Rate Of Collagen Synthesis Research Articles

POSSIBLE ROLES OF ANTIOXIDANTS IN ROTATOR CUFF TENDINOPATHY

The rotator cuff tendinopathy is one of the most common shoulder problems leading to full-thickness rotator cuff tendon tear and, eventually, to degenerative arthritis. Recent research on rotator cuff tendon degeneration has focused on its relationship to cell death. The types of cell death known to be associated with rotator cuff tendon degeneration are apoptosis, necrosis, and autophagic cell death. The increased incidence of cell death in degenerative tendon tissue may affect the rates of collagen synthesis and repair, possibly weakening tendon tissue and increasing the risk of tendon rupture. The biomolecular mechanisms of the degenerative changes leading to apoptotic cell death in rotator cuff tenofibroblasts have been identified as oxidative-stress-related cascade mechanisms. Furthermore, apoptosis, necrosis, and autophagic cell death are all known to be mediated by oxidative stress, a condition in which ROS (reactive oxygen species) are overproduced. Lower levels of oxidative stress trigger apoptosis; higher levels mediate necrosis. Although the signaltransduction pathway leading to autophagy has not yet been fully established, ROS are known to be essential to autophagy. A neuronal theory regarding rotator cuff degeneration has been developed from the findings that glutamate, a neural transmitter, is present in increased concentrations in tendon tissues with tendinopathy and that it induces rat supraspinatus tendon cell death. Recent studies have reported that hypoxia involved in rotator cuff tendon degeneration. Because antioxidants are known to scavenge for intracellular ROS, some studies have been conducted to determine whether antioxidants can reduce cell death in rotator cuff tendon-origin fibroblasts. The first study reported that an antioxidant has the ability to reduce apoptosis in oxidative-stressed rotator cuff tenofibroblasts. The second study reported that antioxidants have both antiapoptotic effects and antinecrotic effects on rotator cuff tendon-origin fibroblasts exposed to an oxidative stimulus. The third study reported that an antioxidant has antiautophagic-cell-death effects on rotator cuff tendon-origin fibroblasts exposed to an oxidative stimulus. The fourth study reported that glutamate markedly increases cell death in rotator cuff tendonorigin fibroblasts. The glutamate-induced cytotoxic effects were reduced by an antioxidant, demonstrating its cytoprotective effects against glutamate-induced tenofibroblast cell death. The fifth study reported that hypoxia significantly increases intracellular ROS and apoptosis. The hypoxia-induced cytotoxic effects were markedly attenuated by antioxidants, demonstrating their cytoprotective effects against hypoxia-induced tenofibroblast cell death. In conclusion, antioxidants have cytoprotective effects on tenofibroblasts exposed in vitro to an oxidative stressor, a neurotransmitter, or hypoxia. These cytoprotective effects result from antiapoptotic, antinecrotic, and antiautophagic actions involving the inhibition of ROS formation. These findings suggest that antioxidants may have therapeutic potential for rotator cuff tendinopathy. Further studies must be conducted in order to apply these in vitro findings to clinical situations.

Seladelpar combined with complementary therapies improves fibrosis, inflammation, and liver injury in a mouse model of nonalcoholic steatohepatitis.

Seladelpar, a selective peroxisome proliferator-activated receptor δ (PPARδ) agonist, improves markers of hepatic injury in human liver diseases, but histological improvement of nonalcoholic steatohepatitis (NASH) and liver fibrosis has been challenging with any single agent. To discover how complementary agents could work with seladelpar to achieve optimal outcomes, this study evaluated a variety of therapeutics (alone and in combination) in a mouse model of NASH. Mice on a high-fat amylin liver NASH (AMLN) diet were treated for 12 wk with seladelpar, GLP-1-R (glucagon-like peptide-1 receptor) agonist liraglutide, apoptosis signal-regulating kinase 1 (ASK1) inhibitor selonsertib, farnesoid X receptor (FXR) agonist obeticholic acid, and with seladelpar in combination with liraglutide or selonsertib. Seladelpar treatment markedly improved plasma markers of liver function. Seladelpar alone or in combination resulted in stark reductions in liver fibrosis (hydroxyproline, new collagen synthesis rate, mRNA indices of fibrosis, and fibrosis staining) compared with vehicle and the other single agents. Robust reductions in liver steatosis were also observed. Seladelpar produced a reorganization of metabolic gene expression, particularly for those genes promoting peroxisomal and mitochondrial lipid oxidation. In summary, substantial improvements in NASH and NASH-induced fibrosis were observed with seladelpar alone and in combination with liraglutide in this model. Broad gene expression analysis suggests seladelpar should be effective in concert with diverse mechanisms of action.NEW & NOTEWORTHY NASH is a chronic, progressive, and increasingly problematic liver disease that has been resistant to treatment with individual therapeutics. In this study using a diet-induced mouse model of NASH, we found that the PPARδ agonist seladelpar reduced fibrosis and NASH pathology alone and in combinations with a GLP-1-R agonist (liraglutide) or an ASK1 inhibitor (selonsertib). Liver transcriptome analysis comparing each agent and coadministration suggests seladelpar should be effective in combination with a variety of therapeutics.

