Endoglin Haploinsufficiency Promotes Fibroblast Accumulation during Wound Healing through Akt Activation

Accurate regulation of dermal fibroblast function plays a crucial role in wound healing. Many fibrotic diseases are characterized by a failure to conclude normal tissue repair and the persistence of fibroblasts inside lesions. In the present study we demonstrate that endoglin haploinsufficiency promotes fibroblast accumulation during wound healing. Moreover, scars from endoglin-heterozygous (Eng^+/−) mice show persisting fibroblasts 12 days after wounding, which could lead to a fibrotic scar. Endoglin haploinsufficiency results in increased proliferation and migration of primary cultured murine dermal fibroblasts (MDFs). Moreover, Eng^+/− MDF have diminished responses to apoptotic signals compared with control cells. Altogether, these modifications could explain the augmented presence of fibroblasts in Eng^+/− mice wounds. We demonstrate that endoglin expression regulates Akt phosphorylation and that PI3K inhibition abolishes the differences in proliferation between endoglin haploinsufficient and control cells. Finally, persistent fibroblasts in Eng^+/− mice wound co-localize with a greater degree of Akt phosphorylation. Thus, endoglin haploinsufficiency seems to promote fibroblast accumulation during wound healing through the activation of the PI3K/Akt pathway. These studies open new non-Smad signaling pathway for endoglin regulating fibroblast cell function during wound healing, as new therapeutic opportunities for the treatment of fibrotic wounds.     

Mucosal Healing and the Risk of Ischemic Heart Disease or Atrial Fibrillation in Patients with Celiac Disease; A Population-Based Study

Background

Patients with celiac disease (CD), characterized histologically by villous atrophy (VA) of the small intestine, have an increased risk of ischemic heart disease (IHD) and atrial fibrillation (AF), risks that persist for years after commencing the gluten-free diet. It is unknown whether persistent VA on follow-up biopsy, rather than mucosal healing, affects the risk of IHD or AF.

Methods

We identified patients with histologic evidence of CD diagnosed at all 28 pathology departments in Sweden. Among patients who underwent a follow-up small intestinal biopsy, we compared patients with persistent VA to those who showed histologic improvement, with regard to the development of IHD (angina pectoris or myocardial infarction) or AF.

Results

Among patients with CD and a follow-up biopsy (n = 7,440), the median age at follow-up biopsy was 25 years, with 1,063 (14%) patients who were ≥60 years at the time of follow-up biopsy. Some 196 patients developed IHD and 205 patients developed AF. After adjusting for age, gender, duration of CD, calendar period, and educational attainment, there was no significant effect of persistent VA on IHD (adjusted HR 0.97; 95%CI 0.73–1.30). Adjusting for diabetes had a negligible effect (adjusted HR 0.98; 95%CI 0.73–1.31). There was no significant association between persistent VA and the risk of AF (adjusted HR 0.98; 95%CI 0.74–1.30).

Conclusions

In this population-based study of patients with CD, persistent VA on follow-up biopsy was not associated with an increased risk of IHD or AF. Failed mucosal healing does not influence the risk of these cardiac events.     

Excisional Wound Healing Is Delayed in a Murine Model of Chronic Kidney Disease

Background

Approximately 15% of the United States population suffers from chronic kidney disease (CKD), often demonstrating an associated impairment in wound healing. This study outlines the development of a surgical murine model of CKD in order to investigate the mechanisms underlying this impairment.

Methods

CKD was induced in mice by partial cauterization of one kidney cortex and contralateral nephrectomy, modifying a previously published technique. After a minimum of 6-weeks, splinted, dorsal excisional wounds were created to permit assessment of wound healing parameters. Wounds were harvested on postoperative days (POD) 0, 3, 7, and 14 for histological, immunofluorescent, and quantitative PCR (qPCR).

Results

CKD mice exhibited deranged blood chemistry and hematology profiles, including profound uremia and anemia. Significant decreases in re-epithelialization and granulation tissue deposition rates were found in uremic mice wounds relative to controls. On immunofluorescent analysis, uremic mice demonstrated significant reductions in cellular proliferation (BrdU) and angiogenesis (CD31), with a concurrent increase in inflammation (CD45) as compared to controls. CKD mice also displayed differential expression of wound healing-related genes (VEGF, IL-1β, eNOS, iNOS) on qPCR.

Conclusions

These findings represent the first reported investigation of cutaneous healing in a CKD animal model. Ongoing studies of this significantly delayed wound healing phenotype include the establishment of renal failure model in diabetic strains to study the combined effects of CKD and diabetes.     

