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

Novel Anti-Inflammatory Approaches to COPD

Airway inflammation, driven by different types of inflammatory cells and mediators, plays a fundamental role in COPD and its progression. Neutrophils, eosinophils, macrophages, and CD4+ and CD8+ T lymphocytes are key players in this process, although the extent of their participation varies according to the patient's endotype. Anti-inflammatory medications may modify the natural history and progression of COPD. However, since airway inflammation in COPD is relatively resistant to corticosteroid therapy, innovative pharmacological anti-inflammatory approaches are required. The heterogeneity of inflammatory cells and mediators in annethe different COPD endo-phenotypes requires the development of specific pharmacologic agents. Indeed, over the past two decades, several mechanisms that influence the influx and/or activity of inflammatory cells in the airways and lung parenchyma have been identified. Several of these molecules have been tested in vitro models and in vivo in laboratory animals, but only a few have been studied in humans. Although early studies have not been encouraging, useful information emerged suggesting that some of these agents may need to be further tested in specific subgroups of patients, hopefully leading to a more personalized approach to treating COPD.

The Emerging Role of MMP12 in the Oral Environment

Matrix metalloproteinase-12 (MMP12), or macrophage metalloelastase, plays important roles in extracellular matrix (ECM) component degradation. Recent reports show MMP12 has been implicated in the pathogenesis of periodontal diseases. To date, this review represents the latest comprehensive overview of MMP12 in various oral diseases, such as periodontitis, temporomandibular joint dysfunction (TMD), orthodontic tooth movement (OTM), and oral squamous cell carcinoma (OSCC). Furthermore, the current knowledge regarding the distribution of MMP12 in different tissues is also illustrated in this review. Studies have implicated the association of MMP12 expression with the pathogenesis of several representative oral diseases, including periodontitis, TMD, OSCC, OTM, and bone remodelling. Although there may be a potential role of MMP12 in oral diseases, the exact pathophysiological role of MMP12 remains to be elucidated. Understanding the cellular and molecular biology of MMP12 is essential, as MMP12 could be a potential target for developing therapeutic strategies targeting inflammatory and immunologically related oral diseases.

The conjunctival transcriptome in Ethiopians after trichiasis surgery: associations with the development of eyelid contour abnormalities and the effect of oral doxycycline treatment

Background: Surgery to correct trichiasis is a key component of the World Health Organisation trachoma control strategy, however unfavourable outcomes such as eyelid contour abnormalities (ECA) following surgery are relatively common. This study aimed to understand the transcriptional changes associated with the early development of ECA and the impact of doxycycline, which has anti-inflammatory and anti-fibrotic properties, upon these transcription patterns. Methods: One thousand Ethiopians undergoing trichiasis surgery were enrolled in a randomised controlled trial following informed consent. Equal groups of randomly assigned individuals were orally administered with 100mg/day of doxycycline (n=499) or placebo (n=501) for 28 days. Conjunctival swabs were collected immediately prior to surgery and at one- and six-months post-surgery. 3' mRNA sequencing was performed on paired baseline and one-month samples from 48 individuals; 12 in each treatment/outcome group (Placebo-Good outcome, Placebo-Poor outcome, Doxycycline-Good outcome, Doxycycline-Poor outcome). qPCR validation was then performed for 46 genes of interest in 145 individuals who developed ECA at one month and 145 matched controls, using samples from baseline, one and six months. Results: All treatment/outcome groups upregulated genes associated with wound healing pathways at one month relative to baseline, however no individual differences were detected between groups. The summed expression of a highly coexpressed cluster of pro-fibrotic genes was higher in patients that developed ECA in the placebo group relative to controls. qPCR validation revealed that all genes in this cluster and a number of other pro-inflammatory genes were strongly associated with ECA, however these associations were not modulated by trial arm. Conclusions: The development of post-operative ECA is associated with overexpression of pro-inflammatory and pro-fibrotic genes including growth factors, matrix metalloproteinases, collagens and extracellular matrix proteins. There was no evidence that doxycycline modulated the association between gene expression and ECA.

Matrix Metalloproteinases and Glaucoma

Matrix metalloproteinases (MMPs) are enzymes that decompose extracellular matrix (ECM) proteins. MMPs are thought to play important roles in cellular processes, such as cell proliferation, differentiation, angiogenesis, migration, apoptosis, and host defense. MMPs are distributed in almost all intraocular tissues and are involved in physiological and pathological mechanisms of the eye. MMPs are also associated with glaucoma, a progressive neurodegenerative disease of the eyes. MMP activity affects intraocular pressure control and apoptosis of retinal ganglion cells, which are the pathological mechanisms of glaucoma. It also affects the risk of glaucoma development based on genetic pleomorphism. In addition, MMPs may affect the treatment outcomes of glaucoma, including the success rate of surgical treatment and side effects on the ocular surface due to glaucoma medications. This review discusses the various relationships between MMP and glaucoma.

