Compromised Wound Research Articles

Pedicled ALT-flap for soft tissue reconstruction in the trochanteric area.

Coverage of soft tissue defects following surgery at the trochanteric area is challenging. Revision surgery in case of compromised wound healing may lead to soft tissue defects requiring reconstruction with pedicled or free flaps. Previous access to the hip joint may jeopardize neurovascular structures relevant to the flap. In this study, we evaluated if the use of a pedicled anterior lateral thigh (ALT) flap is a valuable option for soft tissue reconstruction. In this retrospective study, seven patients were included. Defect etiology was tumor resection in one case, screw osteosynthesis in another case and total hip arthroplasty in three cases. All patients underwent reconstruction by proximal pedicled anterior lateral thigh (ALT) flap. Pedicled ALT flap was a safe procedure in all cases. One patient showed delayed wound healing with need for additional surgery. No further complications were observed. Pedicled ALT flap transfer represents a reliable option for soft tissue coverage in the trochanteric area after primary surgery such as hip arthroplasty, osteosynthesis or tumor resection.

Multifunctional polymeric nanofibrous scaffolds enriched with azilsartan medoxomil for enhanced wound healing.

A prolonged and compromised wound healing process poses a significant clinical challenge, necessitating innovative solutions. This research investigates the potential application of nanotechnology-based formulations, specifically nanofiber (NF) scaffolds, in addressing this issue. The study focuses on the development and characterization of multifunctional nanofibrous scaffolds (AZL-CS/PVA-NF) composed of azilsartan medoxomil (AZL) enriched chitosan/polyvinyl alcohol (CS/PVA) through electrospinning. The scaffolds underwent comprehensive characterization both in vitro and in vivo. The mean diameter and tensile strength of AZL-CS/PVA-NF were determined to be 240.42 ± 3.55nm and 18.05 ± 1.18MPa, respectively. A notable drug release rate of 93.86 ± 2.04%, was observed from AZL-CS/PVA-NF over 48h at pH 7.4. Moreover, AZL-CS/PVA-NF exhibited potent antimicrobial efficacy for Staphylococcus aureus and Pseudomonas aeruginosa. The expression levels of Akt and CD31 were significantly elevated, while Stat3 showed a decrease, indicating a heightened tissue regeneration rate with AZL-CS/PVA-NF compared to other treatment groups. In vivo ELISA findings revealed reduced inflammatory markers (IL-6, IL-1β, TNF-α) within treated skin tissue, implying a beneficial effect on injury repair. The comprehensive findings of the present endeavour underscore the superior wound healing activity of the developed AZL-CS/PVA-NF scaffolds in a Wistar rat full-thickness excision wound model. This indicates their potential as novel carriers for drugs and dressings in the field of wound care.

Management of Late Radiation Tissue Injury Ulcers With Continuous Topical Oxygen Therapy Supports Wound Healing in Patients of Advanced Age Following Mohs Surgery: A Case Series

Background. The long-term chronic effect of radiotherapy is commonly referred to as LRTI. Clinical complications such as skin atrophy, tissue fibrosis, endothelial damage, ulcer formation, and compromised wound healing are common sequela. Despite advances in medicine over the past decade, there remains a need for effective treatments for LRTI skin necrosis and ulcerations. Materials and Methods. This case series discusses cTOT in 3 patients of advanced age with LRTI wounds having undergone Mohs surgery. All wounds had been recalcitrant to multiple wound care treatments. All patients suffered with significant wound pain as well. Results. cTOT resulted in complete wound healing in all 3 patient cases. Additionally, all 3 patients reported a significant reduction in wound pain during the course of therapy. Conclusions. The positive outcomes exhibited in this case series suggest that cTOT is an effective treatment in the management of Mohs surgery patients with compromised wound healing due to radiation, advanced age, and comorbidities.

