Transforming growth factor beta (TGF-beta) in inflammation: a cause and a cure

Tumor necrosis factor-α-treated human adipose-derived stem cells enhance inherent radiation tolerance and alleviate in vivo radiation-induced capsular contracture

INTRODUCTION

Post-mastectomy radiotherapy plays a crucial role in breast cancer treatment but can lead to an inflammatory response causing soft tissue damage, particularly radiation-induced capsular contracture (RICC), impacting breast reconstruction outcomes. Adipose-derived stem cells (ADSCs), known for their regenerative potential via paracrine capacity, exhibit inherent radiotolerance. The influence of tumor necrosis factor-alpha (TNF-α) on ADSCs has been reported to enhance the paracrine effect of ADSCs, promoting wound healing by modulating inflammatory responses.

OBJECTIVE

This study investigates the potential of TNF-α-treated human ADSCs (T-hASCs) on silicone implants to alleviate RICC, hypothesizing to enhance suppressive effects on RICC by modulating inflammatory responses in a radiation-exposed environment.

METHODS

In vitro, T-hASCs were cultured on various surfaces to assess viability after exposure to radiation up to 20 Gy. In vivo, T-hASC and non-TNF-α-treated hASC (C-hASCs)-coated membranes were implanted in mice before radiation exposure, and an evaluation of the RICC mitigation took place 4 and 8 weeks after implantation. In addition, the growth factors released from T-hASCs were assessed.

RESULTS

In vitro, hASCs displayed significant radiotolerance, maintaining consistent viability after exposure to 10 Gy. TNF-α treatment further enhanced radiation tolerance, as evidenced by significantly higher viability than C-hASCs at 20 Gy. In vivo, T-hASC-coated implants effectively suppressed RICC, reducing capsule thickness. T-hASCs exhibited remarkable modulation of the inflammatory response, suppressing M1 macrophage polarization while enhancing M2 polarization. The elevated secretion of vascular endothelial growth factor from T-hASCs is believed to induce macrophage polarization, potentially reducing RICC.

CONCLUSION

This study establishes T-hASCs as a promising strategy for ameliorating the adverse effects experienced by breast reconstruction patients after mastectomy and radiation therapy. The observed radiotolerance, anti-fibrotic effects, and immune modulation suggest the possibility of enhancing patient outcomes and quality of life. Further research and clinical trials are warranted for broader clinical uses.

Multi-System-Level Analysis with RNA-Seq on Pterygium Inflammation Discovers Association between Inflammatory Responses, Oxidative Stress, and Oxidative Phosphorylation

A pterygium is a common conjunctival degeneration and inflammatory condition. It grows onto the corneal surface or limbus, causing blurred vision and cosmetic issues. Ultraviolet is a well-known risk factor for the development of a pterygium, although its pathogenesis remains unclear, with only limited understanding of its hereditary basis. In this study, we collected RNA-seq from both pterygial tissues and conjunctival tissues (as controls) from six patients (a total of twelve biological samples) and retrieved publicly available data, including eight pterygium samples and eight controls. We investigated the intrinsic gene regulatory mechanisms closely linked to the inflammatory reactions of pterygiums and compared Asian (Korea) and the European (Germany) pterygiums using multiple analysis approaches from different perspectives. The increased expression of antioxidant genes in response to oxidative stress and DNA damage implies an association between these factors and pterygium development. Also, our comparative analysis revealed both similarities and differences between Asian and European pterygiums. The decrease in gene expressions involved in the three primary inflammatory signaling pathways-JAK/STAT, MAPK, and NF-kappa B signaling-suggests a connection between pathway dysfunction and pterygium development. We also observed relatively higher activity of autophagy and antioxidants in the Asian group, while the European group exhibited more pronounced stress responses against oxidative stress. These differences could potentially be necessitated by energy-associated pathways, specifically oxidative phosphorylation.

Correlation Between Proinflammatory Cytokine Expression and Clinical Data in Apical Granuloma

INTRODUCTION

This study was intended to evaluate the expression of inflammatory cytokines commonly secreted by CD4+ T cells (IL-2, IL-5, IL-17, TGF-β, TNF-α, and IFN-γ) in apical granulomas and correlate with the clinical conditions and time elapsed since root canal treatment.

METHODS

Eighteen biopsy specimens obtained by periradicular surgery of teeth with post-treatment apical periodontitis and diagnosed as apical granuloma were available from the oral pathology laboratory. Silanized slides containing paraffin sections were used for immunohistochemical reactions. Images were analyzed by using an optical microscopy and each slide was subdivided into 5 fields at high magnification.

RESULTS

IFN-γ and TGF-β were the cytokines with the highest expression levels. There were statistically significant differences when comparing IL-2 and IFN-γ (P < .05), and IL-2 and TGF-β (P < .05). Comparison between the detected cytokines and clinical data and time of treatment demonstrated significant correlation (P < .05) between lower expression of IL-2 and the presence of painful symptoms, absence of sinus tract, and treatments performed more than 4 years before. It was also possible to observe a significant correlation between lower expression of IL-5 and treatments performed less than 4 years before (P < .05).

CONCLUSION

IFN-γ and TGF-β were highly expressed in apical granulomas. However, only IL-2 and IL-5 levels were associated with clinical data and time since previous root canal treatment.

Intestinal macrophages in pathogenesis and treatment of gut leakage: current strategies and future perspectives

Macrophages play key roles in tissue homeostasis, defense, disease, and repair. Macrophages are highly plastic and exhibit distinct functional phenotypes based on micro-environmental stimuli. In spite of several advancements in understanding macrophage biology and their different functional phenotypes in various physiological and pathological conditions, currently available treatment strategies targeting macrophages are limited. Macrophages' high plasticity and diverse functional roles-including tissue injury and wound healing mechanisms-mark them as potential targets to mine for efficient therapeutics to treat diseases. Despite mounting evidence on association of gut leakage with several extraintestinal diseases, there is no targeted standard therapy to treat gut leakage. Therefore, there is an urgent need to develop therapeutic strategies to treat this condition. Macrophages are the cells that play the largest role in interacting with the gut microbiota in the intestinal compartment and exert their intended functions in injury and repair mechanisms. In this review, we have summarized the current knowledge on the origins and phenotypes of macrophages. The specific role of macrophages in intestinal barrier function, their role in tissue repair mechanisms, and their association with gut microbiota are discussed. In addition, currently available therapies and the putative tissue repair mediators of macrophages for treating microbiota dysbiosis induced gut leakage are also discussed. The overall aim of this review is to convey the intense need to screen for microbiota induced macrophage-released prorepair mediators, which could lead to the identification of potential candidates that could be developed for treating the leaky gut and associated diseases.

Role of Elevated Serum TGF-β1 and the Common Promoter TGFB1-509C/T Polymorphism in the Development and Progression of Primary Glial Tumors and Brain Metastases

Background and Objectives: The role of transforming growth factor-beta1 (TGF-β1) has been widely studied in the context of carcinogenesis. It has been involved in the pathogenesis of primary brain tumors or brain metastases due to its pleiotropic effects on immune regulation and tissue homeostasis. In line with recent findings, the aim of the current study was to examine the role of circulating TGF-β1 and the -509C/T functional polymorphism (rs1800469) in the TGFB1 gene promoter in the susceptibility and progression of primary brain tumors and brain metastases among patients from the Bulgarian population. Materials and Methods: Cases with a confirmed diagnosis were genotyped by the polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP). Serum TGF-β1 levels were determined by ELISA. Immunohistochemical evaluation of the expression of TGF-β1 and the TGF-β1 receptor-type II was conducted. Results: We observed that TGF-β1 serum levels correlate with the genotype and are sex-related. TGF-β1 serum levels were significantly elevated in patients compared to controls. Additionally, the T/T-genotype determined higher circulating levels of the cytokine. The same genotype determined the shorter median survival after surgery for the patients. The immunohistochemical analysis revealed a statistical tendency: cases expressing TGF-β1 in the cytoplasm had elevated levels of the cytokine in the serum compared to the negative cases. Conclusions: Overall, our results indicate a negative effect of the T-allele on the predisposition and prognosis of brain malignancies, and the genetically determined higher TGF-β1 serum levels might contribute to the worse prognosis and metastatic capacity of brain malignancies.

