Changes in retinal microvascular diameter in patients with diabetes

Optical Identification of Diabetic Retinopathy Using Hyperspectral Imaging

The severity of diabetic retinopathy (DR) is directly correlated to changes in both the oxygen utilization rate of retinal tissue as well as the blood oxygen saturation of both arteries and veins. Therefore, the current stage of DR in a patient can be identified by analyzing the oxygen content in blood vessels through fundus images. This enables medical professionals to make accurate and prompt judgments regarding the patient's condition. However, in order to use this method to implement supplementary medical treatment, blood vessels under fundus images need to be determined first, and arteries and veins then need to be differentiated from one another. Therefore, the entire study was split into three sections. After first removing the background from the fundus images using image processing, the blood vessels in the images were then separated from the background. Second, the method of hyperspectral imaging (HSI) was utilized in order to construct the spectral data. The HSI algorithm was utilized in order to perform analysis and simulations on the overall reflection spectrum of the retinal image. Thirdly, principal component analysis (PCA) was performed in order to both simplify the data and acquire the major principal components score plot for retinopathy in arteries and veins at all stages. In the final step, arteries and veins in the original fundus images were separated using the principal components score plots for each stage. As retinopathy progresses, the difference in reflectance between the arteries and veins gradually decreases. This results in a more difficult differentiation of PCA results in later stages, along with decreased precision and sensitivity. As a consequence of this, the precision and sensitivity of the HSI method in DR patients who are in the normal stage and those who are in the proliferative DR (PDR) stage are the highest and lowest, respectively. On the other hand, the indicator values are comparable between the background DR (BDR) and pre-proliferative DR (PPDR) stages due to the fact that both stages exhibit comparable clinical-pathological severity characteristics. The results indicate that the sensitivity values of arteries are 82.4%, 77.5%, 78.1%, and 72.9% in the normal, BDR, PPDR, and PDR, while for veins, these values are 88.5%, 85.4%, 81.4%, and 75.1% in the normal, BDR, PPDR, and PDR, respectively.

Peptide Lv augments intermediate-conductance calcium-dependent potassium channels (KCa3.1) in endothelial cells to promote angiogenesis

Peptide Lv is a small endogenous secretory peptide that is expressed in various tissues and conserved across different species. Patients with diabetic retinopathy, an ocular disease with pathological angiogenesis, have upregulated peptide Lv in their retinas. The pro-angiogenic activity of peptide Lv is in part through promoting vascular endothelial cell (EC) proliferation, migration, and sprouting, but its molecular mechanism is not completely understood. This study aimed to decipher how peptide Lv promotes EC-dependent angiogenesis by using patch-clamp electrophysiological recordings, Western immunoblotting, quantitative PCR, and cell proliferation assays in cultured ECs. Endothelial cells treated with peptide Lv became significantly hyperpolarized, an essential step for EC activation. Treatment with peptide Lv augmented the expression and current densities of the intermediate-conductance calcium-dependent potassium (KCa3.1) channels that contribute to EC hyperpolarization but did not augment other potassium channels. Blocking KCa3.1 attenuated peptide Lv-elicited EC proliferation. These results indicate that peptide Lv-stimulated increases of functional KCa3.1 in ECs contributes to EC activation and EC-dependent angiogenesis.

Effects of sleeve gastrectomy on lipid and energy metabolism in ZDF rats via PI3K/AKT pathway

Sleeve Gastrectomy (SG), as the most effective bariatric surgery, has been using to chronically lose weight and control glucose metabolism in Type 2 diabetes mellitus patients. However, the underlining mechanism is still unclear. In this study, we performed SG on Zucker diabetes fatty (ZDF) rat and investigated visceral lipid metabolism and energy metabolism. After performance of SG, weight, food intake, fasting plasma glucose (FPG) and oral glucose tolerance teat (OGTT) of rats were measured. Furthermore, whole-body metabolic parameters were obtained through TSE LabMaster. Blood lipid and renal function were analyzed by serum from rats' tail vein. Furthermore, the renal genes expression was either detected by real-time PCR, while western blotting was employed to detect the AKT/PI3K proteins level in rats' kidney. Compared to control groups, body weight of ZDF rats treated with SG were significantly reduced, simultaneously with glucose homeostasis and energy metabolism improved including RER (P<0.05), energy expenditure (P<0.05) at night and activity of animal. Meanwhile, serum lipid of ZDF rats after SG was decreased, and renal function recovered. Histology analysis confirmed that the size of perirenal adipose from SD treated ZDF rats obviously decreased (P<0.001), effectively stimulating up-regulation of lipogenesis genes (P<0.05), while adipogenesis genes (P<0.05) in kidney was down-regulated. In addition, phosphorylation of PI3K (p-PI3K) and AKT (p-AKT) in rats kidney were significantly decreased in SG group (P<0.05). Weight loss, food intake, fasting plasma glucose and glucose tolerance in SG surgery rats were improved, which were coincident with energy metabolism changes. In conclusion, SG improves lipid and energy metabolism in ZDF rats model due to activating PI3K/Akt signaling pathway, which was contributed to the mechanism of bariatric surgery toward kidney.