Evaluation of Biofilm Inhibitory Efficacy of Bacopa monnieri, Acalypha indica and Calotropis gigantea Extracts and their Combination Against Wound Colonizing Bacteria Pseudomonas aeruginosa and Staphylococcus Aureus

Key factors in compromised wound healing primarily include bacterial colonization and infection. Extensive use of systemic antibiotics, preferred choice of treatment for clinically infected wounds, is often accompanied with emergence of bacterial resistance. Quorum sensing (QS), density dependent chemical communication, is emerging as a promising area of research since most infectious microorganisms operate this mechanism to realize their pathogenic potential. Foregoing research indicates the potential of studying medicinal plant extracts/components and their combinations as vital inhibitors of QS regulated virulence factors’ production. Our study aims to understand the potential of three plant extracts and their combinations as vital inhibitors of QS regulated virulence factor’s production by two wound pathogens and to achieve this our objectives are to perform their violacein inhibitory (on C. violaceum) and biofilm inhibitory properties (on Pseudomonas aeruginosa and Staphylococcus aureus). Minimum inhibitory concentration (MIC) of aqueous plant extracts against P aeruginosa and S aureus was performed (two-fold serial microdilution). Violacein inhibition was assayed using agar well diffusion while biofilm inhibition by crystal violet method. Organisms presented 5mg/ml (Bacopa monnieri ), 2.5mg/ml (Acalypha indica), and 2.5mg/ml (Calotropis gigantea) as MIC. Three sets of individual extract concentrations (sub-MIC in μg/ml) and their corresponding combinations were used for this study. Extracts exhibited more significant (P<0.0001) violacein inhibition in combination than individually. Biofilm inhibition by extracts' combination was also significantly (P<0.001) higher than that of individual extracts indicating a possible positive herb-herb interaction of phytoconstituents (synergistic or complementary). The relative decrease in response to individual extracts in higher concentrations (set 'c') by both organisms point to possible recalcitrance behavior generally exhibited by bacteria on exposure to higher antibacterial agents. The improved antibiofilm efficacy exhibited by this novel combination may serve as an alternative approach in managing wound colonization by biofilm-producing bacteria and hence faster-wound healing.

The pathogenesis, epidemiology and biomarkers of susceptibility of pulmonary fibrosis in COVID-19 survivors.

Pulmonary fibrosis (PF), a pathological outcome of chronic and acute interstitial lung diseases associated tocompromised wound healing, is a key component of the "post-acute COVID-19 syndrome" that may severely complicate patients' clinical course. Although inconclusive, available data suggest that more than a third of hospitalized COVID-19 patients develop lung fibrotic abnormalities after their discharge from hospital. The pathogenesis of PF in patients recovering from a severe acute case of COVID-19 is complex, and several hypotheses have been formulated toexplain its development. An analysis of the data that ispresently available suggests that biomarkers of susceptibility could help to identify subjects with increased probability of developing PF and may represent a means to personalize the management of COVID-19's long-term effects. Our review highlights the importance of both patient-related and disease-related contributing risk factors for PF in COVID-19 survivors and makes it definitely clear the possible use of acute phase and follow-up biomarkers for identifying the patients at greatest risk of developing this disease.

A Case of a Patient Who Successfully Achieved Early Wound Closure by Local Negative Pressure Wound Therapy (NPWT) against Compromised Wound Healing after Arterio-Venous Graft Infection

The primary treatment strategy for arterio-venous graft (AVG) infection includes appropriate antibiotic use and removal of the infected graft. It is well known that patients with hemodialysis are likely to experience compromised wound healing, which often leads to various postoperative complications. Negative pressure wound therapy (NPWT) is a non-invasive procedure that promotes wound healing by sealing the wound under negative pressure. Although NPWT is practically accepted in general surgery, there are only a few reports of this strategy to the vascular access operation for patients with hemodialysis due to the possibility of severe bleeding. In the present report, we report a case of a patient who successfully achieved safe and early wound closure by NPWT against compromised wound healing after AVG infection.

Association of Systemic or Intravitreal Antivascular Endothelial Growth Factor (Anti-VEGF) and Impaired Wound Healing in Pediatric Patients: Collagen to the Rescue.

