Reduced angiogenesis and delay in wound healing in angiotensin II type 1a receptor-deficient mice

Surgical Management of Breast Capsular Contracture-A Multi-institutional Data Analysis of Risk Factors for Early Complications

BACKGROUND

Capsular contracture (CC) is a common complication following implant-based breast surgery, often requiring surgical intervention. Yet, little is known about risk factors and outcomes following CC surgery.

METHODS

We reviewed the American College of Surgeons National Surgical Quality Improvement Program database (2008-2021) to identify female patients diagnosed with CC and treated surgically. Outcomes of interest included the incidence of surgical and medical complications at 30-days, reoperations, and readmissions. Confounder-adjusted multivariable analyses were performed to establish risk factors.

RESULTS

5,057 patients with CC were identified (mean age: 55 ± 12 years and mean body mass index [BMI]: 26 ± 6 kg/m2). While 2,841 (65%) women underwent capsulectomy, capsulotomy was performed in 742 patients (15%). Implant removal and replacement were recorded in 1,160 (23%) and 315 (6.2%) cases, respectively. 319 (6.3%) patients experienced postoperative complications, with 155 (3.1%) reoperations and 99 (2.0%) readmissions. While surgical adverse events were recorded in 139 (2.7%) cases, 86 (1.7%) medical complications occurred during the 30 day follow-up. In multivariate analyses, increased BMI (OR: 1.04; p = 0.009), preoperative diagnosis of hypertension (OR: 1.48; p = 0.004), and inpatient setting (OR: 4.15; p < 0.001) were identified as risk factors of complication occurrence.

CONCLUSION

Based on 14 years of multi-institutional data, we calculated a net 30 day complication rate of 6.3% after the surgical treatment of CC. We identified higher BMI, hypertension, and inpatient setting as independent risk factors of postoperative complications. Plastic surgeons may wish to integrate these findings into their perioperative workflows, thus optimizing patient counseling and determining candidates' eligibility for CC surgery.

LEVEL OF EVIDENCE III

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 online Instructions to Authors www.springer.com/00266 .

Integrated-omics profiling unveils the disparities of host defense to ECM scaffolds during wound healing in aged individuals

Extracellular matrix (ECM) scaffold membranes have exhibited promising potential to better the outcomes of wound healing by creating a regenerative microenvironment around. However, when compared to the application in younger individuals, the performance of the same scaffold membrane in promoting re-epithelialization and collagen deposition was observed dissatisfying in aged mice. To comprehensively explore the mechanisms underlying this age-related disparity, we conducted the integrated analysis, combing single-cell RNA sequencing (scRNA-Seq) with spatial transcriptomics, and elucidated six functionally and spatially distinctive macrophage groups and lymphocytes surrounding the ECM scaffolds. Through intergroup comparative analysis and cell-cell communication, we characterized the dysfunction of Spp1+ macrophages in aged mice impeded the activation of the type Ⅱ immune response, thus inhibiting the repair ability of epidermal cells and fibroblasts around the ECM scaffolds. These findings contribute to a deeper understanding of biomaterial applications in varied physiological contexts, thereby paving the way for the development of precision-based biomaterials tailored specifically for aged individuals in future therapeutic strategies.

A Biologic and Physical Characterization of an Injectable Amniotic Membrane Designed for Treating Diabetic Foot Ulcers

INTRODUCTION

Globally, the health and quality of life of millions of people are negatively affected by diabetic foot ulcers (DFUs). To treat these chronic wounds, a novel injectable drug for closing DFUs composed of micronized amniotic membrane was developed. This new therapeutic drug for wound repair expands on traditional allograft therapies by allowing extracellular matrix proteins, growth factors, and cytokines to reach wound anatomies in DFUs that are difficult to treat. The aim of this study was to evaluate the components of the injectable drug.

METHODS

Liquid chromatography with tandem mass spectrometry and a Quantibody® human cytokine array were conducted to identify and characterize growth factors and proteins known to contribute to wound healing. In addition, hyaluronic acid was quantified and compared between the injectable and human amniotic fluid using a hyaluronan enzyme-linked immunosorbent assay. Cell proliferation, migration, angiogenesis, and viability were evaluated to assess the performance of the novel injectable in vitro. The rheometric properties of the product were evaluated by assessing it pre- and post-injection through a 22-gauge needle to measure the viscosity using a shear- and temperature-dependent viscosity protocol.

RESULTS

Liquid chromatography with tandem mass spectrometry and Quantibody® human cytokine array revealed growth factors and proteins imperative for wound healing. The quantified hyaluronic acid was compared between the injectable and human amniotic fluid, resulting in a statistically significant difference, with higher protein concentrations found in the injectable. In vitro qualitative and quantitative analysis confirmed an increase in cell viability, proliferation, and migration when treated with the drug. An evaluation of the rheometric properties of the injectable drug after passing through a 22-gauge cannula presented no alterations to the biologic drug.

CONCLUSIONS

Collectively, these data present the potential of a novel injectable drug for the treatment of DFUs.

Evidence of a causal relationship between blood pressure and pathological scars: a bidirectional Mendelian randomization study

Background

Recent advancements in basic medicine and epidemiology suggest a potential influence of blood pressure on scar formation, yet the specifics of this relationship are not fully understood. This study aims to clarify the causal link between blood pressure and the development of pathological scars using Mendelian randomization (MR).

Methods

This study employed genetic variants closely linked to blood pressure as instrumental variables to explore the relationship between blood pressure and pathological scars. The inverse variance weighted (IVW) method was used for analysis.

