The Versatile Role of Matrix Metalloproteinase for the Diverse Results of Fibrosis Treatment

A Novel Gene DUSP8 Missense Mutation Causes Nonsyndromic Hereditary Gingival Fibromatosis by Dysregulating Lysine Lactylation

AIMS

The goal of this study was to explore new candidate genes and pathogenesis mechanisms of nonsyndromic hereditary gingival fibromatosis (nsHGF) and to provide an experimental basis for the diagnosis of nsHGF.

METHODS

Whole-exome sequencing (WES) was performed on peripheral blood DNA from three nsHGF family members to screen for new candidate genes, and Sanger sequencing and related databases were used to verify the pathogenicity of this gene deficiency. Moreover, the effects of gene deficiency on the biological characteristics of human gingival fibroblasts (HGFs) were evaluated via cell proliferation assays, extracellular matrix (ECM) deposition detection, cell apoptosis and cell cycle assessment, cell migration and gene expression analyses.

RESULTS

A novel missense mutation in dual-specificity phosphatase 8 (DUSP8, c.1348C>T, p.R450C), which is in the nsHGF-related GINGF4 locus, was identified via WES analysis. A functional study revealed that knocking down DUSP8 expression increased cell proliferation, cell migration and the expression of profibrotic factors (particularly COL1A1), inhibited cell apoptosis, and ultimately resulted in nsHGF. Similarly, this DUSP8 mutation inhibited the expression of the encoded protein and promoted cell proliferation and the expression of profibrotic factors. In addition, both DUSP8 knockdown and DUSP8 mutation induced nsHGF by accelerating glycolysis and panlysine lactylation (Kla) to promote cell proliferation and the expression of ECM-related factors.

CONCLUSION

DUSP8 deficiency might be a novel pathogenic factor that contributes to nsHGF.

CCL24 and Fibrosis: A Narrative Review of Existing Evidence and Mechanisms

Tissue fibrosis results from a dysregulated and chronic wound healing response accompanied by chronic inflammation and angiogenesis. Regardless of the affected organ, fibrosis shares the following common hallmarks: the recruitment of immune cells, fibroblast activation/proliferation, and excessive extracellular matrix deposition. Chemokines play a pivotal role in initiating and advancing these fibrotic processes. CCL24 (eotaxin-2) is a chemokine secreted by immune cells and epithelial cells, which promotes the trafficking of immune cells and the activation of profibrotic cells through CCR3 receptor binding. Higher levels of CCL24 and CCR3 were found in the tissue and sera of patients with fibro-inflammatory diseases, including primary sclerosing cholangitis (PSC), systemic sclerosis (SSc), and metabolic dysfunction-associated steatohepatitis (MASH). This review delves into the intricate role of CCL24 in fibrotic diseases, highlighting its impact on fibrotic, immune, and vascular pathways. We focus on the preclinical and clinical evidence supporting the therapeutic potential of blocking CCL24 in diseases that involve excessive inflammation and fibrosis.

Synovial Matrix Remodeling and Inflammatory Profile in Disc Displacement of the Temporomandibular Joint: An Observational Case-Control Study

Background: Pain-related temporomandibular joint disorders (TMJD) are a major public health problem, including the diagnoses of disc displacement (DD) with and without reduction (DDwR/DDwoR). Objectives: The study aimed to examine the matrix remodeling and the inflammatory profile in synovial tissues of patients with TMJ-DD, with a view to understand the pathophysiology, and to contribute to the development of tissue-based diagnostic criteria. Methods: This laboratory-based observational case-control study included 30 synovial tissue samples obtained from 30 patients, diagnosed with delayed (DO) or sudden (SO) onset of DDwoR, which were compared against the reference patient material, DDwR (n = 10/diagnosis group). Tissue samples were investigated histologically and via quantitative immunohistochemistry for a panel of antibodies targeted against extracellular matrix proteins and inflammatory markers. The data were analyzed using a generalized linear model with a gamma family distribution (p < 0.05). Results: Quantification of immunostaining revealed significant differences in the distribution of collagen type III (DO, p < 0.001), lumican (DO, p < 0.05), matrix metalloproteinase-2 (DO, p < 0.05), CD4 T-helper cells (DO, p < 0.01; SO, p < 0.001), and CD68 monocytic immune cells (both SO and DO, p < 0.001) in DDwoR groups compared to the reference patient material, DDwR. Conclusions: The observations confirmed differences in matrix remodeling and an increase in local inflammatory activity in the DDwoR diagnosis compared to the reference patient material, DDwR. The study highlighted the importance of synovial tissue characterization to unite micropathology and clinical findings, leading to more reliable diagnostic tools.

Integrating Natural Deep Eutectic Solvents into Nanostructured Lipid Carriers: An Industrial Look

The industries are searching for greener alternatives for their productions due to the rising concern about the environment and creation of waste and by-products without industrial utility for that specific line of products. This investigation describes the development of two stable nanostructured lipid carriers (NLCs): one is the formulation of a standard NLC, and the other one is the same NLC formulation associated with a natural deep eutectic solvent (NaDES). The research presents the formulation paths of the NLCs through completeness, which encompass dynamic light scattering (DLS), zeta potential tests, and pH. Transmission electron microscopy (TEM) and confocal microscopy were performed to clarify the morphology. Cytotoxicity tests with zebrafish were realized, and the results are complementary to the in vitro outcomes reached with fibroblast L132 tests by the MTT technique and the zymography test. Infrared spectroscopy and X-ray diffractometry tests elucidated the link between the physicochemical characteristics of the formulation and its behavior and properties. Different cooling techniques were explored to prove the tailorable properties of the NLCs for any industrial applications. In conclusion, the compiled results show the successful formulation of new nanocarriers based on a sustainable, eco-friendly, and highly tailorable technology, which presents low cytotoxic potential.