MicroRNA-499-5p inhibits transforming growth factor-β1-induced Smad2 signaling pathway and suppresses fibroblast proliferation and collagen synthesis in rat by targeting TGFβ-R1

BackgroundAtrial fibrosis has been recognized as a typical pathological change in atrial fibrillation. Although present evidence suggests that microRNA-499-5p (miR-499-5p) plays an important role in the development of atrial fibrosis, the specific mechanism is not fully understood. Therefore, this study attempted to assess the influence of miR-499-5p on atrial fibroblasts and explore the potential molecular mechanism.MethodsAtrial fibroblasts from sprague dawley rat were respectively transfected with miR-499-5p mimic, miR-499-5p negative control and miR-499-5p inhibitor, atrial fibroblasts without any treatment were also established. Cell counting kit-8 assay and transwell assay were used to detect the proliferation and migration of atrial fibroblasts in each group. Expressions of miR-499-5p, TGF-β1, smad2, α-SMA, collagen-I and TGFβ-R1 in mRNA and protein level were subsequently detected via quantitative real-time polymerase chain reaction and western blot. Furthermore, the prediction of the binding sites of miR-499-5p and TGFβ-R1 was performed via the bioinformatics online software TargetScan and verified by dual luciferase reporter.ResultsBy utilizing miR-499-5p-transfected atrial fibroblasts model, expression of miR-499-5p in the miR-499-5p mimic group was upregulated, while it was downregulated in the miR-499-5p inhibitor group. Upregulated miR-499-5p expression led to a significant decrease in the proliferative and migratory ability of cultured atrial fibroblasts, while downregulated miR-499-5p expression led to a significant increase in the proliferative and migratory ability of cultured atrial fibroblasts. Additionally, upregulated miR-499-5p expression made a significant rise in TGF-β1-induced mRNA and protein expression of TGF-β1, TGFβ-R1, smad2, α-SMA and collagen-I in atrial fibroblasts. Furthermore, results from the dual luciferase reporter conformed that miR-499-5p may repress TGFβ-R1 by binding the 3′UTR of TGFβ-R1 directly.ConclusionsmiR-499-5p is able to inhibit the activation of transforming growth factor β-induced Smad2 signaling and eventually suppressed the proliferation, migration and invasion of atrial fibroblasts and collagen synthesis by targeting TGFβ-R1.

Practical Review on Delayed Primary Closure: Basic Science and Clinical Applications.

Wound healing complications present a significant burden on both patients and health-care systems, and understanding wound healing principles is crucial across medical and surgical specialties to help mitigate such complications. One of these longstanding principles, specifically delayed primary closure (DPC), described as mechanically closing a wound after several days of secondary intention healing, lacks clear consensus on its definition, indications, and outcomes. This practical review examines wound healing fundamentals, focusing on DPC, its execution, indications, and comparative outcomes. A PubMed literature search was conducted to retrieve studies on DPC. Inclusion criteria included comparative studies assessing outcomes and complications between DPC and other closure techniques, as well as articles investigating DPC's underlying physiology. Twenty-three comparative studies met inclusion criteria. DPC wounds have significantly higher partial pressure of oxygen, higher blood flow, and higher rates of collagen synthesis and remodeling activity, all of which help explain DPC wounds' superior mechanical strength. DPC seems most beneficial in contaminated wounds, such as complicated appendectomies, postcardiac surgery wounds, and complicated abdominal wall reconstructions, where it has been associated with lower rates of surgical site infections. This practical review provides an evidence-based approach to DPC, its physiology, technique, and indications. Based on the existing literature, the authors recommend that DPC wounds should be dressed in saline/betadine soaks, changed and irrigated daily, with delayed closure lasting between 3 and 5 days or until the infection has resolved. The clearest indications for DPC are in the context of contaminated abdominal surgery and sternal wound dehiscence post cardiac surgery.

