry indicated that contrary to the promising results in vitro, there was little difference between ADSCs cultured on tenocyte-imprinted PDMS and untreated ADSCs. The results of such studies could lead to the production of inexpensive cell culture plates or biomaterials that can induce differentiation in stem cells without growth factors or other supplements.

Tissue expanders; review of indications, results and outcome during 15 years' experience.

BACKGROUND: Tissue expanders (TE) are frequently used worldwide. In this study we surveyed outcome of our patients retrospectively during 15 years. MATERIALS AND METHODS: We had 1105 patients for whom 3059 TEs have been used. Demographic data, age, sex, indications, type of tissue expander devices, volume of devices, site of scar and site TE insertion, our technique for tissue expander insertion and flap design, complications and outcome were gathered. A complete and through technical points and tips will be discussed. RESULTS: In 91% of patients overexpansion was done. (Expansion ratio=2.1-4.5). Re-expansion has been done in about 12% of patients. Complications were perforation of skin of pocket (11%) or exposure, infection (6%), dehiscence of the wound (1.5%), perforation of the port or disconnection of the tubes (2.1%), expansion of the scar itself (1%), saggy flap (3%), dog ear (5%), lack of adhesions of flap to its new site (4%). OUTCOME: In 93% of the patients we could totally remove the scar. Around 9.1% of our patients had two sessions of expansion in the same area and 2.9% had three sessions of expansion. 51% of our patients were highly satisfied and 42% were satisfied of the results of expansion. CONCLUSION: Our patients were satisfied with the results. In 12% cases we have done re-expansion. Re-expansion is possible as long as you have enough thickness of dermis in the skin. More than 50% of our patients were optimistic for 2nd or 3rd session of re-expansion.

Complications after craniofacial reconstruction with calcium phosphate cements: a case report and review of the literature.

Among different graft materials for craniofacial reconstruction, calcium phosphate cements have the advantages of alloplastic grafts and wide use. The authors report a case of foreign body reaction following frontal reconstruction with JectOS (an injectable calcium orthophosphate cement; Kasios) and reviewed the literature on complications of this material after craniofacial reconstruction from 2002 to 2017. Complications were categorized into two groups: immunologic reactions (consisting of seroma collection, chronic sinus mucosa swelling, and foreign body reaction) and non-immune events (infection, fragmentation, and ejection). It is wise to use calcium phosphate-based material only in selected cases with small defects, and long-term follow-up is needed to observe their consequences.

Why burn patients are referred?

BACKGROUND: Many burn patients are needed to be referred to a tertiary burn hospital according to the American Burn Association (ABA) criteria. The purpose of this study was to verify the reasons for referring of the burn patients to the hospital. MATERIALS AND METHODS: For 2 years, we prospectively surveyed the burn patients referred to a tertiary teaching burn hospital. Data for the following variables were collected and analyzed with SPSS software V21.0: causes of burn; age; gender; total body surface area (TBSA) measured at the referring center; TBSA measured at the receiving center; concomitant diseases and traumas; the reason for referral; condition of patients before and during the transportation; transportation time; presence of infection; presence of inhalation injury, electrical injury, and chemical injury; child abuse; insurance coverage; and results and outcomes of patients. RESULTS: A total of 578 burn patients (33.6% of the total admissions) were referred in the study period. Among these patients, 70.9% were females. The mean (SD) age of the patients was 35.3 (19.69) years. The mean (SD) of TBSA was 45.2 (26.3). Of the 578 patients, 45% were referred by request of the family or patients; 9% were referred because lack of diagnostic facility, approximately 43% were referred because of the need to be admitted in a tertiary burn center, 0.7% were referred because of a lack of capacity at other hospitals, and 0.5% were referred because of an error in the estimation of TBSA. CONCLUSIONS: A total of 45% of the referrals were by request of the family and patients. Tele-medicine may help to establish a direct contact between expert burn physicians and the patients and thus reduce unnecessary transfers. Approximately 9% of the referrals were because of lack of some diagnostic facilities.

Economical Burden of Burn Injuries in a Developing Country.

Burn injuries have economical impacts on patients in several ways. Understanding the charges of burn treatment is very important for patients, families, governmental authorities, and insurance companies. During the protocol of their treatment, they may be admitted several times for treatment of acute burn and then for reconstructive treatments of burn's complications. Calculating the hospital burn charges can serve as an objective criteria for authorities to plan for a sufficient budget for acute burn treatment, for additional management for chronic complications, and as a guide for planning preventive and public educational programs. The authors used data of their burn registry program. During more than 3 years, the authors had 912 patients with multiple admissions for burns. All of hospital costs during several admissions were recorded. Men were 71% and women were 29% of the patients. Burns caused by flame were the most frequent (50.1%) followed by scald (34.0%). Mean hospital stay was 14.1 days (range, 0-64 days). Patients with TBSA equal to or less than 10% were 38.8%, TBSA between 11 and 22% were 29.1%, and TBSA more than 23% were 32.1%. Those who were admitted for 30 days or less were 34.1%, those between 31 and 131 days were 32.7%, and those with more than 132 days of admission were 33.2%. Mean hospital cost for all patients during the 3 years was about $2766 (range, from $143 to $33,566; median = 1586.93; SE = 93.84). The patients were admitted for treatment of acute burns and later admitted for reconstruction of the burn sequels. Total number of admissions was up to six times (median = 2). About 66.27% of the total charges were the cost of first admission, 19.39% the cost of second admission, 7.34% the cost of third admission, 3.56% for fourth admission, 2.3% for fifth admission, and 1.15% for last or sixth admission. The authors conducted a multiple linear regression test. Male sex, TBSA, length of stay, and number of admissions were significantly related to total treatment charges. But "age" did not influence the charges. Mean total cost of several burn admissions in one patient was around $2766. TBSA, length of stay, male sex, and number of admissions were significantly related to the hospital costs.

Acceleration of bone regeneration in bioactive glass/gelatin composite scaffolds seeded with bone marrow-derived mesenchymal stem cells over-expressing bone morphogenetic protein-7.

In this research, the osteoinduction effect of a novel variant of bone morphogenetic protein-7 (BMP-7), delivered through bone marrow mesenchymal stem cells (BM-MSCs) seeded on bioactive glass/gelatin nanocomposite scaffolds, was evaluated in a calvarial critical size defect in rats. After being harvested and characterized in vitro, BM-MSCs were infected by a plasmid vector containing BMP-7 encoding gene enriched with a heparin-binding site (B2BMP-7) to assess its osteogenic effects in vivo. The animals were randomly categorized into three groups receiving the scaffold alone (group I), the scaffold seeded with BM-MSCs (group II), and the scaffold seeded with manipulated BM-MSCs (group III). After 2, 4 and 12 postoperative weeks, the animals were sacrificed and the harvested specimens were analyzed using histological and immunohistochemical staining. The results of in vitro tests (preliminary screening) showed that the synthesized scaffolds were biocompatible constructs supporting cell attachment and expansion. The in vivo results revealed higher osteogenesis in the defects filled with the B2BMP-7 excreting BM-MSCs/scaffolds compared to the other two groups. After 12weeks of implantation, fully mature newly formed bone was detected throughout the damaged site, which indicates a synergistic effect of cells, scaffolds and growth factors in the process of tissue regeneration. Therefore, bioactive glass-containing scaffolds pre-seeded with manipulated BM-MSCs exhibit an effective combination to improve osteogenesis in bone defects, and the approach followed in this work could have a significant impact in the development of novel tissue engineering constructs.