The Effects of Chronic Immunosuppressive Treatment on Morphological Changes in Cardiac Tissue and the Balance between Matrix Metalloproteinases (MMP-2 and MMP-9) and Their Inhibitors in the Rat Heart

Using different three-drug immunosuppressive treatment regimens in a rat model, we aimed to determine the effects of long-term therapy on metalloproteinase-2 and metalloproteinase-9 activity and the expression of their inhibitors, as well as to assess the morphology of the animals' cardiac tissue. Our results suggest that chronic use of immunosuppressive drugs disrupts the balance between the activity of MMPs and TIMPs. Depending on the type of drug regimen used, this leads to abnormalities in the cardiac structure, collagen fiber accumulation, or cardiomyocyte hypertrophy. The information obtained in the present study allows us to conclude that the chronic treatment of rats with the most common clinical immunosuppressive regimens may contribute to abnormalities in the myocardial structure and function. The results presented in this study may serve as a prelude to more in-depth analyses and additional research into the optimal selection of an immunosuppressive treatment with the lowest possible risk of cardiovascular complications for patients receiving organ transplants.

Bioactive Compounds and Cardiac Fibrosis: Current Insight and Future Prospect

Cardiac fibrosis is a pathological condition characterized by excessive deposition of collagen and other extracellular matrix components in the heart. It is recognized as a major contributor to the development and progression of heart failure. Despite significant research efforts in characterizing and identifying key molecular mechanisms associated with myocardial fibrosis, effective treatment for this condition is still out of sight. In this regard, bioactive compounds have emerged as potential therapeutic antifibrotic agents due to their anti-inflammatory and antioxidant properties. These compounds exhibit the ability to modulate fibrogenic processes by inhibiting the production of extracellular matrix proteins involved in fibroblast to myofibroblast differentiation, or by promoting their breakdown. Extensive investigation of these bioactive compounds offers new possibilities for preventing or reducing cardiac fibrosis and its detrimental consequences. This comprehensive review aims to provide a thorough overview of the mechanisms underlying cardiac fibrosis, address the limitations of current treatment strategies, and specifically explore the potential of bioactive compounds as therapeutic interventions for the treatment and/or prevention of cardiac fibrosis.

Anti-Fibrotic Effects of RF Electric Currents

Hypertrophic scars and keloids are two different manifestations of excessive dermal fibrosis and are caused by an alteration in the normal wound-healing process. Treatment with radiofrequency (RF)-based therapies has proven to be useful in reducing hypertrophic scars. In this study, the effect of one of these radiofrequency therapies, Capacitive Resistive Electrical Transfer Therapy (CRET) on biomarkers of skin fibrosis was investigated. For this, in cultures of human myofibroblasts treated with CRET therapy or sham-treated, proliferation (XTT Assay), apoptosis (TUNEL Assay), and cell migration (Wound Closure Assay) were analyzed. Furthermore, in these cultures the expression and/or localization of extracellular matrix proteins such as α-SMA, Col I, Col III (immunofluorescence), metalloproteinases MMP1 and MMP9, MAP kinase ERK1/2, and the transcription factor NFκB were also investigated (immunoblot). The results have revealed that CRET decreases the expression of extracellular matrix proteins, modifies the expression of the metalloproteinase MMP9, and reduces the activation of NFκB with respect to controls, suggesting that this therapy could be useful for the treatment of fibrotic pathologies.

Diagnostic and prognostic biomarkers reflective of cardiac remodelling in diabetes mellitus: A scoping review

AIMS

The aim of this scoping review is to evaluate the current biomarkers used in the assessment of adverse cardiac remodelling in people with diabetes mellitus (DM) and in the diagnosis and prognosis of subsequent cardiovascular disease. We aim to discuss the biomarkers' pathophysiological roles as a reflection of the cardiac remodelling mechanisms in the presence of DM.

METHODS

We performed the literature search to include studies from 2003 to 2021 using the following databases: MEDLINE, Scopus, Web of Science, PubMed, and Cochrane library. Articles that met our inclusion criteria were screened and appraised before being included in this review. The PRISMA guidelines for Scoping Reviews were followed.

RESULTS

Our literature search identified a total of 43 eligible articles, which were included in this scoping review. We identified 15 different biomarkers, each described by at least two studies, that were used to determine signs of cardiac remodelling in cardiovascular disease (CVD) and people with DM. NT-proBNP was identified as the most frequently employed biomarker in this context; however, we also identified emerging biomarkers including hs-CRP, hs-cTnT, and Galectin-3.

CONCLUSION

There is a complex relationship between DM and cardiovascular health, where more research is needed. Current biomarkers reflective of adverse cardiac remodelling in DM are often used to diagnose other CVDs, such as NT-proBNP for heart failure. Hence there is a need for identification of specific biomarkers that can detect early signs of cardiac remodelling in the presence of DM. Further research into these biomarkers and mechanisms can deepen our understanding of their role in DM-associated CVD and lead to better preventative therapies.