Bevacizumab is a humanized monoclonal antibody to vascular endothelial growth factor (VEGF) that has been used as a systemic chemotherapy treatment of various malignancies in adults since 2000. It has been used for pediatric patients over the last decade. In addition, bevacizumab is used for neonatal intravitreal administration for retinopathy of prematurity, a major complication of preterm birth, characterized by incomplete and abnormal vascularization of the retina that can lead to retinal detachment and blindness without treatment. The objective of this multiple case series is to report impaired wound healing seen in 3 adolescents and 1 premature neonate receiving bevacizumab and to propose collagen-based dermal template as a choice for the management of such wounds. The 3 adolescents were undergoing treatment of malignancies and developed wound healing complication within weeks of receiving anti-VEGF. The premature neonate experienced an extravasation and had a slow wound healing trajectory after receiving intravitreal administration of bevacizumab for retinopathy of prematurity. All wounds achieved closure following topical treatment with a collagen dermal template. Use of bevacizumab is increasing in the pediatric population. Clinicians should be aware of compromised wound healing and higher likelihood of wound dehiscence after bevacizumab administration. We recommend waiting for at least 4 to 6 weeks between anti-VEGF administration (either systemic or vitreous) and elective surgical procedures, consistent with adult literature recommendations. If patient has an existing wound, we assert that bevacizumab should not be administered until that wound is healed. If wound healing is stalled, we recommend dermal template as a safe and effective accelerator of wound healing.

A bridge too far? An academic-national security practitioner dialogue on research collaboration across the divide

ABSTRACT In a well-known article, Marc Sageman (2014, The stagnation in terrorism research. Terrorism and Political Violence, 26(4)) foregrounds what he calls the ‘unbridgeable gaps’ between national security agencies and academics on the question of accessing and analysing the empirical data upon which innovative terrorism research depends. Yet while the divide between academic research and national security policy and practice can be pronounced, it is also mediated by the existence of common territory. This includes ideas about what constitutes ‘the public good’, despite bringing varied institutional, personal and philosophical approaches to how that good is understood and enacted. At their best, where these collaborations are embraced and nurtured, they can become unparalleled opportunities for expanded learning, constructive provocation and informed debate, bringing different forms of expertise to bear on understanding and reducing the risks and impacts of terrorism. At their worst, they can be minefields of compromised independence, ethical and reputational wounds, censorship, exploitation, and hollow research and policy agendas. We take up these issues through an edited collaborative dialogue between an academic and a national security practitioner, drawing on both the scholarly literature and our own experience as collaborators to explore the benefits, conflicts and risks of academic-national security collaboration.

HDL nanoparticles have wound healing and anti-inflammatory properties and can topically deliver miRNAs.

microRNAs regulate numerous biological processes, making them potential therapeutic agents. Problems with delivery and stability of these molecules have limited their usefulness as treatments. We demonstrate that synthetic high-density lipoprotein nanoparticles (HDL NPs) topically applied to the intact ocular surface are taken up by epithelial and stromal cells. microRNAs complexed to HDL NPs (miR-HDL NPs) are similarly taken up by cells and tissues and retain biological activity. Topical treatment of diabetic mice with either HDL NPs or miR-HDL NPs significantly improved corneal re-epithelialization following wounding compared with controls. Mouse corneas with alkali burn-induced inflammation, topically treated with HDL NPs, displayed clinical, morphological and immunological improvement. These results should yield a novel HDL NP-based eye drop for patients with compromised wound healing ability (diabetics) and/or corneal inflammatory diseases (e.g. dry eye).

Impact of platelet-rich plasma on cell migration processes after external radiation

To overcome the compromised wound healing in radiation induced chronic wounds platelet-rich plasma (PRP), as therapeutic agent, is current subject of studies. PRP is associated with pro-angiogenic effects. Nevertheless, effects of platelet-rich plasma in cutaneous wound healing processes are poorly understood so far. In this study, the migration of endothelial cells, fibroblasts and keratinocytes in conjunction with platelet-rich plasma treatment is investigated in the context of radiation effects. Additionally, cell proliferation and viability after external radiation was analyzed regarding treatment by platelet-rich plasma. All cell cultures showed a trend towards decreasing proliferation and viability after irradiation irrespective of PRP. Upon PRP treatment, irradiated fibroblasts as well as endothelial cells showed an enhanced proliferation whereas proliferation and viability of keratinocytes was reduced after PRP treatment. Scratch assays support the positive effect of PRP on fibroblast and endothelial cell migration, whereas a negative effect on keratinocytes was observed after PRP treatment. The present study documents both deleterious effects of external radiation as well as the protective effect of PRP. In summary, increased viability, proliferation and migration are indeed a consequence of the pro-proliferative effect exerted by PRP. Therefore, treatment with PRP products might be useful in the management of chronic radiogenic wounds.