Results

Our analysis identified a notable association where higher blood pressure was correlated with a lower risk of pathological scars. Specifically, an increase in diastolic blood pressure (odds ratio [OR] per standard deviation increase: 0.67 [95% Confidence Interval [CI], 0.49-0.99]), systolic blood pressure (OR per standard deviation increase: 0.66 [95% CI, 0.46-0.93]), and hypertension (pooled OR: 0.39 [95% CI, 0.18-0.85]) were significantly associated with a reduced risk of keloids. Similarly, a genetic predisposition to hypertension (pooled OR: 0.31 [95% CI, 0.11-0.89]) was significantly associated with a reduced risk of hypertrophic scars. Neither reverse MR analysis nor Steiger's test indicated a significant reverse causal relationship between hypertension and either keloids or hypertrophic scars.

Conclusion

The findings suggest a protective role of higher blood pressure against the development of pathological scars, including keloids and hypertrophic scars. However, the inconsistency observed across different MR methods warrants cautious interpretation and underscores the need for further investigation to confirm these findings.

Renin-angiotensin-aldosterone system inhibitors as a risk factor for chronic subdural hematoma recurrence: A matter of debate

OBJECTIVES

Chronic subdural hematoma (cSDH) is a common central nervous system condition. Recent reports indicate that cSDH affects long-term prognosis; however, its definitive risk factors remain unknown. An antihypertensive drug, renin-angiotensin-aldosterone system inhibitors (RAASi), can affect vascular permeability and cell proliferation processes, which may suppress the recurrence of cSDH. However, several studies have reported negative results to this effect. Therefore, we aimed to evaluate antihypertensive drugs, including RAASi, as risk factors for recurrent cSDH.

MATERIALS AND METHODS

A total of 203 consecutive cases of surgically treated cSDH were retrospectively reviewed. Clinical and radiological parameters were compared between the groups with and without cSDH recurrence to identify risk factors.

RESULTS

Of the included cases, 68 (33.5%) used RAASi and 37 (18.2%) developed recurrence within 60 days of surgery. In the multiple logistic regression analysis adjusted by composite risk score, the odds ratios (95% confidence interval) of RAASi, calcium channel blockers, diuretics, β and α blockers, for the recurrent risk of cSDH after surgery were 2.49 (1.16, 5.42), 1.79 (0.84, 3.82), 1.83 (0.62, 4.87), 0.90 (0.28, 2.44), and 0.96 (0.21, 3.20), respectively. The Cox proportional hazard model also demonstrated that RAASi-use was an independent risk factor for cSDH recurrence.

CONCLUSIONS

Present series suggests RAASi-use as a risk factor for cSDH recurrence, although the role of RAASi-use in cSDH remains debatable. Further studies for deeper understanding of the microenvironment of hematoma and the surroundings are preferable. (235 words).

Endothelial Injury Syndromes after Allogeneic Hematopoietic Stem Cell Transplantation: Angiopetin-2 as a Novel Predictor of the Outcome and the Role of Functional Autoantibodies against Angiotensin II Type 1 and Endothelin A Receptor

Transplant-associated thrombotic microangiopathy (TMA) occurs in a significant percentage of patients after allogeneic stem cell transplantation (allo-SCT) and is associated with significant morbidity and mortality. The aim of the present study was to examine the association of serum angiopoetin-2 (Ang2) levels and the presence of antibodies against angiotensin II type 1 (AT1R) and ndothelin A Recreptor (ETAR) with the outcome of patients with TMA and/or graft-versus-host disease (GVHD) after allo-SCT. Analysis of our data showed that elevated serum Ang2 levels at the time of TMA diagnosis are significantly associated with increased non-relapse mortality and decreased overall survival. To our knowledge, this is the first study demonstrating an association between raised Ang2 levels and poor outcomes in patients with TMA. Antibodies against AT1R (AT1R-Abs) and ETAR (ETAR-Abs) were detected in 27% and 23% of the patients, respectively, but there was no association between the presence of autoantibodies and the outcome of patients with TMA. However, a significant finding was the strong positive correlation between the presence of AT1R-Abs with the occurrence of chronic fibrotic GVHD, such as scleroderma and cryptogenic organizing pneumonia, raising the possibility of the contribution of autoantibodies in the pathogenesis of fibrotic GVHD manifestations.

Efficacy of Topical Losartan in Management of Mammoplasty and Abdominoplasty Scars: A Randomized, Double-Blind Clinical Trial

BACKGROUND

Annually, millions of people suffer from skin scars' psychological and physical disadvantages. Pathologic scars prevention is challenging and requires developing feasible and effective therapeutic strategies. Regarding promising results of losartan (an angiotensin 1 receptor inhibitor) on skin scar in preclinical studies, we aimed to assess the losartan ointment's impact on surgical scars in a clinical setting.

MATERIAL AND METHOD

Twenty-four patients with surgical wounds were enrolled from Razi hospital's plastic and reconstructive surgery department. The patients were trained to apply ointments 14-18 days post-surgery on the determined scar side, twice a day for 6 months. Two dermatologists independently evaluated scar formation at 3 and 6-month follow-ups using the Vancouver Scar Scale (VSS) score.

RESULT

Twenty-four female patients with cosmetic surgeries were included. The mean VSS score of losartan-treated sides was 7.1 ± 2.06 (at month 3) and 5.21 ± 1.71 (at month 6) that significantly were different from placebo-treated sides (9.77 ± 1.55 and 8.31 ± 1.88 at 3 and 6 months, respectively) (P value < 0.001 and < 0.001, respectively, for months 3 and 6). The subset analysis demonstrated a significant improvement in height (P value < 0.001 at 3 and 6 months), pliability (P value  < 0.001 at 3 and 6 months), and vascularity (P value < 0.001 at 3 and 6 months) subsets at losartan compared to placebo-treated side. Losartan ointment was well tolerated with no complication.

CONCLUSION

Losartan ointment successfully improved scar formation in mammoplasty and abdominoplasty patients. The losartan preventive effect should be confirmed in future large-scale studies with long-term follow-ups.

LEVEL OF EVIDENCE II

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 online Instructions to Authors   www.springer.com/00266 .

