Project description:BackgroundAdjunctive dexamethasone reduces mortality from tuberculous meningitis, but how it produces this effect is not known. Matrix metalloproteinases (MMPs) are important in the immunopathology of many inflammatory CNS diseases thus we hypothesized that that their secretion is important in TBM and might be influenced by dexamethasone.Methodology/principal findingsThe kinetics of cerebrospinal fluid (CSF) MMP and tissue inhibitors of MMPs (TIMPs) concentrations were studied in a subset of HIV uninfected adults (n = 37) with TBM recruited to a randomized, placebo-controlled trial of adjuvant dexamethasone. Analysis followed a pre-defined plan. Dexamethasone significantly reduced CSF MMP-9 concentrations in early follow up samples (median 5 days (range 3-8) of treatment), but had no significant influence on other MMPs/TIMPs. Additionally CSF MMP-9 concentration was strongly correlated to concomitant CSF neutrophil count.Conclusions/significanceDexamethasone decreased CSF MMP-9 concentrations early in treatment and this may represent one mechanism by which corticosteroids improve outcome in TBM. The strong correlation between CSF MMP-9 and neutrophil count suggests that polymorphonuclear leukocytes may play a central role in the early pathogenesis of TBM.
Project description:Matrix metalloproteinase-9 is increased in renal tissue in human kidney disease, but its role as a biomarker for kidney disease has not been fully evaluated yet. The aim of this study was to evaluate serum MMP-9 (sMMP-9) and urinary MMP-9 (uMMP-9) concentrations in dehydrated horses. Dehydrated horses were prospectively included. Blood and urinary samples were taken at admission, and after 12, 24, and 48 h (t0, t12, t24, t48), an anti-equine MMP-9 sandwich ELISA was used. Four healthy horses served as the controls. Serum creatinine, urea, symmetric dimethylarginine (SDMA), urine-specific gravity, urinary protein concentration, fractional sodium excretion, and urinary gamma-glutamyl transferase/creatinine ratio (uGGT/Cr) were measured. Statistical analysis included a repeated measures ANOVA and mixed linear regression model. Overall, 40 dehydrated horses were included (mild dehydration 13/40, moderate 16/40, severe 11/40). Acute kidney injury was found in 1/40 horses; 7/40 horses showed elevated serum creatinine, 11/40 horses elevated serum SDMA, and 5/28 elevated uGGT/Cr at presentation. In dehydrated horses, sMMP-9 concentrations were significantly higher on t0 (median: 589 ng/mL, range: 172-3597 ng/mL) compared to t12 (340 ng/mL, 132-1213 ng/mL), t24 (308 ng/mL, 162-1048 ng/mL), and t48 (258 ng/mL, 130-744 ng/mL). In healthy horses, sMMP-9 (239 ng/mL, 142-508 ng/mL) showed no differences over time or compared to patients. uMMP-9 and uMMP-9/creatinine did not differ over time or to the controls. No differences were found between dehydration groups. Urinary casts (p = 0.001; estimate = 135) and uGGT/Cr (p = 0.03; estimate = 6.5) correlated with sMMP-9. Serum urea was associated with uMMP-9/Cr (p = 0.01, estimate 0.9). In conclusion, sMMP-9 was elevated at arrival in dehydrated patients compared to later measurements. Correlations to uGGT/Cr and urinary casts need further evaluation.
