Effect of electroacupuncture on the degradation of collagen in pelvic floor supporting tissue of stress urinary incontinence rats

INTRODUCTION AND HYPOTHESIS

To examine the changes induced by electroacupuncture in stress urinary incontinence (SUI) rats, including the urodynamics and collagen degradation-related cytokine molecular biological expression changes, and to explore the effect and mechanism of EA treatment in SUI.

METHODS

Female SPF Sprague-Dawley rats were randomly assigned to five groups (n = 10): sham, model, electroacupuncture control, electroacupuncture, and blocker. The leak point pressure (LPP) and maximum bladder capacity (MBC) were measured for each group of rats, and collagen I, collagen III, matrix metalloproteinases (MMPs), and tissue inhibitor of metalloproteinase (TIMPs) in the anterior vaginal wall of rats in each group were determined by reverse transcription-polymerase chain reaction and western blotting. The data were analyzed by one-way analysis of variance or Kruskal-Wallis test.

RESULTS

Electroacupuncture Shenshu (BL23) and Huiyang (BL35) increased the LPP and MBC in SUI rats (P < 0.05). Electroacupuncture treatment significantly increased the protein expression of collagen I and collagen III in the anterior vaginal wall of SUI rats (P < 0.05) and significantly reduced the protein expression of MMP1, MMP2, and MMP9 (P < 0.05).

CONCLUSIONS

Electroacupuncture stimulation can alleviate the signs of SUI, and its mechanism is related to the degradation of collagen in the anterior vaginal wall.

Tetracycline ameliorates silica-induced pulmonary inflammation and fibrosis via inhibition of caspase-1

Background

Inhalation of dust containing silica particles is associated with severe pulmonary inflammation and lung injury leading to chronic silicosis including fibrotic remodeling of the lung. Silicosis represents a major global health problem causing more than 45.000 deaths per year. The inflammasome-caspase-1 pathway contributes to the development of silica-induced inflammation and fibrosis via IL-1β and IL-18 production. Recent studies indicate that tetracycline can be used to treat inflammatory diseases mediated by IL-1β and IL-18. Therefore, we hypothesized that tetracycline reduces silica-induced lung injury and lung fibrosis resulting from chronic silicosis via limiting IL-1β and IL-18 driven inflammation.

Methods

To investigate whether tetracycline is a therapeutic option to block inflammasome-caspase-1 driven inflammation in silicosis, we incubated macrophages with silica alone or combined with tetracycline. The in vivo effect of tetracycline was determined after intratracheal administration of silica into the mouse lung.

Results

Tetracycline selectively blocks IL-1β production and pyroptotic cell death via inhibition of caspase-1 in macrophages exposed to silica particles. Consistent, treatment of silica-instilled mice with tetracycline significantly reduced pulmonary caspase-1 activation as well as IL-1β and IL-18 production, thereby ameliorating pulmonary inflammation and lung injury. Furthermore, prolonged tetracycline administration in a model of chronic silicosis reduced lung damage and fibrotic remodeling.

Conclusions

These findings suggest that tetracycline inhibits caspase-1-dependent production of IL-1β in response to silica in vitro and in vivo. The results were consistent with tetracycline reducing silica-induced pulmonary inflammation and chronic silicosis in terms of lung injury and fibrosis. Thus, tetracycline could be effective in the treatment of patients with silicosis as well as other diseases involving silicotic inflammation.

The effect of additional antimicrobial therapy on the outcomes of patients with idiopathic pulmonary fibrosis: a systematic review and meta-analysis

Background

The effect of additional antimicrobial agents on the clinical outcomes of patients with idiopathic pulmonary fibrosis (IPF) is unclear.

Methods

We performed comprehensive searches of randomized control trials (RCTs) that compared the clinical efficacy of additional antimicrobial agents to those of placebo or usual care in the treatment of IPF patients. The primary outcome was all-cause mortality, and the secondary outcomes were changes in forced vital capacity (FVC), diffusing capacity of the lung for carbon monoxide (DLCO), and the risk of adverse events (AEs).

