The impact of sensory neuropathy and inflammation on epithelial wound healing in diabetic corneas

A carbon nanotube/pyrrolidonecarboxylic acid zinc sponge for programmed management of diabetic wounds: Hemostatic, antibacterial, anti-inflammatory, and healing properties

Wound healing in patients with diabetes is challenging because of chronic inflammation, inadequate vascularization, and susceptibility to infection. Current wound dressings often target specific stages of healing and lack comprehensive therapeutic approaches. This study introduces a novel approach using a photodetachable sponge scaffold incorporating carbon nanotubes (CNTs), known for their high photothermal conversion efficiency, electrical conductivity, and water absorption properties. The scaffold incorporated pyrrolidonecarboxylic acid zinc (PC1Z2), a compound with anti-inflammatory and moisturizing properties, which was cross-linked within a network of CNTs and a decellularized dermal matrix. The resulting shape-memory sponge scaffold actively interfaces with endogenous electric fields, facilitating electrical signal transmission to skin cells and accelerating tissue repair. Upon exposure to near-infrared (NIR) light, the PC1Z2 scaffold enhanced antibacterial efficacy (98 %) through photothermal conversion, promoting tissue metabolism at the wound site. Notably, the scaffold absorbed wound exudates and gradually released Zn2+, effectively reducing chronic inflammation in the mice. In a diabetic rat wound model, the PC1Z2 scaffold absorbed exudates, reduced inflammation, and accelerated granulation tissue formation, wound angiogenesis, and re-epithelialization. This innovative PC1Z2 sponge dressing shows promise for enhancing the healing of diabetic wounds.

Oxygen uptake at the ocular surface in diabetic animals is impaired in response to central corneal injury

Poor wound healing is one of the most devastating complications in late-stage diabetic patients. The avascular cornea does not rely on circulation for its oxygen consumption, uptaking it mainly from the atmosphere. Previous studies demonstrated that oxygen uptake (O2U) in diabetic experimental animals and patients is significantly lower than in the non-diabetic condition. Our recent experiments show that upon wounding of the central cornea the O2U decreased across the ocular surface, followed by two increases at 6-24 h, and at 72 h, which appeared to be important for proper wound healing. It is however not known whether the two distinct O2U increases are maintained in diabetic ocular surface in response to corneal injury. In this study, we used an optic-fiber oxygen micro-sensor to measure O2U across the ocular surface of streptozotocin (STZ)- induced diabetic mice and age-matched control mice following injury to the central cornea. We found that the injury causes an immediate and substantial reduction of O2U across the ocular surface. O2U in non-diabetic corneas increases at 2-6 h post wounding (hpw), decreasing again before the second rise to peak at 72 hpw, especially at the limbus. O2U in the diabetic cornea decreases more markedly than that of non-diabetic control. This defective diabetic O2U persisted, precluding the two dynamic rises in O2U, leading to a failure in recovery. Altogether, our results suggest a previously unknown mechanism of a defective O2U response to injury in the diabetic ocular surface, which warrants further research and may lead to new therapeutic paths.

Potential Role of CD99 Signaling Pathway in Schwann Cell Dysfunction in Diabetic Foot Ulcers Based on Single-Cell Transcriptome Analysis

Background: Schwann cell (SC) dysfunction contributes to the delayed healing of diabetic foot ulcers (DFUs). However, the underlying molecular mechanism regarding the unregulated SC function is poorly understood. Thus, we examined the single-cell transcriptome data from different DFU states focusing on SC characteristics. Methods: The single-cell RNA sequencing (scRNA-seq) data of DFU was obtained from the Gene Expression Omnibus (GEO) database, covering foot skin samples from nondiabetic patients, diabetic patients without DFU, DFU healers, and DFU nonhealers. After scRNA-seq data processing, downscaling, and cell cluster identification, cell communication analysis was performed by the CellChat package. Furthermore, we subclustered SC populations and ran the trajectory inference and pseudotime analysis to investigate the dynamic changes in SC. Finally, the significant pathways were validated with a db/db mouse wound model. Results: scRNA-seq analysis revealed different SC percentages and gene markers across the DFU groups. We identified that the CD99 signaling pathway was upregulated in the DFU nonhealer group. In the db/db mouse wound model, we observed that CD99 was highly expressed in the demyelinated area of the peripheral nerve fibers. Conclusion: Our study elucidated that the CD99 pathway activation may play a crucial role in SC dysfunction of DFU, providing insights into the peripheral glia regulation mechanism and potential therapeutic target of DFU.