Project description:BackgroundMetalloproteinase inhibitors can protect mice against experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). Matrix metalloproteinase-9 (MMP-9) has been implicated, but it is not clear if other MMPs are also involved, including matrilysin/MMP-7 - an enzyme capable of cleaving proteins that are essential for blood brain barrier integrity and immune suppression.ResultsHere we report that MMP-7-deficient (mmp7-/-) mice on the C57Bl/6 background are resistant to EAE induced by myelin oligodendrocyte glycoprotein (MOG). Brain sections from MOG-primed mmp7-/-mice did not show signs of immune cell infiltration of the CNS, but MOG-primed wild-type mice showed extensive vascular cuffing and mononuclear cell infiltration 15 days after vaccination. At the peak of EAE wild-type mice had MMP-7 immuno-reactive cells in vascular cuffs that also expressed the macrophage markers Iba-1 and Gr-1, as well as tomato lectin. MOG-specific proliferation of splenocytes, lymphocytes, CD4+ and CD8+ cells were reduced in cells isolated from MOG-primed mmp7-/- mice, compared with MOG-primed wild-type mice. However, the adoptive transfer of splenocytes and lymphocytes from MOG-primed mmp7-/- mice induced EAE in naïve wild-type recipients, but not naïve mmp7-/- recipients. Finally, we found that recombinant MMP-7 increased permeability between endothelial cells in an in vitro blood-brain barrier model.ConclusionOur findings suggest that MMP-7 may facilitate immune cell access or re-stimulation in perivascular areas, which are critical events in EAE and multiple sclerosis, and provide a new therapeutic target to treat this disorder.
Project description:BackgroundHypophosphatemia is common in severe infections including malaria. Previous studies suggested that serum phosphate concentrations correlate with temperature, but it is unclear whether the type of infection and other factors occurring during infection influence this association. Here relationships were investigated between serum phosphate levels, cause of fever, demographic, clinical and laboratory parameters.MethodsAnonymized data were analysed from 633 adults with malaria or other febrile illness admitted to Northwick Park Hospital, London, UK. Univariable and multivariable generalized linear model analyses were performed to examine associations with serum phosphate levels. Interaction terms were included to investigate whether cause of fever (malaria vs other illness), malaria parasite species, or malaria severity influenced the association of other variables with phosphate.ResultsHypophosphatemia was common in subjects with malaria (211/542 (39%)), and in other febrile illnesses (24/91 (26%)), however median phosphate levels did not differ significantly by diagnostic group, parasite species or severity of malaria. In all analyses, there were highly significant negative associations between serum phosphate and axillary temperature, and positive associations between serum phosphate and platelet count. There were no significant interactions between these variables and cause of fever, parasite species or severity of illness. Sodium and potassium concentrations were associated with serum phosphate in subjects with malaria and when data from all subjects was combined.ConclusionSerum phosphate is consistently associated with temperature and platelet count in adults with diverse causes of fever. This may be a consequence of phosphate shifts from plasma into cells to support ATP generation for thermogenesis and platelet activation.
Project description:The pregnancy complication preeclampsia (PE), which occurs in approximately 3% to 8% of human pregnancies, is characterized by placental pathologies that can lead to significant fetal and maternal morbidity and mortality. Currently, the only known cure is delivery of the placenta. As the etiology of PE remains unknown, it is vital to find models to study this common syndrome. Here we show that matrix metalloproteinase-9 (MMP9) deficiency causes physiological and placental abnormalities in mice, which mimic features of PE. As with the severe cases of this syndrome, which commence early in gestation, MMP9-null mouse embryos exhibit deficiencies in trophoblast differentiation and invasion shortly after implantation, along with intrauterine growth restriction or embryonic death. Reciprocal embryo transfer experiments demonstrated that embryonic MMP9 is a major contributor to normal implantation, but maternal MMP9 also plays a role in embryonic trophoblast development. Pregnant MMP9-null mice bearing null embryos exhibited clinical features of PE as VEGF dysregulation and proteinuria accompanied by preexisting elevated blood pressure and kidney pathology. Thus, our data show that fetal and maternal MMP9 play a role in the development of PE and establish the MMP9-null mice as a much-needed model to study the clinical course of this syndrome.