Results

Four RCTs including a total of 1055 patients (528 receiving additional antibiotics and 527 receiving placebo or usual care) were included in this meta-analysis. Among the study group, 402 and 126 patients received co-trimoxazole and doxycycline, respectively. The all-cause mortality rates were 15.0% (79/528) and 14.0% (74/527) in the patients who did and did not receive additional antibiotics, respectively (odds ratio [OR] 1.07; 95% confidence interval [CI] 0.76 to 1.51; p = 0.71). No significant difference was observed in the changes in FVC (mean difference [MD], 0.01; 95% CI − 0.03 to 0.05; p = 0.56) and DLCO (MD, 0.05; 95% CI − 0.17 to 0.28; p = 0.65). Additional use of antimicrobial agents was also associated with an increased risk of AEs (OR 1.65; 95% CI 1.19 to 2.27; p = 0.002), especially gastrointestinal disorders (OR 1.54; 95% CI 1.10 to 2.15; p = 0.001).

Conclusions

In patients with IPF, adding antimicrobial therapy to usual care did not improve mortality or lung function decline but increased gastrointestinal toxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01839-0.

Peptide PD29 treats bleomycin-induced pulmonary fibrosis by inhibiting the TGF-β/smad signaling pathway

Pulmonary fibrosis (PF) is an end-stage change in lung disease characterized by fibroblast proliferation, massive extracellular matrix (ECM) aggregation with inflammatory damage, and severe structural deterioration. PD29 is a 29-amino acid peptide which has the potential to alleviate PF pathogenesis via three mechanisms: anti-angiogenesis, inhibition of matrix metalloproteinase activities, and inhibition of integrins. In this study, fibrotic lung injuries were induced in SD rats by a single intratracheal instillation of 5 mg/kg bleomycin (BLM). Then, these rats were administered 7.5, 5, or 2.5 mg/kg PD29 daily for 30 days. BLM induced-syndromes including structure distortion, excessive deposition of ECM, excessive inflammatory infiltration, and pro-inflammatory cytokine release were used to evaluate the protective effect of PD-29. Oxidative stress damage in lung tissues was attenuated by PD29 in a dose-dependent manner. The expression of TGF-β1 and the phosphorylation of Smad-2/-3-its downstream targets-were enhanced by BLM and weakened by PD29. In vitro, PD29 inhibited TGF-β1-induced epithelial-mesenchymal transition (EMT) and transformation in A549 cells and mouse primary fibroblasts into myofibroblasts. In summary, PD29 reversed EMT and transformation of fibroblasts into myofibroblasts in vitro and prevented PF in vivo possibly by suppressing the TGF-β1/Smad pathway.

Inhalation treatment of idiopathic pulmonary fibrosis with curcumin large porous microparticles

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease with high mortality and poor prognosis. Curcumin shows anti-inflammatory effect by suppressing pro-inflammatory cytokines and inhibiting NF-κB mediated inflammation. Here, we developed inhalable curcumin-loaded poly(lactic-co-glycolic)acid (PLGA) large porous microparticles (LPMPs) for the treatment of IPF. Curcumin LPMPs were rough and loose particles with many pores on the surfaces and channels in the inner spaces. The mean geometric diameter of them was larger than 10 µm while the aerodynamic diameter was only 3.12 µm due to their porous structures. They showed a fine particle fraction (FPF) <4.46 μm of 13.41%, 71% cumulative release after 9 h, and more importantly, they avoided uptake by alveolar macrophages. Therefore, most of released curcumin had opportunities to enter lung tissues. Rat pulmonary fibrosis models were established via once intratracheal administration of bleomycin. Curcumin powders and curcumin LPMPs were administered on Days 2, 7, 14, and 21. Curcumin LPMPs remarkably attenuated lung injuries, decreased hydroxyproline contents, reduced the synthesis of collagen I, and inhibited the expressions of TNF-α, TGF-β1, NF-κB p65 and MMP9. Moreover, curcumin LPMPs showed higher antifibrotic activity than curcumin powders. Curcumin LPMPs are a promising inhalable medication for the treatment of IPF.

