Background: Endothelial damage is an initial step of macro- and micro-vasculature dysfunctions in diabetic patients, accounting for a high incidence of diabetic vascular complications, such as atherosclerosis, nephropathy, retinopathy, and neuropathy. However, clinic lacks effective therapeutics targeting diabetic vascular complications. In field of regenerative medicine, mesenchymal stem cells, such as human umbilical cord-derived MSCs (hucMSCs), have great potential in treating tissue damage.Methods: To determine whether hucMSCs infusion could repair diabetic vascular endothelial damage and how it works, this study conducted in vivo experiment on streptozotocin-induced diabetic rat model to test body weight, fasting blood glucose (FBG), serum ICAM-1 and VCAM-1 levels, histopathology and immunohistochemical staining of aorta segments. In vitro experiment was further conducted to determine the effects of hucMSCs on diabetic vascular endothelial damage, applying assays of resazurin staining, MTT cell viability, wound healing, transwell migration, and matrigel tube formation on human umbilical vein endothelial cells (HUVECs). RNA sequencing (RNAseq) and molecular experiment were conducted to clarify the mechanism of hucMSCs.Results: The in vivo data revealed that hucMSCs partially restore the alterations of body weight, FBG, serum ICAM-1 and VCAM-1 levels, histopathology of aorta and reversed the abnormal phosphorylation of ERK in diabetic rats. By using the conditioned medium of hucMSCs (MSC-CM), the in vitro data revealed that hucMSCs improved cell viability, wound healing, migration and angiogenesis of the high glucose-damaged HUVECs through a paracrine action mode, and the altered gene expressions ofIL-6, TNF-α,ICAM-1,VCAM-1,BAX,P16,P53andET-1were significantly restored by MSC-CM. RNAseq incorporated with real-time PCR and Western blot results clarified that high glucose activated MAPK/ERK signaling in HUVECs, while MSC-CM reversed the abnormal phosphorylation of ERK and overexpressions ofMKNK2,ERBB3,MYCandDUSP5in MAPK/ERK signaling pathway.Conclusions: HucMSCs not only ameliorated blood glucose but also protected vascular endothelium from diabetic damage, in which MAPK/ERK signaling mediated its molecular mechanism of paracrine action. Our findings provided novel knowledge of hucMSCs in the treatment of diabetes and suggested a prospective strategy for the clinical treatment of diabetic vascular complications.

Background: Diabetic nephropathy (DN) is one of the most severe complications of diabetes mellitus, which is characterized by early occurrence of albuminuria and end-stage glomerulosclerosis. Senescence and autophagy of podocytes play an important role in DN development. Human umbilical cord-derived mesenchymal stem cells (hucMSCs) have potential in the treatment of diabetes and its complications. However, the role of hucMSCs in the treatment of DN and the underlying mechanism remain unclear. Methods: In vivo, a streptozotocin-induced diabetic male Sprague Dawley rat model was established to determine the renoprotective effect of hucMSCs on DN by biochemical analysis, histopathology, and immunohistochemical staining of renal tissues. And the distribution of hucMSCs in various organs in rats within 168 h was analyzed. In vitro, CCK8 assay, wound healing assay, and β-galactosidase staining were conducted to detect the beneficial effects of hucMSCs on high glucose-induced rat podocytes. Real-time PCR and western blot assays were applied to explore the mechanism of action of hucMSCs. Results: The in vivo data revealed that hucMSCs were distributed into kidneys and significantly protected kidneys from diabetic damage. The in vitro data indicated that hucMSCs improved cell viability, wound healing, senescence of the high glucose-damaged rat podocytes through a paracrine action mode. Besides, the altered expressions of senescence-associated genes (p16, p53, and p21) and autophagy-associated genes (Beclin-1, p62, and LC3) were improved by hucMSCs. Mechanistically, hucMSCs protected high glucose-induced injury in rat podocytes by activating autophagy and attenuating senescence through the AMPK/mTOR pathway. Conclusions: In conclusion, hucMSCs might be a promising therapeutic strategy for the clinical treatment of DN-induced renal damages.

Diabetic foot ulcer (DFU) is a main diabetic complication with unmet treatment needs. This study applied human umbilical cord-derived mesenchymal stem cells-hyaluronic acid (hucMSCs-HA) gel to treat DFU in a noninvasive external way and investigated its paracrine action and mechanism. In this study, after analyzing the physical and biological properties of HA gel, hucMSCs-HA gel was applied in 2 in vivo models (types I and II DFU), and a molecular mechanism was investigated. To evaluate the paracrine action of hucMSCs, hucMSCs-conditional medium (MSC-CM) was collected to treat 1 in vivo model (type I DFU) and 2 in vitro models (high glucose (HG)-injured human umbilical vein endothelial cells (HUVECs) and human skin fibroblasts (HSFs)). The results indicated that HA gel with a porous microstructure underwent over 90% degradation and swelled to the maximum value within 48 h. In vivo, hucMSCs-HA gel accelerated wound healing of DFU rats by improving re-epithelialization, collagen deposition, and angiogenesis, in which a paracrine action of hucMSCs was confirmed and the phosphorylation of p38, ERK1/2, JNK, and Akt was increased. In vitro, MSC-CM improved cell viability, wound healing, migration, tube formation, cell senescence, and abnormal expressions (TNF-α, IL-1β, IL-6, ET-1, p16 genes, and PCNA protein) of HUVECs, also improved cell viability, wound healing, antioxidant stress, and abnormal expressions (COL1, COL3, COL4, SOD1, SOD2 genes, and PCNA protein) of HSFs. Summarily, noninvasive external application of hucMSCs-HA gel shows great perspective against DFU and exerts wound healing effects through the MAPK and Akt pathways-mediated paracrine mechanism.