Effect of Percutaneous Biliary Drainage on Enzyme Activity of Serum Matrix Metalloproteinase-9 in Patients with Malignant Hilar Obstructive Hyperbilirubinemia

Background and Objectives. Cholestasis activates complex mechanisms of liver injury and as a result has an increased production of matrix metalloproteinases (MMP). Depending on the stage of liver disease, different matrix metalloproteinases expressions have been detected and could serve as indirect biomarkers as well as therapeutic targets. MMP-9 proteolytic activity has a proven role in both liver regeneration and neoplastic cell invasion in various malignancies. The purpose of this prospective cohort study was to evaluate the effect of external biliary drainage on enzyme activity of MMP-9 in the serum of patients with malignant hilar biliary obstruction. Materials and Methods. Between November 2020 and April 2021, 45 patients with malignant hilar biliary obstruction underwent percutaneous biliary drainage following determination of serum MMP-9 enzyme activity (before treatment and 4 weeks after the treatment) by gelatin zymography. Results. MMP-9 values decreased statistically significantly 4 weeks after percutaneous biliary drainage (p = 0.028) as well as the value of total bilirubin (p < 0.001), values of direct bilirubin (p < 0.001), aspartate aminotransferase (AST) (p < 0.001), alanine transaminase (ALT) (p < 0.001), and gamma-glutamyl transferase (GGT) (p < 0.001). Conclusions. In patients with malignant hilar biliary obstruction treated by external percutaneous biliary drainage for cholestasis resolution, a significant reduction in MMP-9 serum values was noted 4 weeks after the treatment.

Effects of Expression of Matrix Metalloproteinases and Discoidin Domain Receptors in Ligamentum Flavum Fibrosis in Patients with Degenerative Lumbar Canal Stenosis

STUDY DESIGN

This is a retrospective cohort study.

PURPOSE

This study aimed to clarify the role of crosstalk between discoidin domain receptors (DDRs) and matrix metalloproteinases (MMPs) in the ligamentum flavum (LF) fibrosis obtained from patients with degenerative lumbar canal stenosis (DLCS).

OVERVIEW OF LITERATURE

The DDRs, DDR1 and DDR2, are cell surface receptors and have an essential role in collagen fiber accumulation in several fibrotic diseases. MMPs are one of the critical factors in extracellular matrix remodeling and elastic fiber degradation in LF tissues. However, the crosstalk between DDRs and MMPs and the role of this molecular signal in LF fibrosis remain unclear.

METHODS

A total of 35 patients were divided into two groups in this study. Spinal surgery was performed in 23 of these patients with the diagnosis of DLCS. Twelve patients with lumbar disk herniation (LDH) were included in the control group. On axial T2-weighted magnetic resonance imaging, LF thickness was measured bilaterally at the level of the facet joint. Histology, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot analyses were performed on LF tissue samples. LF tissues were stained with hematoxylin and eosin. In addition, the grade of fibrosis was histologically assessed using Masson trichrome triple staining. DDR1 and DDR2 Western blot analyses were performed. DDR1, DDR2, MMP2, MMP3, MMP9, and MMP13 expression levels were measured using qRT-PCR analysis.

RESULTS

The grade of fibrosis and LF thickness were significantly higher in the DLCS patients than in the LDH patients. DDR1 and DDR2 gene expression and protein levels in LF tissues are significantly greater in DLCS samples than in control samples, according to both qRT-PCR and Western blot analyses. In addition, we detected a significant expression of the MMP3, MMP9, and MMP13, which are known to have important roles in extracellular matrix remodeling in DLCS. Furthermore, we discovered a link between DDR protein levels and LF thickness, fibrosis, and MMP3/MMP9.

CONCLUSIONS

Our results indicate that DDR1, DDR2, and MMP3 and MMP9 signals can be correlated with each other in LF tissues and be promoted LF fibrosis leading to spinal canal narrowing in patients with DLCS.

Polyphenol-driven facile assembly of a nanosized acid fibroblast growth factor-containing coacervate accelerates the healing of diabetic wounds

Diabetic wounds are challenging to heal due to complex pathogenic abnormalities. Routine treatment with acid fibroblast growth factor (aFGF) is widely used for diabetic wounds but hardly offers a satisfying outcome due to its instability. Despite the emergence of various nanoparticle-based protein delivery approaches, it remains challenging to engineer a versatile delivery system capable of enhancing protein stability without the need for complex preparation. Herein, a polyphenol-driven facile assembly of nanosized coacervates (AE-NPs) composed of aFGF and Epigallocatechin-3-gallate (EGCG) was constructed and applied in the healing of diabetic wounds. First, the binding patterns of EGCG and aFGF were predicted by molecular docking analysis. Then, the characterizations demonstrated that AE-NPs displayed higher stability in hostile conditions than free aFGF by enhancing the binding activity of aFGF to cell surface receptors. Meanwhile, the AE-NPs also had a powerful ability to scavenge reactive oxygen species (ROS) and promote angiogenesis, which significantly accelerated full-thickness excisional wound healing in diabetic mice. Besides, the AE-NPs suppressed the early scar formation by improving collagen remodeling and the mechanism was associated with the TGF-β/Smad signaling pathway. Conclusively, AE-NPs might be a potential and facile strategy for stabilizing protein drugs and achieving the scar-free healing of diabetic wounds. STATEMENT OF SIGNIFICANCE: Diabetic chronic wound is among the serious complications of diabetes that eventually cause the amputation of limbs. Herein, a polyphenol-driven facile assembly of nanosized coacervates (AE-NPs) composed of aFGF and EGCG was constructed. The EGCG not only acted as a carrier but also possessed a therapeutic effect of ROS scavenging. The AE-NPs enhanced the binding activity of aFGF to cell surface receptors on the cell surface, which improved the stability of aFGF in hostile conditions. Moreover, AE-NPs significantly accelerated wound healing and improved collagen remodeling by regulating the TGF-β/Smad signaling pathway. Our results bring new insights into the field of polyphenol-containing nanoparticles, showing their potential as drug delivery systems of macromolecules to treat diabetic wounds.