TGF-beta signal transduction: biology, function and therapy for diseases

The transforming growth factor beta (TGF-β) is a crucial cytokine that get increasing concern in recent years to treat human diseases. This signal controls multiple cellular responses during embryonic development and tissue homeostasis through canonical and/or noncanonical signaling pathways. Dysregulated TGF-β signal plays an essential role in contributing to fibrosis via promoting the extracellular matrix deposition, and tumor progression via inducing the epithelial-to-mesenchymal transition, immunosuppression, and neovascularization at the advanced stage of cancer. Besides, the dysregulation of TGF-beta signal also involves in other human diseases including anemia, inflammatory disease, wound healing and cardiovascular disease et al. Therefore, this signal is proposed to be a promising therapeutic target in these diseases. Recently, multiple strategies targeting TGF-β signals including neutralizing antibodies, ligand traps, small-molecule receptor kinase inhibitors targeting ligand-receptor signaling pathways, antisense oligonucleotides to disrupt the production of TGF-β at the transcriptional level, and vaccine are under evaluation of safety and efficacy for the forementioned diseases in clinical trials. Here, in this review, we firstly summarized the biology and function of TGF-β in physiological and pathological conditions, elaborated TGF-β associated signal transduction. And then, we analyzed the current advances in preclinical studies and clinical strategies targeting TGF-β signal transduction to treat diseases.

Mycobacterium tuberculosis: Implications of Ageing on Infection and Maintaining Protection in the Elderly

Several reports have suggested that ageing negatively affects the human body resulting in the alteration of various parameters important for sufficient immune health. Although, the breakdown of innate and adaptive immunity has been hypothesized to increase an individual's susceptibility to infections including Mycobacteria tuberculosis (M. tb), little research has been done to bridge this gap and understand the pathophysiology underlying how ageing increases the pathogenesis of M. tb infection. Our objective was to study research from a plethora of resources to better understand the pathogenesis of ageing and its link to the human immune system. To achieve this goal, this article explores how ageing decreases the collective T-cell immune response, reduces glutathione (GSH) production, over activates the mammalian target of rapamycin (mTORC1) pathway, inhibits autophagy and mitophagy, and alters various protective genes/transcription factors. Specifically highlighting how each of these pathways cripple an individual's immune system and increases their susceptibility from M. tb infection. Furthermore, research summarized in this article gives rise to an additional mechanism of susceptibility to M. tb infection which includes a potential defect in antigen presenting by dendritic cells rather than the T-cells response. Inflammaging has also been shown to play a role in the ageing of the immune system and can also potentially be a driving factor for increased susceptibility to M. tb infection in the elderly. In addition, this article features possible preventative strategies that could decrease infections like M. tb in this population. These strategies would need to be further explored and range from immunomodulators, like Everolimus to antioxidant supplementation through GSH intake. We have also proposed the need to research these therapies in conjunction with the administration of the BCG vaccine, especially in endemic populations, to better understand the risk contracting M. tb infection as well as ways to prevent infection in the first place.

Tibetan Medicine Shi-Wei-Gan-Ning-San Alleviates Carbon Tetrachloride-Induced Chronic Liver Injury by Inhibiting TGF-β1 in Wistar Rats

Background. Shi-Wei-Gan-Ning-San (SWGNS) is a classic Tibetan prescription, which has obvious clinical effects in the treatment of viral hepatitis, fatty liver, liver fibrosis, liver cirrhosis, liver cancer, and other liver injuries. However, animal studies and mechanism studies are still lacking. This study aimed to investigate its hepatoprotective efficacy and pharmacological mechanism in animal experiments. Methods. Chronic liver injury was induced by oral administration of carbon tetrachloride (CCl4) in Wistar rats for 13 weeks. SWGNS was administered orally to rats at doses of 235, 705, and 1410 mg/kg for 13 weeks. Blood samples were collected for biochemical, ELISA, and radioimmunoassay. Livers were harvested for H&E and immunohistochemical staining. The major constituents of SWGNS were analyzed by HPLC. In vitro experiments were used to explore the protective effect of Crocin on BRL-3A in the environment of H2O2. Results. SWGNS reversed weight loss is induced by CCl4. Serum assays showed that SWGNS reduced CCl4-induced alanine aminotransferase, aspartate aminotransferase, total bilirubin, and γ-glutamyltransferase levels and increased the total protein and albumin levels. Histopathological evaluation showed that SWGNS alleviated hepatic steatosis, fibrosis, and inflammation. Furthermore, SWNGS reduced CCl4-induced elevations of TGF-β1, hyaluronic acid, laminin, and collagen IV in serum and reduced the high expression of α-SMA in tissues. Moreover, Crocin I and II are the main components of SWGNS. Crocin attenuated the damaging effects of H2O2 on BRL-3A. Conclusions. In conclusion, SWGNS alleviated CCl4-induced chronic liver injury by inhibiting the TGF-β1 pathway. This plays an important role in promoting traditional Tibetan medicine in clinical practice.

Endothelial Cell TGF-β (Transforming Growth Factor-Beta) Signaling Regulates Venous Adaptive Remodeling to Improve Arteriovenous Fistula Patency

BACKGROUND

Arteriovenous fistulae (AVF) are the gold standard for vascular access for hemodialysis. Although the vein must thicken and dilate for successful hemodialysis, excessive wall thickness leads to stenosis causing AVF failure. Since TGF-β (transforming growth factor-beta) regulates ECM (extracellular matrix) deposition and smooth muscle cell (SMC) proliferation-critical components of wall thickness-we hypothesized that disruption of TGF-β signaling prevents excessive wall thickening during venous remodeling.

METHODS

A mouse aortocaval fistula model was used. SB431542-an inhibitor of TGF-β receptor I-was encapsulated in nanoparticles and applied to the AVF adventitia in C57BL/6J mice. Alternatively, AVFs were created in mice with conditional disruption of TGF-β receptors in either SMCs or endothelial cells. Doppler ultrasound was performed serially to confirm patency and to measure vessel diameters. AVFs were harvested at predetermined time points for histological and immunofluorescence analyses.

RESULTS

Inhibition of TGF-β signaling with SB431542-containing nanoparticles significantly reduced p-Smad2-positive cells in the AVF wall during the early maturation phase (days 7-21) and was associated with decreased AVF wall thickness that showed both decreased collagen density and decreased SMC proliferation. SMC-specific TGF-β signaling disruption decreased collagen density but not SMC proliferation or wall thickness. Endothelial cell-specific TGF-β signaling disruption decreased both collagen density and SMC proliferation in the AVF wall and was associated with reduced wall thickness, increased outward remodeling, and improved AVF patency.

CONCLUSIONS

Endothelial cell-targeted TGF-β inhibition may be a translational strategy to improve AVF patency.