Effects of antihypertensive drugs on surgical outcomes of breast reconstruction: a nationwide population-based claim study

Background

Experimental studies have reported that angiotensin receptor blockers (ARBs) increase the risk of surgical complications. However, clinical data on their effect on surgical outcomes are limited. The aim of this study was to investigate the impact of perioperative use of ARBs on the outcomes of breast reconstruction using population-based claim data.

Methods

Data of patients who underwent direct-to-implant or abdomen-based autologous breast reconstruction after total mastectomy from April 2015 to December 2018 were obtained from the Health Insurance Review and Assessment Service database. The patients were categorized as ARB, non-ARB, control, and non-hypertension groups. The effects of ARBs on surgical complications, length of hospital stay, and complication-related medical costs were evaluated.

Results

Of the 9,036 patients who met the inclusion criteria, 5,192 underwent direct-to-implant reconstruction, and 3,844 underwent abdomen-based autologous reconstruction. The length of hospital stay was the longest and the surgical complication rate and complication-related medical cost were the highest in the ARB group after both reconstruction methods. Compared with non-treatment with antihypertensive drugs, ARB use was found to be an independent risk factor for surgical complications in direct-to-implant reconstruction [odds ratio (OR), 1.96; 95% confidence interval (CI), 1.09-3.50; P=0.0237] and complication-related medical cost (OR, 1.93; 95% CI, 1.10-3.40; P=0.0221) in abdomen-based autologous reconstruction.

Conclusions

Perioperative ARB use was associated with adverse postoperative breast reconstruction outcomes. These findings might have a significant impact on perioperative antihypertensive management; nevertheless, further studies are warranted to confirm the study findings.

Emerging importance of ACE2 in external stratified epithelial tissues

Angiotensin converting enzyme 2 (ACE2), a component of the renin-angiotensin system (RAS), has been identified as the receptor for the SARS-CoV-2. Several RAS components including ACE2 and its substrate Ang II are present in both eye and skin, two stratified squamous epithelial tissues that isolate organisms from external environment. Our recent findings in cornea and others in both skin and eye suggest contribution of this system, and specifically of ACE2 in variety of physiological and pathological responses of these organ systems. This review will focus on the role RAS system plays in both skin and cornea, and will specifically discuss our recent findings on ACE2 in corneal epithelial inflammation, as well as potential implications of ACE2 in patients with COVID-19.

Amphetamine Induces Oxidative Stress, Glial Activation and Transient Angiogenesis in Prefrontal Cortex via AT1-R

Background: Amphetamine (AMPH) alters neurons, glia and microvessels, which affects neurovascular unit coupling, leading to disruption in brain functions such as attention and working memory. Oxidative stress plays a crucial role in these alterations. The angiotensin type I receptors (AT₁-R) mediate deleterious effects, such as oxidative/inflammatory responses, endothelial dysfunction, neuronal oxidative damage, alterations that overlap with those observed from AMPH exposure. Aims: The aim of this study was to evaluate the AT₁-R role in AMPH-induced oxidative stress and glial and vascular alterations in the prefrontal cortex (PFC). Furthermore, we aimed to evaluate the involvement of AT₁-R in the AMPH-induced short-term memory and working memory deficit. Methods: Male Wistar rats were repeatedly administered with the AT₁-R blocker candesartan (CAND) and AMPH. Acute oxidative stress in the PFC was evaluated immediately after the last AMPH administration by determining lipid and protein peroxidation. After 21 off-drug days, long-lasting alterations in the glia, microvessel architecture and to cognitive tasks were evaluated by GFAP, CD11b and von Willebrand immunostaining and by short-term and working memory assessment. Results: AMPH induced acute oxidative stress, long-lasting glial reactivity in the PFC and a working memory deficit that were prevented by AT₁-R blockade pretreatment. Moreover, AMPH induces transient angiogenesis in PFC via AT₁-R. AMPH did not affect short-term memory. Conclusion: Our results support the protective role of AT₁-R blockade in AMPH-induced oxidative stress, transient angiogenesis and long-lasting glial activation, preserving working memory performance.

MicroRNA-139-5p upregulation is associated with diabetic endothelial cell dysfunction by targeting c-jun

Dysfunction of endothelial cells (ECs) and their progenitor cells is an important feature of diabetic vascular disease. MicroRNA (miR)-139-5p is involved in inhibiting the metastasis and progression of diverse malignancies. However, the role of miR-139-5p in ECs still remains unclarified. Here we demonstrated that miR-139-5p expression was elevated in endothelial colony-forming cells (ECFCs) isolated from patients with diabetes, ECs derived from the aorta of diabetic rodents, and human umbilical vein endothelial cells (HUVECs) cultured in high glucose media. MiR-139-5p mimics inhibited tube formation, migration, proliferation, and down-regulated expression of c-jun, vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF)-B, in ECFCs and HUVECs, respectively; moreover, miR-139-5p inhibitors reversed the tendency. Further, gain- and-loss function experiments and ChIP assay indicated that miR-139-5p regulate functions of ECFCs by targeting c-jun-VEGF/PDGF-B pathway. In vivo experiments (Matrigel plug assay and hindlimb ischemia model) showed that miR-139-5p downregulation further promoted ECFC-mediated angiogenesis and blood perfusion. In conclusion, diabetes-mediated high miR-139-5p expression inhibits the c-jun-VEGF/PDGF-B pathway, thus decreasing ECFCs migration, tube formation and proliferation, which subsequently reduces ECs survival. Therefore, miR-139-5p might be an important therapeutic target in the treatment of diabetic vasculopathy in the future.

