As wound healing continues to be a challenge for the medical field, wound management has become an essential factor for healthcare systems. Nanotechnology is a domain that could provide different new approaches concerning regenerative medicine. It is worth mentioning the importance of nanoparticles, which, when embedded in biomaterials, can induce specific properties that make them of interest in applications as materials for wound dressings. In the last years, nano research has taken steps to develop molecular engineering strategies for different self-assembling biocompatible nanoparticles. It is well-known that nanomaterials can improve burn treatment and also the delayed wound healing process. In this review, the first-line of bioactive nanomaterials-based dressing categories frequently applied in clinical practice, including semi-permeable films, semipermeable foam dressings, hydrogel dressings, hydrocolloid dressings, alginate dressings, non-adherent contact layer dressings, and multilayer dressings will be discussed. Additionally, this review will highlight the lack of high-quality evidence and the necessity for future advanced trials because current wound healing therapies generally fail to provide an excellent clinical outcome, either structurally or functionally. The use of nanomaterials in wound management represents a unique tool that can be specifically designed to closely reflect the underlying physiological processes in tissue repair.

Nanomaterials for Wound Dressings: An Up-to-Date Overview.

Skeletal muscle tissue is characterized by high metabolic requirements, defined structure and high regenerative potential. As such, it constitutes an appealing platform for tissue engineering to address volumetric defects, as proven by recent works in this field. Several issues common to all engineered constructs constrain the variety of tissues that can be realized in vitro, principal among them the lack of a vascular system and the absence of reliable cell sources; as it is, the only successful tissue engineering constructs are not characterized by active function, present limited cellular survival at implantation and possess low metabolic requirements. Recently, functionally competent constructs have been engineered, with vascular structures supporting their metabolic requirements. In addition to the use of biochemical cues, physical means, mechanical stimulation and the application of electric tension have proven effective in stimulating the differentiation of cells and the maturation of the constructs; while the use of co-cultures provided fine control of cellular developments through paracrine activity. This review will provide a brief analysis of some of the most promising improvements in the field, with particular attention to the techniques that could prove easily transferable to other branches of tissue engineering.

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Skeletal muscle tissue engineering: strategies for volumetric constructs.

A 3D microvascularized gelatin hydrogel is produced using thermoresponsive sacrificial poly(N-isopropylacrylamide) microfibers. The capillary-like microvascular network allows constant perfusion of media throughout the thick hydrogel, and significantly improves the viability of human neonatal dermal fibroblasts encapsulated within the gel at a high density.

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Development of 3D Microvascular Networks Within Gelatin Hydrogels Using Thermoresponsive Sacrificial Microfibers.

Objective To identify and clarify current evidence supporting and disputing the effectiveness of perioperative antibiotic use for common otolaryngology procedures. Data Sources PubMed, Embase (OVID), and CINAHL (EBSCO). Review Methods English-language, original research (systematic reviews/meta-analyses, randomized control trials, prospective or retrospective cohort studies, case-control studies, or case series) studies that evaluated the role of perioperative antibiotic use in common otolaryngology surgeries were systematically extracted using standardized search criteria by 2 investigators independently. Conclusions Current evidence does not support routine antibiotic prophylaxis for tonsillectomy, simple septorhinoplasty, endoscopic sinus surgery, clean otologic surgery (tympanostomy with tube placement, tympanoplasty, stapedectomy, and mastoidectomy), and clean head and neck surgeries (eg, thyroidectomy, parathyroidectomy, salivary gland excisions). Antibiotic prophylaxis is recommended for complex septorhinoplasty, skull base surgery (anterior and lateral), clean-contaminated otologic surgery (cholesteatoma, purulent otorrhea), and clean-contaminated head and neck surgery (violation of aerodigestive tract, free flaps). In these cases, antibiotic use for 24 to 48 hours postoperatively has shown equal benefit to longer duration of prophylaxis. Despite lack of high-quality evidence, the US Food and Drug Administration suggests antibiotic prophylaxis for cochlear implantation due to the devastating consequence of infection. Data are inconclusive regarding postoperative prophylaxis for nasal packing/splints after sinonasal surgery. Implications for Practice Evidence does not support the use of perioperative antibiotics for most otolaryngologic procedures. Antibiotic overuse and variability among providers may be due to lack of formal practice guidelines. This review can help otolaryngologists understand current evidence so they can make informed decisions about perioperative antibiotic usage.

Evidence-Based Use of Perioperative Antibiotics in Otolaryngology.

Infections are leading causes of morbidity and mortality in the advanced aged. Various factors including immunosenescens, comorbid chronic diseases, and alterations in normal physiological organ functions may modify the frequency and severity of infections in elderly patients. Normal body reactions to ensuing infection, such as increased body temperature, may be blunted in those patients causing difficulties in differential diagnosis between infection and other diseases. In severe infections the respiratory and urinary tracts are the most frequently involved systems which may be accompanied by severe sepsis. Bacteremia and sepsis are also associated with indwelling vascular catheters in the elderly who are admitted to the intensive care unit (ICU). Older patients are more vulnerable to the Clostridioides difficile infection, as well. Although the general management of infections in severely ill elderly patients is not different than in younger patients, meticulous care in fluid management and careful individualized optimization in antibiotic therapy, along with the other principals of antimicrobial stewardship are warranted in order to prevent increased mortality caused by infection. Organized team management when treating critically ill elderly patients in the ICU is essential and will reduce the morbidity and mortality due to infection in such patients.