The Role of Transforming Growth Factor Beta in Joint Homeostasis and Cartilage Regeneration

Transforming growth factor-beta (TGF-β) is an important regulator of joint homeostasis, of which dysregulation is closely associated with the development of osteoarthritis (OA). In normal conditions, its biological functions in a joint environment are joint protective, but it can be dramatically altered in different contexts, making its therapeutic application a challenge. However, with the deeper insights into the TGF-β functions, it has been proven that TGF-β augments cartilage regeneration by chondrocytes, and differentiates both the precursor cells of chondrocytes and stem cells into cartilage-generating chondrocytes. Following documentation of the therapeutic efficacy of chondrocytes augmented by TGF-β in the last decade, there is an ongoing phase III clinical trial examining the therapeutic efficacy of a mixture of allogeneic chondrocytes and TGF-β-overexpressing cells. To prepare cartilage-restoring chondrocytes from induced pluripotent stem cells (iPSCs), the stem cells are differentiated mainly using TGF-β with some other growth factors. Of note, clinical trials evaluating the therapeutic efficacy of iPSCs for OA are scheduled this year. Mesenchymal stromal stem cells (MSCs) have inherent limitations in that they differentiate into the osteochondral pathway, resulting in the production of poor-quality cartilage. Despite the established essential role of TGF-β in chondrogenic differentiation of MSCs, whether the coordinated use of TGF-β in MSC-based therapy for degenerated cartilage is effective is unknown. We herein reviewed the general characteristics and mechanism of action of TGF-β in a joint environment. Furthermore, we discussed the core interaction of TGF-β with principal cells of OA cell-based therapies, the chondrocytes, MSCs, and iPSCs. Impact Statement Transforming growth factor-beta (TGF-β) has been widely used as a core regulator to improve or formulate therapeutic regenerative cells for degenerative joints. It differentiates stem cells into chondrocytes and improves the chondrogenic potential of differentiated chondrocytes. Herein, we discussed the overall characteristics of TGF-β and reviewed the comprehension and utilization of TGF-β in cell-based therapy for degenerative joint disease.

Contribution of dipeptidyl peptidase 10 to airway dysfunction in patients with NSAID-exacerbated respiratory disease

BACKGROUND

Genetic variants of dipeptidyl peptidase 10 (DPP10) have been suggested to contribute to the development of NSAID-exacerbated respiratory disease (NERD). However, the mechanisms of how DPP10 contributes to NERD phenotypes remain unclear.

OBJECTIVE

To demonstrate the exact role of DPP10 in the pathogenesis of NERD.

METHODS

Patients with NERD (n = 110), those with aspirin-tolerant asthma (ATA, n = 130) and healthy control subjects (HCs, n = 80) were enrolled. Clinical characteristics were analysed according to the serum DPP10 levels in both NERD and ATA groups. The function of DPP10 in airway inflammation and remodelling was investigated with in vitro, ex vivo and in vivo experiments.

RESULTS

NERD patients had higher levels of serum DPP10 and TGF-β1 with lower FEV₁ than ATA patients or HCs (p < .05 for each). NERD patients with higher DPP10 levels had higher TGF-β1, but lower FEV₁ (p < .05 for all), whilst no differences were noted in ATA patients. Moreover, the seum DPP10 levels had a positive correlation with TGF-β1 (r = 0.384, p < .001), but a negative correlation with FEV₁ (r = -0.230, p = .016) in NERD patients. In in vitro studies, expression of DPP10 in airway epithelial cells was enhanced by TGF-β1 treatments. Furthermore, DPP10 was found to be produced from immune cells and this molecule induced the ERK phosphorylation in airway epithelial cells, which was suppressed by anti-DPP10 treatment. In asthmatic mouse models, increased levels of DPP10 in the serum and TGF-β1 in the bronchoalveolar lavage fluid were noted, which were suppressed by anti-DPP10 treatment. Moreover, anti-DPP10 treatment inhibited the ERK phosphorylation and extracellular matrix deposition in the lungs.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings suggest that increased production of DPP10 may contribute to TGF-β1-mediated airway dysfunction in NERD patients, where blockade of DPP10 may have potential benefits.

Noise-Induced Hearing Loss: Updates on Molecular Targets and Potential Interventions

Noise overexposure leads to hair cell loss, synaptic ribbon reduction, and auditory nerve deterioration, resulting in transient or permanent hearing loss depending on the exposure severity. Oxidative stress, inflammation, calcium overload, glutamate excitotoxicity, and energy metabolism disturbance are the main contributors to noise-induced hearing loss (NIHL) up to now. Gene variations are also identified as NIHL related. Glucocorticoid is the only approved medication for NIHL treatment. New pharmaceuticals targeting oxidative stress, inflammation, or noise-induced neuropathy are emerging, highlighted by the nanoparticle-based drug delivery system. Given the complexity of the pathogenesis behind NIHL, deeper and more comprehensive studies still need to be fulfilled.

Mutual inter-regulation between iNOS and TGF-β1: Possible molecular and cellular mechanisms of iNOS in wound healing

Abnormal wound healing with excessive scarring is a major health problem with socioeconomic and psychological impacts. In human, chronic wounds and scarring are associated with upregulation of the inducible nitric oxide synthase (iNOS). Recently, we have shown physiological regulation of iNOS in wound healing. Here, we sought to investigate the possible mechanistic role of iNOS in wound healing using biochemical and immunohistochemical assays. We found: (a) iNOS is the main source of wound nitric oxide (NO), (b) NOS inhibition in the wound, downregulated iNOS protein, mRNA and enzymatic activity, and reduced wound NO, and (c) iNOS inhibition resulted in delayed healing at early time points, and excessive scarring at late time points. Furthermore, molecular and cellular analysis of the wound showed that iNOS inhibition significantly (P < 0.05) increased TGF-β1 mRNA and protein levels, fibroblasts and collagen deposition. These latter findings suggest that iNOS might be exerting its action in the wound by signaling through TGF-β1 that activates wound fibroblasts to produce excessive collagen. Our current findings provide further support that iNOS is crucial for physiological wound healing, and suggest that dysregulation of iNOS during the inflammatory phase impairs healing, and results in disfiguring post-healing scarring. Thus, the mutual feedback regulation between iNOS and TGF-β1 at the gene, protein and functional levels might be the mechanism through which iNOS regulates the healing. Monitoring and maintenance of wound NO levels might be important for healing and avoiding long-term complications in susceptible people including patients with diabetic wounds, venous ulcers or keloid prone.

Pro-Fibrotic CD26-Positive Fibroblasts Are Present in Greater Abundance in Breast Capsule Tissue of Irradiated Breasts

BACKGROUND

Breast capsular contracture is a major problem following implant-based breast reconstruction, particularly in the setting of radiation therapy. Recent work has identified a fibrogenic fibroblast subpopulation characterized by CD26 surface marker expression.

OBJECTIVES

This work aimed to investigate the role of CD26-positive fibroblasts in the formation of breast implant capsules following radiation therapy.

METHODS

Breast capsule specimens were obtained from irradiated and nonirradiated breasts of 10 patients following bilateral mastectomy and unilateral irradiation at the time of expander-implant exchange, under institutional review board approval. Specimens were processed for hematoxylin and eosin staining as well as for immunohistochemistry and fluorescence activated cell sorting for CD26-positive fibroblasts. Expression of fibrotic genes and production of collagen were compared between CD26-positive, CD26-negative, and unsorted fibroblasts.

RESULTS

Capsule specimens from irradiated breast tissue were thicker and had greater CD26-postive cells on immunofluorescence imaging and on fluorescence activated cell sorting analysis than did capsule specimens from the nonirradiated breast. Compared with CD26-negative fibroblasts, CD26-positive fibroblasts produced more collagen and had increased expression of the profibrotic genes IL8, TGF-β1, COL1A1, and TIMP4.

CONCLUSIONS

CD26-positive fibroblasts were found in a significantly greater abundance in capsules of irradiated compared with nonirradiated breasts and demonstrated greater fibrotic potential. This fibrogenic fibroblast subpopulation may play an important role in the development of capsular contracture following irradiation, and its targeted depletion or moderation may represent a potential therapeutic option.