Mechanism of fibrosis inhibition in laser induced choroidal neovascularization by doxycycline

To explore the mechanisms underlying doxycycline suppression of fibrosis in laser-induced choroidal neovascularization (LCNV), C57BL/6J male mice (aged from 6 to 8 weeks) received intraperitoneal injections of PBS/doxycycline solution from one day before laser injury until they were sacrificed. Leakage was assessed by FA, and CNV (stained by IB4) or fibrosis (stained by collagen type I) size was measured. The percentage of Pan-keratin⁺α-SMA⁺ cells was counted in the eyes' cryostat sections by immunohistochemistry. qPCR was used to measure the mRNA of markers of pan-macrophages, M1 and M2-type macrophages (M1 and M2), markers of EMT, and markers in the downstream of STAT6 signaling. Western blotting was used to analyze the expression of Arg-1, α-SMA, E-cadherin, pSTAT6 and STAT6. Our data showed that doxycycline inhibited leakage from CNV, areas of CNV on day 7 and day 14, and suppressed fibrosis, and the ratio of fibrotic/angiogenic areas during day 7 to day 35. We also showed attenuation of EMT in the doxycycline group. The percentage of Pan-keratin⁺α-SMA⁺ cells was lower in the doxycycline group than in the control group. The mRNA and protein levels of mesenchymal markers were downregulated in the doxycycline group, while the epithelial marker was upregulated. In addition, our data showed that the protein expression of Arg-1, the mRNA expression of M1 and M2-markers, were both inhibited by doxycycline, while the level of pan-macrophages (f4/80) showed no significant difference in two groups. Finally, our results showed that doxycycline was able to modulate the STAT6 signaling in transcript and protein levels. Accordingly, we suggested that the mechanism of doxycycline-mediated inhibition of fibrosis in CNV occurs through the STAT6 pathway.

Doxycycline attenuates paraquat-induced pulmonary fibrosis by downregulating the TGF-β signaling pathway

Background

Paraquat (PQ) is a highly efficient herbicide that remains widely used in agriculture. However, the inappropriate application of this herbicide may cause multiple organ injuries including pulmonary injury. In this study, we report that doxycycline (Doxy) treats PQ-induced pulmonary fibrosis (PF).

Methods

Mice with PQ-induced PF were treated with different doses of Doxy by intragastric administration. Human lung cancer cell line A549 pre-treated with TGF-β1 (5 ng/mL) were treated with Doxy hydrochloride (3.4 µM).

Results

PF was observed from day 28 in PQ-treated group and Doxy treatments significantly reduced pulmonary coefficient, histopathological score and collagen content in a dose-dependent manner. Doxy can inhibit the expression levels of plasma inflammation cytokines at day 28 after modeling and reduced inflammatory response at early stage of PQ-induced lung injury. Immunohistochemical staining assay and proteomic analysis indicated that Doxy could restore ectopic epithelial-mesenchymal transition (EMT) induced by PQ-treatment by regulating numerous TGF-β signaling related proteins.

Conclusions

The findings suggest that Doxy can restore the balance of epithelial-mesenchymal cells and attenuate PQ-induced PF by downregulating the TGF-β signaling pathway.