Cutaneous Epithelial to Mesenchymal Transition Activator ZEB1 Regulates Wound Angiogenesis and Closure in a Glycemic Status-Dependent Manner.

Epithelial to mesenchymal transition (EMT) and wound vascularization are two critical interrelated processes that enable cutaneous wound healing. Zinc finger E-box binding homeobox 1 (ZEB1), primarily studied in the context of tumor biology, is a potent EMT activator. ZEB1 is also known to contribute to endothelial cell survival as well as stimulate tumor angiogenesis. The role of ZEB1 in cutaneous wounds was assessed using Zeb1+/- mice, as Zeb1-/- mice are not viable. Quantitative stable isotope labeling by amino acids in cell culture (SILAC) proteomics was used to elucidate the effect of elevated ZEB1, as noted during hyperglycemia. Under different glycemic conditions, ZEB1 binding to E-cadherin promoter was investigated using chromatin immunoprecipitation. Cutaneous wounding resulted in loss of epithelial marker E-cadherin with concomitant gain of ZEB1. The dominant proteins downregulated after ZEB1 overexpression functionally represented adherens junction pathway. Zeb1+/- mice exhibited compromised wound closure complicated by defective EMT and poor wound angiogenesis. Under hyperglycemic conditions, ZEB1 lost its ability to bind E-cadherin promoter. Keratinocyte E-cadherin, thus upregulated, resisted EMT required for wound healing. Diabetic wound healing was improved in ZEB+/- as well as in db/db mice subjected to ZEB1 knockdown. This work recognizes ZEB1 as a key regulator of cutaneous wound healing that is of particular relevance to diabetic wound complication.

Dural sealants for the management of cerebrospinal fluid leakage after intradural surgery: current status and future perspectives

ABSTRACTIntroduction: Cerebrospinal fluid leakage is a complication after intradural surgery and is associated with severe secondary complications like compromised wound healing and meningitis. Dural sealants are meant to augment the primary dural closure in order to achieve a watertight closure.Areas covered: This review summarizes the efficacy of currently available dural sealants. Potential future improvements and biomaterials are discussed.Expert opinion: The use of a dural sealant seems to be the logical method to prevent CSF leakage. However, based on the efficacy of currently available dural sealants according to systematic reviews and in vitro studies, a significant effective dural sealant seems is still lacking. A new dural sealant has to be thoroughly assessed before clinical application in in vitro, in vivo and clinical trials. A new research area within sealant development might be the introduction of dural sealants with both antimicrobial and analgesic properties.

Development and Characterization of a Rabbit Model of Compromised Maxillofacial Wound Healing.

Background: Tissue engineering technologies aiming to enhance maxillofacial wound healing are often tested in vivo in preclinical models that do not necessarily reflect the complexity of the clinical need. The aim of this study was to develop a rabbit model of compromised craniofacial wound healing that more accurately mimics clinical scenarios.Materials and Methods: An experimental group of rabbits received fractionated radiation of the mandible totaling 36 Gy. Four weeks after irradiation, both the experimental group and control group (n = 10/group) underwent a surgical procedure creating a critical size defect in the mandibular bone. Four weeks after surgery, tissue healing was assessed using microcomputed tomography (μCT), maximum intensity projection (MIP) scoring, and histopathology.Results: μCT analysis and MIP scoring showed decreased mineralized tissue in the defect area of irradiated animals compared to the control group. Histopathology showed necrosis in the experimental group.Conclusions: Irradiated animals showed significantly compromised wound healing compared to controls. This preclinical model presents a clinically relevant environment for the investigation of novel wound healing technologies in a compromised critical size bone defect.Impact StatementMaxillofacial defects often present the clinical challenge of a compromised wound bed. Preclinical evaluation of tissue engineering techniques developed to facilitate healing and reconstruction typically involves animal models with ideal wound beds. The healthy wound bed scenario does not fully mimic the complex clinical environment in patients, which can lead to technology failure when translating from preclinical in vivo research to clinical use. The reported preclinical animal model of compromised wound healing enables investigation of tissue engineering technologies in a more clinically relevant scenario, potentially fostering translation of promising results in preclinical research to patients.