Project description:BackgroundThe concentration of antiretrovirals in CSF is often utilized as a surrogate for CNS drug exposure. This measurement does not consider pharmacodynamic or combinative effects of ART. We have developed a novel endpoint measurement to assess antiretroviral activity of CSF from subjects on ART.MethodsCSF samples were obtained from patients receiving tenofovir/emtricitabine (245/200 mg once daily) with either rilpivirine (25 mg once daily) or lopinavir/ritonavir/maraviroc (400/100/150 mg twice daily) and HIV-uninfected controls. Antiviral activity of ART-containing CSF was assessed in cell cultures using PBMCs and neuro-derived glial (U87) and astrocyte (373) cell lines. Infectivity model half-maximal inhibitory concentration (IMIC50) values were calculated and expressed as -log2IMIC50. Results were correlated with CSF antiretroviral concentrations.ResultsCompared with controls, CSF from both ART studies demonstrated in vitro antiretroviral activity in all models. CSF antiretroviral activity of patients on lopinavir/ritonavir/maraviroc was significantly greater than that of patients on rilpivirine [-log2IMIC50 (95% CI) 4.82 (4.74-4.89) versus 3.43 (3.33-3.54) in PBMCs, 3.06 (2.98-3.15) versus 2.56 (2.46-2.65) in U87 cells and 6.00 (6.11-5.88) versus 4.90 (5.09-4.72) in 373 cells, respectively]. Positive correlations were observed for individual CSF antiretroviral activity in different cellular models with CSF concentrations of rilpivirine (P = 0.040 in 373 cells) and lopinavir (P = 0.048 in 373 cells), but not maraviroc.ConclusionsAntiviral activity of CSF from patients on ART was successfully calculated and was greater with a regimen containing four active drugs compared with three active drugs. The use of neuro-derived cell lines alongside PBMCs to assess the effect of ART on CSF may act as a useful future clinical research tool.
Project description:MMP-11 is a key factor in physiopathological tissue remodeling. As an active form is secreted, its activity must be tightly regulated to avoid detrimental effects. Although TIMP-1 and TIMP-2 reversibly inhibit MMP-11, another more drastic scenario, presumably via hydrolysis, could be hypothesized. In this context, we have investigated the possible implication of MMP-14, since it exhibits a spatiotemporal localization similar to MMP-11. Using native HFL1-produced MMP-11 and HT-1080-produced MMP-14 as well as recombinant proteins, we show that MMP-11 is a MMP-14 substrate. MMP-14 cleaves MMP-11 catalytic domain at the PGG(P1)-I(P1')LA and V/IQH(P1)-L(P1')YG scissile bonds, two new cleavage sites. Interestingly, a functional test showed a dramatical reduction in MMP-11 enzymatic activity when incubated with active MMP-14, whereas inactive point-mutated MMP-14 had no effect. This function is conserved between human and mouse. Thus, in addition to the canonical reversible TIMP-dependent inhibitory system, irreversible MMP proteolytic inactivation might occur by cleavage of the catalytic domain in a MMP-dependent manner. Since MMP-14 is produced by HT-1080 cancer cells, whereas MMP-11 is secreted by HFL1 stromal cells, our findings support the emerging importance of tumor-stroma interaction/cross-talk. Moreover, they highlight a Janus-faced MMP-14 function in the MMP cascade, favoring activation of several pro-MMPs, but limiting MMP-11 activity. Finally, both MMPs are active at the cell periphery. Since MMP-14 is present at the cell membrane, whereas MMP-11 is soluble into the cellular microenvironment, this MMP-14 function might represent one critical regulatory mechanism to control the extent of pericellular MMP-11 bioavailability and protect cells from excessive/inappropriate MMP-11 function.
