Roles of microRNAs in abdominal aortic aneurysm pathogenesis and the possibility of their use as biomarkers.

Abdominal aortic aneurysm (AAA) is a dangerous condition involving pathological dilation of the aortic wall. Due to the asymptomatic course of this disease and the dangerous consequences of its rupture, it is important to identify its specific bio-markers expressed as early as possible. Different expression profiles of microRNAs (miRNAs) were detected in patients diagnosed with AAA. MicroRNAs are small non-coding RNA molecules that regulate the expression of other genes at the translation stage. miRNAs affecting translation can lead to abnormal remodeling of extracellular matrix, inhibition of the cell cycle, cell aging or intensified inflammation. This review summarizes current knowledge about the role of microRNAs in the context of formation and development of abdominal aorta aneurysm and the possibility of using some miRNAs as bio-markers, and also provides basic information about miRNAs and aneurysms.

Magnetic resonance spectroscopy as a predictor of conversion of mild cognitive impairment to dementia.

BACKGROUND AND PURPOSE: Proton magnetic resonance spectroscopy ((1)H-MRS) is one of the imaging techniques that could be potentially useful for identification of patients with mild cognitive impairment (MCI) who are at increased risk of developing dementia. The aim of the study was to investigate if there is a difference in brain metabolism between stable MCI patients and converters to dementia and if a use of (1)H-MRS can predict the conversion from MCI to dementia. MATERIAL AND METHODS: Forty-one amnestic MCI patients and 35 cognitively unimpaired controls were examined by (1)H-MRS (TE - 35 ms) at baseline. Metabolite ratios (NAA/Cr, Cho/Cr, mI/Cr, Glx/Cr, NAA/Cho) were estimated in four different brain regions: posterior cingulate gyrus (PCG), left hippocampus (LH), cortical area of right (RPL) and left parietal lobe (LPL). Participants were followed up for a period of 12 months. RESULTS: Twelve subjects with MCI progressed to Alzheimer's disease (AD) after one year. Analysis showed that the NAA/Cr ratio in the LH was significantly lower in MCI patients than in controls (p=0.008), but there were no differences in metabolite ratios at baseline between MCI converters and stable subjects. mI/Cr ratio in RPL predicted the conversion to AD with sensitivity 70% and specificity 85% (p<0.0004). Coexistence of diabetes improved prediction, yielding 70% sensitivity and 96% specificity (p<0.0001). CONCLUSIONS: (1)H-MRS in MCI can be a predictor of cognitive decline and conversion to dementia, especially in MCI patients with coexisting diabetes. Further studies are needed to confirm this finding.

Two novel COL1A1 mutations in patients with osteogenesis imperfecta (OI) affect the stability of the collagen type I triple-helix.

Osteogenesis imperfecta (OI) is a bone dysplasia caused by mutations in the COL1A1 and COL1A2 genes. Although the condition has been intensely studied for over 25 years and recently over 800 novel mutations have been published, the relation between the location of mutations and clinical manifestation is poorly understood. Here we report missense mutations in COL1A1 of several OI patients. Two novel mutations were found in the D1 period. One caused a substitution of glycine 200 by valine at the N-terminus of D1 in OI type I/IV, lowering collagen stability by 50% at 34 degrees C. The other one was a substitution of valine 349 by phenylalanine at the C-terminus of D1 in OI type I, lowering collagen stability at 37.5 degrees C. Two other mutations, reported before, changed amino residues in D4. One was a lethal substitution changing glycine 866 to serine in genetically identical twins with OI type II. That mutated amino acid was near the border of D3 and D4. The second mutation changed glycine 1040 to serine located at the border of D4 and D0.4, in a proband manifesting OI type III, and lowered collagen stability at 39 degrees C (2 degrees C lower than normal). Our results confirm the hypothesis on a critical role of the D1 and D4 regions in stabilization of the collagen triple-helix. The defect in D1 seemed to produce a milder clinical type of OI, whereas the defect in the C-terminal end of collagen type caused the more severe or lethal types of OI.