ZOUSH Ointment with the Properties of Antibacterial Moreover,Burn Wound Healing

International Journal of Peptide Research and Therapeutics - Pseudomonas aeruginosa is a third hospital infection agent, and it is the second essential factor in wound infections. Despite many...     

Angiopoietin-like 4 Interacts with Matrix Proteins to Modulate Wound Healing

A dynamic cell-matrix interaction is crucial for a rapid cellular response to changes in the environment. Appropriate cell behavior in response to the changing wound environment is required for efficient wound closure. However, the way in which wound keratinocytes modify the wound environment to coordinate with such cellular responses remains less studied. We demonstrated that angiopoietin-like 4 (ANGPTL4) produced by wound keratinocytes coordinates cell-matrix communication. ANGPTL4 interacts with vitronectin and fibronectin in the wound bed, delaying their proteolytic degradation by metalloproteinases. This interaction does not interfere with integrin-matrix protein recognition and directly affects cell-matrix communication by altering the availability of intact matrix proteins. These interactions stimulate integrin- focal adhesion kinase, 14-3-3, and PKC-mediated signaling pathways essential for effective wound healing. The deficiency of ANGPTL4 in mice delays wound re-epithelialization. Further analysis revealed that cell migration was impaired in the ANGPTL4-deficient keratinocytes. Altogether, the findings provide molecular insight into a novel control of wound healing via ANGPTL4-dependent regulation of cell-matrix communication. Given the known role of ANGPTL4 in glucose and lipid homeostasis, it is a prime therapeutic candidate for the treatment of diabetic wounds. It also underscores the importance of cell-matrix communication during angiogenesis and cancer metastasis.     

Salivary Microbiota and Metabolome Associated with Celiac Disease

This study aimed to investigate the salivary microbiota and metabolome of 13 children with celiac disease (CD) under a gluten-free diet (treated celiac disease [T-CD]). The same number of healthy children (HC) was used as controls. The salivary microbiota was analyzed by an integrated approach using culture-dependent and -independent methods. Metabolome analysis was carried out by gas chromatography-mass spectrometry–solid-phase microextraction. Compared to HC, the number of some cultivable bacterial groups (e.g., total anaerobes) significantly (P < 0.05) differed in the saliva samples of the T-CD children. As shown by community-level catabolic profiles, the highest Shannon''s diversity and substrate richness were found in HC. Pyrosequencing data showed the highest richness estimator and diversity index values for HC. Levels of Lachnospiraceae, Gemellaceae, and Streptococcus sanguinis were highest for the T-CD children. Streptococcus thermophilus levels were markedly decreased in T-CD children. The saliva of T-CD children showed the largest amount of Bacteroidetes (e.g., Porphyromonas sp., Porphyromonas endodontalis, and Prevotella nanceiensis), together with the smallest amount of Actinobacteria. T-CD children were also characterized by decreased levels of some Actinomyces species, Atopobium species, and Corynebacterium durum. Rothia mucilaginosa was the only Actinobacteria species found at the highest level in T-CD children. As shown by multivariate statistical analyses, the levels of organic volatile compounds markedly differentiated T-CD children. Some compounds (e.g., ethyl-acetate, nonanal, and 2-hexanone) were found to be associated with T-CD children. Correlations (false discovery rate [FDR], <0.05) were found between the relative abundances of bacteria and some volatile organic compounds (VOCs). The findings of this study indicated that CD is associated with oral dysbiosis that could affect the oral metabolome.     

Senescence,Wound Healing,and Cancer: the PAI-1 Connection

Prolonged propagation of primary diploid fibroblasts in culture activates an ageing process known as replicative senescence, which is considered to provide a barrier against oncogenic transformation. Remarkably, both cell autonomous tumor-suppressive and cell non-autonomous tumor-promoting effects of senescent cells have been reported. Recently, we described that the p53 target gene plasminogen activator inhibitor-1 (PAI-1) is an essential mediator of replicative senescence. PAI-1 antagonizes the protease urokinase-type plasminogen activator (uPA). Both are secreted factors and involved in heterotypic signaling processes such as wound healing, angiogenesis and metastasis. Both uPA and PAI-1 are expressed in senescent cells and their relative abundance controls proliferation downstream of p53. Here, we present data that the effects of PAI- 1 and uPA in the senescence response are not strictly cell autonomous. We discuss these findings in the context of the emerging roles of PAI-1 and uPA in heterotypic cellular signaling in senescence, wound healing and metastasis.     