The regulatory mechanisms of proline and hydroxyproline metabolism: Recent advances in perspective.

For diverse human tumors, growth and metastasis are dependent on proline synthesis, but the mechanisms underlying this association are not clear. Proline incorporated into collagen is primarily synthesized from glutamine. Thus, rates of collagen synthesis are modulated by the enzymes of proline synthesis. On the other hand, the hydroxylation of collagen proline requires αKG, ascorbate and ferrous iron, substrates necessary for the epigenetic demethylation of DNA and histones. The metabolic relationship of proline and hydroxyproline degradation are initiated by distinct dehydrogenases but the respective oxidized products, P5C and OH-P5C are substrates for P5C Reductase and P5C Dehydrogenase allowing for mutual competition. This provides a model by which proline synthesis in cancer plays a role in reprogramming gene expression. The metabolism of proline and hydroxyproline are also linked to the HIF response to hypoxia. Hypoxia increased the expression of ALDH18A1, which is the limiting step in proline and collagen synthesis. Hydroxyproline increases levels of HIF-1α presumably by inhibiting its degradation. These new findings allow the suggestion that there is a regulatory axis from glutamine to proline and collagen synthesis, and the release of free hydroxyproline can feed back on the HIF pathway.

THE ACTIVATION OF THE DERMIS EXTRACELLULAR MATRIX SYNTHESIS AFTER THE THERMAL BURN

It is known that the healing of skin wounds of various etiologies is a multistage process characterized by certain intercellular interactions that affect the adhesion of dermal cells, their migration and differentiation. The modern strategy of tissue engineering mostly attracted for the use of the patient's own cells to create in vitro a vascularized extracellular matrix, which is characterized by the absence of exogenous material, which brings the regeneration process identity to the physiological one. The aim of this study was the morphological transformations of the dermis in the burn area using a biodegradable calcium-containing filler, which acts as a dynamic and multifunctional regulator of the cellular activity of the dermis. The study was performed on 30 laboratory outbred rats. All animals were given a third-degree burn, then the animals were divided into two groups: control and experimental. On the 14th day after the application of the burn, the rats of the experimental group were injected with an injectable implant preparation based on calcium hydroxyapatite «Radiesse». In the group of control animals, sterile saline was used. Biological material was taken at the time corresponding to 2 and 4 months. To assess the morphological state of the burn zone, histological sections of skin preparations were stained with hematoxylin and eosin, according to Mallory, Masson and Van Gieson. Collagen types I and III were also determined by immunohistochemistry. The data obtained suggest that the use of a calcium-containing filler is promising for skin regeneration after a burn and can provide an extracellular matrix of the dermis with a composition and architecture of a collagen network close to natural. Differentiated detection of type I and III collagens confirmed the activation of the rate of collagen synthesis by fibroblasts in both the dermis of the burn zone and in the implant zone by the end of the second month. The assessment of the tissue entropy index confirms the similarity of the structural organization as dermis of the natural as restored after the burn and the use of the preparation. The strategy proposed in the experiment, using the body's own cells to synthesize an extracellular matrix similar to the natural one, can be an alternative to existing methods of burn treatment.

17α-estradiol, a lifespan-extending compound, attenuates liver fibrosis by modulating collagen turnover rates in male mice.

Estrogen signaling is protective against chronic liver diseases, although men and a subset of women are contraindicated for chronic treatment with 17β-estradiol (17β-E2) or combination hormone replacement therapies. We sought to determine if 17α-estradiol (17α-E2), a naturally occurring diastereomer of 17β-E2, could attenuate liver fibrosis. We evaluated the effects of 17α-E2 treatment on collagen synthesis and degradation rates using tracer-based labeling approaches in male mice subjected to carbon tetrachloride (CCl4)-induced liver fibrosis. We also assessed the effects of 17α-E2 on markers of hepatic stellate cell (HSC) activation, collagen cross-linking, collagen degradation, and liver macrophage content and polarity. We found that 17α-E2 significantly reduced collagen synthesis rates and increased collagen degradation rates, which was mirrored by declines in transforming growth factor β1 (TGF-β1) and lysyl oxidase-like 2 (LOXL2) protein content in liver. These improvements were associated with increased matrix metalloproteinase 2 (MMP2) activity and suppressed stearoyl-coenzyme A desaturase 1 (SCD1) protein levels, the latter of which has been linked to the resolution of liver fibrosis. We also found that 17α-E2 increased liver fetuin-A protein, a strong inhibitor of TGF-β1 signaling, and reduced proinflammatory macrophage activation and cytokines expression in the liver. We conclude that 17α-E2 reduces fibrotic burden by suppressing HSC activation and enhancing collagen degradation mechanisms. Future studies will be needed to determine if 17α-E2 acts directly in hepatocytes, HSCs, and/or immune cells to elicit these benefits.