Peripheral Neuropathy Symptoms and Ocular Surface Lesions in Patients with Type 2 Diabetes Mellitus and Dry Eye: A Clinical Correlational Study

INTRODUCTION

Reduced corneal sensation in individuals with type 2 diabetes mellitus (T2DM) leads to a dissociation between dry eye disease (DED) signs and symptoms, thereby affecting diagnostic accuracy. This study aimed to investigate the correlation between ocular surface signs and diabetic peripheral neuropathy (DPN) symptoms in patients with T2DM-associated DED.

METHODS

The Michigan Neuropathy Screening Instrument Questionnaire (MNSIQ) was used to categorize patients with T2DM into MNSIQ-DPN and non-DPN groups. Ocular irritation symptoms were evaluated using the Ocular Surface Disease Index (OSDI) questionnaire. Ocular surface lesions were assessed via Cochet-Bonnet esthesiometry, corneal fluorescein staining (CFS), the Schirmer I tear test (SIT), tear meniscus height (TMH), noninvasive keratography break-up time (NIKf-BUT), and the meibomian gland loss (MGL) grade detected by OCULUS. Corneal nerve fiber parameters were evaluated using in vivo confocal microscopy (IVCM).

RESULTS

A total of 116 patients with T2DM, comprising 76 non-DPN patients and 40 MNSIQ-DPN patients, along with 51 age-matched participants without diabetes, were enrolled. Although OSDI scores were equivalent between MNSIQ-DPN patients and non-DPN patients, MNSIQ-DPN patients presented significantly more severe CFS (p < 0.001), meibomian gland dysfunction (MGD) (p < 0.001), corneal nerve fiber loss (p < 0.001), sensory dysfunction (p = 0.02), and corneal microneuromas (p < 0.001). The MNSIQ score was significantly positively correlated with CFS (p < 0.001); MGD (p < 0.01); corneal nerve fiber loss, including corneal nerve fiber density and length and branch density, in the paracentral (all p < 0.001) and inferior-whorl areas (p < 0.01, p < 0.05 and p < 0.01, respectively); and corneal microneuromas, characterized by increased microneuroma numbers (p < 0.001) and areas (p < 0.001) in these regions.

CONCLUSION

MNSIQ scores were significantly and robustly correlated with the presence of corneal epithelial defects, MGD, and nerve fiber loss in patients with T2DM. These findings suggest that DPN is a critical factor in diabetic ocular surface complications, highlighting the importance of the MNSIQ for assessing these conditions.

Electro- and Magneto-Active Biomaterials for Diabetic Tissue Repair: Advantages and Applications

The diabetic tissue repair process is frequently hindered by persistent inflammation, infection risks, and a compromised tissue microenvironment, which lead to delayed wound healing and significantly impact the quality of life for diabetic patients. Electromagnetic biomaterials offer a promising solution by enabling the intelligent detection of diabetic wounds through electric and magnetic effects, while simultaneously improving the pathological microenvironment by reducing oxidative stress, modulating immune responses, and exhibiting antibacterial action. Additionally, these materials inherently promote tissue regeneration by regulating cellular behavior and facilitating vascular and neural repair. Compared to traditional biomaterials, electromagnetic biomaterials provide advantages such as noninvasiveness, deep tissue penetration, intelligent responsiveness, and multi-stimuli synergy, demonstrating significant potential to overcome the challenges of diabetic tissue repair. This review comprehensively examines the superiority of electromagnetic biomaterials in diabetic tissue repair, elucidates the underlying biological mechanisms, and discusses specific design strategies and applications tailored to the pathological characteristics of diabetic wounds, with a focus on skin wound healing and bone defect repair. By addressing current limitations and pursuing multi-faceted strategies, electromagnetic biomaterials hold significant potential to improve clinical outcomes and enhance the quality of life for diabetic patients.

OTUD1 delays wound healing by regulating endothelial function and angiogenesis in diabetic mice

INTRODUCTION

Diabetic non-healing wounds represent a major complication of diabetes, primarily due to impaired angiogenesis. Ovarian tumor deubiquitinase 1 (OTUD1), a deubiquitinase, has been implicated in vascular pathophysiology; however, its role in endothelial dysfunction and angiogenesis during diabetic wound healing is still poorly understood.