Dynamic human liver proteome atlas reveals functional insights into disease pathways

Deeper understanding of liver pathophysiology would benefit from a comprehensive quantitative proteome resource at cell type resolution to predict outcome and design therapy. Here, we quantify more than 150,000 sequence-unique peptides aggregated into 10,000 proteins across total liver, the major liver cell types, time course of primary cell cultures, and liver disease states. Bioinformatic analysis reveals that half of hepatocyte protein mass is comprised of enzymes and 23% of mitochondrial proteins, twice the proportion of other liver cell types. Using primary cell cultures, we capture dynamic proteome remodeling from tissue states to cell line states, providing useful information for biological or pharmaceutical research. Our extensive data serve as spectral library to characterize a human cohort of non-alcoholic steatohepatitis and cirrhosis. Dramatic proteome changes in liver tissue include signatures of hepatic stellate cell activation resembling liver cirrhosis and providing functional insights. We built a web-based dashboard application for the interactive exploration of our resource (www.liverproteome.org).

Obeticholic Acid Reduces Kidney Matrix Metalloproteinase Activation following Partial Hepatic Ischemia/Reperfusion Injury in Rats

We have previously demonstrated that the farnesoid X receptor (FXR) agonist obeticholic acid (OCA) protects the liver via downregulation of hepatic matrix metalloproteinases (MMPs) after ischemia/reperfusion (I/R), which can lead to multiorgan dysfunction. The present study investigated the capacity of OCA to modulate MMPs in distant organs such as the kidney. Male Wistar rats were dosed orally with 10 mg/kg/day of OCA (5 days) and were subjected to 60-min partial hepatic ischemia. After 120-min reperfusion, kidney biopsies (cortex and medulla) and blood samples were collected. Serum creatinine, kidney MMP-2, and MMP-9-dimer, tissue inhibitors of MMPs (TIMP-1, TIMP-2), RECK, TNF-alpha, and IL-6 were monitored. MMP-9-dimer activity in the kidney cortex and medulla increased after hepatic I/R and a reduction was detected in OCA-treated I/R rats. Although not significantly, MMP-2 activity decreased in the cortex of OCA-treated I/R rats. TIMPs and RECK levels showed no significant differences among all groups considered. Serum creatinine increased after I/R and a reduction was detected in OCA-treated I/R rats. The same trend occurred for tissue TNF-alpha and IL-6. Although the underlying mechanisms need further investigation, this is the first study showing, in the kidney, beneficial effects of OCA by reducing TNF-alpha-mediated expression of MMPs after liver I/R.

Concentration of Serum Matrix Metalloproteinase-3 in Patients With Primary Biliary Cholangitis

Background and Aims

Metalloproteinases (MMPs) are involved in many distinct processes in the liver. Matrix metalloproteinase-3 (MMP-3) plays an important role in connective tissue remodeling, degradation of collagen (types II, III, IV, IX, and X), proteoglycans, fibronectin, laminin, and elastin. In addition, MMP-3 can also activate other MMPs such as MMP-1, MMP-7, and MMP-9. Primary biliary cholangitis (PBC) is a cholestatic, autoimmune liver disease, characterized by the progressive destruction of intrahepatic bile ducts, leading to cholestasis, fibrosis, cirrhosis, and liver failure. Fibrosis is the result of an imbalance between production and degradation of the extracellular matrix surrounding hepatocytes. Our aim in the present study was to determine whether the measurement of serum MMP-3 is clinically useful for assessing ongoing liver fibrosis in patients with PBC.

Methods

The MMP-3 concentration was determined in 182 PBC patients and 80 non-PBC controls using a commercially available ELISA kit.

Results

Higher concentrations of MMP-3 were found in 61% of PBC patients. PBC subjects had greater MMP-3 levels than controls: 68.9 ± 62.6 vs 21.3 ± 7.4 ng/mL, p &lt; 0.001 for healthy subjects; 68.9 ± 62.6 vs 22.7 ± 7.6 ng/mL, p = 0.022 for autoimmune hepatitis controls; and 68.9 ± 62.6 vs 37.2 ± 17.4 ng/mL, p = 0.002 for primary sclerosing cholangitis controls. The serum MMP-3 concentration was significantly elevated in patients with higher bilirubin concentration (107.6 ± 85.8 vs 61.6 ± 46.1 ng/mL, p &lt; 0.001) and was correlated with the level of antimitochondrial antibodies specific for PBC. The concentration of MMP-3 in sera of PBC patients was also found to correlate with the state of liver fibrosis (OR = 4.3; p &lt; 0.01).

