Risk factor analysis for diabetic foot ulcer-related amputation including Controlling Nutritional Status score and neutrophil-to-lymphocyte ratio.

Diabetic foot ulcer often leads to amputation, and both nutritional status and immune function have been associated with this process. We aimed to investigate the risk factors of diabetic ulcer-related amputation including the Controlling Nutritional Status score and neutrophil-to-lymphocyte ratio biomarker. We evaluated data from hospital in patients with diabetic foot ulcer, performing univariate and multivariate analyses to screen for high-risk factors and Kaplan-Meier analysis to correlate high-risk factors with amputation-free survival. Overall, 389 patients underwent 247 amputations over the follow-up period. After correction to relevant variables, we identified five independent risk factors for diabetic ulcer-related amputation: ulcer severity, ulcer site, peripheral arterial disease, neutrophil-to-lymphocyte ratio and nutritional status. Amputation-free survival was lower for the moderate-to-severe versus mild cases, for the plantar forefoot versus hindfoot location, for the concomitant peripheral artery disease versus without and in the high versus low neutrophil-to-lymphocyte ratio (all p < 0.01). The results showed that ulcer severity (p < 0.01), ulcer site (p < 0.01), peripheral artery disease (p < 0.01), neutrophil-to-lymphocyte ratio (p < 0.01) and Controlling Nutritional Status score (p < 0.05) were independent risk factors for amputation in diabetic foot ulcer patients and have predictive values for diabetic foot ulcer progression to amputation.

Characterization of inflammatory profiles and endothelial dysfunction in diabetic limb arterial occlusion.

Our study aims to detect the changes of adiponectin (APN), endothelin 1 (ET)-1, nitric oxide (NO), cystatin C (cysC) in diabetic limb arterial occlusion (DLAO) patients and unravel their associations with endothelial function. Total 240 type 2 diabetes mellitus (T2DM) patients were divided into a DM group (n = 80, ankle brachial index (ABI) ≥ 0.9) and a DLAO group (n = 160, ABI < 0.9). ABI, flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD), serum APN, ET-1, NO, and cysC were compared. There were significant increases in cysC and ET-1, and significant decreases in APN, NO, FMD and NMD of DLAO patients compared to T2DM patients. Serum APN and NO were positively correlated with ABI, while serum cysC and ET-1 were negatively correlated with ABI. cysC, ET-1 and diastolic blood pressure (DBP) were independent predictors of the severity of DLAO. Serum APN was positively correlated with FMD, NMD and NO, but was negatively correlated with ET-1 and cysC. FMD and NMD were positively correlated with APN and NO, and negatively correlated with ET-1 and cysC. Our study deciphers opposite roles of APN, NO, cysC and ET-1 in the development of DLAO and maintaining endothelial function.

Monolayer surface chemistry enables 2-colour single molecule localisation microscopy of adhesive ligands and adhesion proteins.

Nanofabricated and nanopatterned surfaces have revealed the sensitivity of cell adhesion to nanoscale variations in the spacing of adhesive ligands such as the tripeptide arginine-glycine-aspartic acid (RGD). To date, surface characterisation and cell adhesion are often examined in two separate experiments so that the localisation of ligands and adhesion proteins cannot be combined in the same image. Here we developed self-assembled monolayer chemistry for indium tin oxide (ITO) surfaces for single molecule localisation microscopy (SMLM). Cell adhesion and spreading were sensitive to average RGD spacing. At low average RGD spacing, a threshold exists of 0.8 RGD peptides per µm2 that tether cells to the substratum but this does not enable formation of focal adhesions. These findings suggest that cells can sense and engage single adhesive ligands but ligand clustering is required for cell spreading. Thus, our data reveal subtle differences in adhesion biology that may be obscured in ensemble measurements.

Ultralow- and Low-Background Surfaces for Single-Molecule Localization Microscopy of Multistep Biointerfaces for Single-Molecule Sensing.

Single-molecule localization microscopy (SMLM) has created the opportunity of pushing fluorescence microscopy from being a biological imaging tool to a surface characterization and possibly even a quantitative analytical tool. The latter could be achieved by molecular counting using pointillist SMLM data sets. However, SMLM is especially sensitive to background fluorescent signals, which influences any subsequent analysis. Therefore, fabricating sensing surfaces that resist nonspecific adsorption of proteins, even after multiple modification steps, has become paramount. Herein is reported two different ways to modify surfaces: dichlorodimethylsilane-biotinylated bovine serum albumin-Tween-20 (DbT20) and poly-l-lysine grafted polyethylene glycol (PLL-PEG) mixed with biotinylated PLL-PEG (PLL-PEG/PEGbiotin). The results show that the ability to resist nonspecific adsorption of DbT20 surfaces deteriorates with an increase in the number of modification steps required after the addition of the DbT20, which limits the applicability of this surface for SMLM. As such, a new surface for SMLM that employs PLL-PEG/PEGbiotin was developed that exhibits ultralow amounts of nonspecific protein adsorption even after many modification steps. The utility of the surface was demonstrated for human influenza hemagglutinin-tagged mEos2, which was directly pulled down from cell lysates onto the PLL-PEG/PEGbiotin surface. The results strongly indicated that the PLL-PEG/PEGbiotin surface satisfies the criteria of SMLM imaging of a negligible background signal and negligible nonspecific adsorption.