Promotion of conjunctival fibroblast-mediated collagen gel contraction by mast cells through up-regulation of matrix metalloproteinase release and activation

Mast cells and conjunctival fibroblasts contribute to conjunctival wound healing and allergic ocular inflammation. The number of mast cells in the conjunctiva is increased in individuals with cicatricial fibrosis-causing ocular surface diseases and after glaucoma filtering surgery, suggesting that these cells may contribute to the scarring observed after such surgery. We studied the potential mechanism of fibroblast-mast cell interaction in the healing of conjunctival wounds using a three-dimensional collagen gel culture system. We found that mast cells derived from the bone marrow of mice embedded in a collagen gel did not induce gel contraction. However, an increase in mast cells was associated with increased collagen gel contraction mediated by mouse conjunctival fibroblasts. The extent of collagen degradation was not affected by the co-culture of mast cells and conjunctival fibroblasts. Gelatin zymography disclosed that mast cells increased the amounts of both the pro form of matrix metalloproteinase (MMP)-9 and the active form of MMP-2 in supernatants of conjunctival fibroblast cultures. Furthermore, the potentiating effect of mast cells on contraction of the collagen gel through conjunctival fibroblasts was attenuated by the addition of a synthetic MMP inhibitor. Thus, current results suggest that mast cells accelerate the conjunctival fibroblast-dependent contraction of collagen gel by increasing the release as well as activation of MMPs. Therefore, the interaction between mast cells and conjunctival fibroblasts may contribute to conjunctival scar formation after glaucoma filtering surgery.

Preparing the ocular surface for glaucoma filtration surgery: an unmet clinical need

The mutual relationship among medical therapy, ocular surface (OS) and filtration surgery (FS) represents one of the most crucial issues in glaucoma management. As the long-term use of intraocular pressure-lowering medications significantly affect the OS health, patients with an uncontrolled disease frequently undergo glaucoma surgery in less-than-ideal conditions. As we known, OS changes strongly affect the post-operative bleb filtration capability. Therefore, improving the OS conditions before proceeding with FS is needed. Currently, given the rapid diffusion of new surgical procedures, this need is even more perceived. Nevertheless, despite surgeons retain the OS preparation of primary importance, and recognize the OS disease (OSD) as the only modifiable risk factor for filtration failure, there is no agreement on which strategies should be preferred to prepare patients. This is largely due to the lack of validated guidelines, which forces clinicians to adopt personal approaches based on evidence derived from low-quality studies. In this review, we provided an overview of risk factors involved in the FS failure, with particular attention to those depending on OS changes, and how OSD negatively affects the aqueous humor resorption after surgery. Moreover, we reported the most exploited measures to mitigate the OSD before surgery, the possible reasons underlying the absence of shared approaches, and the upcoming area of intervention to preserve the OS health during glaucoma management. Finally, based on the current evidence, we proposed a pre-operative outline reporting the main risk factors that should be considered before surgery, and the therapeutical options available to improve the OS.

The Anticancer Potential of Doxycycline and Minocycline-A Comparative Study on Amelanotic Melanoma Cell Lines

Malignant melanoma is still a serious medical problem. Relatively high mortality, a still-growing number of newly diagnosed cases, and insufficiently effective methods of therapy necessitate melanoma research. Tetracyclines are compounds with pleiotropic pharmacological properties. Previously published studies on melanotic melanoma cells ascertained that minocycline and doxycycline exerted an anti-melanoma effect. The purpose of the study was to assess the anti-melanoma potential and mechanisms of action of minocycline and doxycycline using A375 and C32 human amelanotic melanoma cell lines. The obtained results indicate that the tested drugs inhibited proliferation, decreased cell viability, and induced apoptosis in amelanotic melanoma cells. The treatment caused changes in the cell cycle profile and decreased the intracellular level of reduced thiols and mitochondrial membrane potential. The exposure of A375 and C32 cells to minocycline and doxycycline triggered the release of cytochrome c and activated initiator and effector caspases. The anti-melanoma effect of analyzed drugs appeared to be related to the up-regulation of ERK1/2 and MITF. Moreover, it was noticed that minocycline and doxycycline increased the level of LC3A/B, an autophagy marker, in A375 cells. In summary, the study showed the pleiotropic anti-cancer action of minocycline and doxycycline against amelanotic melanoma cells. Considering all results, it could be concluded that doxycycline was a more potent drug than minocycline.

Doxycycline Ameliorates the Severity of Experimental Proliferative Vitreoretinopathy in Mice

After successful surgeries for patients with rhegmatogenous retinal detachment, the most common cause of retinal redetachment is proliferative vitreoretinopathy (PVR), which causes severe vision impairment and even blindness worldwide. Until now, the major treatment for PVR is surgical removal of the epiretinal membrane, while effective treatment to prevent PVR is still unavailable. Therefore, we investigated the potential of doxycycline, an antibiotic in the tetracycline class, to treat PVR using a mouse model. We used the human retinal pigment epithelial cell line, ARPE-19, for in vitro and in vivo studies to test doxycycline for PVR treatment. We found that doxycycline suppressed the migration, proliferation, and contraction of ARPE-19 cells with reduced p38 MAPK activation and total MMP activity. Intravitreal doxycycline and topical tetracycline treatment significantly ameliorated the PVR severity induced by ARPE-19 cells in mice. PVR increased the expression of MMP-9 and IL-4 and p38 MAPK phosphorylation and modestly decreased IL-10. These effects were reversed by doxycycline and tetracycline treatment in the mouse retina. These results suggest that doxycycline will be a potential treatment for PVR in the future.