Conclusions

Our study demonstrated significantly higher MMP-3 levels in PBC patients than in healthy and pathological controls. Increased MMP-3 concentrations were positively correlated with various clinical and immunological parameters, and advanced liver fibrosis. The level of MMP-3 was associated with hepatic dysfunction and could play a role in the pathophysiology of hepatic fibrosis in PBC.

The Effects and Mechanisms of the Rapamycin-eluting Stent in Urethral Stricture Prevention in Rabbits

BACKGROUND

Rapamycin was shown to reduce transforming growth factor β1 (TGF-β1) expression, inhibit the Mammalian target of rapamycin function, and prevent TGF-β1-induced pulmonary fibrosis. Rapamycin-eluting stents (RES) were successfully used to prevent coronary artery restenosis. Urethral stricture is one of the most challenging problems in urology. Thus, combining the pharmacological effects of rapamycin and the mechanical support of the stent on the urethra may prevent urethral stricture formation. However, the use of RES for urethral stricture treatment has not been studied.

AIMS

To observe the effects of RES in urethral stricture in a rabbit model.

STUDY DESIGN

Animal experimentation.

METHODS

Twenty adult male New Zealand rabbits were randomly divided into control, urethral stricture model, bare-metal stent, and RES groups. The rabbits in the control group underwent urethroscopy alone without electrocoagulation. The rabbit model of urethral stricture was established by electrocoagulation using a self-made electrocoagulation device under direct vision using ureteroscopy. After model establishment, the rabbits in the bare-metal stent and RES groups received stent placement by ureteroscopy. On day 30, retrograde urethrography was performed to assess urethral stricture formation, ureteroscopy to remove the stents, and histological examinations to assess the degree of fibrosis. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were used to evaluate the expression levels of TGF-β1, Smad3, and matrix metalloproteinase 1 (MMP1).

RESULTS

Urethral stricture formation was seen in the model group, whereas not in the bare-metal stent group. The bare-metal stents did not displace but were difficult to remove. In the RES group, RES was dislodged in itself at postoperative day 27 in one rabbit, whereas successfully removed by ureteroscopy in the remaining four rabbits, and urethral stricture formation was not seen on retrograde urethrography after stent removal. Histological examination revealed a large number of dense fibroblasts and blue-stained collagen fibers in the bare-metal stent group, whereas the number of fibroblasts and collagen fibers under the mucosa was reduced in the RES group. RT-qPCR and Western blot analyses showed that the messenger ribonucleic acid (mRNA) and protein expression of TGF-β1and Smad3 was significantly decreased, and mRNA and protein expression of MMP1 was significantly increased in the RES group than that in the model ((P < 0.001) and bare-metal stent groups (P < 0.001).

CONCLUSION

RES can effectively prevent electrocoagulation-induced urethral stricture in rabbits. The mechanism may be related to the effect of rapamycin on inhibiting TGF-β1 and Smad3 expression and promoting MMP1 expression in urethral tissues.

Hepatic fibrosis 2022: Unmet needs and a blueprint for the future

Steady progress over four decades toward understanding the pathogenesis and clinical consequences of hepatic fibrosis has led to the expectation of effective antifibrotic drugs, yet none has been approved. Thus, an assessment of the field is timely, to clarify priorities and accelerate progress. Here, we highlight the successes to date but, more importantly, identify gaps and unmet needs, both experimentally and clinically. These include the need to better define cell-cell interactions and etiology-specific elements of fibrogenesis and their link to disease-specific drivers of portal hypertension. Success in treating viral hepatitis has revealed the remarkable capacity of the liver to degrade scar in reversing fibrosis, yet we know little of the mechanisms underlying this response. Thus, there is an exigent need to clarify the cellular and molecular mechanisms of fibrosis regression in order for therapeutics to mimic the liver's endogenous capacity. Better refined and more predictive in vitro and animal models will hasten drug development. From a clinical perspective, current diagnostics are improving but not always biologically plausible or sufficiently accurate to supplant biopsy. More urgently, digital pathology methods that leverage machine learning and artificial intelligence must be validated in order to capture more prognostic information from liver biopsies and better quantify the response to therapies. For more refined treatment of NASH, orthogonal approaches that integrate genetic, clinical, and pathological data sets may yield treatments for specific subphenotypes of the disease. Collectively, these and other advances will strengthen and streamline clinical trials and better link histologic responses to clinical outcomes.

Injection of Matrix Metalloproteinase-9 Leads to Ventricular Remodeling

OBJECTIVE

Previous studies have found that some ventricular remodeling is accompanied by increased matrix metalloproteinase-9 (MMP-9) in vivo, and MMP-9 inhibitors can reduce ventricular remodeling. However, there is still no direct evidence that MMP-9 causes ventricular remodeling. In this study, MMP-9 was injected into rats to observe whether MMP-9 caused ventricular remodeling, thereby providing direct evidence of MMP-9-induced ventricular remodeling.