Effects of angiotensin-II on brain endothelial cell permeability via PPARalpha regulation of para- and trans-cellular pathways

Angiotensin-II (Ang-II) is a key factor in hypertension, diabetes and aging, which are all primary risk factors for CNS disease. Furthermore, Ang-II may play under-appreciated roles in neurogenesis, angiogenesis and CNS remodeling. Therefore, any contemplated attempts for neurorestorative therapies in the CNS should consider the context of Ang-II signaling. Here, we investigate how Ang-II may regulate cerebral endothelial permeability, a key functional feature of the neurovascular unit. Exposure of human brain endothelial cell cultures to Ang-II increased its permeability to BSA-Alexa488 tracer. Immunocytochemistry and pulse-chase experiments suggested that both para-cellular as well as trans-cellular pathways were involved. Candesartan but not PD123319 blocked Ang-II permeability effects, suggesting that Ang-II effects may be mediated via type 1 receptor. Immunocytochemistry and western blots showed that Ang-II disrupted the membrane distributions of ZO-1 and VE-Cad, decreased total levels of JAM-A and Mfsd2a, and increased Cav1. These effects of Ang-II were accompanied by dephosphorylation of PPARalpha. Finally, Ang-II-induced increases in endothelial permeability were ameliorated by PPARalpha agonists. Taken together, these studies suggest that Ang-II may disrupt both para- and trans-cellular permeability in cerebral endothelium, and PPARalpha-related pathways may offer potential therapeutic targets for ameliorating these effects in cell-based regenerative medicine.

Antibodies against Angiotensin II Type 1 and Endothelin A Receptors: Relevance and pathogenicity

Antibodies against two G-protein coupled receptors (GPCRs), angiotensin II type 1 receptor (AT1R) and endothelin A receptor (ETAR) are among a growing number of autoantibodies that are found to be associated with allograft dysfunction. AT1R antibodies (AT1Rabs) and ETAR antibodies (ETARabs) have been shown to activate their target receptors and affect signaling pathways. Multiple single center reports have shown an association between presence of these antibodies and acute or chronic rejection and graft loss in kidney, heart, liver, lung and composite tissue transplantations. However, the characteristics of patients that are most likely to develop adverse outcomes, the phenotypes associated with graft damage solely due to these antibodies, and the antibody titer required to cause dysfunction are areas that remain controversial. This review compiles existing knowledge on the effect of antibodies against GPCRs in other diseases in order to bridge the gap in knowledge within transplantation biology. Future areas for research are highlighted and include the need for functional assays and treatment protocols for transplant patients who present with AT1Rabs and ETARabs. Understanding how antibodies that activate GPCRs influence transplantation outcome will have direct clinical implications for preemptive evaluation of transplant candidates as well as the post-transplant care of organ recipients.

Biobehavioral Mechanisms Associated With Nonhealing Wounds and Psychoneurologic Symptoms (Pain, Cognitive Dysfunction, Fatigue, Depression, and Anxiety) in Older Individuals With Chronic Venous Leg Ulcers

The prevalence and incidence of chronic venous leg ulcers (CVLUs) are increasing worldwide, as are the associated financial costs. Although it has long been known that their underlying etiology is venous insufficiency, the molecular aspects of healing versus nonhealing, as well as the psychoneurologic symptoms (PNS; pain, cognitive dysfunction, fatigue, depression, and anxiety) associated with CVLUs remain understudied. In this biobehaviorally focused review, we aim to elucidate the complex mechanisms that link the biological and molecular aspects of CLVUs with their PNS. Innovations in "omics" research have increased our understanding of important wound microenvironmental factors (e.g., inflammation, microbial pathogenic biofilm, epigenetic processes) that may adversely alter the wound bed's molecular milieu so that microbes evade immune detection. Although these molecular factors are not singularly responsible for wound healing, they are major components of wound development, nonhealing, and PNS that, until now, have not been amenable to systematic study, especially over time. Further, this review explores our current understanding of the molecular mechanisms by which the immune activation that contributes to the development and persistence of CVLUs also leads to the development, persistence, and severity of wound-related PNS. We also make recommendations for future research that will expand the field of biobehavioral wound science. Biobehavioral research that focuses on the interrelated mechanisms of PNS will lead to symptom-management interventions that improve quality of life for the population burdened by CVLUs.

VEGF Receptor 1-Expressing Macrophages Recruited from Bone Marrow Enhances Angiogenesis in Endometrial Tissues

Angiogenesis is critical in maintenance of endometrial tissues. Here, we examined the role of VEGF receptor 1 (VEGFR1) signaling in angiogenesis and tissue growth in an endometriosis model. Endometrial fragments were implanted into the peritoneal wall of mice, and endometrial tissue growth and microvessel density (MVD) were determined. Endometrial fragments from wild-type (WT) mice grew slowly with increased angiogenesis determined by CD31⁺ MVD, peaking on Day 14. When tissues from WT mice were transplanted into VEGFR1 tyrosine kinase-knockout mice, implant growth and angiogenesis were suppressed on Day 14 compared with growth of WT implants in a WT host. The blood vessels in the implants were not derived from the host peritoneum. Immunostaining for VEGFR1 suggested that high numbers of VEGFR1⁺ cells such as macrophages were infiltrated into the endometrial tissues. When macrophages were deleted with Clophosome N, both endometrial tissue growth and angiogenesis were significantly suppressed. Bone marrow chimera experiments revealed that growth and angiogenesis in endometrial implants were promoted by host bone marrow-derived VEGFR1⁺/CD11b⁺ macrophages that accumulated in the implants, and secreted basic fibroblast growth factor (bFGF). A FGF receptor kinase inhibitor, PD173047 significantly reduced size of endometrial tissues and angiogenesis. VEGFR1 signaling in host-derived cells is crucial for growth and angiogenesis in endometrial tissue. Thus, VEGFR1 blockade is a potential treatment for endometriosis.

Balance and circumstance: The renin angiotensin system in wound healing and fibrosis

The tissue renin angiotensin system (tRAS) is a locally-acting master-modulator of tissue homeostasis and regeneration. Through these abilities, it is emerging as an attractive target for therapies aiming to restore tissue homeostasis in conditions associated with disturbed wound healing. The tRAS can be divided into two axes - one being pro-inflammatory and pro-fibrotic and one being anti-inflammatory and anti-fibrotic. However, the division of the axes is fuzzy and imperfect as the axes are codependent and the outcome of tRAS activation is determined by the context. Although the tRAS is a local system it shares its key enzymes, ligands and receptors with the systemic RAS and is consequently also targeted by repurposing of drugs developed against the systemic RAS to manage hypertension. With a focus on the skin we will here discuss the tRAS, its involvement in physiological and pathological wound healing, and the therapeutic aptitude of its targeting to treat chronic wounds and fibrosis.