Effect of UVA1 on hypertrophic scarring in the rabbit ear model

Hypertrophic scars (HTSs) are common and cause functional and psychological morbidity. UVA1 (340-400 nm) phototherapy has been previously shown to be effective in the treatment of localized scleroderma, systemic sclerosis, and POEMS syndrome with minimal side effects, all of which are presented as collagen fibrils hyperplasia that is common with scarring in skin histology. In the present study, we aimed to investigate the impact of UVA1 on the protein expression of TGF-β signal pathway and myofibroblasts in a rabbit model of cutaneous scarring. Full-thickness skin wounds (2 cm × 5 cm in diameter) were made in New Zealand white rabbits to establish the hypertrophic scarring model. New Zealand white rabbits were divided into two treatment groups (n=30 wounds per group with an equal number of controls): medium-dose of UVA1 phototherapy group: 60 J/cm2; high-dose of UVA1 phototherapy group: 110 J/cm2. Left ears were used for treatment and the right ones were used for control. Treatment was administered five times weekly for 6 weeks. Treated and untreated control wounds were harvested at various time points and examined by histologic examination, immunohistochemical assessment, and ultrastructural evaluation. The results showed that UVA1 phototherapy caused a significant reduction in dermal thickness by histological features, whereas the scar index was descended significantly in both medium- and high-dose UVA1 groups compared with the control group. Examination of immunohistochemistry also revealed a marked suppression of tissue growth factor-β (TGF-β) (both medium- and high-dose), α smooth muscle actin (α-SMA) (only high-dose), and tissue inhibitor of metalloproteinase 1 (TIMP-1) (only high-dose), and apparent increase in matrix metalloproteinases (MMP-1) (both medium- and high-dose) compared with the control. The ultrastructural evaluation showed the collagen fibers' diameter had shrunk, and that fibroblastic cytoplasm was not affluent and in a quiescent stage. These findings of the present study suggested that administration of UVA1 irradiation is effective to improve the experimental HTS model and raises a possibility of the therapeutic approach of UVA1 in the scar. Although not directly examined in the present study, MMP inhibition is hypothesized to be responsible for this effect. However, early UVA1 treatment could not prevent the formation of scar model.

Characteristics of matrix metalloproteinases and their role in embryogenesis of the mammalian respiratory system

The human respiratory system appears as an outgrowth from the ventral wall of the primary foregut and its development includes a series of subsequent processes, dependent on the interactions between endothelial cells, respiratory epithelium and extracellular matrix (ECM). These interactions determine the acquisition of normal structural and functional features of the newly created tissues. The essential role in the morphogenesis of the respiratory system is performed by matrix metalloproteinases (MMPs). MMPs are endopeptidases containing zinc ion in their active center, necessary for the processes of hydrolysis of peptide bonds of substrates. The production of MMPs takes place in most connective tissue cells, leukocytes, macrophages, vascular endothelial cells as well as in neurons, glial cells and in tumor cells. Like other proteolytic enzymes, MMPs are produced and secreted in the form of inactive pro-enzymes, and their activation occurs in the extracellular space. MMPs perform both physiological and pathological functions during tissue modeling and their role in embryogenesis is based on the regulation of angiogenesis processes, stroma formation and cells migration. This article aims to characterize, discuss and demonstrate the activity and the role of MMPs in the subsequent stages of respiratory development.

A Tenon's capsule/bulbar conjunctiva interface biomimetic to model fibrosis and local drug delivery

Glaucoma filtration surgery is one of the most effective methods for lowering intraocular pressure in glaucoma. The surgery efficiently reduces intra-ocular pressure but the most common cause of failure is scarring at the incision site. This occurs in the conjunctiva/Tenon’s capsule layer overlying the scleral coat of the eye. Currently used antimetabolite treatments to prevent post-surgical scarring are non-selective and are associated with potentially blinding side effects. Developing new treatments to target scarring requires both a better understanding of wound healing and scarring in the conjunctiva, and new means of delivering anti-scarring drugs locally and sustainably. By combining plastic compression of collagen gels with a soft collagen-based layer, we have developed a physiologically relevant model of the sub-epithelial bulbar conjunctiva/Tenon’s capsule interface, which allows a more holistic approach to the understanding of subconjunctival tissue behaviour and local drug delivery. The biomimetic tissue hosts both primary human conjunctival fibroblasts and an immune component in the form of macrophages, morphologically and structurally mimicking the mechanical proprieties and contraction kinetics of ex vivo porcine conjunctiva. We show that our model is suitable for the screening of drugs targeting scarring and/or inflammation, and amenable to the study of local drug delivery devices that can be inserted in between the two layers of the biomimetic. We propose that this multicellular-bilayer engineered tissue will be useful to study complex biological aspects of scarring and fibrosis, including the role of inflammation, with potentially significant implications for the management of scarring following glaucoma filtration surgery and other anterior ocular segment scarring conditions. Crucially, it uniquely allows the evaluation of new means of local drug delivery within a physiologically relevant tissue mimetic, mimicking intraoperative drug delivery in vivo.