Free Gracilis Muscle Flap for Sarcoma Reconstruction: 19 Years of Clinical Experience.

Background Sarcoma treatment necessitates high-dose chemoradiation therapy and wide surgical margins that create wounds that are difficult to reconstruct. Many techniques have been developed to cover these defects, originating with muscle flaps such as the rectus abdominis and latissimus dorsi. The gracilis flap, which is best known in contemporary practice as a microneurovascular flap for functional reconstructions, is not usually considered a robust option for reconstruction after sarcoma extirpation. Methods We reviewed records of 22 patients (9 women) at our institution who underwent reconstructive surgery after sarcoma extirpation using gracilis flaps for soft-tissue coverage from 1998 to 2017. Neurotized gracilis flaps were excluded. The mean patient age was 51 years (range, 18–85 years), and mean length of follow-up was 53 months (range, 9–156 months). Patients had 7 tumor types, with fibrosarcomas and undifferentiated tumors being most common. There were 23 defects (mean size, 118 cm2 (range, 54–200 cm2)). Defects were located most commonly in the foot and leg (n=9 each), upper extremity (n=4), and head and neck (n=1). The primary outcome was the flap success rate. Secondary outcomes were rates of major complications (unplanned reoperations, infections requiring intravenous antibiotics, and amputations); minor complications (superficial infections, partial skin-graft loss, partial flap necrosis, fluid collections treated in the office, and cosmetic reoperations); and sarcoma recurrence. Results Twenty-one flaps (91%) survived. Six patients (27%) experienced a major complication, and 12 patients (54%) experienced a minor complication. There were 2 amputations, for a limb salvage rate of 91%. Conclusions This series shows that the gracilis is well suited to covering large, compromised wounds across diverse anatomic features, which are the hallmark of sarcoma resections. The high rate of limb salvage and minimal donor-site morbidity further support the use of this flap as a first-line option for sarcoma reconstruction.

Staphylococcus aureus Biofilm Infection Compromises Wound Healing by Causing Deficiencies in Granulation Tissue Collagen.

The objective of this work was to causatively link biofilm properties of bacterial infection to specific pathogenic mechanisms in wound healing. Staphylococcus aureus is one of the four most prevalent bacterial species identified in chronic wounds. Causatively linking wound pathology to biofilm properties of bacterial infection is challenging. Thus, isogenic mutant stains of S. aureus with varying degree of biofilm formation ability was studied in an established preclinical porcine model of wound biofilm infection. Isogenic mutant strains of S. aureus with varying degree (ΔrexB > USA300 > ΔsarA) of biofilm-forming ability were used to infect full-thickness porcine cutaneous wounds. Compared with that of ΔsarA infection, wound biofilm burden was significantly higher in response to ΔrexB or USA300 infection. Biofilm infection caused degradation of cutaneous collagen, specifically collagen 1 (Col1), with ΔrexB being most pathogenic in that regard. Biofilm infection of the wound repressed wound-edge miR-143 causing upregulation of its downstream target gene matrix metalloproteinase-2. Pathogenic rise of collagenolytic matrix metalloproteinase-2 in biofilm-infected wound-edge tissue sharply decreased collagen 1/collagen 3 ratio compromising the biomechanical properties of the repaired skin. Tensile strength of the biofilm infected skin was compromised supporting the notion that healed wounds with a history of biofilm infection are likely to recur. This study provides maiden evidence that chronic S. aureus biofilm infection in wounds results in impaired granulation tissue collagen leading to compromised wound tissue biomechanics. Clinically, such compromise in tissue repair is likely to increase wound recidivism.

An Ovol2-Zeb1 transcriptional circuit regulates epithelial directional migration and proliferation.