OBJECTIVES

This study explores whether OTUD1 influences angiogenesis and its underlying mechanisms.

METHODS

We developed OTUD1 knockout mice and induced type 1 and type 2 diabetes mellitus (T1DM and T2DM) by administering streptozotocin (STZ) alone or in combination with a high-fat diet (HFD), respectively. Human umbilical vein endothelial cells (HUVECs) incubated with high glucose and palmitic acid (HG + PA) were utilized to imitate hyperglycemia-induced endothelial dysfunction in vitro. Mass spectrometry combined with immunoprecipitation analysis was used to analyze the interacting proteins of OTUD1. Moreover, we developed endothelial-specific OTUD1 knockdown db/db mice using an adeno-associated virus serotype 2/BI30 (AAV2/BI30) vector.

RESULTS

Increased OTUD1 expressions were observed both in diabetic wound tissues and in HUVECs treated with HG + PA. OTUD1 deficiency promoted angiogenesis and fibrosis in wound tissues of T1DM and T2DM mice and alleviated HG + PA-induced endothelial migration inhibition, tube formation impairment, and oxidative stress in HUVECs. Mechanistically, OTUD1 directly interacted with β-catenin, reducing its K63-linked ubiquitination at residues K496, K508, and K625 via its catalytic site C320. This modification facilitated β-catenin phosphorylation, restricted its nuclear translocation, and downregulated the expression of angiogenesis-related factors. Finally, pharmacological inhibition of β-catenin reversed the improvement of delayed wound healing induced by OTUD1 knockdown in db/db mice.

CONCLUSION

These findings elucidate the OTUD1-β-catenin pathway's role in endothelial dysfunction-associated angiogenesis and suggest OTUD1 as a promising therapeutic target for diabetic non-healing wounds.

Mechanisms and therapeutic opportunities in metabolic aberrations of diabetic wounds: a narrative review

Metabolic aberrations are fundamental to the complex pathophysiology and challenges associated with diabetic wound healing. These alterations, induced by the diabetic environment, trigger a cascade of events that disrupt the normal wound-healing process. Key factors in this metabolic alternation include chronic hyperglycemia, insulin resistance, and dysregulated lipid and amino acid metabolism. In this review, we summarize the underlying mechanisms driving these metabolic changes in diabetic wounds, while emphasizing the broad implications of these disturbances. Additionally, we discuss therapeutic approaches that target these metabolic anomalies and how their integration with existing wound-healing treatments may yield synergistic effects, offering promising avenues for innovative therapies.

Corneal Epithelial Defects in Diabetic Patients Following Pars Plana Vitrectomy

Diabetes mellitus is a known risk factor for corneal epithelial defects (CEDs) after pars plana vitrectomy (PPV), but it is unclear if diabetes severity or specific diabetic risk factors are associated with an increased risk of CED. The purpose of this retrospective cohort study was to identify factors associated with CED and healing time in association with diabetes severity in diabetic patients following PPV. The electronic health record database at University of Florida in Gainesville was queried to identify patients who underwent PPV for retinal detachment (RD) between April 2016 and April 2022. Patient charts were reviewed for clinical data including type of diabetes (if present), diabetes duration and severity, and associated diabetic comorbidities. The main outcome measures included presence of a CED within one month postoperatively, treatment of CED if present, and CED healing time. A total of 637 patients were analyzed, with a total of 243 eyes (26.5%) that belonged to diabetic patients. The diabetic patients were further separated into a proliferative diabetic retinopathy (PDR) group and a nonproliferative diabetic retinopathy (NPDR) group. Diabetes was associated with the development of an initial CED (p=0.040), consistent with existing literature. There was not a significant difference in CED risk when comparing NPDR and PDR patients, although PDR patients tended to have more severe long-term outcomes with persistent corneal epithelial defects (PCEDs). This suggests that PDR patients may still require closer monitoring and earlier intervention for postoperative CED following PPV, as compared to the NPDR patient population.