Matrix Metalloproteinase Inhibition With Doxycycline Affects the Progression of Posttraumatic Osteoarthritis After Anterior Cruciate Ligament Rupture: Evaluation in a New Nonsurgical Murine ACL Rupture Model

BACKGROUND

Doxycycline has broad-spectrum activity as a matrix metalloproteinase (MMP) inhibitor and thus could reduce the progression of posttraumatic osteoarthritis (PTOA) after anterior cruciate ligament (ACL) rupture.

HYPOTHESIS

Doxycycline would inhibit progression of PTOA in a murine ACL rupture model.

STUDY DESIGN

Controlled laboratory study.

METHODS

For the in vitro study, cadaveric C57BL/6 male mice knees (N = 108) were used for the development of a nonsurgical ACL rupture model. For the in vivo study, 24 C57BL/6 male mice then underwent ACL rupture with our manual procedure and were divided into 4 groups: untreated control; doxycycline, 10 mg/kg/d; doxycycline, 50 mg/kg/d; and doxycycline, 100 mg/kg/d. Doxycycline was administered in drinking water beginning immediately after ACL rupture. Radiographic imaging and paw prints were evaluated at 3, 7, 14, and 28 days. The foot length and toe spread were analyzed as measures of function. Histology and MMP-13 immunohistochemistry were done at 4 weeks.

RESULTS

Radiographs demonstrated anterior tibial subluxation and meniscal extrusion after ACL rupture, confirming knee joint instability without fractures. Statistically significant differences in gait were found between the intact and experimental groups. Histologic examination demonstrated cartilage damage, meniscal tears, and mild osteoarthritis after ACL rupture, similar to what occurs in human patients. Hypertrophy of the posterior horn of the medial and lateral meniscus was found, and tears of the posterior horn of the menisci were common. All doxycycline groups had a lower score than the untreated control group, indicating less cartilage damage. The posterior tibia of the untreated group had the most cartilage damage as compared with the 3 doxycycline groups, with a significant difference between the untreated and 50-mg/kg/d doxycycline groups, suggesting that the latter dose may protect against proteoglycan loss and decrease the progression of osteoarthritis. The nondoxycycline group had the highest synovial inflammation score among all groups, indicating that doxycycline has an inhibitory effect on synovitis. There was significantly lower MMP-13 expression on the tibia in the doxycycline-treated groups, with a positive correlation between doxycycline concentration and MMP-13 inhibition.

CONCLUSION

Modulation of MMP-13 activity by doxycycline treatment may offer a novel biological pathway to decrease the progression of PTOA after ACL rupture.

CLINICAL RELEVANCE

Doxycycline is an approved, readily available drug with infrequent side effects of photosensitivity and gastrointestinal symptoms. Future clinical trials could evaluate doxycycline to reduce or prevent progressive cartilage damage after ACL rupture.

The Wound Healing Effect of Doxycycline after Corneal Alkali Burn in Rats

Purpose

To evaluate the wound healing effect of doxycycline and its underlying mechanisms in a rat model of corneal alkali burn.

Methods

Male SD rats were administered 1.0 N NaOH in the right cornea for 25 seconds and randomly divided into the doxycycline group and the control group, with 84 rats in each group. 1.0 g·L⁻¹ doxycycline eye drops (doxycycline group) or vehicle (control group) was topically instilled onto the rat cornea after chemical injury. Three days, 7 days, and 14 days after alkali burn, microscopy was used to observe corneal wound healing by fluorescein staining and the degree of corneal opacity. The expression of transforming growth factor-beta 1 (TGF-β1) and matrix metalloproteinase-9 (MMP-9) was detected by RT-PCR and ELISA, alpha-smooth muscle actin (a-SMA) levels were measured by immunofluorescent staining, and Western blot assays for TGF-β1, a-SMA, and nuclear factor-kappa B (NF-κB) were also performed.

Results

Corneal wound healing and corneal opacity scores were better in the doxycycline group than in the control group. Three, 7, and 14 days after corneal alkali burn, a significant increase in TGF-β1 was observed in corneas from the control group, compared with the corneas from the doxycycline group (P < 0.05). The corneal levels of MMP-9 in the doxycycline group were lower than those in the control group 3 days and 7 days after alkali burn (P < 0.05). In addition, doxycycline inhibited α-SMA expression and suppressed NF-κB expression.

Conclusion

Doxycycline treatment promoted corneal healing and reduced corneal opacity in SD rats. Doxycycline protected the cornea from alkali burn injury by reducing TGF-β1, MMP-9, NF-κB, and α-SMA expression.