LEVEL OF EVIDENCE: 2

Muscle-strain injury exudate favors acute tissue healing and prolonged connective tissue formation in humans

Traumatic strain injury in skeletal muscle is often associated with fluid accumulation at the site of rupture, but the role of this injury exudate (EX) in cellular responses and healing is unknown. We aimed to characterize the EX sampled from human hamstring or calf muscles following a strain injury (n = 12). The cytokine and growth-factor profile, gene expression, and transcriptome analysis of EX-derived cells were compared with blood taken simultaneously from the same individuals. Cellular responses to the EX were tested in 3-dimensional (3D) culture based on primary human fibroblasts and myoblasts isolated from hamstring muscles. The EX contained a highly proinflammatory profile with a substantial expression of angiogenic factors. The proinflammatory profile was present in samples taken early postinjury and in samples aspirated several weeks postinjury, suggesting persistent inflammation. Cells derived from the EX demonstrated an increased expression of fibrogenic, adipogenic, and angiogenesis-related genes in comparison with blood cells. The injury EX stimulated fibroblast proliferation 2-fold compared with plasma, whereas such an effect was not seen for myoblasts. Finally, in 3D cell culture, the EX induced an up-regulation of connective tissue-related genes. In summary, EX formation following a muscle-strain injury stimulates fibroblast proliferation and the synthesis of connective tissue in fibroblasts. This suggests that the EX promotes an acute tissue-healing response but potentially also contributes to the formation of fibrotic tissue in the later phases of tissue repair.-Bayer, M. L., Bang, L., Hoegberget-Kalisz, M., Svensson, R. B., Olesen, J. L., Karlsson, M. M., Schjerling, P., Hellsten, Y., Hoier, B., Magnusson, S. P., Kjaer, M. Muscle-strain injury exudate favors acute tissue healing and prolonged connective tissue formation in humans.

Silicone breast implant modification review: overcoming capsular contracture

Background

Silicone implants are biomaterials that are frequently used in the medical industry due to their physiological inertness and low toxicity. However, capsular contracture remains a concern in long-term transplantation. To date, several studies have been conducted to overcome this problem. This review summarizes and explores these trends.

Main body

First, we examined the overall foreign body response from initial inflammation to fibrosis capsule formation in detail and introduced various studies to overcome capsular contracture. Secondly, we introduced that the main research approaches are to inhibit fibrosis with anti-inflammatory drugs or antibiotics, to control the topography of the surface of silicone implants, and to administer plasma treatment. Each study examined aspects of the various mechanisms by which capsular contracture could occur, and addressed the effects of inhibiting fibrosis.

Conclusion

This review introduces various silicone surface modification methods to date and examines their limitations. This review will help identify new directions in inhibiting the fibrosis of silicone implants.

Thermogel Loaded with Low-Dose Paclitaxel as a Facile Coating to Alleviate Periprosthetic Fibrous Capsule Formation

Medical-grade silicones as implants have been utilized for decades. However, the postoperative complications, such as capsular formation and contracture, have not yet been fully controlled and resolved. The aim of the present study is to elucidate whether the capsular formation can be alleviated by local and sustained delivery of low-dose paclitaxel (PTX) during the critical phase after the insertion of silicone implants. A biocompatible and thermogelling poly(lactic acid- co-glycolic acid)- b-poly(ethylene glycol)- b-poly(lactic acid- co-glycolic acid) triblock copolymer was synthesized by us. The micelles formed by the amphiphilic polymers in water could act as a reservoir for the solubilization of PTX, a very hydrophobic drug. The concentrated polymer aqueous solution containing PTX exhibited a sol-gel transition upon heating and formed a thermogel depot at body temperature. In vitro release tests demonstrated that the entrapped microgram-level PTX displayed a sustained release manner up to 57 days without a significant initial burst effect. Customized silicone implants coated with the PTX-loaded thermogels at various drug concentrations were inserted into the pockets of the subpanniculus carnosus plane of rats. The histological observations performed 1 month postoperation showed that the sustained release of PTX with an appropriate dose significantly reduced the peri-implant capsule thickness, production and deposition of collagen, and expression of contracture-mediating factors compared with bare silicone implants. More importantly, such an optimum dose had an excellent repeatability for the suppression of the capsular formation. Therefore, this study provides a strategic foothold regarding the sustained release of low-dose PTX to alleviate fibrotic capsule formation after implantation, and the microgram-level PTX-loaded thermogel holds great potential as an "all-purpose antifibrosis coating" for veiling the surfaces of various implantable medical devices.

Periostin Promotes Fibroblast Migration and Inhibits Muscle Repair After Skeletal Muscle Injury

BACKGROUND

Skeletal muscle injury (SMI) can cause physical disability due to insufficient recovery of the muscle. The development of muscle fibrosis after SMI has been widely regarded as a principal cause of this failure to recover. Periostin (Postn) exacerbates tissue fibrosis in various organs. We investigated whether Postn is involved in the pathophysiology after SMI.

METHODS

Partial laceration injuries of the gastrocnemius were created in wild-type (WT) and Postn knockout (Postn) mice. We examined the expression of the Postn gene before and after SMI. Regeneration and fibrosis of skeletal muscle were evaluated by histological analyses, and recovery of muscle strength was measured by physiological testing. Immunohistochemistry was used to examine the number and proliferative potential of infiltrating fibroblasts in injured muscle. A trans-well migration assay was used to assess the migration capability of fibroblasts. Control immunoglobulin G (IgG) or Postn-neutralizing antibody (Postn-nAb) was injected into injured muscle at 7 and 14 days after injury (dpi). We evaluated the effects of Postn-nAb on muscle repair after SMI.

RESULTS

The expression of Postn was dramatically upregulated after SMI. Compared with WT mice, Postn mice had improved muscle recovery and attenuated fibrosis as well as a significantly reduced number of infiltrating fibroblasts. The proliferative potential of these fibroblasts in WT and Postn mice was comparable at 14 dpi; however, the migration capability of fibroblasts was significantly enhanced in the presence of Postn (mean, 258%; 95% confidence interval, 183% to 334%). Moreover, the administration of Postn-nAb inhibited fibroblast infiltration and promoted muscle repair after SMI.

CONCLUSIONS

Postn exacerbates fibrotic scar formation through the promotion of fibroblast migration into injured muscle after SMI. Treatment with Postn-nAb is effective for attenuating fibrosis and improving muscle recovery after SMI.

CLINICAL RELEVANCE

Our findings may provide a potential therapeutic strategy to enhance muscle repair and functional recovery after SMI.

Dual surface modification of PDMS-based silicone implants to suppress capsular contracture

In this study, we report a new physicochemical surface on poly(dimethylsiloxane) (PDMS)-based silicone implants in an effort to minimize capsular contracture. Two different surface modification strategies, namely, microtexturing as a physical cue and multilayer coating as a chemical cue, were combined to achieve synergistic effects. The deposition of uniformly sized microparticles onto uncured PDMS surfaces and the subsequent removal after curing generated microtextured surfaces with concave hemisphere micropatterns. The size of the individual micropattern was controlled by the microparticle size. Micropatterns of three different sizes (37.16, 70.22, and 97.64 μm) smaller than 100 μm were produced for potential application to smooth and round-shaped breast implants. The PDMS surface was further chemically modified by layer-by-layer (LbL) deposition of poly-l-lysine and hyaluronic acid. Short-term in vitro experiments demonstrated that all the PDMS samples were cytocompatible. However, lower expression of TGF-β and α-SMA, the major profibrotic cytokine and myofibroblast marker, respectively, was observed in only multilayer-coated PDMS samples with larger size micropatterns (70.22 and 97.64 μm), thereby confirming the synergistic effects of physical and chemical cues. An in vivo study conducted for 8 weeks after implantation in rats also indicated that PDMS samples with larger size micropatterns and multilayer coating most effectively inhibited capsular contracture based on analyses of tissue inflammation, number of macrophage, fibroblast and myofibroblast, TGF-β expression, collagen density, and capsule thickness.

