Neural differentiation of canine mesenchymal stem cells/multipotent mesenchymal stromal cells.

BACKGROUND: The ability of adipose tissue-derived multipotent mesenchymal stromal cells/mesenchymal stem cells (ASCs) to differentiate in neural lineages promises progress in the field of regenerative medicine, especially for replacing neuronal tissue damaged by different neurological disorders. Reprogramming of ASCs can be induced by the growth medium with neurogenic inductors and specific growth factors. We investigated the neural differentiation potential of canine ASCs using several growth media (KEM, NIMa, NIMb, NIMc) containing various combinations of neurogenic inductors: B27 supplement, valproic acid, forskolin, N2-supplement, and retinoic acid. Cells were first preconditioned in the pre-differentiation neural induction medium (mitogenically stimulated; STIM1), followed by the induction of neuronal differentiation. RESULTS: After 3, 6, and 9 days of neural induction, elongated neural-like cells with bipolar elongations were observed, and some oval cells with light nuclei appeared. The expression of neuronal markers tubulin beta III (TUBB3), neurofilament H (NF-H), microtubule-associated protein-2 (MAP2), and glial fibrillary acidic protein (GFAP) was observed using immunocytochemistry, which confirmed the differentiation into neurons and glial cells. Flow cytometry analysis showed high GFAP expression (between 70 and 90% of all cells) after cells had been growing three days in the neural induction medium a (NIMa). Around 25% of all cells also expressed adult neuronal markers NF-H and MAP2. After nine days of ASCs differentiation, the expression of all neural markers was reduced. There were no differences between the neural differentiation of ASCs isolated from female or male dogs. CONCLUSIONS: The differentiation repertoire of canine ASCs extends beyond mesodermal lineages. Using a defined neural induction medium, the canine ASCs differentiated into neural lineages and expressed markers of neuronal and glial cells, and also displayed the typical neuronal morphology. Differentiated ASCs can thus be a source of neural cellular lineages for the regenerative therapy of nerve damage and could be useful in the future for therapy or the modelling of neurodegenerative diseases.

Multi locus sequence typing (MLST) used as a tool to confirm the ability of susceptible Helicobacter pylori strains to gain resistance to clarithromycin during eradication therapy.

BACKGROUND/AIMS: Primary resistance of H. pylori to clarithromycin is the most common reason for eradication failure, followed by mixed susceptible/ resistant H. pylori strain infection. To distinguish between mixed infections and H. pylori switch to resistance phenotype during eradication therapy, we proceeded with multi locus sequence typing (MLST) of H. pylori strains isolated from gastric biopsy samples of patients before and after eradication therapy. METHODOLOGY: We collected H. pylori isolates from gastric biopsies from 133 patients who were never treated for H. pylori. Five patients had eradication failure with the first isolate susceptible and second isolate resistant to clarithromycin. To analyse genotypes of first and second H. pylori isolates, we compared H. pylori strain sequences of 7 housekeeping genes with MLST. RESULTS: Five patients had clarithromycin-sensitive H. pylori before eradication therapy and gained H. pylori-resistant to clarithromycin after eradication therapy. The sensitive and resistant colonies of each of the H. pylori populations, taken from patients before/after antibiotic therapy, had identical sequence types (ST) obtained with MLST. CONCLUSIONS: The factors favouring H. pylori survival and switch to antibiotic-resistance during eradication therapy probably enable milder environmental conditions for H. pylori persistence during therapy. One of such factor is the ineffective destruction of mucosa-adhered H. pylori by immune cells during therapy which may be due to locally induced immune deficit by H. pylori molecules like strain specific H. pylori lipopolysaccharides.