The conjunctival transcriptome in Ethiopians after trichiasis surgery: associations with the development of eyelid contour abnormalities and the effect of oral doxycycline treatment

Background: Surgery to correct trichiasis is a key component of the World Health Organisation trachoma control strategy, however unfavourable outcomes such as eyelid contour abnormalities (ECA) following surgery are relatively common. This study aimed to understand the transcriptional changes associated with the early development of ECA and the impact of doxycycline, which has anti-inflammatory and anti-fibrotic properties, upon these transcription patterns. Methods: One thousand Ethiopians undergoing trichiasis surgery were enrolled in a randomised controlled trial following informed consent. Equal groups of randomly assigned individuals were orally administered with 100mg/day of doxycycline (n=499) or placebo (n=501) for 28 days. Conjunctival swabs were collected immediately prior to surgery and at one- and six-months post-surgery. 3’ mRNA sequencing was performed on paired baseline and one-month samples from 48 individuals; 12 in each treatment/ECA outcome group. qPCR validation was then performed for 46 genes of interest in 145 individuals who developed ECA at one month and 145 matched controls, using samples from baseline, one and six months. Results: All treatment/outcome groups upregulated genes associated with wound healing pathways at one month relative to baseline, however no individual differences were detected between groups. The summed expression of a highly coexpressed cluster of pro-fibrotic genes was higher in patients that developed ECA in the placebo group relative to controls. qPCR validation revealed that all genes in this cluster and a number of other pro-inflammatory genes were strongly associated with ECA, however these associations were not modulated by trial arm. Conclusions: The development of post-operative ECA is associated with overexpression of pro-inflammatory and pro-fibrotic genes including growth factors, matrix metalloproteinases, collagens and extracellular matrix proteins. There was no evidence that doxycycline modulated the association between gene expression and ECA.

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.

Oral doxycycline for the prevention of postoperative trachomatous trichiasis in Ethiopia: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Trachomatous trichiasis is treated surgically to prevent sight loss. Unfavourable surgical outcomes remain a major challenge. We investigated the hypothesis that doxycycline might reduce the risk of postoperative trichiasis following surgery in patients with trachomatous trichiasis through anti-matrix metalloproteinase and anti-inflammatory activity.

METHODS

In this randomised, double-blind, placebo-controlled trial, adults (aged >18 years) with upper lid trachomatous trichiasis in association with tarsal conjunctive scarring were recruited through community-based screening and surgical outreach campaigns in Ethiopia. Individuals who had previously had eyelid surgery were excluded. Participants were randomly assigned (1:1), with random block sizes of four or six, to receive oral doxycycline (100 mg once a day) or placebo for 28 days immediately after trichiasis surgery. Randomisation was stratified by surgeon. Patients, investigators, surgeons, and all other study team members were masked to study group allocation and treatment. Participants were examined at 10 days, and 1, 6, and 12 months after surgery. The primary outcome was the cumulative proportion of individuals who developed postoperative trichiasis by 12 months. Primary analyses were done in all participants who attended at least one of the four follow-up assessments. Safety analyses were done in all participants who attended either the 10 day or 1 month follow-up assessments. This trial is registered with the Pan African Clinical Trials Registry, number PACTR201512001370307.

FINDINGS

Between Dec 21, 2015, and April 6, 2016, 1000 patients with trichiasis were enrolled and randomly assigned to treatment (499 patients to doxycycline, 501 patients to placebo). All but one participant attended at least one follow-up assessment. Thus, 999 participants were assessed for the primary outcome: 498 in the doxycycline group and 501 in the placebo group. By month 12, 58 (12%) of 498 patients in the doxycycline group and 62 (12%) of 501 patients in the placebo group had developed postoperative trichiasis (adjusted odds ratio 0·91, 95% CI 0·61 to 1·34, p=0·63), with a risk difference of -0·5% (-4·5% to 3·5%). Significantly more patients in the doxycycline group had an adverse event than in the placebo group (18 [4%] of 498 vs six [1%] of 501; odds ratio 3·09, 95% CI 1·21-7·84; p=0·02). The most frequent adverse events in the doxycycline group were gastritis symptoms (n=9), constipation (n=4), and diarrhoea (n=4).

INTERPRETATION

Doxycycline did not reduce the risk of postoperative trichiasis and is therefore not indicated for the improvement of outcomes following trachomatous trichiasis surgery. Surgical programmes should continue to make efforts to strengthen surgical training and supervision to improve outcomes.

FUNDING

The Wellcome Trust.

Assessment of solid microneedle rollers to enhance transmembrane delivery of doxycycline and inhibition of MMP activity

Many chronic wounds exhibit high matrix metalloproteinase (MMP) activity that impedes the normal wound healing process. Intradermal delivery (IDD) of sub-antimicrobial concentrations of doxycycline, as an MMP inhibitor, could target early stages of chronic wound development and inhibit further wound progression. To deliver doxycycline intradermally, the skin barrier must be disrupted. Microneedle rollers offer a minimally invasive technique to penetrate the skin by creating multiple microchannels that act as temporary conduits for drugs to diffuse through. In this study, an innovative and facile approach for delivery of doxycycline across Strat-M^TM membrane was investigated using microneedle rollers. The quantity and rate of doxycycline diffusing through the micropores directly correlated with increasing microneedle lengths (250, 500 and 750 μm). Treatment of Strat-M^TM with microneedle rollers resulted in a reduction in fibroblast-mediated collagen gel contraction and MMP activity compared with untreated Strat-M^TM. Our results show that treatment of an epidermal mimetic with microneedle rollers provides sufficient permeabilization for doxycycline diffusion and inhibition of MMP activity. We conclude that microneedle rollers are a promising, clinically ready tool suitable for delivery of doxycycline intradermally to treat chronic wounds.