Review of human supraspinatus tendon mechanics. Part II: tendon healing response and characterization of tendon health.

Overuse injuries of the rotator cuff, particularly of the supraspinatus tendon (SST), are highly prevalent and debilitating in work, sport, and daily activities. Despite the clinical significance of these injuries, there remains a large degree of uncertainty regarding the pathophysiology of injury, optimal methods of nonoperative and operative repair, and how to adequately assess tendon injury and healing. The tendon response to fatigue damage resulting from overuse is different from that of acute rupture and results in either an adaptive (healing) or a maladaptive (degenerative) response. Factors associated with the degenerative response include increasing age, smoking, hypercholesterolemia, biological sex (variable by tendon), diabetes mellitus, and excessive load post fatigue damage. After injury, the average healing rate of tendon is approximately 1% per day and may be significantly influenced by biologic sex (females have lower collagen synthesis rates) and excessive load after damage. Although magnetic resonance imaging (MRI) is considered the gold standard in assessing acute tears as well as tendinopathic change in the SST, ultrasonography has proven to be a valuable tool to measure tendinopathic change in real time. Ultrasonography can determine multiple mechanical and structural parameters of the SST that are altered in fatigue loading. Thus, ultrasonography may be utilized to understand how these parameters change in response to SST overuse, and may aid in determining the activity level that places the SST at greater risk of rupture.

Pseudohypoxic HIF pathway activation dysregulates collagen structure-function in human lung fibrosis.

Extracellular matrix (ECM) stiffening with downstream activation of mechanosensitive pathways is strongly implicated in fibrosis. We previously reported that altered collagen nanoarchitecture is a key determinant of pathogenetic ECM structure-function in human fibrosis (Jones et al., 2018). Here, through human tissue, bioinformatic and ex vivo studies we provide evidence that hypoxia-inducible factor (HIF) pathway activation is a critical pathway for this process regardless of the oxygen status (pseudohypoxia). Whilst TGFβ increased the rate of fibrillar collagen synthesis, HIF pathway activation was required to dysregulate post-translational modification of fibrillar collagen, promoting pyridinoline cross-linking, altering collagen nanostructure, and increasing tissue stiffness. In vitro, knockdown of Factor Inhibiting HIF (FIH), which modulates HIF activity, or oxidative stress caused pseudohypoxic HIF activation in the normal fibroblasts. By contrast, endogenous FIH activity was reduced in fibroblasts from patients with lung fibrosis in association with significantly increased normoxic HIF pathway activation. In human lung fibrosis tissue, HIF-mediated signalling was increased at sites of active fibrogenesis whilst subpopulations of human lung fibrosis mesenchymal cells had increases in both HIF and oxidative stress scores. Our data demonstrate that oxidative stress can drive pseudohypoxic HIF pathway activation which is a critical regulator of pathogenetic collagen structure-function in fibrosis.

Increased Adipose Tissue Fibrogenesis, Not Impaired Expandability, Is Associated With Nonalcoholic Fatty Liver Disease.

It is proposed that impaired expansion of subcutaneous adipose tissue (SAT) and an increase in adipose tissue (AT) fibrosis causes ectopic lipid accumulation, insulin resistance (IR), and metabolically unhealthy obesity. We therefore evaluated whether a decrease in SAT expandability, assessed by measuring SAT lipogenesis (triglyceride [TG] production), and an increase in SAT fibrogenesis (collagen production) are associated with NAFLD and IR in persons with obesity. In vivo abdominal SAT lipogenesis and fibrogenesis, expression of SAT genes involved in extracellular matrix (ECM) formation, and insulin sensitivity were assessed in three groups of participants stratified by adiposity and intrahepatic TG (IHTG) content: (1) healthy lean with normal IHTG content (Lean-NL; n=12); (2) obese with normal IHTG content and normal glucose tolerance (Ob-NL; n=25); and (3) obese with NAFLD and abnormal glucose metabolism (Ob-NAFLD; n=25). Abdominal SAT TG synthesis rates were greater (P<0.05) in both the Ob-NL (65.9±4.6g/wk) and Ob-NAFLD groups (71.1±6.7g/wk) than the Lean-NL group (16.2±2.8g/wk) without a difference between the Ob-NL and Ob-NAFLD groups. Abdominal SAT collagen synthesis rate and the composite expression of genes encoding collagens progressively increased from the Lean-NL to the Ob-NL to the Ob-NAFLD groups and were greater in the Ob-NAFLD than the Ob-NL group (P<0.05). Composite expression of collagen genes was inversely correlated with both hepatic and whole-body insulin sensitivity (P<0.001). AT expandability is not impaired in persons with obesity and NAFLD. However, SAT fibrogenesis is greater in persons with obesity and NAFLD than in those with obesity and normal IHTG content, and is inversely correlated with both hepatic and whole-body insulin sensitivity.