METHODS

Forty-eight eight-week-old male Wistar rats were randomly divided, by weight, into control, low-, medium-, and high-dose MMP-9 groups and were administered normal saline or recombinant rat MMP-9 0.7, 1.4, or 2.1 ng/g, respectively, via intraperitoneal injection, twice per week. On the 28th day, six rats were randomly selected from each group (Stage I). The remaining rats continued receiving injections until the 56th day (Stage II). Echocardiography was performed to observe cardiac structure and function, and the left ventricular mass index (LVWI) was calculated. Myocardial pathological changes and the collagen volume fraction (CVF) were observed by HE and VG staining in myocardial tissue. MMP-9 levels in serum were tested using ELISA. Myocardial MMP-9 levels were measured using Western blots, and the myocardial expression levels of MMP-9 mRNA were assessed using RT-PCR.

RESULTS

During Stage I, serum MMP-9 and myocardial MMP-9 mRNA levels are increased; hypertrophic cardiomyocytes, disorderly arrangement of fibers, and endochylema dissolution are observed in the medium- and high-dose groups. The left ventricular weight index (LVWI) and myocardial MMP-9 increased, and the collagen volume fraction (CVF) reduced in the high-dose group. In Stage II, the left ventricular end-diastolic volume (LVEDV) and diameter (LVIDd) are higher, and CVF decreased in the medium- and high-dose groups. Myocardial pathological lesions intensified. Serum MMP-9 in the model groups and myocardial MMP-9 in the medium- and high-dose groups are increased.

CONCLUSIONS

Injection of MMP-9 can lead to ventricular remodeling.

Proteomic profile of mesothelial exosomes isolated from peritoneal dialysis effluent of children with focal segmental glomerulosclerosis

Peritoneal dialysis (PD) is the worldwide recognized preferred dialysis treatment for children affected by end-stage kidney disease (ESKD). However, due to the unphysiological composition of PD fluids, the peritoneal membrane (PM) of these patients may undergo structural and functional alterations, which may cause fibrosis. Several factors may accelerate this process and primary kidney disease may have a causative role. In particular, patients affected by steroid resistant primary focal segmental glomerulosclerosis, a rare glomerular disease leading to nephrotic syndrome and ESKD, seem more prone to develop peritoneal fibrosis. The mechanism causing this predisposition is still unrecognized. To better define this condition, we carried out, for the first time, a new comprehensive comparative proteomic mass spectrometry analysis of mesothelial exosomes from peritoneal dialysis effluent (PDE) of 6 pediatric patients with focal segmental glomerular sclerosis (FSGS) versus 6 patients affected by other primary renal diseases (No FSGS). Our omic study demonstrated that, despite the high overlap in the protein milieu between the two study groups, machine learning allowed to identify a core list of 40 proteins, with ANXA13 as most promising potential biomarker, to distinguish, in our patient population, peritoneal dialysis effluent exosomes of FSGS from No FSGS patients (with 100% accuracy). Additionally, the Weight Gene Co-expression Network Analysis algorithm identified 17 proteins, with PTP4A1 as the most statistically significant biomarker associated to PD vintage and decreased PM function. Altogether, our data suggest that mesothelial cells of FSGS patients are more prone to activate a pro-fibrotic machinery. The role of the proposed biomarkers in the PM pathology deserves further investigation. Our results need further investigations in a larger population to corroborate these findings and investigate a possible increased risk of PM loss of function or development of encapsulating peritoneal sclerosis in FSGS patients, thus to eventually carry out changes in PD treatment and management or implement new solutions.

Distinct Metalloproteinase Expression and Functions in Systemic Sclerosis and Fibrosis: What We Know and the Potential for Intervention

Systemic sclerosis (SSc) is a chronic debilitating idiopathic disorder, characterized by deposition of excessive extracellular matrix (ECM) proteins such as collagen which leads to fibrosis of the skin and other internal organs. During normal tissue repair and remodeling, the accumulation and turnover of ECM proteins are tightly regulated by the interaction of matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of metalloproteinases (TIMPs). SSc is associated with dysregulation of the activity of these proteolytic and inhibitory proteins within the tissue microenvironment, tipping the balance toward fibrosis. The resultant ECM accumulation further perpetuates tissue stiffness and decreased function, contributing to poor clinical outcomes. Understanding the expression and function of these endogenous enzymes and inhibitors within specific tissues is therefore critical to the development of therapies for SSc. This brief review describes recent advances in our understanding of the functions and mechanisms of ECM remodeling by metalloproteinases and their inhibitors in the skin and lungs affected in SSc. It highlights recent progress on potential candidates for intervention and therapeutic approaches for treating SSc fibrosis.

Chronic Thromboembolic Pulmonary Hypertension: the Bench

PURPOSE OF REVIEW

Chronic thromboembolic pulmonary hypertension (CTEPH) is an uncommon complication of acute pulmonary embolism (PE), in which the red, platelet-rich thrombus does not resolve but forms into an organized yellow, fibrotic scar-like obstruction in the pulmonary vasculature. Here we review the pathobiology of CTEPH.

RECENT FINDINGS

Our current knowledge has predominantly been informed by studies of human samples and animal models that are inherently limited in their ability to recapitulate all aspects of the disease. These studies have identified alterations in platelet biology and inflammation in the formation of a scar-like thrombus that comprised endothelial cells, myofibroblasts, and immune cells, along with a small vessel pulmonary arterial hypertension-like vasculopathy. The development of CTEPH-specific therapies is currently hindered by a limited knowledge of its pathobiology. The development of new CTEPH medical therapies will require new insights into its pathobiology that bridge the gap from bench to bedside.