Genotype-Phenotype Associations of IL6 and PRG4 With Conjunctival Fibrosis After Glaucoma Surgery

Importance

Postsurgical fibrosis is a critical determinant of the long-term success of glaucoma surgery, but no reliable biomarkers are currently available to stratify the risk of scarring.

Objective

To compare the clinical phenotype of patients with conjunctival fibrosis after glaucoma surgery with candidate gene expression tissue biomarkers of fibrosis.

Design, Setting, and Participants

In this cross-sectional study, 42 patients were recruited at the time of glaucoma surgery at the Moorfields Eye Hospital from September 1, 2014, to September 1, 2016. The participants were divided into those with fibrosis and those without fibrosis.

Main Outcomes and Measures

Genotype-phenotype correlations of the IL6 or PRG4 gene and detailed clinical phenotype. The IL6 and PRG4 protein expression in conjunctival tissues was also assessed using in situ immunohistochemical analysis. Central bleb area, maximal bleb area, and bleb height were graded on a scale of 1 to 5 (1 indicating 0%; 2, 25%; 3, 50%; 4, 75%; and 5, 100%). Bleb vascularity was graded on a scale of 1 to 5 (1 indicating avascularity; 2, normal; 3, mild; 4, moderate; and 5, severe hyperemia).

Results

A total of 42 patients were recruited during the study period; 28 participants (67%) had previously undergone glaucoma surgery (fibrotic group) (mean [SD] age, 43.8 [3.6 years]; 16 [57%] female; 22 [79%] white), and 14 participants (33%) had not previously undergone glaucoma surgery (nonfibrotic group) (mean [SD] age, 47.7 [6.9] years; 4 [29%] female; 9 [64%] white). The fibrotic group had marked bleb scarring and vascularization and worse logMAR visual acuity. The mean (SD) grades were 1.4 (0.1) for central bleb area, 1.4 (0.1) for bleb height, and 3.4 (0.2) for bleb vascularity. The IL6 gene was upregulated in fibrotic cell lines (mean, 0.040) compared with nonfibrotic cell lines (mean, 0.011) (difference, 0.029; 95% CI, 0.015-0.043; P = .003). The PRG4 gene was also downregulated in fibrotic cell lines (0.002) compared with nonfibrotic cell lines (mean, 0.109; difference, 0.107; 95% CI, 0.104-0.110; P = .03). The study found a strong correlation between the IL6 gene and the number of glaucoma operations (r = 0.94, P < .001) and logMAR visual acuity (r = 0.64, P = .03). A moderate correlation was found between the PRG4 gene and the number of glaucoma operations (r = -0.72, P = .005) and logMAR visual acuity (r = -0.62, P = .03).

Conclusions and Relevance

IL6 and PRG4 represent potential novel tissue biomarkers of disease severity and prognosis in conjunctival fibrosis after glaucoma surgery. Future longitudinal studies with multiple postoperative measures are needed to validate the effect of these potential biomarkers of fibrosis.

Genome-wide RNA-Sequencing analysis identifies a distinct fibrosis gene signature in the conjunctiva after glaucoma surgery

Fibrosis-related events play a part in most blinding diseases worldwide. However, little is known about the mechanisms driving this complex multifactorial disease. Here we have carried out the first genome-wide RNA-Sequencing study in human conjunctival fibrosis. We isolated 10 primary fibrotic and 7 non-fibrotic conjunctival fibroblast cell lines from patients with and without previous glaucoma surgery, respectively. The patients were matched for ethnicity and age. We identified 246 genes that were differentially expressed by over two-fold and p < 0.05, of which 46 genes were upregulated and 200 genes were downregulated in the fibrotic cell lines compared to the non-fibrotic cell lines. We also carried out detailed gene ontology, KEGG, disease association, pathway commons, WikiPathways and protein network analyses, and identified distinct pathways linked to smooth muscle contraction, inflammatory cytokines, immune mediators, extracellular matrix proteins and oncogene expression. We further validated 11 genes that were highly upregulated or downregulated using real-time quantitative PCR and found a strong correlation between the RNA-Seq and qPCR results. Our study demonstrates that there is a distinct fibrosis gene signature in the conjunctiva after glaucoma surgery and provides new insights into the mechanistic pathways driving the complex fibrotic process in the eye and other tissues.

An Ilomastat-CD Eye Drop Formulation to Treat Ocular Scarring

Purpose

The purpose of this study was to develop a topical matrix metalloproteinase inhibitor preparation for antiscarring therapy.