Targeting Oxidative Stress and Mitochondrial Dysfunction in the Treatment of Impaired Wound Healing: A Systematic Review

Wound healing is a well-tuned biological process, which is achieved via consecutive and overlapping phases including hemostasis, inflammatory-related events, cell proliferation and tissue remodeling. Several factors can impair wound healing such as oxygenation defects, aging, and stress as well as deleterious health conditions such as infection, diabetes, alcohol overuse, smoking and impaired nutritional status. Growing evidence suggests that reactive oxygen species (ROS) are crucial regulators of several phases of healing processes. ROS are centrally involved in all wound healing processes as low concentrations of ROS generation are required for the fight against invading microorganisms and cell survival signaling. Excessive production of ROS or impaired ROS detoxification causes oxidative damage, which is the main cause of non-healing chronic wounds. In this context, experimental and clinical studies have revealed that antioxidant and anti-inflammatory strategies have proven beneficial in the non-healing state. Among available antioxidant strategies, treatments using mitochondrial-targeted antioxidants are of particular interest. Specifically, mitochondrial-targeted peptides such as elamipretide have the potential to mitigate mitochondrial dysfunction and aberrant inflammatory response through activation of nucleotide-binding oligomerization domain (NOD)-like family receptors, such as the pyrin domain containing 3 (NLRP3) inflammasome, nuclear factor-kappa B (NF-κB) signaling pathway inhibition, and nuclear factor (erythroid-derived 2)-like 2 (Nrf2).

Tissue repair genes: the TiRe database and its implication for skin wound healing

Wound healing is an inherent feature of any multicellular organism and recent years have brought about a huge amount of data regarding regular and abnormal tissue repair. Despite the accumulated knowledge, modulation of wound healing is still a major biomedical challenge, especially in advanced ages. In order to collect and systematically organize what we know about the key players in wound healing, we created the TiRe (Tissue Repair) database, an online collection of genes and proteins that were shown to directly affect skin wound healing. To date, TiRe contains 397 entries for four organisms: Mus musculus, Rattus norvegicus, Sus domesticus, and Homo sapiens. Analysis of the TiRe dataset of skin wound healing-associated genes showed that skin wound healing genes are (i) over-conserved among vertebrates, but are under-conserved in invertebrates; (ii) enriched in extracellular and immuno-inflammatory genes; and display (iii) high interconnectivity and connectivity to other proteins. The latter may provide potential therapeutic targets. In addition, a slower or faster skin wound healing is indicative of an aging or longevity phenotype only when assessed in advanced ages, but not in the young. In the long run, we aim for TiRe to be a one-station resource that provides researchers and clinicians with the essential data needed for a better understanding of the mechanisms of wound healing, designing new experiments, and the development of new therapeutic strategies. TiRe is freely available online at http://www.tiredb.org.

International Union of Basic and Clinical Pharmacology. XCIX. Angiotensin Receptors: Interpreters of Pathophysiological Angiotensinergic Stimuli [corrected]

The renin angiotensin system (RAS) produced hormone peptides regulate many vital body functions. Dysfunctional signaling by receptors for RAS peptides leads to pathologic states. Nearly half of humanity today would likely benefit from modern drugs targeting these receptors. The receptors for RAS peptides consist of three G-protein-coupled receptors—the angiotensin II type 1 receptor (AT1 receptor), the angiotensin II type 2 receptor (AT2 receptor), the MAS receptor—and a type II trans-membrane zinc protein—the candidate angiotensin IV receptor (AngIV binding site). The prorenin receptor is a relatively new contender for consideration, but is not included here because the role of prorenin receptor as an independent endocrine mediator is presently unclear. The full spectrum of biologic characteristics of these receptors is still evolving, but there is evidence establishing unique roles of each receptor in cardiovascular, hemodynamic, neurologic, renal, and endothelial functions, as well as in cell proliferation, survival, matrix-cell interaction, and inflammation. Therapeutic agents targeted to these receptors are either in active use in clinical intervention of major common diseases or under evaluation for repurposing in many other disorders. Broad-spectrum influence these receptors produce in complex pathophysiological context in our body highlights their role as precise interpreters of distinctive angiotensinergic peptide cues. This review article summarizes findings published in the last 15 years on the structure, pharmacology, signaling, physiology, and disease states related to angiotensin receptors. We also discuss the challenges the pharmacologist presently faces in formally accepting newer members as established angiotensin receptors and emphasize necessary future developments.

NorLeu3-Angiotensin (1-7) [DSC127] as a Therapy for the Healing of Diabetic Foot Ulcers

Significance: Diabetes is a disorder that is well known to delay wound repair resulting in the formation of colonized chronic wounds. Over their lifetime, diabetic patients have a 25% incidence of foot ulcers (DFUs), which contribute to increased risk of morbidity, including osteomyelitis and amputations, and increased burden to the healthcare system. Recent Advances: The only active product approved for the treatment of diabetic ulcers, Regranex^®, is not widely used due to minimal proven efficacy and recent warnings added to the Instructions for Use. A novel topical agent that accelerates healing and increases the proportion of fully healed DFUs, DSC127 [aclerastide; active ingredient, NorLeu³-angiotensin (1-7) (NorLeu³-A(1-7))], is recruiting patients in Phase III clinical trials (NCT01830348 and NCT01849965). NorLeu³-A(1-7) is an analog of the naturally occurring peptide, angiotensin 1-7. The mechanisms of action include induction of progenitor proliferation, accelerated vascularization, collagen deposition, and re-epithelialization. Critical Issues: Current modalities for the treatment of DFUs include strict offloading, bandaging, debridement and, on a limited basis, application of Regranex. Novel potent therapies are needed to combat this significant burden to the diabetic patient and the healthcare system. Future Direction: Preclinical and clinical research shows that DSC127 is highly effective in the closure of diabetic wounds and is superior to Regranex in animal studies. Clinical development of DSC127 as a topical agent for the healing of DFU is underway. Further investigation into the mechanisms by which this product accelerates healing is warranted.