A collagen extraction and deuterium oxide stable isotope tracer method for the quantification of bone collagen synthesis rates in vivo.

The development of safe and practical strategies to prevent weakening of bone tissue is vital, yet attempts to achieve this have been hindered by a lack of understanding of the short‐term (days‐weeks) physiology of bone collagen turnover. To address this, we have developed a method to quantify bone collagen synthesis in vivo, using deuterium oxide (D2O) tracer incorporation techniques combined with gas chromatography pyrolysis isotope‐ratio mass spectrometry (GC‐pyrolysis‐IRMS). Forty‐six male and female rats from a selectively bred model ingested D2O for 3 weeks. Femur diaphyses (FEM), tibia proximal (T‐PRO), and distal (T‐DIS) epiphyses‐metaphyses and tibia mid‐shaft diaphyses (T‐MID) were obtained from all rats after necropsy. After demineralisation, collagen proteins were isolated and hydrolysed and collagen fractional synthetic rates (FSRs) determined by incorporation of deuterium into protein‐bound alanine via GC‐pyrolysis‐IRMS. The collagen FSR for the FEM (0.131 ± 0.078%/day; 95% CI [0.106–0.156]) was greater than the FSR at T‐MID (0.055 ± 0.049%/day; 95% CI [0.040–0.070]; p < 0.001). The T‐PRO site had the highest FSR (0.203 ± 0.123%/day; 95% CI [0.166–0.241]) and T‐DIS the lowest (0.027 ± 0.015%/day; 95% CI [0.022–0.031]). The three tibial sites exhibited different FSRs (p < 0.001). Herein, we have developed a sensitive method to quantify in vivo bone collagen synthesis and identified site‐specific rates of synthesis, which could be applicable to studies of human bone collagen turnover.

Evaluation of Wound Healing Activity of Catharanthus Roseus Aqueous Extract in Adult Albino Rats

Use of plant extracts in the treatment of several ailments is a science known to the mankind since time immemorial. Yet, its popularity is limited owing to the lack of recorded experimental evidence to determine their potential health benefits. C. roseus is a traditional medicinal plant with over 100 identified alkaloids and several other phytochemicals known for various health promoting activities. The aim of the present study was to evaluate C. roseus aqueous extracts’ wound healing potential using incision, excision, and dead space wound models on healthy male albino rats. To assess this, the tissue breaking strength for incision wound model, percent epithelialization and period to complete epithelialization for excision wound model and granuloma break strength, dry weight, and hydroxyproline content for dead space wound model were evaluated after the treatment of the extract in comparison with the standard drug sucralfate. The results obtained demonstrated that the treatment of extract on the wound significantly enhanced tissue breaking strength and reduced the time required for complete epithelialization and was on par with that of the standard drug sucralfate. In the incision wound model, an elevated breaking strength was observed compared to that of the control group. Further, in the dead space wound model, the granuloma dry weight and breaking strength were remarkably elevated along with a concomitant increase in the hydroxyproline content suggesting the enhanced rate of wound contraction rate, collagen synthesis and lowered healing period. In conclusion, the present study demonstrates that C. roseus is effective in wound healing, as shown in the three wound models and thus, further studies to formulate this into a commercial product should be carried out.

In-vivo evaluation of Alginate-Pectin hydrogel film loaded with Simvastatin for diabetic wound healing in Streptozotocin-induced diabetic rats

Previously we developed and characterized a novel hydrogel film wound dressing containing Sodium Alginate and Pectin loaded with Simvastatin with multi-functional properties. This study investigated the in-vivo efficacy of the developed wound dressing on type I diabetic wound model. Experiments were performed on male Wistar rats for the period of 21-days. Animals developed diabetes after intraperitoneal injection (50 mg/kg) of Streptozotocin then randomly divided into different groups. On days 7, 14, and 21 of post-wounding, animals were euthanized and the wounds tissue were harvested for analysis. The wound healing rate, hematology and histological analysis, hydroxyproline assay, and Vascular Endothelial Growth Factor A measurements were noted. The results revealed that the wound dressing healed the wounded area significantly (p < 0.05) higher than the control after 21-day treatment and wound closure was ~99% without any adverse systemic reactions. Histological analysis qualitatively revealed an enhanced re-epithelialization and collagen deposition. Moreover, results also showed an improved rate of collagen synthesis and angiogenesis in the group treated with the hydrogel film loaded with Simvastatin. Thus, the present study demonstrated that developed film holds great potential for the acceleration of diabetic wound healing by its pro-angiogenic effect, faster re-epithelialization and increased collagen deposition.