Methods

The broad spectrum matrix metalloproteinase inhibitor ilomastat was formulated using 2-hydroxypropyl-β-cyclodextrin in aqueous solution. In vitro activity of ilomastat-cyclodextrin (ilomastat-CD) was examined using fibroblasts seeded in collagen. Permeation of ilomastat-CD eye drop through pig eye conjunctiva was confirmed using Franz diffusion cells. Ilomastat-CD eye drop was applied to rabbit eyes in vivo, and the distribution of ilomastat in ocular tissues and fluids was determined by liquid chromatography-mass spectroscopy.

Results

The aqueous solubility of ilomastat-CD was ∼1000 μg/mL in water and 1400 μg/mL in PBS (pH 7.4), which is greater than ilomastat alone (140 and 160 μg/mL in water and PBS, respectively). The in vitro activity of ilomastat-CD to inhibit collagen contraction in the presence of human Tenon fibroblast cells was unchanged compared to uncomplexed ilomastat. Topically administered ilomastat-CD in vivo to rabbit eyes resulted in a therapeutic concentration of ilomastat being present in the sclera and conjunctiva and within the aqueous humor.

Conclusions

Ilomastat-CD has the potential to be formulated as an eye drop for use as an antifibrotic, which may have implications for the prevention of scarring in many settings, for example glaucoma filtration surgery.

Local delivery of novel MRTF/SRF inhibitors prevents scar tissue formation in a preclinical model of fibrosis

The myocardin-related transcription factor/serum response factor (MRTF/SRF) pathway represents a promising therapeutic target to prevent fibrosis. We have tested the effects of new pharmacological inhibitors of MRTF/SRF signalling in a preclinical model of fibrosis. CCG-222740, a novel MRTF/SRF inhibitor, markedly decreased SRF reporter gene activity and showed a greater inhibitory effect on MRTF/SRF target genes than the previously described MRTF-A inhibitor CCG-203971. CCG-222740 was also five times more potent, with an IC₅₀ of 5 μM, in a fibroblast-mediated collagen contraction assay, was less cytotoxic, and a more potent inhibitor of alpha-smooth muscle actin protein expression than CCG-203971. Local delivery of CCG-222740 and CCG-203971 in a validated and clinically relevant rabbit model of scar tissue formation after glaucoma filtration surgery increased the long-term success of the surgery by 67% (P < 0.0005) and 33% (P < 0.01), respectively, and significantly decreased fibrosis and scarring histologically. Unlike mitomycin-C, neither CCG-222740 nor CCG-203971 caused any detectable epithelial toxicity or systemic side effects with very low drug levels measured in the aqueous, vitreous, and serum. We conclude that inhibitors of MRTF/SRF-regulated gene transcription such as CCG-222740, potentially represent a new therapeutic strategy to prevent scar tissue formation in the eye and other tissues.

Linking immune responses with fibrosis in allergic eye disease

PURPOSE OF REVIEW

Here, we explore an emerging theme in the literature, which is the role of dendritic cells in the causation of fibrosis. To fully appreciate this pathway to disease, we also review the most recent literature regarding dendritic cell biology as it pertains to ocular surface tissues. On the basis of this information, we propose a unifying hypothesis for how dendritic cells may cause conjunctival fibrosis in the allergy setting.

RECENT FINDINGS

Work in models of airway remodeling and liver fibrosis has pointed to a potentially central role for dendritic cells in the pathobiology of fibrosis. Indeed, these cells are recognized as the most potent antigen-presenting cells, and as such activate T lymphocytes that are profibrotic under certain conditions. However, recent findings suggest a more direct role for dendritic cells, which opens up the possibility that a similar pathway may be relevant in the causation of conjunctival fibrosis, particularly in allergic eye disease.

SUMMARY

Conjunctival fibrosis is a serious clinical concern and is associated with chronic inflammation of the ocular surface tissue, such as in allergic eye disease. Dendritic cells are required in mediating allergic disease by activating pathologic T lymphocytes. Recent findings pointing to a central role for dendritic cell in fibrosis may, however, mean that these cells could also be contributing directly to conjunctival fibrosis. If so, furthering our understanding of dendritic cells could lead to the identification of novel and more effective therapeutic strategies to treat this disease.

Fibroblasts profiling in scarring trachoma identifies IL-6 as a functional component of a fibroblast-macrophage pro-fibrotic and pro-inflammatory feedback loop

Trachoma is a conjunctiva scarring disease, which is the leading infectious cause of blindness worldwide. Yet, the molecular mechanisms underlying progressive fibrosis in trachoma are unknown. To investigate the contribution of local resident fibroblasts to disease progression, we isolated conjunctival fibroblasts from patients with scarring trachoma and matching control individuals, and compared their gene expression profiles and functional properties in vitro. We show that scarring trachoma fibroblasts substantially differ from control counterparts, displaying pro-fibrotic and pro-inflammatory features matched by an altered gene expression profile. This pro-inflammatory signature was exemplified by increased IL-6 expression and secretion, and a stronger response to macrophage-mediated stimulation of contraction. We further demonstrate that scarring trachoma fibroblasts can promote Akt phosphorylation in macrophages in an IL-6 –dependent manner. Overall this work has uncovered a distinctive molecular fingerprint for scarring trachoma fibroblasts, and identified IL-6- as a potential contributor to the chronic conjunctival fibrosis, mediating reciprocal pro-fibrotic/pro-inflammatory interactions between macrophages and fibroblasts.

