Genetic Polymorphism of Matrix Metalloproteinase-9 and Susceptibility to Myocardial Infarction: A Meta-Analysis

Objective. Current findings on the association between MMP-9 rs3918242 and susceptibility to myocardial infarction (MI) are inconsistent, and their definite relationship is discussed in this meta-analysis. Methods. Eligible literatures reporting MMP-9 rs3918242 and susceptibility to MI were searched in PubMed, Cochrane Library, CNRI, and VIP using keywords such as “MMP-9”, “matrix metallopeptidase-9” and “myocardial infarction”, “acute myocardial infarction”, “AMI”, and “polymorphism”. Data from eligible literatures were extracted for calculating OR and corresponding 95% CI using RevMan 5.3 and STATA12.0. Results. Ten independent literatures reporting MMP-9 rs3918242 and susceptibility to MI were enrolled. Compared with subjects carrying CT&TT genotype of MMP-9 rs3918242, susceptibility to MI was lower in those carrying CC genotype ( OR = 1.49 , 95 % CI = 1.19 – 1.86 , P = 0.0004 ). Such a significance was observed in the overdominant ( OR = 1.27 , 95 % CI = 1.14 – 1.41 , P < 0.0001 ) and allele genetic models ( OR = 1.43 , 95 % CI = 1.17 – 1.74 , P = 0.0005 ) as well. This finding was also valid in the Asian population. Conclusions. Mutation on MMP-9 rs3918242 has a potential relevance with susceptibility to MI.

Unveiling a Hidden Biomarker of Inflammation and Tumor Progression: The 65 kDa Isoform of MMP-9 New Horizons for Therapy

Cancer metastasis is a stage of the disease where therapy is mostly ineffective; hence, the need to find reliable markers of its onset. The metalloproteinase-9 (MMP-9, gelatinase B) in its 82 kDa active form, is a good candidate, but here we show that the correspondent little known 65 kDa active MMP-9 isoform, often misrepresented with the other gelatinase MMP-2, is a more suitable marker. Sera from patients with lung and breast cancer were analyzed by bidimensional zymography to detect the activity of MMP-9 and MMP-2. Enzyme identity was confirmed by comparison with MMP-9 standards and by western blotting. The 65 kDa isoform of MMP-9 is a suitable biomarker to monitor tumor progression from tissue neoplasms to metastatic stage, as its activity begins to appear when disease severity increases and becomes very high in metastasis. Moreover, the 65 kDa MMP-9, which derives from the 82 kDa MMP-9, no longer responds to natural MMP-9 inhibitors. As its activity cannot be controlled, its appearance may warn that the pathological process is becoming irreversible. Identification and inhibition of the enzymes converting the inhibitor-sensitive 82 kDa MMP-9 into the corresponding “wild” 65 kDa MMP-9 may allow to develop therapies capable of blocking metastases.

Exendin-4 Preserves Blood-Brain Barrier Integrity via Glucagon-Like Peptide 1 Receptor/Activated Protein Kinase-Dependent Nuclear Factor-Kappa B/Matrix Metalloproteinase-9 Inhibition After Subarachnoid Hemorrhage in Rat

In this study, we investigated the role of Exendin-4 (Ex-4), a glucagon-like peptide 1 receptor (GLP-1R) agonist, in blood-brain barrier (BBB) disruption after subarachnoid hemorrhage (SAH) in rats. The endovascular perforation model of SAH was performed in Sprague-Dawley rats. Ex-4 was intraperitoneally injected 1 h after SAH induction. To elucidate the underlying molecular mechanism, small interfering ribonucleic acid (siRNA) for GLP-1R and Dorsomorphin, a specific inhibitor of adenosine monophosphate-activated protein kinase (AMPK), were intracerebroventricularly injected 48 h before induction of SAH correspondingly. Immunofluorescence results supported GLP-1R expressed on the endothelial cells of microvessels in the brain after SAH. Administration of Ex-4 significantly reduced brain water content and Evans blue extravasation in both hemispheres, which improved neurological scores at 24 h after SAH. In the mechanism study, Ex-4 treatment significantly increased the expression of GLP-1R, p-AMPK, IκB-α, Occludin, and Claudin-5, while the expression of p-nuclear factor-kappa B (NF-κB) p65, matrix metalloproteinase-9 (MMP-9), and albumin was significantly decreased. The effects of Ex-4 were reversed by the intervention of GLP-1R siRNA or Dorsomorphin, respectively. In conclusion, Ex-4 could preserve the BBB integrity through GLP-1R/AMPK-dependent NF-κB/MMP-9 inhibition after SAH, which should be further investigated as a potential therapeutic target in SAH.