Nerve growth factor loaded hypotonic eye drops for corneal nerve repair

Neurotrophic keratopathy is a degenerative disease caused by corneal nerve damage, leading to corneal ulceration. Recombinant human nerve growth factor (rhNGF) was approved for neurotrophic keratitis therapy; however, the excipients of the eye drops are not optimized for its controlled release. To this aim, we introduce the hypotonic hydrogel PF127 as an excipient for rhNGF in eye drops. We confirmed the formation of a hydrogel using a vial-inversion test and based on rheological properties. The hydrogel exerts shear-thinning behavior upon sweep test with a favorable transmittance and a natural refractive index. Moreover, the hydrogel exhibited fast and sustained rhNGF release kinetic, along with constant dissolution and the formation of a network-like structure. The release of rhNGF was confirmed by the proliferation of PC12 cells and its protective effect on damaged axons of dorsal root ganglia cells. The hydrogel performed accordingly in the in-situ ocular gelation and ocular surface retention test. We further confirmed that labeled proteins were released from the hydrogel to the cornea. Preclinical testing in mice showed that rhNGF hydrogels supported the recovery from corneal epithelial defects: they reduced the defect size and increased corneal nerve density. Schirmer's test revealed improved corneal nerve function based on tear secretion. The hydrogel resists clearance from blinking and enhances the intraocular absorption of rhNGF. The ocular surface, retinal thickness, and the ciliary body and retina remained unchanged. Together, these findings suggest that the hypotonic PF127 hydrogel is a suitable rhNGF delivery system to prepare eye drops for potential use in neurotrophic keratopathy.

CD4+CD25- T-Cell-Secreted IFN-γ Promotes Corneal Nerve Degeneration in Diabetic Mice

Purpose

This study aimed to explore the relationship between corneal nerve degeneration and elevated dendritic cells (DCs) in diabetic keratopathy.

Methods

Corneas from diabetic and healthy mice were analyzed using single-cell RNA sequencing. Corneal nerve density and DC and T-cell infiltration were quantified through whole-mount corneal staining. Freshly isolated mouse trigeminal ganglion (TG) neurons were co-cultured with immature DCs, mature DCs, activated CD8+ T cells, and CD4+CD25- T cells. TG neurite outgrowth was assessed to identify potential effector cells driving corneal nerve degeneration. In addition, interferon-gamma (IFN-γ) and blocking antibodies were used to evaluate their effects on TG neurite outgrowth and corneal nerve degeneration in mice.

Results

Compared with age-matched healthy mice, diabetic mice exhibited a significant reduction in corneal nerve density and sensitivity, along with increased infiltration of DCs, CD4+ T cells, and CD8+ T cells. In vitro co-culture experiments revealed that CD4+CD25- T cells, rather than DCs and CD8+ T cells, significantly inhibited TG neurite outgrowth. Among cytokines, elevated IFN-γ in diabetic corneas impaired TG neurite outgrowth and induced corneal nerve degeneration, whereas IL-4 and IL-17 had no such effect. Blocking IFN-γ alleviated CD4+CD25- T-cell-induced inhibition of TG neurite outgrowth and corneal nerve degeneration in diabetic mice.

Conclusions

CD4+CD25- T cells, but not DCs or CD8+ T cells, contribute to corneal nerve degeneration in diabetic mice, a process partially mediated by IFN-γ.

Research progress of corneal characteristics and changes in primary angle‑closure glaucoma (Review)

The cornea plays a crucial role in the refractive system of the eyeball, and its changes can significantly impact the visual quality of patients with glaucoma. In patients with primary angle-closure glaucoma, several corneal alterations occur, including changes in corneal thickness and curvature, modification in corneal epithelial cells and nerves, activation of inflammatory cells, and variations in the number and morphology of stromal and endothelial cells. These morphological and structural changes in the cornea are mainly influenced by acute or chronic elevation of intraocular pressure and treatment. In the present review the corneal morphological changes and regularities associated with primary angle-closure glaucoma are examined.

Norepinephrine regulates epithelial-derived neurotrophins expression and sensory nerve regeneration through ADRB2 receptor