The hepatoprotective effect of silibinin after hepatic ischemia/reperfusion in a rat model is confirmed by immunohistochemistry and qRT-PCR

OBJECTIVES

We investigated the positive effect of silibinin after IV administration as silibinin-hydroxypropyl-β-cyclodextrin lyophilized product, by measuring gene expression and liver tissue protein levels of tumor necrosis factor-α, interleukin-6, monocyte chemoattractant protein-1, matrix metalloproteinases matrix metalloproteinases and tissue inhibitor of matrix metalloproteinases-2.

METHODS

63 Wistar rats of age 13.24±4.40 weeks underwent ischemia/reperfusion (I/R) injury of the liver. The animals were randomized into three groups: Sham (S; n = 7); Control (C; n-28); silibinin (Si; n-28). The C and Si groups underwent 45 min ischemia. Si received silibinin-hydroxypropyl-β-cyclodextrin intravenously immediately before reperfusion at a dose of 5 mg/kg. Both groups were further divided into 4 subgroups, based on euthanasia time (i.e., 60, 120, 180 and 240 min).

KEY FINDINGS

qRT-PCR results confirmed the statistically significant reduction of the expression of the pro-inflammatory factors at 240 min after I/R injury (tumor necrosis factor-α: P < 0.05; MCR1: P < 0.05) and matrix metalloproteinases (matrix metalloproteinases 2: P < 0.05; matrix metalloproteinases 3: P < 0.05) and the increase of tissue inhibitor of matrix metalloproteinases-2 in liver tissue in the Si group. Moreover, results of immunohistochemistry levels confirmed that at 240 min pro-inflammatory factors (tumor necrosis factor-α: P < 0.05; MCR1: P < 0.05) and matrix metalloproteinases ( matrix metalloproteinases 2: P < 0.05; matrix metalloproteinases 3: P < 0.05) had a statistically significantly lower expression in the Si group while tissue inhibitor of matrix metalloproteinases-2 had a higher expression.

CONCLUSIONS

Silibinin may have a beneficial effect on the protection of the liver.

Heparanase inhibition preserves the endothelial glycocalyx in lung grafts and improves lung preservation and transplant outcomes

The endothelial glycocalyx (eGC) is considered a key regulator of several mechanisms that prevent vascular injury and disease. Degradation of this macromolecular layer may be associated with post-transplant graft dysfunction. In this study, we aimed to demonstrate the benefits of eGC protection via heparanase inhibition on graft quality. We established rat models of lung grafts with damaged or preserved eGC using ischemic insult and transplanted the grafts into recipients. Lung grafts were also subjected to normothermic ex vivo lung perfusion for detailed assessment under isolated conditions. Physiologic parameters and eGC-associated cellular events were assessed in grafts before and after reperfusion. Structurally degraded eGC and highly activated heparanase were confirmed in lungs with ischemic insult. After transplant, lungs with damaged eGC exhibited impaired graft function, inflammation, edema, and inflammatory cell migration. Increased eGC shedding was evident in the lungs after reperfusion both in vivo and ex vivo. These reperfusion-related deficiencies were significantly attenuated in lungs with preserved eGC following heparanase inhibition. Our studies demonstrated that eGC plays a key role in maintaining lung graft quality and function. Heparanase inhibition may serve as a potential therapeutic to preserve eGC integrity, leading to improved post-transplant outcomes.

Recent Findings on Cell-Based Therapies for COVID19-Related Pulmonary Fibrosis

COVID-19 has spread worldwide, including the United States, United Kingdom, and Italy, along with its site of origin in China, since 2020. The virus was first found in the Wuhan seafood market at the end of 2019, with a controversial source. The clinical symptoms of COVID-19 include fever, cough, and respiratory tract inflammation, with some severe patients developing an acute and chronic lung injury, such as acute respiratory distress syndrome (ARDS) and pulmonary fibrosis (PF). It has already claimed approximately 300 thousand human lives and the number is still on the rise; the only way to prevent the infection is to be safe till vaccines and reliable treatments develop. In previous studies, the use of mesenchymal stem cells (MSCs) in clinical trials had been proven to be effective in immune modulation and tissue repair promotion; however, their efficacy in treating COVID-19 remains underestimated. Here, we report the findings from past experiences of SARS and MSCs, and how SARS could also induce PF. Such studies may help to understand the rationale for the recent cell-based therapies for COVID-19.

Aged Skeletal Muscle Retains the Ability to Remodel Extracellular Matrix for Degradation of Collagen Deposition after Muscle Injury

Aging causes a decline in skeletal muscle function, resulting in a progressive loss of muscle mass, quality, and strength. A weak regenerative capacity is one of the critical causes of dysfunctional skeletal muscle in elderly individuals. The extracellular matrix (ECM) maintains the tissue framework structure in skeletal muscle. As shown by previous reports and our data, the gene expression of ECM components decreases with age, but the accumulation of collagen substantially increases in skeletal muscle. We examined the structural changes in ECM in aged skeletal muscle and found restricted ECM degradation. In aged skeletal muscles, several genes that maintain ECM structure, such as transforming growth factor β (TGF-β), tissue inhibitors of metalloproteinases (TIMPs), matrix metalloproteinases (MMPs), and cathepsins, were downregulated. Muscle injury can induce muscle repair and regeneration in young and adult skeletal muscles. Surprisingly, muscle injury could not only efficiently induce regeneration in aged skeletal muscle, but it could also activate ECM remodeling and the clearance of ECM deposition. These results will help elucidate the mechanisms of muscle fibrosis with age and develop innovative antifibrotic therapies to decrease excessive collagen deposition in aged muscle.