Mechanism of Blood–Heart-Barrier Leakage: Implications for COVID-19 Induced Cardiovascular Injury

Although blood–heart-barrier (BHB) leakage is the hallmark of congestive (cardio-pulmonary) heart failure (CHF), the primary cause of death in elderly, and during viral myocarditis resulting from the novel coronavirus variants such as the severe acute respiratory syndrome novel corona virus 2 (SARS-CoV-2) known as COVID-19, the mechanism is unclear. The goal of this project is to determine the mechanism of the BHB in CHF. Endocardial endothelium (EE) is the BHB against leakage of blood from endocardium to the interstitium; however, this BHB is broken during CHF. Previous studies from our laboratory, and others have shown a robust activation of matrix metalloproteinase-9 (MMP-9) during CHF. MMP-9 degrades the connexins leading to EE dysfunction. We demonstrated juxtacrine coupling of EE with myocyte and mitochondria (Mito) but how it works still remains at large. To test whether activation of MMP-9 causes EE barrier dysfunction, we hypothesized that if that were the case then treatment with hydroxychloroquine (HCQ) could, in fact, inhibit MMP-9, and thus preserve the EE barrier/juxtacrine signaling, and synchronous endothelial-myocyte coupling. To determine this, CHF was created by aorta-vena cava fistula (AVF) employing the mouse as a model system. The sham, and AVF mice were treated with HCQ. Cardiac hypertrophy, tissue remodeling-induced mitochondrial-myocyte, and endothelial-myocyte contractions were measured. Microvascular leakage was measured using FITC-albumin conjugate. The cardiac function was measured by echocardiography (Echo). Results suggest that MMP-9 activation, endocardial endothelial leakage, endothelial-myocyte (E-M) uncoupling, dyssynchronous mitochondrial fusion-fission (Mfn2/Drp1 ratio), and mito-myocyte uncoupling in the AVF heart failure were found to be rampant; however, treatment with HCQ successfully mitigated some of the deleterious cardiac alterations during CHF. The findings have direct relevance to the gamut of cardiac manifestations, and the resultant phenotypes arising from the ongoing complications of COVID-19 in human subjects.

Matrix Metalloproteinase-9 and Topical Cyclosporine Are Associated with Conjunctival Microbiota Culture Positivity in Korean Patients with Stevens-Johnson Syndrome

BackgroundStevens-Johnson syndrome (SJS) is an abnormal immune-response causing extensive exfoliation of the mucocutaneous tissue including conjunctiva. While several factors are associated with the alteration of conjunctival microbiota, the conjunctiva of SJS patients are found to harbor a different microbiota compared to healthy subjects. We investigated the conjunctival microbiota of Korean SJS patients, and identified factors associated with the conjunctival microbiota and its positive culture.MethodsMedical records were retrospectively reviewed in 30 SJS patients who had undergone conjunctival swab culture sampling. Chronic ocular surface complications score (COCS), tear break-up time (TBUT), tear matrix metalloproteinase 9 (MMP9), and results of conjunctival swab culture were assessed.Results Positive culture was seen in 58.1%. Gram positive bacteria was most commonly isolated, among which Coagulase-negative Staphylococci (45.5%) and Corynebacterium species (40.9%) were predominantly observed. Tear MMP9 positivity was observed significantly more in the positive culture group (100%) compared to the negative culture group (75%) (P = 0.040). In patients who had repetitive cultures, positive- persistence group had more patients using topical cyclosporine compared to the negative-transition group (90.0% vs 33.3%, respectively, P = 0.041). No significant difference was found between COCS and conjunctival swab culture result, and the same as in TBUT and conjunctival swab culture result.ConclusionOur study suggest that tear MMP9 positivity may reflect the presence of an abnormal ocular surface microbiota and topical cyclosporine may be related to persistent culture positivity in SJS patients.

Changes in Tear Osmolarity and Matrix Metalloproteinase-9 Relative to Ocular Discomfort after Femtosecond Laser-Assisted Cataract Surgery

The aim of this study was to evaluate the changes in tear osmolarity and matrix metalloproteinase-9 (MMP-9) and their relationships with ocular discomfort in patients after femtosecond laser-assisted cataract surgery (FLACS). This retrospective observational case series reviewed medical records of 51 eyes of 51 patients who underwent FLACS. Tear osmolarity and MMP-9 were evaluated preoperatively and at 1 day, 1 week, and 1 month postoperatively. Tear osmolarity ≥ 310 mOsm/L and MMP-9 ≥ trace positive were defined as abnormal results. The ocular surface disease index (OSDI) was evaluated preoperatively and postoperatively at 1 month. Tear osmolarity level and the number of eyes with abnormal tear osmolarity results did not change significantly up to 1 month after surgery. MMP-9 level and the number of eyes with abnormal MMP-9 results increased at 1-day postoperatively and then decreased at 1-month postoperatively (all p < 0.001). Among the OSDI subscales, ocular discomfort was aggravated (p < 0.001) but the visual function score improved at 1 month postoperatively (p < 0.001). Ocular discomfort aggravated after FLACS without an increase in either tear osmolarity or MMP-9. Ocular discomfort which patients commonly experience after FLACS may be due to etiology other than development or aggravation of dry eye disease.