Norepinephrine (NE) is mainly released by sympathetic nerve terminals to act on organs and tissues. After corneal epithelial debridement, we found that the sympathetic nerve fibers penetrated the limbus and regenerated toward the cornea within 24 h post-wounding. Topical NE application recapitulated the characteristics of delayed corneal epithelial wound healing and nerve regeneration in healthy mice, accompanied by the partial depletion of multiple neurotrophins, such as nerve growth factor and glial cell-derived nerve growth factor. Moreover, the diabetes mellitus (DM) mice exhibited corneal sensory nerve dysfunction and increased plasma and corneal NE contents, which were rescued by 6-hydroxydopamine (6-OHDA) and bretylium. In the cell culture model, the conditioned medium of NE-treated corneal epithelial cells inhibited trigeminal ganglion (TG) neurite outgrowth, which was reversed by the β2 adrenergic receptor (ADRB2) antagonist, but not by the β1 adrenergic receptor (ADRB1) antagonist. Topical application of the ADRB2 antagonist recovered the expression of corneal neurotrophins, and promoted corneal epithelial and nerve regeneration in DM mice. Taken together, the NE-ADRB2 axis regulates corneal neurotrophin expression and nerve regeneration in mice. Topical application of the ADRB2 antagonist may represent a promising therapeutic strategy for diabetic corneal sensory nerve dysfunction.

Association of serum magnesium level with small fiber neuropathy in patients with type 2 diabetes

Purpose

We aimed to investigate the association between serum magnesium (Mg) levels and small fiber neuropathy among patients with type 2 diabetes mellitus (T2DM).

Methods

This study retrospectively collected data from patients with T2DM. Patients were divided based on the quartiles of the serum concentrations of Mg. Corneal confocal microscopy (CCM) was employed to determine the morphological parameters of corneal nerve fibers, including corneal nerve fiber length (CNFL), fiber density (CNFD), and branch density (CNBD). Pearson correlation analysis and multiple linear regression analyses were conducted to investigate the association between the serum levels of Mg and the morphological parameters of corneal nerve fibers.

Results

In total, 136 patients with T2DM were enrolled in this study. All morphological parameters of corneal nerve fibers increased with the increasing quartiles of serum Mg levels. Using Pearson correlation analysis, we found a significant and positive association between the serum levels of Mg and CNFL (r = 0.550, p < 0.001), CNFD (r = 0.432, p < 0.001), and CNBD (r = 0.425, p < 0.001). After adjusting for covariates, the serum levels of Mg remained positively correlated with CNFL (β = 0.495, p < 0.001), CNFD (β = 0.361, p < 0.001), and CNBD (β = 0.374, p < 0.001) in the fully adjusted model.

Conclusion

The serum levels of Mg were positively and independently correlated with the morphological parameters of the corneal nerve among patients with T2DM. Serum Mg levels can serve as a potential biomarker for screening corneal small fiber neuropathy in patients with T2DM.

Exosomes derived from adipose mesenchymal stem cells promote corneal injury repair and inhibit the formation of scars by anti-apoptosis

In the corneal wound healing process, epithelial cell re-epithelialization and migration are the critical first steps following an injury. As the disease progresses, orderly regeneration of corneal stromal collagen and mild corneal stromal fibrosis are vital for corneal function reconstruction. Exosomes derived from adipose-derived mesenchymal stem cells (ADSCs-Exos) have emerged as a promising therapy due to their anti-oxidant, anti-apoptosis, and tissue repair properties. In this study, we successfully isolated exosomes via differential centrifugation and verified their effective extraction through transmission electron microscopy and nanoparticle tracking analysis. In vitro, ADSCs-Exos increased corneal epithelial cell migration by 20 % and reduced oxidative damage by 50 %. In addition, ADSCs-Exos demonstrated remarkable wound healing properties in corneal tissue. This effect was attributed to their ability to inhibit apoptosis of corneal stroma cells by upregulating Bax and downregulating Bcl2, reducing the Bax/Bcl2 protein expression ratio from 1 to 0.45. This decrease may subsequently inhibit α-SMA expression, thereby preventing corneal scarring. Overall, this research has elucidated the effects and potential targets of ADSCs-Exos in promoting corneal wound repair, offering a novel and promising approach for treating corneal injuries.

Notoginsenoside R1 alleviates blue light-induced corneal injury and wound healing delay by binding to and inhibiting TRIB1

BACKGROUND

With the escalating use of digital devices, blue light (BL) exposure has emerged as a critical concern due to its potential to cause ocular damage. This study explores the protective effects of notoginsenoside R1 (NR1), a bioactive compound from Panax notoginseng (Burkill) F.H. Chen (Sanqi), against BL-induced corneal epithelial injury.

PURPOSE

This research aims to investigate the protective effects of NR1 on BL-induced corneal injury and wound healing delay.