Mathematical Modeling in Wound Healing,Bone Regeneration and Tissue Engineering

The processes of wound healing and bone regeneration and problems in tissue engineering have been an active area for mathematical modeling in the last decade. Here we review a selection of recent models which aim at deriving strategies for improved healing. In wound healing, the models have particularly focused on the inflammatory response in order to improve the healing of chronic wound. For bone regeneration, the mathematical models have been applied to design optimal and new treatment strategies for normal and specific cases of impaired fracture healing. For the field of tissue engineering, we focus on mathematical models that analyze the interplay between cells and their biochemical cues within the scaffold to ensure optimal nutrient transport and maximal tissue production. Finally, we briefly comment on numerical issues arising from simulations of these mathematical models.     

Thioredoxin Is Involved in Endothelial Cell Extracellular Transglutaminase 2 Activation Mediated by Celiac Disease Patient IgA

Purpose

To investigate the role of thioredoxin (TRX), a novel regulator of extracellular transglutaminase 2 (TG2), in celiac patients IgA (CD IgA) mediated TG2 enzymatic activation.

Methods

TG2 enzymatic activity was evaluated in endothelial cells (HUVECs) under different experimental conditions by ELISA and Western blotting. Extracellular TG2 expression was studied by ELISA and immunofluorescence. TRX was analysed by Western blotting and ELISA. Serum immunoglobulins class A from healthy subjects (H IgA) were used as controls. Extracellular TG2 enzymatic activity was inhibited by R281. PX12, a TRX inhibitor, was also employed in the present study.

Results

We have found that in HUVECs CD IgA is able to induce the activation of extracellular TG2 in a dose-dependent manner. Particularly, we noted that the extracellular modulation of TG2 activity mediated by CD IgA occurred only under reducing conditions, also needed to maintain antibody binding. Furthermore, CD IgA-treated HUVECs were characterized by a slightly augmented TG2 surface expression which was independent from extracellular TG2 activation. We also observed that HUVECs cultured in the presence of CD IgA evinced decreased TRX surface expression, coupled with increased secretion of the protein into the culture medium. Intriguingly, inhibition of TRX after CD IgA treatment was able to overcome most of the CD IgA-mediated effects including the TG2 extracellular transamidase activity.

Conclusions

Altogether our findings suggest that in endothelial cells CD IgA mediate the constitutive activation of extracellular TG2 by a mechanism involving the redox sensor protein TRX.     

Wound Healing Improvement with PHD-2 Silenced Fibroblasts in Diabetic Mice

Background

Hypoxia-inducible factor 1α is the central regulator of the hypoxia-induced response which results in the up-regulation of angiogenic factors. Its activity is under precise regulation of prolyl-hydroxylase domain 2. We hypothesized that PHD2 silenced fibroblasts would increase the expression of angiogenic factors, which might contribute to the improvement of the diabetic wound healing.

Materials and Methods

50 dB/db mice were employed and randomly assigned into five groups with 10 mice in each: group 1 (untreated cell), group 2 (PHD2 silenced cell), group 3 (L-mimosine treated cells), group 4 (nontargeting siRNA treated cells) and group 5 (sham control). Fibroblasts were cultivated from the dermis of mice in each group and treated with PHD2 targeting siRNA, L-mimosine and non-targeting siRNA respectively. A fraction of the fibroblasts were employed to verify the silencing rate of PHD2 after 48 hours. The autologous fibroblasts (treated and untreated) labeled with adenovirus-GFP were implanted around the wound (Φ6mm), which was created on the dorsum of each mouse. The status of wounds was recorded periodically. Ten days postoperatively, 3 mice from each group were sacrificed and wound tissues were harvested. Molecular biological examinations were performed to evaluate the expressions of cytokines. 28 days postoperatively, the remaining mice were sacrificed. Histological examinations were performed to evaluate the densities of GFP+ cells and capillaries.

Results

The expression of PHD2 reduced to 12.5%, and the expressions of HIF-1α and VEGFa increased significantly after PHD2 siRNA treatment. With the increasing expressions of HIF-1α and VEGFa, the time to wound closure in group 2 was less than 2 weeks. Increased numbers of GFP+ cells and capillaries were observed in group 2.

Conclusion

PHD2 siRNA treatment not only increased the expression of HIF1α and VEGFa, but also improved the fibroblast proliferation. These effects might contribute to the improvement of the diabetic wound healing.     