Inhibition of epithelial-to-mesenchymal transition and pulmonary fibrosis by methacycline

A high-throughput small-molecule screen was conducted to identify inhibitors of epithelial-mesenchymal transition (EMT) that could be used as tool compounds to test the importance of EMT signaling in vivo during fibrogenesis. Transforming growth factor (TGF)-β1-induced fibronectin expression and E-cadherin repression in A549 cells were used as 48-hour endpoints in a cell-based imaging screen. Compounds that directly blocked Smad2/3 phosphorylation were excluded. From 2,100 bioactive compounds, methacycline was identified as an inhibitor of A549 EMT with the half maximal inhibitory concentration (IC50) of roughly 5 μM. In vitro, methacycline inhibited TGF-β1-induced α-smooth muscle actin, Snail1, and collagen I of primary alveolar epithelial cells . Methacycline inhibited TGF-β1-induced non-Smad pathways, including c-Jun N-terminal kinase, p38, and Akt activation, but not Smad or β-catenin transcriptional activity. Methacycline had no effect on baseline c-Jun N-terminal kinase, p38, or Akt activities or lung fibroblast responses to TGF-β1. In vivo, 100 mg/kg intraperitoneal methacycline delivered daily beginning 10 days after intratracheal bleomycin improved survival at Day 17 (P < 0.01). Bleomycin-induced canonical EMT markers, Snail1, Twist1, collagen I, as well as fibronectin protein and mRNA, were attenuated by methacycline (Day 17). Methacycline did not attenuate inflammatory cell accumulation or alter TGF-β1-responsive genes in alveolar macrophages. These studies identify a novel inhibitor of EMT as a potent suppressor of fibrogenesis, further supporting the concept that EMT signaling is important to lung fibrosis. The findings also provide support for testing the impact of methacycline or doxycycline, an active analog, on progression of human pulmonary fibrosis.

Active matrix metalloprotease-9 is associated with the collagen capsule surrounding the Madurella mycetomatis grain in mycetoma

Madurella mycetomatis is the main causative organism of eumycetoma, a persistent, progressive granulomatous infection. After subcutaneous inoculation M. mycetomatis organizes itself in grains inside a granuloma with excessive collagen accumulation surrounding it. This could be contributing to treatment failure towards currently used antifungal agents. Due to their pivotal role in tissue remodelling, matrix metalloproteinases-2 (MMP-2) and 9 (MMP-9) or tissue inhibitor of metalloproteinases (TIMP) might be involved in this process. Local MMP-2 and MMP-9 expression was assessed by immunohistochemistry while absolute serum levels of these enzymes were determined in mycetoma patients and healthy controls by performing ELISAs. The presence of active MMP was determined by gelatin zymography. We found that both MMP-2 and MMP-9 are expressed in the mycetoma lesion, but the absolute MMP-2, -9, and TIMP-1 serum levels did not significantly differ between patients and controls. However, active MMP-9 was found in sera of 36% of M. mycetomatis infected subjects, whereas this active form was absent in sera of controls (P<0.0001). MMP-2, MMP-9, and TIMP-1 polymorphisms in mycetoma patients and healthy controls were determined through PCR-RFLP or sequencing. A higher T allele frequency in TIMP-1 (+372) SNP was observed in male M. mycetomatis mycetoma patients compared to controls. The presence of active MMP-9 in mycetoma patients suggest that MMP-9 is activated or synthesized by inflammatory cells upon M. mycetomatis infection. Inhibiting MMP-9 activity with doxycycline could prevent collagen accumulation in mycetoma, which in its turn might make the fungus more accessible to antifungal agents.

Eumycetoma, mainly caused by the fungus Madurella mycetomatis, is a chronic infection which, without treatment, results in deformation of the infected body part. Inside the body, the fungus organises itself in grains which are surrounded by collagen. This collagen could act as a natural barrier for antifungal agents. Since collagen modulation is regulated by matrix metalloproteinase-2 (MMP-2), MMP-9 and tissue inhibitors of metalloproteinases (TIMPs), these enzymes could play a role in the formation of the collagen capsule surrounding the fungal grain. Indeed, we demonstrated that MMPs were found surrounding the mycetoma grain and that measurable levels of both MMPs were found in serum of both mycetoma patients and healthy controls. Only in mycetoma patients the active form MMP-9 was found. The presence of active MMP-9 in the serum of mycetoma-patients was not the result of lower levels TIMP-1 but more likely from differences in allele frequencies in the TIMP-1 gene. In conclusion, our results showed an increased MMP-9 activity in mycetoma patients. We hypothesize that inhibition of MMP-9 activity by doxycycline will result in breakdown of the collagen capsule surrounding the grain, which in turn will make the entrance of antifungal drugs into the grain easier.