STATEMENT OF SIGNIFICANCE

Although poly(dimethylsiloxane) (PDMS)-based silicone implants have been widely used for various applications including breast implants, they usually cause typical side effects called as capsular contracture. Prior studies have shown that microtexturing and surface coating could reduce capsular contracture. However, previous methods are limited in their scope for application, and it is difficult to obtain FDA approval because of the large and nonuniform size of the microtexture as well as the use of toxic chemical components. Herein, those issues could be addressed by creating a microtexture of size less than 100 m, with a narrow size distribution and using layer-by-layer deposition of a biocompatible polymer without using any toxic compounds. Furthermore, this is the first attempt to combine microtexture with multilayer coating to obtain synergetic effects in minimizing the capsular contracture.

TGF-β1 affinity peptides incorporated within a chitosan sponge scaffold can significantly enhance cartilage regeneration

Scaffold incorporated with affinity peptides can efficiently promote cartilage regeneration without exogenous addition of growth factors and cells.

Transforming Growth Factor Beta is regulated by a Glucocorticoid-Dependent Mechanism in Denervation Mouse Bone

Bone growth and remodeling is inhibited by denervation in adults and children, resulting in alterations of linear growth and bone mass and increased risk for osteoporosis and pathologic fractures. Transforming growth factor beta (TGF-β) isoforms are a key group of growth factors that enhance bone formation. To explore the relation between denervation-induced reduction of bone formation and TGF-β gene expression, we measured mRNA levels of TGF-β in denervation mouse bone and found decreased mRNA levels of TGF-β1, TGF-β2 and TGF-β3. These changes were accompanied by diminishing weight loss, bone mineral density (BMD), trabecular thickness, trabecular separation and trabecular number of femur and lumbar, serum osteocalcin, total calcium, intact parathyroid hormone, and increased serum C telopeptide. Recombinant human TGF-β1 (rhTGF-β1) prevented denervation-induced reduction of BMD further supporting our hypothesis that denervation-induced reduction of bone formation is a result of inhibition of TGF-β gene expression. In addition, antiprogestins RU 38486 blunted the denervation-induced decrease in mRNA levels of TGF-β group, while dexamethasone (DEX) decreased TGF-β group mRNA levels in normal mice. Furthermore, the denervated-mice exhibited a threefold increase in plasma corticosterone. These results suggest that denervation-induced reduction of bone formation may be regulated by glucocorticoids via inhibition of TGF-β gene expression at least in part.

Anti-inflammatory Mechanisms Triggered by Apoptotic Cells during Their Clearance

In the human body, billions of cells die by apoptosis every day. The subsequent clearance of apoptotic cells by phagocytosis is normally efficient enough to prevent secondary necrosis and the consequent release of cell contents that would induce inflammation and trigger autoimmunity. In addition, apoptotic cells generally induce an anti-inflammatory response, thus removal of apoptotic cells is usually immunologically silent. Since the first discovery that uptake of apoptotic cells leads to transforming growth factor (TGF)-β and interleukin (IL)-10 release by engulfing macrophages, numerous anti-inflammatory mechanisms triggered by apoptotic cells have been discovered, including release of anti-inflammatory molecules from the apoptotic cells, triggering immediate anti-inflammatory signaling pathways by apoptotic cell surface molecules via phagocyte receptors, activating phagocyte nuclear receptors following uptake and inducing the production of anti-inflammatory soluble mediators by phagocytes that may act via paracrine or autocrine mechanisms to amplify and preserve the anti-inflammatory state. Here, we summarize our present knowledge about how these anti-inflammatory mechanisms operate during the clearance of apoptotic cells.

Targeting TGF-β Mediated SMAD Signaling for the Prevention of Fibrosis

Fibrosis occurs when there is an imbalance in extracellular matrix (ECM) deposition and degradation. Excessive ECM deposition results in scarring and thickening of the affected tissue, and interferes with tissue and organ homeostasis – mimicking an exaggerated “wound healing” response. Many transforming growth factor-β (TGF-β) ligands are potent drivers of ECM deposition, and additionally, have a natural affinity for the ECM, creating a concentrated pool of pro-fibrotic factors at the site of injury. Consequently, TGF-β ligands are upregulated in many human fibrotic conditions and, as such, are attractive targets for fibrosis therapy. Here, we will discuss the contribution of TGF-β proteins in the pathogenesis of fibrosis, and promising anti-fibrotic approaches that target TGF-β ligands.

Labor prediction based on the expression patterns of multiple genes related to cervical maturation in human term pregnancy

PROBLEM

This study explored the possibility of evaluating cervical maturation using swabbed cervical cell samples at term pregnancy, and aimed to develop a novel approach to predict labor onset.

METHOD OF STUDY

Women with uncomplicated pregnancies (n=117 from 62 women at term pregnancy) were recruited. Messenger RNA expression levels of cervical cells for ten genes were quantified by qPCR. Principal component analysis (PCA) was conducted, and principal components that significantly contributed to the prediction of days to delivery were determined.

RESULTS

PCA demonstrated that 76% of the expression information from the ten genes can be represented by three principal components (PC1-3). By the multiple regression analysis, PC2 and Bishop score but not PC1 or PC3 were significant variables in the prediction of days to delivery.

CONCLUSION

These findings support the concurrent assessment of multiple gene activities in cervical cells as a promising approach to predict the initiation of labor.

Prolonged, acute suppression of cysteinyl leukotriene to reduce capsular contracture around silicone implants

We hypothesize that periodically early, local suppression of cysteinyl leukotrienes (CysLTs), which are potent inflammatory mediators, can reduce the fibrotic capsular contracture around silicone implants. We tested this hypothesis with the silicone implants enabled with the sustained release of montelukast, a CysLT receptor antagonist, for 3 and 15days. In this work, we inserted each of the distinct implants into the pocket of the subpanniculus carnosus plane of living rats and performed histological and immunofluorescent (IF) analyses of the tissues biopsied at predetermined periods for 12weeks after implant insertion. The implants with montelukast exhibited significantly reduced polymorphonuclear leukocytes (i.e., PMNs), implying a concurrent reduction of CysLT. This effect was more prominent after long-term local montelukast exposure. Thus, fewer fibroblasts were recruited, thereby reducing transforming growth factor (TGF)-β and myofibroblasts in the tissue around the implant. Therefore, the fibrotic capsule formation, which was assessed using the capsule thickness and collagen density, decreased along with the myofibroblasts. Additionally, the tissue biopsied at the experimental end point exhibited significantly decreased mechanical stiffness.

STATEMENT OF SIGNIFICANCE

Capsular contracture is troublesome, making the tissues hardened around the silicone implant. This causes serious pain and discomfort to the patients, often leading to secondary surgery for implant replacement. To resolve this, we suggest a strategy of long-term, local suppression of cysteinyl leukotriene, an important mediator present during inflammation. For this, we propose a silicone implant abled to release a drug, montelukast, in a sustained manner. We tested our drug-release implant in living animals, which exhibited a significant decrease in capsule formation compared with the intact silicone implant. Therefore, we conclude that the sustained release of montelukast at the local insertion site represents a promising way to reduce capsular contracture around silicone implants.