Combination of Adrenomedullin with Its Binding Protein Accelerates Cutaneous Wound Healing

Cutaneous wound continues to cause significant morbidity and mortality in the setting of diseases such as diabetes and cardiovascular diseases. Despite advances in wound care management, there is still an unmet medical need exists for efficient therapy for cutaneous wound. Combined treatment of adrenomedullin (AM) and its binding protein-1 (AMBP-1) is protective in various disease conditions. To examine the effect of the combination treatment of AM and AMBP-1 on cutaneous wound healing, full-thickness 2.0-cm diameter circular excision wounds were surgically created on the dorsum of rats, saline (vehicle) or AM/AMBP-1 (96/320 μg kg BW) was topically applied to the wound daily and wound size measured. At days 3, 7, and 14, skin samples were collected from the wound sites. AM/AMBP-1 treated group had significantly smaller wound surface area than the vehicle group over the 14-day time course. At day 3, AM/AMBP-1 promoted neutrophil infiltration (MPO), increased cytokine levels (IL-6 and TNF-α), angiogenesis (CD31, VEGF and TGFβ-1) and cell proliferation (Ki67). By day 7 and 14, AM/AMBP-1 treatment decreased MPO, followed by a rapid resolution of inflammation characterized by a decrease in cytokines. At the matured stage, AM/AMBP-1 treatment increased the alpha smooth muscle actin expression (mature blood vessels) and Masson-Trichrome staining (collagen deposition) along the granulation area, and increased MMP-9 and decreased MMP-2 mRNA expressions. TGFβ-1 mRNA levels in AM/AMBP-1 group were 5.3 times lower than those in the vehicle group. AM/AMBP-1 accelerated wound healing by promoting angiogenesis, collagen deposition and remodeling. Treatment also shortened the days to reach plateau for wound closure. Thus, AM/AMBP-1 may be further developed as a therapeutic for cutaneous wound healing.     

Hypocalcemia after Alendronate Therapy in a Patient with Celiac Disease

ObjectiveTo describe a patient with osteoporosis who was treated with alendronate and developed hypocalcemia, which ultimately led to the diagnosis of celiac sprue.MethodsWe present the clinical and laboratory findings in a patient with osteoporosis, in whom hypocalcemia developed after treatment with alendronate. This patient was subsequently diagnosed with celiac sprue. The pertinent literature regarding orally administered bisphosphonate-induced hypocalcemia is reviewed.ResultsA 79-year-old man who was diagnosed with osteoporosis was treated with alendronate. He was subsequently found to have asymptomatic hypocalcemia (serum calcium concentration, 8.3 mg/dL), which resolved after alendronate therapy was discontinued. He was then treated with calcium, vitamin D, and calcitonin nasal spray, which did not cause hypocalcemia. Because of his reduced bone density, however, he was subsequently referred for endocrine consultation. Evaluation at that time showed normal levels of serum calcium, phosphorus, creatinine, alkaline phosphatase, 25-hydroxyvitamin D, thyrotropin, and parathyroid hormone as well as 24-hour urine calcium excretion. An endomysial antibody titer was dramatically elevated. Upper endoscopy showed villous atrophy, and small bowel biopsy confirmed the presence of villous blunting and chronic inflammation, consistent with celiac sprue. He was treated with a gluten-free diet and then subsequently treated with orally administered risedronate, which he tolerated well without evidence of hypocalcemia.ConclusionTo the best of our knowledge, this is the first report of orally administered bisphosphonate-induced hypocalcemia, which subsequently led to the diagnosis of previously unrecognized, otherwise asymptomatic celiac sprue. Patients with unexplained hypocalcemia should be screened for celiac sprue, even in the absence of gastrointestinal symptoms. (Endocr Pract. 2007;13:403-407)     

Shock Wave Treatment Enhances Cell Proliferation and Improves Wound Healing by ATP Release-coupled Extracellular Signal-regulated Kinase (ERK) Activation

Shock wave treatment accelerates impaired wound healing in diverse clinical situations. However, the mechanisms underlying the beneficial effects of shock waves have not yet been fully revealed. Because cell proliferation is a major requirement in the wound healing cascade, we used in vitro studies and an in vivo wound healing model to study whether shock wave treatment influences proliferation by altering major extracellular factors and signaling pathways involved in cell proliferation. We identified extracellular ATP, released in an energy- and pulse number-dependent manner, as a trigger of the biological effects of shock wave treatment. Shock wave treatment induced ATP release, increased Erk1/2 and p38 MAPK activation, and enhanced proliferation in three different cell types (C3H10T1/2 murine mesenchymal progenitor cells, primary human adipose tissue-derived stem cells, and a human Jurkat T cell line) in vitro. Purinergic signaling-induced Erk1/2 activation was found to be essential for this proliferative effect, which was further confirmed by in vivo studies in a rat wound healing model where shock wave treatment induced proliferation and increased wound healing in an Erk1/2-dependent fashion. In summary, this report demonstrates that shock wave treatment triggers release of cellular ATP, which subsequently activates purinergic receptors and finally enhances proliferation in vitro and in vivo via downstream Erk1/2 signaling. In conclusion, our findings shed further light on the molecular mechanisms by which shock wave treatment exerts its beneficial effects. These findings could help to improve the clinical use of shock wave treatment for wound healing.