Doxycycline prevents matrix remodeling and contraction by trichiasis-derived conjunctival fibroblasts

PURPOSE

Trachoma is a conjunctival scarring disease, which is the leading infectious cause of blindness worldwide. Elimination of blinding trachoma is being held back by the high rate of trichiasis recurrence following surgery. There is currently no treatment available to suppress the profibrotic state and reduce recurrence. Although the mechanisms underlying trichiasis development are unknown, the profibrotic phenotype has been linked to matrix metalloproteinase (MMP) expression. Doxycycline, a well-known tetracycline antibiotic, can act as a broad MMP inhibitor and has showed some success in preventing fibrosis in various clinical contexts. The purpose of this work was to assess the antiscarring properties of doxycycline in an in vitro model of trichiasis fibroblast-mediated tissue contraction.

METHODS

Primary cultures of fibroblasts were established from conjunctival samples obtained from normal donors or during surgery for trachomatous trichiasis. The effect of doxycycline on matrix contraction was investigated in our standard collagen gel contraction model. Cell morphology and matrix integrity were assessed using confocal reflection microscopy. Quantitative real time polymerase chain reaction and a FRET-based assay were used to measure MMP expression and activity, respectively.

RESULTS

Doxycycline treatment successfully suppressed the contractile phenotype of trichiasis fibroblasts, matrix degradation, and significantly altered the expression of MMP1, MMP9, and MMP12 associated with the profibrotic phenotype.

CONCLUSIONS

In view of the results presented here and the wider use of doxycycline in clinical settings, we propose that doxycycline might be useful as a treatment to prevent recurrence following trichiasis surgery.

TIMP3 is the primary TIMP to regulate agonist-induced vascular remodelling and hypertension

AIMS

Hypertension is accompanied by structural remodelling of vascular extracellular matrix (ECM). Tissue inhibitor of metalloproteinases (TIMPs) inhibits matrix metalloproteinases (MMPs) that degrade the matrix structural proteins. In response to a hypertensive stimulus, the balance between MMPs and TIMPs is altered. We examined the role of TIMPs in agonist-induced hypertension.

METHODS AND RESULTS

We subjected TIMP-knockout mice to angiotensin II (Ang II) infusion, and found that Ang-II-induced hypertension in TIMP1(-/-), TIMP2(-/-), and TIMP4(-/-) mice was comparable to wild-type (WT) mice, but significantly suppressed in TIMP3(-/-) mice. Ex vivo pressure myography analyses on carotid and mesenteric arteries revealed that Ang-II-infused TIMP3(-/-) arteries were more distensible with impaired elastic recoil compared with the WT group. The acute response to vasoconstriction and vasodilation was intact in TIMP3(-/-) mesenteric and carotid arteries. Mesenteric arteries from TIMP3(-/-)-Ang II mice exhibited a reduced media-to-lumen ratio, suppressed collagen and elastin levels, elevated elastase and gelatinase proteolytic activities compared with WT-Ang II. TIMP3(-/-)-Ang II carotid arteries also showed adverse structural remodelling. Treatment of mice with doxycycline, a matrix metalloproteinase inhibitor, improved matrix integrity in mesenteric and carotid arteries in TIMP3(-/-)-Ang II and differentially regulated elastin and collagen levels in WT-Ang II vs. TIMP3(-/-)-Ang II.

CONCLUSION

Our study demonstrates a critical role for TIMP3, among all TIMPs, is preserving arterial ECM in response to Ang II. It is critical to acknowledge that the suppressed Ang-II-induced hypertension in TIMP3(-/-) mice is not a protective mechanism but owing to adverse remodelling in arterial matrix.