Directional migration is inherently important for epithelial tissue regeneration and repair, but how it is precisely controlled and coordinated with cell proliferation is unclear. Here, we report that Ovol2, a transcriptional repressor that inhibits epithelial-to-mesenchymal transition (EMT), plays a crucial role in adult skin epithelial regeneration and repair. Ovol2-deficient mice show compromised wound healing characterized by aberrant epidermal cell migration and proliferation, as well as delayed anagen progression characterized by defects in hair follicle matrix cell proliferation and subsequent differentiation. Epidermal keratinocytes and bulge hair follicle stem cells (Bu-HFSCs) lacking Ovol2 fail to expand in culture and display molecular alterations consistent with enhanced EMT and reduced proliferation. Live imaging of wound explants and Bu-HFSCs reveals increased migration speed but reduced directionality, and post-mitotic cell cycle arrest. Remarkably, simultaneous deletion of Zeb1 encoding an EMT-promoting factor restores directional migration to Ovol2-deficient Bu-HFSCs. Taken together, our findings highlight the important function of an Ovol2-Zeb1 EMT-regulatory circuit in controlling the directional migration of epithelial stem and progenitor cells to facilitate adult skin epithelial regeneration and repair.

Complications following single-level interbody fusion procedures: an ACS-NSQIP study.

Controversy exists over the ability of various lumbar interbody fusion techniques to realign global and regional balance and their effect on patient outcomes. This is a retrospective cohort study to compare thirty-day postoperative outcomes between anterior and posterior interbody fusion techniques within a large national database. A retrospective cohort study utilizing the National Surgical Quality Improvement Program (NSQIP) database included 2,372 (29.9%) single-level anterior/direct lateral interbody fusions (ALIF/DLIF) and 5,563 (70.1%) single-level posterior/transforaminal lateral interbody fusions (PLIF/TLIF) between 2013 and 2014. Emergent cases, fracture cases, and preoperative compromised wounds were not analyzed. Primary thirty-day outcomes included mortality, return to operating room, readmission, length of stay, and other major complications. Minor outcomes included urinary tract infection, superficial incisional site infection, and perioperative blood transfusion within 72 hours. ALIF/DLIF was performed more for degenerative lumbar disc disease (31.0% vs. 13.9%, P<0.001), whereas PLIF/TLIF was utilized more for spondylolisthesis (19.1% vs. 24.4%, P<0.001). Thirty-day mortality was significantly higher with ALIF/DLIF (0.3% vs. 0.1%, P=0.021) in the univariate analysis and persisted in the multivariate analysis (OR =12.8; 95% CI, 1.37-119.6; P=0.025). Significantly more PLIF/TLIF patients required blood transfusions within 72 hours of surgery (9.6% vs. 7.6%, P=0.005). This difference did not persist in the multivariate analysis after controlling for covariates. Elevated ASA physical status classification, age >60, prior bleeding disorder, and preoperative anemia were significantly associated with blood transfusion requirement. More deep venous thrombosis occurred (DVT) with ALIF/DLIF compared to PLIF/TLIF (1.0% vs. 0.6%, P=0.025), which persisted in the multivariate analysis (OR =2.03; 95% CI, 1.13-3.65; P=0.017). Although numerous techniques can be utilized in the treatment approach to various lumbar pathologies, anterior approaches have an increased risk of developing a perioperative DVT and early mortality. Transfusion risk is more strongly associated with elevated American Society of Anesthesiologists (ASA) class, increased age, preoperative anemia, and patients with bleeding disorders.

Pinealectomia em ratas Wistar (Rattus norvegicus albinus): descrição de um novo método cirúrgico

