Occurrence of Antimicrobial Resistance Genes in the Oral Cavity of Cats with Chronic Gingivostomatitis.

Feline chronic gingivostomatitis (FCGS) is a severe immune-mediated inflammatory disease with concurrent oral dysbiosis (bacterial and fungal). Broad-spectrum antibiotics are used empirically in FCGS. Still, neither the occurrence of antimicrobial-resistant (AMR) bacteria nor potential patterns of co-occurrence between AMR genes and fungi have been documented in FCGS. This study explored the differential occurrence of AMR genes and the co-occurrence of AMR genes with oral fungal species. Briefly, 14 clinically healthy (CH) cats and 14 cats with FCGS were included. Using a sterile swab, oral tissue surfaces were sampled and submitted for 16S rRNA and ITS-2 next-generation DNA sequencing. Microbial DNA was analyzed using a proprietary curated database targeting AMR genes found in bacterial pathogens. The co-occurrence of AMR genes and fungi was tested using point biserial correlation. A total of 21 and 23 different AMR genes were detected in CH and FCGS cats, respectively. A comparison of AMR-gene frequencies between groups revealed statistically significant differences in the occurrence of genes conferring resistance to aminoglycosides (ant4Ib), beta-lactam (mecA), and macrolides (mphD and mphC). Two AMR genes (mecA and mphD) showed statistically significant co-occurrence with Malassezia restricta. In conclusion, resistance to clinically relevant antibiotics, such as beta-lactams and macrolides, is a significant cause for concern in the context of both feline and human medicine.

Down-regulation of p27kip1 increases proliferation of progenitor cells in adult rats.

Cyclin-dependent kinases (CDK) mediate the cell division cycle during G1 phase and CDK inhibitors negatively regulate the cell cycle. We investigated expression of the CDK inhibitor p27Kip1 and the effects of PI-3K/Akt on proliferation of progenitors in the subventricular zone of adult rat. Western blots and immunostaining revealed that 4 days after stroke, p27kip1 levels decreased and were absent in nuclei of the ipsilateral subventricular zone cells 7 days after stroke. Reduction in p27kip1 levels was concurrent with significant increases in BrdU immunoreactive cells in the subventricular zone. Treatment of stroke neurospheres with LY294002 significantly (p<0.05) reduced the numbers of neurospheres from 32 +/-5 in the stroke group to 14 +/- 3 in the stroke and LY294002 group. Collectively, our data suggest that stroke induced neural progenitor proliferation is mediated by down-regulation of p27Kip1 and activation of Akt.

Sildenafil (Viagra) induces neurogenesis and promotes functional recovery after stroke in rats.

BACKGROUND AND PURPOSE: We tested the hypothesis that sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor, promotes functional recovery and neurogenesis after stroke. METHODS: Male Wistar rats were subjected to embolic middle cerebral artery occlusion. Sildenafil (Viagra) was administered orally for 7 consecutive days starting 2 or 24 hours after stroke onset at doses of 2 or 5 mg/kg per day. Ischemic rats administered the same volume of tap water were used as a control group. Functional outcome tests (foot-fault, adhesive removal) were performed. Rats were killed 28 days after stroke for analysis of infarct volume and newly generated cells within the subventricular zone and the dentate gyrus. Brain cGMP levels, expression of PDE5, and localized cerebral blood flow were measured in additional rats. RESULTS: Treatment with sildenafil significantly (P<0.05) enhanced neurological recovery in all tests performed. There was no significant difference of infarct volume among the experimental groups. Treatment with sildenafil significantly (P<0.05) increased numbers of bromodeoxyuridine-immunoreactive cells in the subventricular zone and the dentate gyrus and numbers of immature neurons, as indicated by betaIII-tubulin (TuJ1) immunoreactivity in the ipsilateral subventricular zone and striatum. The cortical levels of cGMP significantly increased after administration of sildenafil, and PDE5 mRNA was present in both nonischemic and ischemic brain. CONCLUSIONS: Sildenafil increases brain levels of cGMP, evokes neurogenesis, and reduces neurological deficits when given to rats 2 or 24 hours after stroke. These data suggest that this drug that is presently in the clinic for sexual dysfunction may have a role in promoting recovery from stroke.

Correlation of VEGF and angiopoietin expression with disruption of blood-brain barrier and angiogenesis after focal cerebral ischemia.

In an effort to elucidate the molecular mechanisms underlying cerebral vascular alteration after stroke, the authors measured the spatial and temporal profiles of blood-brain barrier (BBB) leakage, angiogenesis, vascular endothelial growth factor (VEGF), associated receptors, and angiopoietins and receptors after embolic stroke in the rat. Two to four hours after onset of ischemia, VEGF mRNA increased, whereas angiopoietin 1 (Ang 1) mRNA decreased. Three-dimensional immunofluorescent analysis revealed spatial coincidence between increases of VEGF immunoreactivity and BBB leakage in the ischemic core. Two to 28 days after the onset of stroke, increased expression of VEGF/VEGF receptors and Ang/Tie2 was detected at the boundary of the ischemic lesion. Concurrently, enlarged and thin-walled vessels were detected at the boundary of the ischemic lesion, and these vessels developed into smaller vessels via sprouting and intussusception. Three-dimensional quantitative analysis of cerebral vessels at the boundary zone 14 days after ischemia revealed a significant (P < 0.05) increase in numbers of vessels (n = 365) compared with numbers (n = 66) in the homologous tissue of the contralateral hemisphere. Furthermore, capillaries in the penumbra had a significantly smaller diameter (4.8 +/- 2.0 microm) than capillaries (5.4 +/- 1.5 microm) in the homologous regions of the contralateral hemisphere. Together, these data suggest that acute alteration of VEGF and Ang 1 in the ischemic core may mediate BBB leakage, whereas upregulation of VEGF/VEGF receptors and Ang/Tie2 at the boundary zone may regulate neovascularization in ischemic brain.