Drupin, a cysteine protease from Ficus drupacea latex accelerates excision wound healing in mice

Wound healing is a tightly regulated physiological process that restores tissue integrity after injury. Plant latex proteases (PLPs) are considered an integral part in herbal wound care as it interferes at different phases of the wound healing process. Although many studies have reported the involvement of PLPs in healing process, an in-depth investigation is required to understand the molecular mechanism. Hence, the effect of PLPs with fibrinolytic activity on wound healing was investigated systematically using mouse excision wound model. Among 29 latices from Ficus genus tested, Ficus drupacea exhibited potent fibrinolytic activity. Cysteine protease responsible for fibrinolysis was purified from the F. drupacea latex named it as drupin, tested for its wound healing efficacy. The accelerated wound healing was mediated by downregulation of matrix metalloprotease (MMP)-9 without altering MMP-8 expression. Besides, drupin enhanced the rate of collagen synthesis at the wound site by increasing arginase 1 activity. And also, drupin increased the expression of arginase 1 in macrophages and involved in cell proliferation, and migration via MAP kinase and PI3K/Akt pathways. Overall, the present study highlights the interference of drupin in wound healing by increased arginase 1 activity and collagen synthesis, and cell proliferation and migration.

Influence of Oral Contraceptive Use on Adaptations to Resistance Training.

Introduction: The majority of young women use oral contraceptives (OCs). Use of OCs has been associated with lower myofibrillar protein and tendon collagen synthesis rates, but it is unknown whether OCs will limit the adaptive response of myotendinous tissue to resistance training.Design and Methods: Fourteen healthy untrained young regular OC users (24 ± 1 years, fat% 32 ± 1, 35 ± 2 ml⋅min-1⋅kg-1) and 14 NOC users (non-OC, controls) (24 ± 1 years, fat% 32 ± 2, 34 ± 2 ml⋅min-1⋅kg-1) performed a 10-week supervised lower extremity progressive resistance training program. Before and after the intervention biopsies from the vastus lateralis muscle and the patellar tendon were obtained. Muscle (quadriceps) and tendon cross-sectional area (CSA) was determined by magnetic resonance imaging (MRI) scans, and muscle fiber CSA was determined by histochemistry. Maximal isometric knee extension strength was assessed by dynamometry while 1 repetition maximum (RM) was determined during knee extension.Results: Training enhanced CSA in both muscle (p < 0.001) and tendon (p < 0.01). A trend toward a greater increase in muscle CSA was observed for OC (11%) compared to NOC (8%) (interaction p = 0.06). Analysis of mean muscle fiber type CSA showed a trend toward an increase in type II muscle fiber area in both groups (p = 0.11, interaction p = 0.98), whereas type I muscle fiber CSA increased in the OC group (n = 9, 3821 ± 197 to 4490 ± 313 mm2, p < 0.05), but not in NOC (n = 7, 4020 ± 348 to 3777 ± 354 mm2, p = 0.40) (interaction p < 0.05). Post hoc analyses indicated that the effect of OCs on muscle mass increase was induced by the OC-users (n = 7), who used OCs containing 30 μg ethinyl estradiol (EE), whereas the response in users taking OCs with 20 μg EE (n = 7) did not differ from NOC. Both the OC and NOC group experienced an increase in maximal knee strength (p < 0.001) and 1RM leg extension (p < 0.001) after the training period with no difference between groups.Conclusion: Use of OCs during a 10-week supervised progressive resistance training program was associated with a trend toward a greater increase in muscle mass and a significantly greater increase in type I muscle fiber area compared to controls. Yet, use of OCs did not influence the overall increase in muscle strength related to training.