The role of TGF-β1 during skeletal muscle regeneration

The injury of adult skeletal muscle initiates series of well-coordinated events that lead to the efficient repair of the damaged tissue. Any disturbances during muscle myolysis or reconstruction may result in the unsuccessful regeneration, characterised by strong inflammatory response and formation of connective tissue, that is, fibrosis. The switch between proper regeneration of skeletal muscle and development of fibrosis is controlled by various factors. Amongst them are those belonging to the transforming growth factor β family. One of the TGF-β family members is TGF-β1, a multifunctional cytokine involved in the regulation of muscle repair via satellite cells activation, connective tissue formation, as well as regulation of the immune response intensity. Here, we present the role of TGF-β1 in myogenic differentiation and muscle repair. The understanding of the mechanisms controlling these processes can contribute to the better understanding of skeletal muscle atrophy and diseases which consequence is fibrosis disrupting muscle function.

Cytokines in Platelet Concentrates

There are many cytokines that have been shown to increase in platelet concentrates during storage including: proinflammatory cytokines, chemokines, and transforming growth factor β. The concentrations of these cytokines can be variable depending on the method of platelet preparation, and the leukocyte and/or platelet concentration in the product. The clinical significance of these cytokines is questionable; however, clinical data suggests that tike proinflammatory cytokines may play an important role in causing febrile non-hemolytic transfusion reactions. The clinical data to support a causative role in these reactions includes: correlational studies where high concentrations of proinflammatory cytokines were associated with a higher frequency of reactions; observational studies showing that the transfusion of platelet products with high leukocyte counts have a higher likelihood of causing reactions; and, experimental studies where products with low cytokine levels seldom cause FNHTR. The clinical relevance of chemokines and other growth factors detected in platelet concentrates remains inconclusive.

Nanolayered siRNA delivery platforms for local silencing of CTGF reduce cutaneous scar contraction in third-degree burns

Wound healing is an incredibly complex biological process that often results in thickened collagen-enriched healed tissue called scar. Cutaneous scars lack many functional structures of the skin such as hair follicles, sweat glands, and papillae. The absence of these structures contributes to a number of the long-term morbidities of wound healing, including loss of function for tissues, increased risk of re-injury, and aesthetic complications. Scar formation is a pervasive factor in our daily lives; however, in the case of serious traumatic injury, scars can create long-lasting complications due to contraction and poor tissue remodeling. Within this report we target the expression of connective tissue growth factor (CTGF), a key mediator of TGFβ pro-fibrotic response in cutaneous wound healing, with controlled local delivery of RNA interference. Through this work we describe both a thorough in vitro analysis of nanolayer coated sutures for the controlled delivery of siRNA and its application to improve scar outcomes in a third-degree burn induced scar model in rats. We demonstrate that the knockdown of CTGF significantly altered the local expression of αSMA, TIMP1, and Col1a1, which are known to play roles in scar formation. The knockdown of CTGF within the healing burn wounds resulted in improved tissue remodeling, reduced scar contraction, and the regeneration of papillary structures within the healing tissue. This work adds support to a number of previous reports that indicate CTGF as a potential therapeutic target for fibrosis. Additionally, we believe that the controlled local delivery of siRNA from ultrathin polymer coatings described within this work is a promising approach in RNA interference that could be applied in developing improved cancer therapies, regenerative medicine, and fundamental scientific research.

TGF-β signalling in tumour associated macrophages

Tumour associated macrophages (TAM) represent an important component of tumour stroma. They develop under the influence of tumour microenvironment where transforming growth factor (TGF)β is frequently present. Activities of TAM regulated by TGFβ stimulate proliferation of tumour cells and lead to tumour immune escape. Despite high importance of TGFβ-induction of TAM activities till now our understanding of the mechanism of this induction is limited. We have previously developed a model of type 2 macrophages (M2) resembling certain properties of TAM. We established that in M2 TGFβRII is regulated on the level of subcellular sorting by glucocorticoids. Further studies revealed that in M2 with high levels of TGFβRII on the surface TGFβ activates not only its canonical Smad2/3-mediated signaling, but also Smad1/5-mediated signaling, what is rather typical for bone morphogenetic protein (BMP) stimulation. Complexity of macrophage populations, however, allows assumption that TGFβ signalling may function in different ways depending on the functional state of the cell. To understand the peculiarities of TGFβ signalling in human TAMs experimental systems using primary cells have to be developed and used together with the modern mathematical modelling approaches.

Topical Administration of Pirfenidone Increases Healing of Chronic Diabetic Foot Ulcers: A Randomized Crossover Study

Only 30 percent of chronic diabetic foot ulcers heal after 20 weeks of standard treatment. Pirfenidone is a drug with biological, anti-inflammatory, and antifibrotic effects. The aim of this study was to evaluate the effect of topical pirfenidone added to conventional treatment in noninfected chronic diabetic foot ulcers. This was a randomized crossover study. Group 1 received topical pirfenidone plus conventional treatment for 8 weeks; after this period, they were switched to receive conventional treatment only for 8 more weeks. In group 2, the order of the treatments was the opposite. The end points were complete ulcer healing and size reduction. Final data were obtained from 35 ulcers in 24 patients. Fifty-two percent of ulcers treated with pirfenidone healed before 8 weeks versus 14.3% treated with conventional treatment only (P = 0.025). Between 8 and 16 weeks, 30.8% ulcers that received pirfenidone healed versus 0% with conventional treatment (P = 0.081). By week 8, the reduction in ulcer size was 100% [73-100] with pirfenidone versus 57.5% with conventional treatment [28.9-74] (P = 0.011). By week 16, the reduction was 93% [42.7-100] with pirfenidone and 21.8% [8-77.5] with conventional treatment (P = 0.050). The addition of topical pirfenidone to conventional treatment significantly improves the healing of chronic diabetic noninfected foot ulcers.

Inflammatory Biomarkers in Refractory Congestive Heart Failure Patients Treated with Peritoneal Dialysis

Proinflammatory cytokines play a pathogenic role in congestive heart failure. In this study, the effect of peritoneal dialysis treatment on inflammatory cytokines levels in refractory congestive heart failure patients was investigated. During the treatment, the patients reached a well-tolerated edema-free state and demonstrated significant improvement in NYHA functional class. Brain natriuretic peptide decreased significantly after 3 months of treatment and remained stable at 6 months. C-reactive protein, a plasma marker of inflammation, decreased significantly following the treatment. Circulating inflammatory cytokines TNF-α and IL-6 decreased significantly after 3 months of peritoneal dialysis treatment and remained low at 6 months. The reduction in circulating inflammatory cytokines levels may be partly responsible for the efficacy of peritoneal dialysis for refractory congestive heart failure.

α7 Nicotinic Receptor Promotes the Neuroprotective Functions of Astrocytes against Oxaliplatin Neurotoxicity

Neuropathies are characterized by a complex response of the central nervous system to injuries. Glial cells are recruited to maintain neuronal homeostasis but dysregulated activation leads to pain signaling amplification and reduces the glial neuroprotective power. Recently, we highlighted the property of α7 nicotinic-acetylcholine-receptor (nAChR) agonists to relieve pain and induce neuroprotection simultaneously with a strong increase in astrocyte density. Aimed to study the role of α7 nAChR in the neuron-glia cross-talk, we treated primary rat neurons and astrocytes with the neurotoxic anticancer drug oxaliplatin evaluating the effect of the α7 nAChR agonist PNU-282987 (PNU). Oxaliplatin (1 μM, 48 h) reduced cell viability and increased caspase-3 activity of neuron monocultures without damaging astrocytes. In cocultures, astrocytes were not able to protect neurons by oxaliplatin even if glial cell metabolism was stimulated (pyruvate increase). On the contrary, the coculture incubation with 10 μM PNU improved neuron viability and inhibited apoptosis. In the absence of astrocytes, the protection disappeared. Furthermore, PNU promoted the release of the anti-inflammatory cytokine TGF-β1 and the expression of the glutamate-detoxifying enzyme glutamine synthetase. The α7 nAChR stimulation protects neurons from oxaliplatin toxicity through an astrocyte-mediated mechanism. α7 nAChR is suggested for recovering the homeostatic role of astrocytes.