Chronic wound repair and healing in older adults: current status and future research

Older adults are more likely to have chronic wounds than younger people, and the effect of chronic wounds on quality of life is particularly profound in this population. Wound healing slows with age, but the basic biology underlying chronic wounds and the influence of age-associated changes on wound healing are poorly understood. Most studies have used in vitro approaches and various animal models, but observed changes translate poorly to human healing conditions. The effect of age and accompanying multimorbidity on the effectiveness of existing and emerging treatment approaches for chronic wounds is also unknown, and older adults tend to be excluded from randomized clinical trials. Poorly defined outcomes and variables; lack of standardization in data collection; and variations in the definition, measurement, and treatment of wounds also hamper clinical studies. The Association of Specialty Professors, in conjunction with the National Institute on Aging and the Wound Healing Society, held a workshop, summarized in this article, to explore the current state of knowledge and research challenges, engage investigators across disciplines, and identify research questions to guide future study of age-associated changes in chronic wound healing.

Chronic wound repair and healing in older adults: current status and future research

The incidence of chronic wounds is increased among older adults, and the impact of chronic wounds on quality of life is particularly profound in this population. It is well established that wound healing slows with age. However, the basic biology underlying chronic wounds and the influence of age-associated changes on wound healing are poorly understood. Most studies have used in vitro approaches and various animal models, but observed changes translate poorly to human healing conditions. The impact of age and accompanying multi-morbidity on the effectiveness of existing and emerging treatment approaches for chronic wounds is also unknown, and older adults tend to be excluded from randomized clinical trials. Poorly defined outcomes and variables, lack of standardization in data collection, and variations in the definition, measurement, and treatment of wounds also hamper clinical studies. The Association of Specialty Professors, in conjunction with the National Institute on Aging and the Wound Healing Society, held a workshop, summarized in this paper, to explore the current state of knowledge and research challenges, engage investigators across disciplines, and identify key research questions to guide future study of age-associated changes in chronic wound healing.

Signaling mechanism underlying the promotion of keratinocyte migration by angiotensin II

Re-epithelialization begins early during skin wound healing and is regulated by various growth factors and cytokines. Angiotensin II promotes the migration of keratinocytes and thereby contributes to wound healing. We investigated the mechanism by which angiotensin II stimulates human keratinocyte migration. Angiotensin II-induced keratinocyte migration was inhibited by an angiotensin II type 1 receptor (AT1R) antagonist (candesartan) or an angiotensin II type 2 receptor (AT2R) antagonist (PD123319) as well as by depletion of AT1R or AT2R. A biased agonist for AT1R, [Sar(1),Ile(4),Ile(8)]angiotensin II, induced cell migration, whereas depletion of β-arrestin2 inhibited angiotensin II-induced migration. Angiotensin II-induced migration was blocked by neutralizing antibodies to transforming growth factor-β (TGF-β) as well as by the TGF-β receptor inhibitor SB431542. The amount of TGF-β1 was increased in the culture medium of angiotensin II-treated cells, and this effect was inhibited by candesartan or PD123319. Both angiotensin II- and TGF-β-induced cell migration were inhibited by neutralizing antibodies to the epidermal growth factor (EGF) receptor but not by those to EGF receptor ligands. Angiotensin II-induced phosphorylation of the EGF receptor, and this effect was inhibited by candesartan, PD123319, SB431542, or depletion of β-arrestin2, but not by neutralizing antibodies to heparin-binding EGF-like growth factor. Our results indicate that β-arrestin-dependent signaling downstream of AT1R as well as AT2R signaling are necessary for angiotensin II-induced keratinocyte migration, and that such signaling promotes generation of the active form of TGF-β, consequent activation of the TGF-β receptor, and transactivation of the EGF receptor by the TGF-β receptor.

Cardiac microvascular rarefaction in hyperthyroidism-induced left ventricle dysfunction

OBJECTIVE

The pathophysiology underlying hyperthyroidism-induced left ventricle (LV) dysfunction and hypertrophy directly involves the heart and indirectly involves the neuroendocrine systems. The effects of hyperthyroidism on the microcirculation are still controversial in experimental models. We investigated the effects of hyperthyroidism on the cardiac function and microcirculation of an experimental rat model.

METHODS

Male Wistar rats (170-250 g) were divided into two groups: the euthyroid group (n = 10), which was treated with 0.9% saline solution, and the hyperthyroid group (n = 10), which was treated with l-thyroxine (600 μg/kg/day, i.p.) during 14 days. An echocardiographic study was performed to evaluate the alterations in cardiac function, structure and geometry. The structural capillary density and the expression of angiotensin II AT1 receptor in the LV were analyzed using histochemistry and immunohistochemistry, respectively.

RESULTS

Hyperthyroidism was found to induce profound cardiovascular alterations, such as systolic hypertension, tachycardia, LV dysfunction, cardiac hypertrophy, and myocardial fibrosis. This study demonstrates the existence of structural capillary rarefaction and the down-regulation of the cardiac angiotensin II AT1 receptor in the myocardium of hyperthyroid rats in comparison with euthyroid rats.

CONCLUSIONS

Microvascular rarefaction may be involved in the pathophysiology of hyperthyroidism-induced cardiovascular alterations.