Multifaceted Role of Matrix Metalloproteinases in Neurodegenerative Diseases: Pathophysiological and Therapeutic Perspectives

Neurodegeneration is the pathological condition, in which the nervous system or neuron loses its structure, function, or both, leading to progressive degeneration or the death of neurons, and well-defined associations of tissue system, resulting in clinical manifestations. Neuroinflammation has been shown to precede neurodegeneration in several neurodegenerative diseases (NDs). No drug is yet known to delay or treat neurodegeneration. Although the etiology and potential causes of NDs remain widely indefinable, matrix metalloproteinases (MMPs) evidently have a crucial role in the progression of NDs. MMPs, a protein family of zinc (Zn²⁺)-containing endopeptidases, are pivotal agents that are involved in various biological and pathological processes in the central nervous system (CNS). The current review delineates the several emerging evidence demonstrating the effects of MMPs in the progression of NDs, wherein they regulate several processes, such as (neuro)inflammation, microglial activation, amyloid peptide degradation, blood brain barrier (BBB) disruption, dopaminergic apoptosis, and α-synuclein modulation, leading to neurotoxicity and neuron death. Published papers to date were searched via PubMed, MEDLINE, etc., while using selective keywords highlighted in our manuscript. We also aim to shed a light on pathophysiological effect of MMPs in the CNS and focus our attention on its detrimental and beneficial effects in NDs, with a special focus on Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), multiple sclerosis (MS), and Huntington's disease (HD), and discussed various therapeutic strategies targeting MMPs, which could serve as potential modulators in NDs. Over time, several agents have been developed in order to overcome challenges and open up the possibilities for making selective modulators of MMPs to decipher the multifaceted functions of MMPs in NDs. There is still a greater need to explore them in clinics.

REX-001, a BM-MNC Enriched Solution, Induces Revascularization of Ischemic Tissues in a Murine Model of Chronic Limb-Threatening Ischemia

Background: Bone Marrow Mononuclear Cells (BM-MNC) constitute a promising alternative for the treatment of Chronic Limb-Threatening ischemia (CLTI), a disease characterized by extensive blockade of peripheral arteries, clinically presenting as excruciating pain at rest and ischemic ulcers which may lead to gangrene and amputation. BM-MNC implantation has shown to be efficient in promoting angiogenesis and ameliorating ischemic symptoms in CLTI patients. However, the variability seen between clinical trials makes necessary a further understanding of the mechanisms of action of BM-MNC, and moreover, to improve trial characteristics such as endpoints, inclusion/exclusion criteria or drug product compositions, in order to implement their use as stem-cell therapy.

Materials: Herein, the effect of REX-001, a human-BM derived cell suspension enriched for mononuclear cells, granulocytes and CD34+ cells, has been assessed in a murine model of CLTI. In addition, a REX-001 placebo solution containing BM-derived red blood cells (BM-RBCs) was also tested. Thus, 24 h after double ligation of the femoral artery, REX-001 and placebo were administrated intramuscularly to Balb-c nude mice (n:51) and follow-up of ischemic symptoms (blood flow perfusion, motility, ulceration and necrosis) was carried out for 21 days. The number of vessels and vascular diameter sizes were measured within the ischemic tissues to evaluate neovascularization and arteriogenesis. Finally, several cell-tracking assays were performed to evaluate potential biodistribution of these cells.

Results: REX-001 induced a significant recovery of blood flow by increasing vascular density within the ischemic limbs, with no cell translocation to other organs. Moreover, cell tracking assays confirmed a decrease in the number of infused cells after 2 weeks post-injection despite on-going revascularization, suggesting a paracrine mechanism of action.

Conclusion: Overall, our data supported the role of REX-001 product to improve revascularization and ischemic reperfusion in CLTI.

Matrix Metalloproteinases as Potential Biomarkers and Therapeutic Targets in Liver Diseases

Chronic liver diseases, characterized by an excessive accumulation of extracellular matrix (ECM) resulting in scar tissue formation, are a growing health problem causing increasing morbidity and mortality worldwide. Currently, therapeutic options for tissue fibrosis are severely limited, and organ transplantation is the only treatment for the end-stage liver diseases. During liver damage, injured hepatocytes release proinflammatory factors resulting in the recruitment and activation of immune cells that activate quiescent hepatic stellate cells (HSCs). Upon activation, HSCs transdifferentiate into highly proliferative, migratory, contractile and ECM-producing myofibroblasts. The disrupted balance between ECM deposition and degradation leads to the formation of scar tissue referred to as fibrosis. This balance can be restored either by reducing ECM deposition (by inhibition of HSCs activation and proliferation) or enhancing ECM degradation (by increased expression of matrix metalloproteinases (MMPs)). MMPs play an important role in ECM remodeling and represent an interesting target for therapeutic drug discovery. In this review, we present the current knowledge about ECM remodeling and role of the different MMPs in liver diseases. MMP expression patterns in different stages of liver diseases have also been reviewed to determine their role as biomarkers. Finally, we highlight MMPs as promising therapeutic targets for the resolution of liver diseases.