Heritability of Transforming Growth Factor-β1 and Tumor Necrosis Factor-Receptor Type 1 Expression and Vitamin D Levels in Healthy Adolescent Twins

Cytokines and vitamin D both have a role in modulating the immune system, and are also potentially useful biomarkers in mental illnesses such as major depressive disorder (MDD) and schizophrenia. Studying the variability of cytokines and vitamin D in a healthy population sample may add to understanding the association between these biomarkers and mental illness. To assess genetic and environmental contributions to variation in circulating levels of cytokines and vitamin D (25-hydroxy vitamin D: 25(OH)D3), we analyzed data from a healthy adolescent twin cohort (mean age 16.2 years; standard deviation 0.25). Plasma cytokine measures were available for 400 individuals (85 MZ, 115 DZ pairs), dried blood spot sample vitamin D measures were available for 378 individuals (70 MZ, 118 DZ pairs). Heritability estimates were moderate but significant for the cytokines transforming growth factor-β1 (TGF-β1), 0.57 (95% CI 0.26–0.80) and tumor necrosis factor-receptor type 1 (TNFR1), 0.50 (95% CI 0.11–0.63) respectively. Measures of 25(OH)D3 were within normal range and heritability was estimated to be high (0.86, 95% CI 0.61–0.94). Assays of other cytokines did not generate meaningful results. These potential biomarkers may be useful in mental illness, with further research warranted in larger sample sizes. They may be particularly important in adolescents with mental illness where diagnostic uncertainty poses a significant clinical challenge.

The FYVE domain of Smad Anchor for Receptor Activation (SARA) is required to prevent skin carcinogenesis, but not in mouse development

Smad Anchor for Receptor Activation (SARA) has been reported as a critical role in TGF-β signal transduction by recruiting non-activated Smad2/3 to the TGF-β receptor and ensuring appropriate subcellular localization of the activated receptor-bound complex. However, controversies still exist in previous reports. In this study, we describe the expression of two SARA isoforms, SARA1 and SARA2, in mice and report the generation and characterization of SARA mutant mice with FYVE domain deletion. SARA mutant mice developed normally and showed no gross abnormalities. Further examination showed that the TGF-β signaling pathway was indeed altered in SARA mutant mice, with the downregulation of Smad2 protein expression. The decreasing expression of Smad2 was caused by enhancing Smurf2-mediated proteasome degradation pathway. However, the internalization of TGF-β receptors into the early endosome was not affected in SARA mutant mouse embryonic fibroblasts (MEFs). Moreover, the downregulation of Smad2 in SARA mutant MEFs was not sufficient to disrupt the diverse cellular biological functions of TGF-β signaling, including growth inhibition, apoptosis, senescence, and the epithelial-to-mesenchymal transition. Our results indicate that SARA is not involved in the activation process of TGF-β signal transduction. Using a two-stage skin chemical carcinogenesis assay, we found that the loss of SARA promoted skin tumor formation and malignant progression. Our data suggest a protective role of SARA in skin carcinogenesis.

TGF-β1 attenuates spinal neuroinflammation and the excitatory amino acid system in rats with neuropathic pain

Previous studies have reported that the intrathecal (i.t.) administration of transforming growth factor β1 (TGF-β1) prevents and reverses neuropathic pain. However, only limited information is available regarding the possible role and effects of spinal TGF-β1 in neuropathic pain. We aimed to investigate the antinociceptive effects of exogenous TGF-β1 on chronic constriction injury (CCI)-induced neuropathic pain in rats. We demonstrated that sciatic nerve injury caused a downregulation of endogenous TGF-β1 levels on the ipsilateral side of the lumbar spinal dorsal gray matter, and that the i.t. administration of TGF-β1 (.01-10 ng) significantly attenuated CCI-induced thermal hyperalgesia in neuropathic rats. TGF-β1 significantly inhibited CCI-induced spinal neuroinflammation, microglial and astrocytic activation, and upregulation of tumor necrosis factor-α. Moreover, i.t. TGF-β1 significantly attenuated the CCI-induced downregulation of glutamate transporter 1, the glutamate aspartate transporter, and the excitatory amino acid carrier 1 on the ipsilateral side. Furthermore, i.t. TGF-β1 significantly decreased the concentrations of 2 excitatory amino acids, aspartate and glutamate, in the spinal dialysates in CCI rats. In summary, we conclude that the mechanisms of the antinociceptive effects of i.t. TGF-β1 in neuropathy may include attenuation of spinal neuroinflammation, attenuation, or upregulation of glutamate transporter downregulation, and a decrease of spinal extracellular excitatory amino acids.

PERSPECTIVE

Clinically, medical treatment is usually initiated after the onset of intractable pain. Therefore, in the present study, i.t. TGF-β1 was designed to be administered 2 weeks after the establishment of CCI pain. Compared to the continuous TGF-β1 infusion mode, single-dose administration seems more convenient and practical to use.

TGF-β1 of no avail as prognostic marker in lyme disease

Background. Within the present in vivo study using the wild type mouse strains C3H/HeN and FVB/N it was intended to (1) measure TGF-β1 expression in the course of lyme disease, (2) examine the potential correlation of TGF-β1 expression with the clinical outcome of a Borrelia infection (with a focus on lyme arthritis), (3) develop a diagnostic tool based on the endogenous factor TGF-β1 to predict the progressivity of lyme disease.

Findings. In the course of lyme disease there was an increase in the serum content of active TGF-β1, which became significant 56 days post infection (p < 0.001). The serum concentration of total TGF-β1 in the course of infection initially decreased then rebounded and subsequently dropped again. Despite considerable individual variations in active TGF-β1 serum concentrations there were no identifiable dissimilarities in the clinical appearance of the mice. Likewise, no correlation could be seen between the serum content of active TGF-β1 and the severity of lyme arthritis of tibiotarsal joints of infected mice.

Conclusions. The present study clearly shows that TGF-β1 is of no avail as prognostic marker in lyme disease. Hence, the search for an endogenous predictive factor, which can be determined in an easy and reliable manner, remains open.

Cancer may be a pathway to cell survival under persistent hypoxia and elevated ROS: a model for solid-cancer initiation and early development

A number of proposals have been made in the past century regarding what may drive sporadic cancers to initiate and develop. Yet the problem remains largely unsolved as none of the proposals have been widely accepted as cancer-initiation drivers. We propose here a driver model for the initiation and early development of solid cancers associated with inflammation-induced chronic hypoxia and reactive oxygen species (ROS) accumulation. The model consists of five key elements: (i)human cells tend to have a substantial gap between ATP demand and supply during chronic hypoxia, which would inevitably lead to increased uptake of glucose and accumulation of its metabolites; (ii) the accumulation of these metabolites will cast mounting pressure on the cells and ultimately result in the production and export of hyaluronic acid; (iii) the exported hyaluronic acid will be degraded into fragments of various sizes, serving as tissue-repair signals, including signals for cell proliferation, cell survival and angiogenesis, which lead to the initial proliferation of the underlying cells; (iv) cell division provides an exit for the accumulated glucose metabolites using them towards macromolecular synthesis for the new cell, and hence alleviate the pressure from the metabolite accumulation; and (v) this process continues as long as the hypoxic condition persists. In tandem, genetic mutations may be selected to make cell divisions and hence survival more sustainable and efficient, also increasingly more uncontrollable. This model also applies to some hereditary cancers as their key mutations, such as BRCA for breast cancer, generally lead to increased ROS and ultimately to repression of mitochondrial activities and up-regulation of glycolysis, as well as hypoxia; hence the energy gap, glucose-metabolite accumulation, hyaluronic acid production and continuous cell division for survival.