MORPHOGISTOSCHEMICAL CHARACTERISTIC OF THE IMPLANT FROM POLYLACTIC ACID

Aim.The study was conducted for the characteristics of the morphoimmunohistochemical status of the implant from polylactic acid (PLA) located in the dermis.Materials and methods.The study was performed on rats (30 individuals) with subdermal administration of the drug in a volume of 0,05 ml. The results were evaluated after two weeks, 1 and 2 months after the injection. The sections were stained with hematoxylin and eosin, according to Van Gieson, with the help of Mallory and Masson reaction. Collagen fibers were studied after the staining with picrosirius red under polarized light. Monoclonal antibodies of CD 68 and antibodies to vimentin were used to determine the expression of immunohistochemical markers.Results. It is shown that the rate of collagen synthesis varies in different parts of the dermis. There is a sharp increase in the volume of the fibrous component around the implant, and there is only a tendency to increase in the synthesis in the implant itself. In this case, the increase in the volume of the extracellular matrix is associated with type I and III collagen.Conclusion.The detected activation of collagen synthesis by fibroblasts can be used as a regulator of the volume of the matrix, which is very important for the modern regenerative medicine.

Multiscale computational model of Achilles tendon wound healing: Untangling the effects of repair and loading.

Mechanical stimulation of the healing tendon is thought to regulate scar anisotropy and strength and is relatively easy to modulate through physical therapy. However, in vivo studies of various loading protocols in animal models have produced mixed results. To integrate and better understand the available data, we developed a multiscale model of rat Achilles tendon healing that incorporates the effect of changes in the mechanical environment on fibroblast behavior, collagen deposition, and scar formation. We modified an OpenSim model of the rat right hindlimb to estimate physiologic strains in the lateral/medial gastrocnemius and soleus musculo-tendon units during loading and unloading conditions. We used the tendon strains as inputs to a thermodynamic model of stress fiber dynamics that predicts fibroblast alignment, and to determine local collagen synthesis rates according to a response curve derived from in vitro studies. We then used an agent-based model (ABM) of scar formation to integrate these cell-level responses and predict tissue-level collagen alignment and content. We compared our model predictions to experimental data from ten different studies. We found that a single set of cellular response curves can explain features of observed tendon healing across a wide array of reported experiments in rats–including the paradoxical finding that repairing transected tendon reverses the effect of loading on alignment–without fitting model parameters to any data from those experiments. The key to these successful predictions was simulating the specific loading and surgical protocols to predict tissue-level strains, which then guided cellular behaviors according to response curves based on in vitro experiments. Our model results provide a potential explanation for the highly variable responses to mechanical loading reported in the tendon healing literature and may be useful in guiding the design of future experiments and interventions.

Effect of QiShenYiQi pill on myocardial collagen metabolism in experimental autoimmune myocarditis rats.

To observe the effect of QiShenYiQi pill (QSYQ) on myocardial collagen metabolism in experimental autoimmune myocarditis rats, and to explore its mechanism of action. Lewis rats underwent the injection of myocardial myosin mixed with freund's complete adjuvant were randomized into three groups: model, valsartan and QSYQ groups. And we treated rats which were injected phosphate buffered saline (PBS) mixed with freund's complete adjuvant as control group. Rats were intervened and euthanized at 4 and 8 weeks. We use alkaline hydrolysis to detect the content of myocardial hydroxyproline (HYP), and ELISA to detect the level of serum procollagen type I carboxyterminal peptide (PICP), procollagen type III amino-terminal peptide (PIIINP), and collagen C telopeptide type I (CTX-I). Myocardial MMP-1 and TIMP-1 protein expression was detected by immunohistochemistry, and myocardial MMP-1 and TIMP-1 mRNA expression was detected by real-time qPCR. QSYQ reduced the content of myocardial HYP, and this reduction was greater over time. QSYQ also reduced the serum concentration of PICP, PIIINP, CTX-I and the PICP/PIIINP ratio, which further reduced over time, whereas its effect on lowering PICP was significantly greater than that of valsartan at 4 and 8 weeks, and lowering CTX-I was significantly greater than that of valsartan at 8 weeks. In addition, after 4 weeks, QSYQ enhanced the protein and mRNA expression of MMP-1 and TIMP-1, and its effect on highering TIMP-1 was significantly greater than that of valsartan, whereas there was no significant difference in the expression of myocardial MMP-1 or TIMP-1 at 8 weeks. QSYQ reduced the ratio of MMP-1/TIMP-1, which further reduced over time, and the effect of QYSQ was significantly greater than that of valsartan after 4 weeks. This study provides evidence that QSYQ can reduce the rate of myocardial collagen synthesis and degradation. It also effectively improved the degree of myocardial fibrosis in experimental autoimmune myocarditis rats and it had a tendency to have a greater effect with longer treatment duration, which is related to the mechanism of regulation of MMP-1 and TIMP-1 expression in the myocardial rat.