A necessidade de manejo adequado antes, durante e após a implementação de procedimentos em animais de laboratório é essencial para proporcionar bem-estar. Portanto, no presente trabalho, objetivou-se padronizar uma nova técnica de pinealectomia em ratas Wistar. Trinta fêmeas nulíparas aos 90 dias de idade foram submetidas à anestesia dissociativa. Após a tricotomia e a assepsia, realizou-se uma incisão na linha média dorsal da cabeça. Com um micromotor e uma broca de aço PM 03, realizou-se a craniotomia; a glândula pineal foi removida por intermédio de um fórceps cápsula arruga. Em seguida, o fragmento ósseo foi recolocado em seu lugar de origem, e a pele aproximada por pontos simples. Finalizado o procedimento cirúrgico, foi realizada antibioticoterapia e soroterapia parenteral. O acompanhamento diário dos animais não evidenciou nenhum comprometimento da ferida operatória com padrão de cicatrização por primeira intenção. Os animais apresentaram normalidade de atos fisiológicos, como alimentação, defecação e micção, assim como socialização com o grupo. Técnicas cirúrgicas vêm sendo realizadas com o desenvolvimento das pesquisas envolvendo a glândula pineal. A técnica ideal para pinealectomia consiste no pouco sangramento, na curta duração da cirurgia e na nitidez da glândula pineal, diminuindo a probabilidade de acidentes neurológicos. Considerando-se os resultados obtidos ao longo do desenvolvimento experimental e clínico, o aprimoramento da técnica cirúrgica utilizando a broca PM03 associada ao fórceps cápsula arruga foi exímio na pesquisa científica da pinealectomia de ratas Wistar em virtude da rapidez e praticidade alcançadas. Tem-se a perspectiva de que este artigo sirva de subsídio para o aprimoramento e a otimização do modelo experimental para posteriores estudos acerca de pesquisas com a glândula pineal e, assim, maior compreensão de sua complexidade sobre todos os sistemas do organismo.

Zinc Binding to MG53 Facilitates Repair of Injury to Cell Membrane

Zinc (Zn) is an essential trace element that participates in a wide range of biological functions, including wound healing. While Zn deficiency has been linked to compromised wound healing and tissue repair in human diseases, the molecular mechanisms underlying Zn-mediated tissue repair remain unknown. Our previous studies established that MG53, a tripartite motif (TRIM) family protein, is an essential component of the cell membrane repair machinery. Domain homology analysis reveals that MG53 contains two Zn-binding motifs. Here we show that Zn-binding to MG53 is indispensible to the assembly of the cell membrane repair machinery. Live cell imaging illustrates that Zn entry from extracellular space is essential for translocation of MG53-containing vesicles to the acute membrane injury sites for formation of a repair patch. The effect of Zn on membrane repair is abolished in the mg53-/- muscle fibers, suggesting that MG53 functions as a potential target for Zn during membrane repair. Mutagenesis studies suggest that both RING and B-box motifs of MG53 constitute Zn-binding domains that contribute to MG53-mediated membrane repair. Overall, this study establishes a base for Zn interaction with MG53 in protection against injury to the cell membrane.

Molecular basis and functional significance of Angiotensin II-induced increase in Discoidin Domain Receptor 2 gene expression in cardiac fibroblasts

Delineation of mechanisms underlying the regulation of fibrosis-related genes in the heart is an important clinical goal as cardiac fibrosis is a major cause of myocardial dysfunction. This study probed the regulation of Discoidin Domain Receptor 2 (DDR2) gene expression and the regulatory links between Angiotensin II, DDR2 and collagen in Angiotensin II-stimulated cardiac fibroblasts. Real-time PCR and western blot analyses showed that Angiotensin II enhances DDR2 mRNA and protein expression in rat cardiac fibroblasts via NADPH oxidase-dependent reactive oxygen species induction. NF-κB activation, demonstrated by gel shift assay, abolition of DDR2 expression upon NF-κB inhibition, and luciferase and chromatin immunoprecipitation assays confirmed transcriptional control of DDR2 by NF-κB in Angiotensin II-treated cells. Inhibitors of Phospholipase C and Protein kinase C prevented Angiotensin II-dependent p38 MAPK phosphorylation that in turn blocked NF-κB activation. Angiotensin II also enhanced collagen gene expression. Importantly, the stimulatory effects of Angiotensin II on DDR2 and collagen were inter-dependent as siRNA-mediated silencing of one abolished the other. Angiotensin II promoted ERK1/2 phosphorylation whose inhibition attenuated Angiotensin II-stimulation of collagen but not DDR2. Furthermore, DDR2 knockdown prevented Angiotensin II-induced ERK1/2 phosphorylation, indicating that DDR2-dependent ERK1/2 activation enhances collagen expression in cells exposed to Angiotensin II. DDR2 knockdown was also associated with compromised wound healing response to Angiotensin II. To conclude, Angiotensin II promotes NF-κB activation that up-regulates DDR2 transcription. A reciprocal regulatory relationship between DDR2 and collagen, involving cross-talk between the GPCR and RTK pathways, is central to Angiotensin II-induced increase in collagen expression in cardiac fibroblasts.