Project description:Reported cases of dengue are rising in South Australia (SA) in travellers returning from dengue-endemic regions. We have undertaken a retrospective analysis to identify the clinical and laboratory characteristics of patients returning to SA with suspected dengue virus (DENV) infection. From 488 requests, 49 (10%) were defined by serology as acute dengue, with the majority of patients (75%) testing as non-structural protein 1 (NS1) and/or IgM positive. Dengue was most commonly acquired in Indonesia (42.9%) with clinical features of fever (95%), headache (41%) and myalgia/arthralgia (56%). The presence of rash (36%) and laboratory findings of neutropenia, leukopenia, thrombocytopenia, but not elevated C-reactive protein, were distinct from findings in DENV-seronegative patients. Available dengue seropositive samples were analysed by RT-PCR, with 14/32 (43.8%) positive by a serotype non-specific DENV assay, but 28/32 positive (87.5%) when also assessed by serotype-specific RT-PCR. Serotype analysis revealed the predominance of DENV-1 and DENV-2 and the presence of DENV-3, but not DENV-4 or Zika virus (ZIKV). Thus, dengue in returned travellers in SA presents in a manner consistent with World Health Organization (WHO) definitions, with symptoms, travel history and laboratory results useful in prioritising the likelihood of dengue. This definition will assist the future management in DENV-non-endemic regions, such as SA.
Project description:Recent molecular studies have shown Mycobacterium porcinum, recovered from cases of lymphadenitis in swine, to have complete 16S rDNA sequence identity and >70% DNA-DNA homology with human isolates within the M. fortuitum third biovariant complex. We identified 67 clinical and two environmental isolates of the M. fortuitum third biovariant sorbitol-negative group, of which 48 (70%) had the same PCR restriction enzyme analysis (PRA) profile as the hsp65 gene of M. porcinum (ATCC 33776(T)) and were studied in more detail. Most U.S. patient isolates were from Texas (44%), Florida (19%), or other southern coastal states (15%). Clinical infections included wound infections (62%), central catheter infections and/or bacteremia (16%), and possible pneumonitis (18%). Sequencing of the 16S rRNA gene (1,463 bp) showed 100% identity with M. porcinum ATCC 33776(T). Sequencing of 441 bp of the hsp65 gene showed four sequevars that differed by 2 to 3 bp from the porcine strains. Clinical isolates were positive for arylsulfatase activity at 3 days, nitrate, iron uptake, D-mannitol, i-myo-inositol, and catalase at 68 degrees C. They were negative for L-rhamnose and D-glucitol (sorbitol). Clinical isolates were susceptible to ciprofloxacin, sulfamethoxazole, and linezolid and susceptible or intermediate to cefoxitin, clarithromycin, imipenem, and amikacin. M. porcinum ATCC 33776(T) gave similar results except for being nitrate negative. These studies showed almost complete phenotypic and molecular identity between clinical isolates of the M. fortuitum third biovariant D-sorbitol-negative group and porcine strains of M. porcinum and confirmed that they belong to the same species. Identification of M. porcinum presently requires hsp65 gene PRA or 16S rRNA or hsp65 gene sequencing.
Project description:The reasons for the viral persistence of hepatitis B virus (HBV) infection are unknown, but are probably related to host immune factors. Several matrix metalloproteinases (MMPs) can regulate an inflammatory response. The aim of this study was to assess the effects of the single nucleotide polymorphisms (SNPs) of MMP-3 and -9 genes on the susceptibility to persistent HBV infection. We studied 489 Korean patients with HBV infection (144 inactive carriers, 182 chronic hepatitis, and 163 liver cirrhosis) and 174 healthy individuals who had recovered from HBV infection. MMP-3 gene SNPs were identified at two polymorphic sites (codon 45 [E45K] and codon 96 [D96D]) and MMP-9 gene SNPs at three polymorphic sites (codon 279 [R279Q], codon 607 [G607G], and codon 668 [Q668R]) in study subjects. The frequency of T allele at third position of codon 96 in the MMP-3 gene was higher in HBV persistence patients when analyzed by co-dominant model (age- and sex-adjusted OR=1.242, 95% CI= 1.001-1.540, p=0.049). In conclusion the T allele at the third position of codon 96 in the MMP-3 gene might be associated with persistent HBV infection.