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Infections in the Elderly Critically-Ill Patients.

Significance: The incidence of pressure ulcers is increasing due to our aging population and the increase in the elderly living with disability. Learning how to manage pressure ulcers appropriately is increasingly important for all professionals in wound care. Recent Advances: Many new dressings and treatment modalities have been developed over the recent years and the goal of this review is to highlight their benefits and drawbacks to help providers choose their tools appropriately. Critical Issues: Despite an increased number of therapies available on the market, none has demonstrated any clear benefit over the others and pressure ulcer treatment remains frustrating and time-consuming. Future Directions: Additional research is needed to develop products more effective in prevention and treatment of pressure ulcers.

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Review of the Current Management of Pressure Ulcers.

Current knowledge of wound healing is based on studies using various in vitro and in vivo wound models. In vitro models allow for biological examination of specific cell types involved in wound healing. In vivo models generally provide the full spectrum of biological responses required for wound healing, including inflammation and angiogenesis, and provide cell-cell interactions not seen in vitro. In this review, the authors aim to delineate the most relevant wound healing models currently available and to discuss their strengths and limitations in their approximation of the human wound healing processes to aid scientists in choosing the most appropriate wound healing models for designing, testing, and validating their experiments.

Laboratory Models for the Study of Normal and Pathologic Wound Healing.

BACKGROUND Recipient-site infection after oropharyngeal reconstruction is a potentially disastrous complication. Although studies suggest that perioperative antibiotics reduces infection rates in these patients from 87% to 20%, there is no consensus regarding what constitutes the most appropriate antibiotic regimen and duration of treatment. METHODS A retrospective review of perioperative antibiotic administration was performed of all patients who underwent local, pedicled, or free flap oropharyngeal reconstruction after oncologic resection by a single surgeon at a single institution between 2007 and 2013 to assess for recipient-site complications. RESULTS Ninety-seven patients underwent 100 reconstructions (61 free flap reconstructions, 39 pedicled/local flap reconstructions) and all received a combination of intravenous (IV) antibiotic agents designed to cover oral flora. There were 23 (23%) recipient-site complications, which included cellulitis (9%), mucocutaneous fistula (5%), abscess (5%), and wound dehiscence (4%). Duration of antibiotic prophylaxis, defined as less than 48 hours (short-course) or greater than 48 hours (long-course), was not a significant predictor of recipient-site complication. Significant risk factors for recipient-site complications were clindamycin prophylaxis (P < 0.008), increased duration of surgery (P < 0.047), and advanced age (P < 0.034). Recipient-site complication was found to be a significant predictor of both increased length of hospital stay (P < 0.001) and increased time to the resumption of enteral feeds (P < 0.035). CONCLUSIONS These data suggest that extended courses of perioperative antibiotics do not confer additional benefits in patients undergoing oropharyngeal reconstruction. We recommend a limited 48-hour course of prophylactic antibiotics with sufficient aerobic and anaerobic coverage to help minimize the incidence of antibiotic-related morbidities.

Perioperative Antibiotics in the Setting of Oropharyngeal Reconstruction: Less Is More.

Tissue engineering endeavors to create replacement tissues and restore function that may be lost through infection, trauma, and cancer. However, wide clinical application of engineered scaffolds has yet to come to fruition due to inadequate vascularization. Here, we fabricate hydrogel constructs using Pluronic(®) F127 as a sacrificial microfiber, creating microchannels within biocompatible, biodegradable type I collagen matrices. Microchannels were seeded with human umbilical vein endothelial cells (HUVEC) or HUVEC and human aortic smooth muscle cells (HASMC) in co-culture, generating constructs with an internal endothelialized microchannel. Histological analysis demonstrated HASMC/HUVEC-seeded constructs with a confluent lining after 7 days with preservation and further maturation of the lining after 14 days. Immunohistochemical staining demonstrated von Willebrand factor and CD31(+) endothelial cells along the luminal surface (neointima) and alpha-smooth muscle actin expressing smooth muscle cells in the subendothelial plane (neomedia). Additionally, the deposition of extracellular matrix (ECM) components, heparan sulfate and basal lamina collagen IV were detected after 14 days of culture. HUVEC-only- and HASMC/HUVEC-seeded microchannel-containing constructs were microsurgically anastomosed to rat femoral artery and vein and perfused, in vivo. Both HUVEC only and HUVEC/HAMSC-seeded constructs withstood physiologic perfusion pressures while their channels maintained their internal infrastructure. In conclusion, we have synthesized and performed microvascular anastomosis of tissue-engineered hydrogel constructs. This represents a significant advancement toward the generation of vascularized tissues and brings us closer to the fabrication of more complex tissues and solid organs for clinical application.

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Tatiana Boyko

Papers

Review of the Current Management of Pressure Ulcers.

Laboratory Models for the Study of Normal and Pathologic Wound Healing.

Perioperative Antibiotics in the Setting of Oropharyngeal Reconstruction: Less Is More.

Fabrication and In Vivo Microanastomosis of Vascularized Tissue-Engineered Constructs

DEL1 protects against chondrocyte apoptosis through integrin binding.