Inhibitory effects of low decibel infrasound on the cardiac fibroblasts and the involved mechanism.

Introduction:Infrasound is a mechanical vibration wave with frequency between 0.0001 and 20 Hz. It has been established that infrasound of 120 dB or stronger is dangerous to humans. However, the biological effects of low decibel infrasound are largely unknown. The purpose of this study was to investigate the effects of low decibel infrasound on the cardiac fibroblasts.Materials and Methods:The cardiac fibroblasts were isolated and cultured from Sprague–Dawley rats. The cultured cells were assigned into the following four groups: control group, angiotensin II (Ang II) group, infrasound group, and Ang II+infrasound group. The cell proliferation and collagen synthesis rates were evaluated by means of [3H]-thymidine and [3H]-proline incorporation, respectively. The levels of TGF-β were determined by enzyme-linked immunosorbent assay. Moreover, RNAi approaches were used for the analysis of the biological functions of miR-29a, and the phosphorylation status of Smad3 was detected using western blotting analysis.Results:The results showed that low decibel infrasound significantly alleviated Ang II-induced enhancement of cell proliferation and collagen synthesis.Discussion:Compared with the control, Ang II markedly decreased the expression of miR-29a levels and increased the secretion of TGF-β and phosphorylation of Smad3, which was partly reversed by the treatment with low decibel infrasound. Importantly, knockdown of miR-29a diminished the effects of infrasound on the cardiac fibroblasts. In conclusion, low decibel infrasound inhibits Ang II-stimulated cardiac fibroblasts via miR-29a targeting TGF-β/Smad3 signaling.

Novel Method for Measuring Hepatic Collagen Turnover Rate in Nonalcoholic Fatty Liver Disease (NAFLD): Comparison of Blood and Liver Biopsy Biomarkers of Fibrogenesis

Background and ObjectivesExcess collagen synthesis in the liver plays a causal role in progression from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH). Markers that identify a patient's risk for progression, characterize disease activity and provide early assessment of treatment efficacy are needed. In particular, the availability of a non‐invasive metric of the rates of liver collagen synthesis (fibrogenesis) and turnover (fibrolysis) would be extremely valuable. We evaluated novel clinical biomarkers that directly quantify hepatic fibrogenesis rate in well‐characterized patients with biopsy‐proven NAFLD.MethodsPatients with suspected NAFLD and a clinical indication for liver biopsy received the stable, non‐radioactive tracer heavy water (2H2O, 50 ml, 2–3 times daily) by mouth for 20–35 days prior to biopsy. A plasma sample was collected weekly. Collagen fractional synthesis rate (FSR) from liver biopsy tissue and FSR of lumican (a proteoglycan involved in collagen fibril assembly that exhibits increased synthesis when collagen synthesis is increased) from plasma were measured by 2H incorporation, using tandem mass spectrometry (LC‐MS/MS). Magnetic resonance elastography (MRE) measurements of liver stiffness were obtained within 2 weeks of biopsy.ResultsFSR of hepatic type I collagen (Col1a1) was significantly elevated in NASH relative to NAFL (0.97% vs 0.43 %/day, p=0.03). Liver Col1a1 FSR also significantly correlated with fibrosis severity by histological score (r= 0.63), with liver stiffness by MRE (r=0.65), and with HbA1c levels (r=0.47). FSRs of fibrillar hepatic collagen subtypes (I and III) were highly correlated (r= 0.94). FSR of circulating plasma lumican correlated strongly with liver collagen FSR (r=0.69) and with liver stiffness (r=0.71).ConclusionWe conclude that hepatic collagen synthesis rates increase with fibrosis severity in NAFLD patients, indicating not only markedly increased absolute rates of collagen synthesis with disease progression but also suggesting that hepatic scar is dynamic even in advanced disease and may therefore be potentially reversible. Importantly, plasma lumican FSR correlates closely with liver collagen FSR and with liver stiffness. Moreover, established clinical risk factors for disease progression (NASH diagnosis, histologic fibrosis score, diabetes) were associated with higher collagen FSR. Non‐invasive kinetic measurements of fibrogenesis, such as plasma lumican FSR, may be helpful as markers of risk for disease progression and as early read outs of treatment response in anti‐fibrotic trials in NASH. Prospective studies are required to establish the predictive power of fibrogenesis rates for disease progression or reversal.Support or Funding InformationKineMed, Inc.