Effects of growth factors on dental stem/progenitor cells

The primary goal of regenerative endodontics is to restore the vitality and functions of the dentin-pulp complex, as opposed to filing of the root canal with bioinert materials. A myriad of growth factors regulates multiple cellular functions including migration, proliferation, differentiation, and apoptosis of several cell types intimately involved in dentin-pulp regeneration. Recent work showing that growth factor delivery, without cell transplantation, can yield pulp-dentin-like tissues in vivo provides one of the tangible pathways for regenerative endodontics. This review synthesizes knowledge on many growth factors that are known or anticipated to be efficacious in dental pulp-dentin regeneration.

Understanding the neuroinflammatory response following concussion to develop treatment strategies

Mild traumatic brain injuries (mTBI) have been associated with long-term cognitive deficits relating to trauma-induced neurodegeneration. These long-term deficits include impaired memory and attention, changes in executive function, emotional instability, and sensorimotor deficits. Furthermore, individuals with concussions show a high co-morbidity with a host of psychiatric illnesses (e.g., depression, anxiety, addiction) and dementia. The neurological damage seen in mTBI patients is the result of the impact forces and mechanical injury, followed by a delayed neuroimmune response that can last hours, days, and even months after the injury. As part of the neuroimmune response, a cascade of pro- and anti-inflammatory cytokines are released and can be detected at the site of injury as well as subcortical, and often contralateral, regions. It has been suggested that the delayed neuroinflammatory response to concussions is more damaging then the initial impact itself. However, evidence exists for favorable consequences of cytokine production following traumatic brain injuries as well. In some cases, treatments that reduce the inflammatory response will also hinder the brain's intrinsic repair mechanisms. At present, there is no evidence-based pharmacological treatment for concussions in humans. The ability to treat concussions with drug therapy requires an in-depth understanding of the pathophysiological and neuroinflammatory changes that accompany concussive injuries. The use of neurotrophic factors [e.g., nerve growth factor (NGF)] and anti-inflammatory agents as an adjunct for the management of post-concussion symptomology will be explored in this review.

Central arterial aging and the epidemic of systolic hypertension and atherosclerosis

The structure and function of central arteries change throughout the lifetime of humans and animals. Since atherosclerosis and hypertension are prevalent in epidemic proportion among older persons, it is reasonable to hypothesize that specific mechanisms that underlie the arterial substrate that has been altered by an "aging process" are intimately linked to arterial diseases. Indeed, recent studies reveal a profile of arterial cell and matrix properties that emerges with advancing age within the grossly normal appearing aortic wall of both animals and humans. This profile is proinflammatory, and is manifested by intimal infiltration of fetal cells, increased production of angiotensin II (Ang II)-signaling pathway molecules, eg, matrix metalloproteases (MMPs), and monocyte chemoattractant protein (MCP-1), transforming growth factor B1 (TGF-beta1), enhanced activation of MMPs, TGF-beta, and NADPH oxidase, and reduced nitric oxide (NO) bioavailability. This profile is similar to that induced at younger ages in experimental animal models of hypertension or atherosclerosis. In humans, this proinflammatory state, which occurs in the absence of lipid deposition, appears to be attributable to aging, per se. Other well known human risk factors, eg, altered lipid metabolism, smoking, and lack of exercise, interact with this arterial substrate that is altered by aging and render the aging human artery fertile soil for facilitation of the initiation and progression of arterial diseases. Therapies to reduce or retard this age-associated proinflammatory state within the grossly appearing arterial wall central arteries, in addition to slowing arterial aging, per se, may have a substantial impact on the quintessential age-associated arterial diseases of our society.

Mnk Kinases in Cytokine Signaling and Regulation of Cytokine Responses

The kinases Mnk1 and Mnk2 are activated downstream of the p38 MAPK and MEK/ERK signaling pathways. Extensive work over the years has shown that these kinases control phosphorylation of the eukaryotic initiation factor 4E (eIF4E) and regulate engagement of other effector elements, including hnRNPA1 and PSF. Mnk kinases are ubiquitously expressed and play critical roles in signaling for various cytokine receptors, while there is emerging evidence that they have important functions as mediators of pro-inflammatory cytokine production. In this review the mechanisms of activation of MNK pathways by cytokine receptors are addressed and their roles in diverse cytokine-dependent biological processes are reviewed. The clinical-translational implications of such work and the relevance of future development of specific MNK inhibitors for the treatment of malignancies and auto-immune disorders are discussed.

Cytokines in muscle damage

Multiple cellular and molecular processes are rapidly activated following skeletal muscle damage to restore normal muscle structure and function. These processes typically involve an inflammatory response and potentially the consequent occurrence of secondary damage before their resolution and the completion of muscle repair or regeneration. The overall outcome of the inflammatory process is potentially divergent, with the induction of prolonged inflammation and further muscle damage, or its active termination and the promotion of muscle repair and regeneration. The final, detrimental, or beneficial effect of the inflammatory response on muscle repair is influenced by specific interactions between inflammatory and muscle cell-derived cytokines that act as positive and/or negative regulators to coordinate local and systemic inflammatory-related events and modulate muscle repair process. A crucial balance between proinflammatory and anti-inflammatory cytokines appears to attenuate an excessive inflammatory reaction, prevent the development of muscle fibrosis, and adequately promote the regenerative process. In this review, we address the interactive cytokine responses following muscle damage, in the context of induction and progression, or resolution of muscle inflammation and the promotion of muscle repair.

Mnk Kinases in Cytokine Signaling and Regulation of Cytokine Responses

The kinases Mnk1 and Mnk2 are activated downstream of the p38 MAPK and MEK/ERK signaling pathways. Extensive work over the years has shown that these kinases control phosphorylation of the eukaryotic initiation factor 4E (eIF4E) and regulate engagement of other effector elements, including hnRNPA1 and PSF. Mnk kinases are ubiquitously expressed and play critical roles in signaling for various cytokine receptors, while there is emerging evidence that they have important functions as mediators of pro-inflammatory cytokine production. In this review the mechanisms of activation of MNK pathways by cytokine receptors are addressed and their roles in diverse cytokine-dependent biological processes are reviewed. The clinical-translational implications of such work and the relevance of future development of specific MNK inhibitors for the treatment of malignancies and auto-immune disorders are discussed.

Small heat shock proteins induce a cerebral inflammatory reaction

More than 80% of Alzheimer's disease (AD) patients have some degree of cerebral amyloid angiopathy (CAA). In addition to arteries and veins, capillaries can also be affected. Capillary CAA (capCAA), rather than CAA in larger vessels, is associated with flame-like amyloid-beta (Aβ) deposits that may extend beyond the vessel wall and radiate into the neuropil, a phenomenon also known as "dyshoric angiopathy." Aβ deposits in AD, parenchymal as well as (cap)CAA and dyshoric angiopathy, are associated with a local inflammatory reaction, including activation of microglial cells and astrocytes that, among others, produce cytokines and reactive oxygen species. This neuroinflammatory reaction may account for at least part of the cognitive decline. In previous studies we observed that small heat shock proteins (sHsps) are associated with Aβ deposits in AD. In this study the molecular chaperones Hsp20, HspB8 and HspB2B3 were found to colocalize with CAA and capCAA in AD brains. In addition, Hsp20, HspB8 and HspB2B3 colocalized with intercellular adhesion molecule 1 (ICAM-1) in capCAA-associated dyshoric angiopathy. Furthermore, we demonstrated that Hsp20, HspB8 and HspB2B3 induced production of interleukin 8, soluble ICAM-1 and monocyte chemoattractant protein 1 by human leptomeningeal smooth muscle cells and human brain astrocytes in vitro and that Hsp27 inhibited production of transforming growth factor beta 1 and CD40 ligand. Our results suggest a central role for sHsps in the neuroinflammatory reaction in AD and CAA and thus in contributing to cognitive decline.