Glomerular repair retardation via blocking of angiotensin II type 1a receptor pathway in a mouse glomerulonephritis model

BACKGROUND/AIMS

To examine the role of the angiotensin II (ATII) type 1a receptor (AT1-R) pathway in renal tissue damage and repair, we investigated reversible glomerular injury in a mouse model of habu snake venom (HSV)-induced glomerulonephritis using AT1-R-deficient (AT1a-/-) mice and AT1-R antagonist-treated mice.

METHODS

Experimental glomerulonephritis was induced by single administration of HSV to AT1a(+/+) mice (HSV group) and AT1a(-/-) mice (KO-HSV group) and AT1-R antagonist-treated BL6 mice (HSV-ARB group). Morphological change and expression levels of type IV collagen, CD31, and vascular endothelial growth factor (VEGF) were analyzed.

RESULTS

The HSV group showed increased mesangial matrix expansion on day 7, which returned to preinjection levels by day 56, while mes-angial matrix expansion and increased type IV collagen expression were seen throughout days 7 to 56 in the KO-HSV group. The KO-HSV group showed fewer CD31-positive capillary loops and a marked decrease in the number of VEGF-positive cells in the glomeruli than the HSV group. VEGF administration to the KO-HSV group facilitated glomerular capillary repair and reconstruction. The HSV-ARB group showed the same delay in glomerular repair as that seen in the KO-HSV group.

CONCLUSION

Our results indicate that blocking of the ATII-AT1R pathway delays glomerular repair via angiogenesis inhibition, followed by reduced induction of VEGF.

Absence of venous valves in mice lacking Connexin37

Venous valves play a crucial role in blood circulation, promoting the one-way movement of blood from superficial and deep veins towards the heart. By preventing retrograde flow, venous valves spare capillaries and venules from being subjected to damaging elevations in pressure, especially during skeletal muscle contraction. Pathologically, valvular incompetence or absence of valves are common features of venous disorders such as chronic venous insufficiency and varicose veins. The underlying causes of these conditions are not well understood, but congenital venous valve aplasia or agenesis may play a role in some cases. Despite progress in the study of cardiac and lymphatic valve morphogenesis, the molecular mechanisms controlling the development and maintenance of venous valves remain poorly understood. Here, we show that in valved veins of the mouse, three gap junction proteins (Connexins, Cxs), Cx37, Cx43, and Cx47, are expressed exclusively in the valves in a highly polarized fashion, with Cx43 on the upstream side of the valve leaflet and Cx37 on the downstream side. Surprisingly, Cx43 expression is strongly induced in the non-valve venous endothelium in superficial veins following wounding of the overlying skin. Moreover, we show that in Cx37-deficient mice, venous valves are entirely absent. Thus, Cx37, a protein involved in cell-cell communication, is one of only a few proteins identified so far as critical for the development or maintenance of venous valves. Because Cxs are necessary for the development of valves in lymphatic vessels as well, our results support the notion of common molecular pathways controlling valve development in veins and lymphatic vessels.

Effects of combined radiation and burn injury on the renin-angiotensin system

The renin-angiotensin system (RAS) plays an important role in wound repair; however, little is known pertaining to RAS expression in response to thermal injury and the combination of radiation plus burn injury (CRBI). The purpose of this study was to test the hypothesis that thermal injury modifies expression of RAS components and CRBI delayed this up-regulation of RAS. Skin from uninjured mice was compared with mice receiving local thermal injury or CRBI (injury site). Skin was analyzed for gene and protein expression of RAS components. There was an initial increase in the expression of various components of RAS following thermal injury. However, in the higher CRBI group there is an initial decrease in AT(1b) (vasoconstriction, pro-proliferative), AT(2) (vasodilation, differentiation), and Mas (vasodilation, anti-inflammatory) gene expression. This corresponded with a delay and decrease in AT(1) , AT(2) , and MAS protein expression in fibroblasts and keratinocytes. The reduction in RAS receptor positive fibroblasts and keratinocytes correlated with a reduction in collagen deposition and keratinocyte infiltration into the wounded area resulting in a delay of reepithelialization following CRBI. These data support the hypothesis that delayed wound healing observed in subjects following radiation exposure may be in part due to decreased expression of RAS.

Sodium nitrite therapy rescues ischemia-induced neovascularization and blood flow recovery in hypertension

Arterial hypertension is a major risk factor that can lead to complication of peripheral vascular disease due, in part, to endothelial dysfunction. Because sodium nitrite (SN) can be converted to nitric oxide (NO), which counteracts endothelial dysfunction, we explored the effect of nitrite on neovascularization following hind limb ischemia in different models of hypertension (HT). Chronic delivery of angiotensin II (Ang II, 400 ng/kg/min) or N(omega)-nitro-L-arginine-methyl-ester (L-NAME, 0.1 g/L) was used for a 2-week period to induce hypertension. Mice were subjected to femoral artery ligation-induced ischemia in the hind limb followed by treatment with SN (50 mg/L) for 2 weeks. SN significantly reduced systolic arterial blood pressure in mice receiving Ang II and L-NAME but had no effect in sham animals. After 2 weeks, blood flow and microangiography showed 60 % ± 1.0 recovery in sham compared with 40 % ± 1.3 in HT mice. Importantly, sham and HT mice treated with SN showed a 100 % blood flow recovery associated with normalization in capillary density. The inhibition of xanthine-oxido-reductase (allopurinol) or VEGFR (SU-5416) prevented the neovascularization in HT mice treated with SN. Cyclic GMP (cGMP) content in the hind limb was significantly increased in mice treated with SN compared with non-treated mice. Nitrite/nitrate content was only increased in the sham group treated with SN. Immunoprecipitation and Western blot analysis revealed an increase in eNOS/Akt/VEGFR phosphorylation in skeletal muscle from mice treated with SN compared with non-treated mice. Our findings indicate that SN therapy rescues the neovascularization and blood flow recovery in the ischemic hind limb of sham and HT mice likely through the Akt/NO/cGMP and VEGFR pathways.