A review of current and novel therapies for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressively fibrotic interstitial lung disease that is associated with a median survival of 2-3 years from initial diagnosis. To date, there is no treatment approved for IPF in the United States, and only one pharmacological agent has been approved outside of the United States. Nevertheless, research over the past 10 years has provided us with a wealth of information on its histopathology, diagnostic work-up, and a greater understanding of its pathophysiology. Specifically, IPF is no longer thought to be a predominantly pro-inflammatory disorder. Rather, the fibrosis in IPF is increasingly understood to be the result of a fibroproliferative and aberrant wound healing cascade. The development of therapeutic targets has shifted in accord with this paradigm change. This review highlights the current understanding of IPF, and the recent as well as novel therapeutics being explored in clinical trials for the treatment of this devastating disease.

N-acetylcysteine downregulation of lysyl oxidase activity alleviating bleomycin-induced pulmonary fibrosis in rats

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease without beneficial therapy, except for lung transplantation. A high oral dose of N-acetylcysteine (NAC) added to prednisone and azathioprine has been found to improve lung function in IPF patients, though the mechanism of action remains poorly understood.

OBJECTIVE

Based on our previous findings showing elevation of glutathione (GSH) content associated with downregulation of lysyl oxidase (LOX) activity, which is essential for collagen deposition, the aim of the present study was to test the hypothesis that NAC alleviates IPF by regulating LOX function.

METHODS

We firstly analyzed the time course of collagen deposition in lung tissue, hydroxyproline content, LOX activity, GSH levels, and transforming growth factor-β(1) (TGF-β(1)) and α-smooth muscle actin (α-SMA) expression in bleomycin (BLM)-induced pulmonary fibrosis in a rat model. Then, we focused our studies on NAC modulation of LOX activity.

RESULTS

LOX activity was increased on day 9 and peaked 14 days after BLM administration, while TGF-β(1) protein peaked on day 9. Interestingly, NAC treatment for 14 days from day 0 reversed LOX activity to normal levels and increased GSH levels in the lung of BLM-dosed rats. Consistently, NAC partially attenuated pulmonary fibrosis and inhibited TGF-β(1) and α-SMA expression in this model.

CONCLUSIONS

Our study supports a novel mechanism of NAC alleviating IPF by inhibition of LOX activity via elevation of lung GSH in BLM-induced pulmonary fibrosis. The TGF-β(1)/α-SMA pathway may also play an important role in modulation of LOX activity.

Respiratory syncytial virus potentiates ABCA3 mutation-induced loss of lung epithelial cell differentiation

ATP-binding cassette transporter A3 (ABCA3) is a lipid transporter active in lung alveolar epithelial type II cells (ATII) and is essential for their function as surfactant-producing cells. ABCA3 mutational defects cause respiratory distress in newborns and interstitial lung disease (ILD) in children. The molecular pathomechanisms are largely unknown; however, viral infections may initiate or aggravate ILDs. Here, we investigated the impact of the clinically relevant ABCA3 mutations, p.Q215K and p.E292V, by stable transfection of A549 lung epithelial cells. ABCA3 mutations strongly impaired expression of the ATII differentiation marker SP-C and the key epithelial cell adhesion proteins E-cadherin and zonula occludens-1. Concurrently, cells expressing ABCA3 mutation acquired mesenchymal features as observed by increased expression of SNAI1, MMP-2 and TGF-β1, and elevated phosphorylation of Src. Infection with respiratory syncytial virus (RSV), the most common viral respiratory pathogen in small children, potentiated the observed mutational effects on loss of epithelial and acquisition of mesenchymal characteristics. In addition, RSV infection of cells harboring ABCA3 mutations resulted in a morphologic shift to a mesenchymal phenotype. We conclude that ABCA3 mutations, potentiated by RSV infection, induce loss of epithelial cell differentiation in ATII. Loss of key epithelial features may disturb the integrity of the alveolar epithelium, thereby comprising its functionality. We suggest the impairment of epithelial function as a mechanism by which ABCA3 mutations cause ILD.