Doxycycline inhibits TGF-β1-induced extracellular matrix production in nasal polyp-derived fibroblasts

BACKGROUND

Doxycycline has been shown to have antibacterial and anti-inflammatory effects and suppresses collagen biosynthesis. The purpose of this study was to evaluate the effects of doxycycline on transforming growth factor (TGF)-β1-induced myofibroblast differentiation and extracellular matrix production in nasal polyp-derived fibroblasts (NPDFs). We also determined the molecular mechanisms of action for doxycycline.

METHODS

NPDFs were isolated from nasal polyps from 8 patients. Doxycycline was used to pretreat TGF-β1-induced NPDFs. Cytotoxicity was evaluated using a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide assay. Expression levels of α-smooth muscle actin (SMA) and fibronectin were measured using Western blot, reverse-transcription polymerase chain reaction, and immunofluorescence staining. Total collagen production was analyzed with the Sircol collagen assay, while mitogen-activated protein kinase (MAPK) and NF-κB activation were determined using Western blot analysis. Luciferase assay was used to evaluate the transcriptional activity of NF-κB.

RESULTS

Although doxycycline (0 to 40 μg/mL) had no significant cytotoxic effects in TGF-β1-induced NPDFs, it significantly reduced the expression levels of α-SMA, fibronectin, and collagen in TGF-β1-induced NPDFs in a dose-dependent manner. Doxycycline also inhibited the TGF-β1-induced activation of p38, c-Jun NH2 -terminal kinase (JNK), and NF-κB, and its inhibitory effects were similar to those of the specific inhibitors for each.

CONCLUSION

Doxycycline has an inhibitory effect on TGF-β1-induced myofibroblast differentiation and extracellular matrix production via the p38 and JNK/NF-κB signal pathways in NPDFs.

Eyelid and Sternum Fibroblasts Differ in Their Contraction Potential and Responses to Inflammatory Cytokines

Background:

Adverse skin scarring varies by anatomical site with, for example, presternal skin showing a greater hypertrophic response when compared with eyelid; such differences have traditionally been attributed to regional variations in skin tension, thickness, and Langer’s lines. Fibroblasts are the main cell implicated in fibrosis, and they too are known to show anatomical variation in their expression, differentiation, and intercellular interactions. We, therefore, investigated whether intrinsic differences in skin fibroblasts derived from separate locations might contribute to the observed discrepancies in clinical scarring.

Methods:

Primary in vitro cultures were established using matched eyelid and presternal skin from 3 healthy donors undergoing blepharoplasty surgery. We used an in vitro collagen gel model of fibroblast-mediated tissue contraction to compare the properties of the dermal fibroblasts from each site. Cell contractile force and matrix stiffness were assessed in 3-dimensional tissue constructs using an automated high-throughput device.

Results:

Dermal fibroblasts isolated from eyelid and sternum differ both in their ability to contract a gel matrix and in their response to cytokine stimulation; despite having lower intrinsic contractile force (P < 0.01) and resting stiffness (P < 0.02), the presternal cells were more contractile (P < 0.001) following stimulation with serum, or inflammatory cytokines transforming growth factor-β (P < 0.01) and interleukin-1β (P < 0.05).

Conclusions:

The propensity to cutaneous scarring may, at least in part, result from intrinsic differences in the local fibroblasts’ ability to contract and their sensitivity to inflammatory cytokines. Improved understanding of the underlying molecular pathways should prove useful in identifying new therapeutic targets for altering surgical and other scarring.

The significance of matrix metalloproteinase (MMP)-2 and MMP-9 in the ischemic stroke

There is a continuous urgent need to explore the pathogenesis and biochemical changes within the infarcted area during acute ischemic stroke (IS). Matrix metalloproteinases (MMPs), prevailing extracellular endopeptideses, can digest proteins located extracellulary, e.g. collagen, proteoglycans, elastin or fibronectin. Among MMPs, gelatinases (MMP-2 and MMP-9) are the most investigated enzymes. Gelatinases possess the ability to active numerous pro-inflammatory agents as chemokine CXCL-8, interleukin 1β or tumor necrosis factor α. Moreover, due to digestion of collagen type IV (the component of basal membranes) and tight junction proteins (TJPs) they facilitate to cross the endothelium by leukocytes. Due to the significant role of gelatinases during brain ischemia, their selective inhibition seems to be an interesting kind of treatment of acute stroke. The synthetic inhibitors of gelatineses decrease the infarct volume in animal models of IS. In clinical practice statins, the lipid-lowering drugs possess the ability to inhibit the activity of MMP-9 during acute IS. This review briefly provides the most important information about the involvement of MMP-2 and MMP-9 in the pathogenesis of brain ischemia.