Influence of arterial hypertension on colonic healing in rats

PURPOSE

Evaluation of colonic healing in spontaneously hypertensive rats.

METHODS

Fifty male, young and inbred rats were used. Twenty-five Wistar Kyoto rats (WKY) as control and twenty-five spontaneously hypertensive rats (SHR) as an experimental group. Colotomy and bowel suture at 2.5 cm from the peritoneal reflection were performed. All animals were allocated randomly into sub-groups for review at the third, seventh and fourteenth days after surgery. We evaluated the concentration of angiotensin II, the burst pressure, epithelialization, the organization of the tunics of the bowel wall, inflammatory response and collagen deposition.

RESULTS

The burst pressure, epithelialization, organization of the tunics and collagen deposition was not significant between groups. The inflammatory reaction was more intense in the control group on the third postoperative day (p=0.023) as the experimental group on the remaining time.

CONCLUSION

Systemic arterial hypertension in rats did not influence significantly the healing process of colonic anastomoses.

Inhibition of the renin-angiotensin system downregulates tissue factor and vascular endothelial growth factor in human breast carcinoma cells

INTRODUCTION

The renin-angiotensin system (RAS) promotes angiogenesis and growth of neoplastic cells. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor AT1 blockers may protect against cancer. Tissue factor (TF), for its involvement in tumor growth, angiogenesis, and metastasis is considered a hallmark of cancer progression. In this study we evaluated whether RAS blockade modulates TF constitutive expression by the metastatic breast carcinoma MDA-MB-231 cell line.

MATERIALS AND METHODS

Cell TF activity was assessed by one stage clotting time, TF and VEGF antigens and mRNA levels by ELISA and RT-PCR, respectively. AT(1) was detected by flow-cytometry and angiotensin-II levels by EIA.

RESULTS

Captopril reduced in a concentration-dependent way both the strong constitutive TF activity (983.2±55.2 vs. 686.7±135.1U/5×10(5) cells with 10μg/ml captopril) and antigen (32.3±5.9 vs. 13.2±6.6ng/ml) in MDA-MB-231. Similar results were observed with enalapril. AT1 was present on cell membrane and losartan, a competitive inhibitor of AT1, reduced TF expression to a degree similar as that exerted by ACE inhibitors. Moreover, captopril and losartan downregulated the constitutive mRNA TF expression by ~35%. Similar results were observed with anti-AT1 and angiotensin II antibodies. In addition, the constitutive VEGF antigen and mRNA levels were reduced in the presence of captopril or losartan, and an anti-VEGF antibody downregulated cell TF activity by ~40%.

CONCLUSIONS

These results could, at least in part, contribute to the discussion about the possible effects of ACE inhibitors and AT1 receptor antagonists in malignancy, and offer new clues to support their use for tumor control.

Accelerated healing of diabetic wounds by NorLeu(3)-angiotensin (1-7)

INTRODUCTION

Diabetes is a disorder that is well known to delay wound repair resulting in the formation of colonized, chronic wounds. The resultant ulcers contribute to increased risk of morbidity, including osteomyelitis and amputations, and increased burden to the healthcare system.

AREAS COVERED

The only active product approved for the treatment of diabetic ulcers, Regranex, has been shown to reduce amputation risk, but is not widely used due to minimal proven efficacy and recent warnings added to the Instructions for Use. This review provides an overview of the development of NorLeu(3)-angiotensin (1-7) (NorLeu(3)-A(1-7)) as an active agent for the treatment of diabetic wounds. NorLeu(3)-A(1-7) is an analog of the naturally occurring peptide, angiotensin 1-7. The mechanisms of action include induction of progenitor proliferation and accelerated vascularization, collagen deposition and re-epithelialization.

EXPERT OPINION

Research to date has shown that NorLeu(3)-A(1-7) is highly effective in the closure of diabetic wounds and is superior to Regranex in animal studies. Further clinical development of this product as a topical agent for the healing of chronic wounds and investigation into the mechanisms by which this product accelerates healing are warranted.

The inducible prostaglandin E synthase mPGES-1 regulates growth of endometrial tissues and angiogenesis in a mouse implantation model

Endometriosis is one of the most common gynecological diseases in women of reproductive age. Although cyclooxygenase (COX)-2 inhibitors are effective in the treatment of endometriosis, the adverse cardiovascular effects associated with these inhibitors have limited their use. Microsomal prostaglandin E synthase-1 (mPGES-1) is an inducible enzyme downstream of COX-2 in prostaglandin E(2) biosynthesis. Previously, we developed mPGES-1 knockout mice (mPGES-1(-/-)) and have identified for the first time the roles of ectopic lesion- and host-associated mPGES-1 in angiogenesis and the growth of endometrial tissues. When mPGES-1(-/-) endometrial fragments were implanted into wild type (WT) mice (mPGES-1(-/-)→WT), or WT fragments implanted into mPGES-1(-/-) mice (WT→mPGES-1(-/-)), the growth of the implants was suppressed at days 14 and 28 after implantation, compared toWT→WT transplantation. An even greater degree of suppression was observed in mPGES-1(-/-) endometrial fragments implanted into mPGES-1(-/-) mice (mPGES-1(-/-)→mPGES-1(-/-)). After WT-WT implantation, mPGES-1 expression was localized at the border of the implanted endometrial tissues. Microvessel density, determined by CD31 immunostaining, was markedly suppressed in the mPGES-1(-/-) endometrial fragments implanted into mPGES-1(-/-) mice, with some suppression also observed in the mPGES-1(-/-)→WT and WT→mPGES-1(-/-) groups. The expression of vascular endothelial growth factor (VEGF-A) was significantly reduced in mPGES-1(-/-) endometrial tissues implanted into mPGES-1(-/-) mice at days 14 and 28, in comparison to the WT→WT group. These results suggested that mPGES-1 enhanced angiogenesis and growth of the endometrial implant, and indicate that mPGES-1 may be a good therapeutic target for endometriosis.