Background. Type 2 diabetes is a major health concern worldwide. The present study is aimed at discovering effective biomarkers for an efficient diagnosis of type 2 diabetes. Methods. Differentially expressed genes (DEGs) between type 2 diabetes patients and normal controls were identified by analyses of integrated microarray data obtained from the Gene Expression Omnibus database using the Limma package. Functional analysis of genes was performed using the R software package clusterProfiler. Analyses of protein‐protein interaction (PPI) performed using Cytoscape with the CytoHubba plugin were used to determine the most sensitive diagnostic gene biomarkers for type 2 diabetes in our study. The support vector machine (SVM) classification model was used to validate the gene biomarkers used for the diagnosis of type 2 diabetes. Results. GSE164416 dataset analysis revealed 499 genes that were differentially expressed between type 2 diabetes patients and normal controls, and these DEGs were found to be enriched in the regulation of the immune effector pathway, type 1 diabetes mellitus, and fatty acid degradation. PPI analysis data showed that five MCODE clusters could be considered as clinically significant modules and that 10 genes (IL1B, ITGB2, ITGAX, COL1A1, CSF1, CXCL12, SPP1, FN1, C3, and MMP2) were identified as “real” hub genes in the PPI network using algorithms such as Degree, MNC, and Closeness. The sensitivity and specificity of the SVM model for identifying patients with type 2 diabetes were 100%, with an area under the curve of 1 in the training as well as the validation dataset. Conclusion. Our results indicate that the SVM‐based model developed by us can facilitate accurate diagnosis of type 2 diabetes.

Background: Mitochondrial dysfunction plays a pivotal role in the onset and progression of diabetic cardiomyopathy (DCM). It is hypothesized that ultrastructural mitochondrial abnormalities, molecular dynamics imbalance, and bioenergetic impairments collectively contribute significantly to cardiac dysfunction. Consequently, investigating mitochondrial ultrastructural changes and metabolic disturbances is crucial for elucidating the mechanistic underpinnings of DCM. Objective: This study aims to comprehensively characterize alterations in mitochondrial ultrastructure and energy metabolism in DCM and examine the interplay between these two factors. Methods: High glucose-treated H9c2 cardiomyocytes and DCM model mice were analyzed via scanning electron microscopy (SEM) and 3D imaging. Three-dimensional morphometric parameters—such as Length3D, Thickness3D, Width3D, Area3D, Volume3D, Anisotropy, Flatness, and Elongation—were quantified to evaluate mitochondrial architecture. At the two-dimensional (2D) level, mitochondria-associated membrane (MAM) parameters were analyzed. Further, detailed statistical analysis was conducted on mitochondrial cristae, including cristae scores, count, width, gap size, and junction widths in myocardial tissues. Mitochondrial dynamics and autophagy-related protein expression (Mfn1, Mfn2, Opa1, p-Drp1(ser616), PINK1, Parkin1) in myocardial tissues were assessed by Western blot. Mitochondrial bioenergetics were measured by ATP content, membrane potential, mtDNA copy number, SOD levels, mitochondrial Ca²⁺ levels, and oxidative phosphorylation (OXPHOS) activity across Complexes I–V in myocardial tissue. Additionally, the oxygen consumption rate (OCR) of viable H9c2 cells was measured using the O2k system. Results: 3D reconstruction revealed key myocardial ultrastructures—including T-tubules, sarcoplasmic reticulum (SR), intercalated discs, and mitochondria—and demonstrated significant differences in mitochondrial morphology and 3D morphometric parameters across subpopulations. Under high glucose (HG) conditions, in vitro analysis showed a reduction in mitochondrial Length3D and Anisotropy in H9c2 cells, accompanied by increases in Thickness3D, Width3D, Flatness, and Elongation. HG exposure also led to an increase in the length of MAM contact sites and the MAM-to-mitochondria perimeter ratio. In vivo, the DCM group exhibited decreased 2D morphometric parameters (length, width, area, perimeter, and shape AP), as well as reductions in 3D measurements (Thickness3D, Width3D, and Volume3D) compared to controls. No significant differences were observed in Length3D, Area3D, Anisotropy, Flatness, and Elongation between groups. 3D surface analysis revealed rough mitochondrial surfaces in the DCM group, while controls displayed smooth surfaces. Control mitochondria exhibited well-aligned, well-defined cristae, whereas DCM mitochondria showed cristae dissolution, disorganized arrangements, and vacuolization within the cristae. The DCM group also had increased cristae junction width and spacing. Additionally, megamitochondria were observed in DCM samples. The DCM group showed a significant increase in MAM contact site length and MAM-to-mitochondria perimeter ratio in myocardial tissue. Molecular analysis revealed decreased expression of fusion proteins (Mfn1, Opa1) and increased levels of p-Drp1(ser616), alongside elevated autophagy markers (PINK1, Parkin1). Bioenergetic dysfunction was evident through decreased ATP production, mitochondrial membrane potential collapse (ΔΨm), reduced mtDNA copy number, decreased SOD levels, impaired activities of complexes I/III/IV/V, and diminished basal/maximal respiration, ATP-linked respiration, and spare respiratory capacity. Conversely, mitochondrial Ca²⁺ levels were elevated in the DCM group, along with increased proton leakage in H9c2 cells. Conclusions: This study establishes a comprehensive framework linking “3D morphology–molecular regulation–metabolic dysfunction,” highlighting the synergistic interplay between mitochondrial ultrastructural remodeling and bioenergetic failure as key drivers of DCM progression. These findings provide valuable insights into DCM pathogenesis and suggest potential therapeutic targets.