METHODS

Human corneal epithelial cells (hCECs) were pretreated with NR1 (0-50 μM) or N-acetylcysteine (NAC, 10 mM), then exposed to BL (570 μW/cm²) for 24 h. Cell viability, proliferation, migration, and ROS levels were assessed using various techniques. In mice, NR1 (25 μM and 50 μM) and NAC (0.3 %) eye drops were administered during BL exposure. Corneal injury, healing rates, cell proliferation, migration, ROS, and inflammation were evaluated. RNA-sequencing, bioinformatics, and molecular binding validation identified tribbles homolog 1 (TRIB1) as a key molecule mitigating BL damage with NR1. Functional studies via gene silencing, overexpression, and pharmacological modulation further explored TRIB1's role in BL exposure.

RESULTS

NR1 significantly reduced BL-induced inflammation, ROS production, and inhibited migration and proliferation in hCECs and murine corneas. It also alleviated BL-induced corneal injury and delayed healing in mice. NR1 inhibited TRIB1 upregulation, a marker of BL-induced injury and healing delay. Overexpression of TRIB1 negated NR1's therapeutic effects on hCECs, while TRIB1 silencing mitigated functional impairment. In mice, increased Trib1 expression caused corneal injury and delayed healing, reversed by NR1 treatment.

CONCLUSION

NR1 shows potential as a therapeutic agent by inhibiting TRIB1 elevation in response to BL exposure, providing a novel promising target for corneal injury and wound healing delay induced by BL, and offering a comprehensive strategy for clinical pharmacological intervention.

Dedifferentiated fat cells-derived exosomes (DFATs-Exos) loaded in GelMA accelerated diabetic wound healing through Wnt/β-catenin pathway

BACKGROUND

Diabetic foot ulcers pose significant challenges for clinicians worldwide. Cell-free exosome therapy holds great potential for wound healing. Dedifferentiated fat cells (DFATs) have been used in tissue engineering and regeneration, but there are no reports on the use of DFATs-derived exosomes in diabetic wound repair.

OBJECTIVES

This study aims to investigate whether DFATs-Exos accelerated diabetic wound healing and explore its potential mechanism.

METHODS

In vitro, DFATs-Exos were harvested from adipose tissue and used to treat endothelial cells (ECs) and fibroblasts. XAV939 was used as a Wnt/β-catenin pathway inhibitor. The biocompatibility of gelatin methacryloyl (GelMA) hydrogel was assessed. In vivo, DFAT-derived exosomes were encapsulated in 10% GelMA hydrogel and applied to a diabetic wound model. Histological analysis and wound closure rates were evaluated.

RESULTS

DFATs-Exos promoted angiogenesis in ECs and significantly alleviated the high glucose-induced inhibition of cell proliferation and migration by activating the Wnt/β-catenin pathway. In vivo, compared to DFAT-Exos or GelMA alone, the DFAT-Exos/GelMA combination accelerated wound closure and enhanced collagen maturity.

CONCLUSION

The DFAT-Exos/GelMA hydrogel significantly promoted wound healing in a diabetic animal model through activation of the Wnt/β-catenin signaling pathway.

Decoding the corneal immune microenvironment in healthy and diabetic mice during corneal wound healing

Diabetic keratopathy (DK) is an underdiagnosed ocular complication of diabetes mellitus. The changes of ocular immune microenvironment contribute to the pathogenesis of DK, while precise mechanisms remain inadequately understood. Here, we employed single-cell RNA sequencing (scRNA-seq) to elucidate the transcriptional alterations of immune cells from diabetic and healthy control mouse corneas during homeostasis and wound healing. Unbiased clustering analysis unveiled 3 major cell subsets and 11 subdivided cell clusters, including T cells, monocyte lineages, and neutrophil subpopulations. The further sub-clustering analysis demonstrated that T cells exhibited cytotoxicity characteristics in both homeostasis and wound healing of diabetic cornea. Moreover, dendritic cells preferred the migratory and maturation phenotype and may recruit and maintain cytotoxic T cells. Macrophages in diabetic cornea preferred the pro-inflammatory M1 phenotype. Under injury conditions, diabetic corneal neutrophils exhibited a more mature and functional possession of neutrophil extracellular traps (NETs). Furthermore, cell-cell communication revealed that the immune cells exhibited hyperactivation and pro-inflammatory responses, while the monocyte lineages exhibited the activating effect on T cells in diabetic cornea. This study represents the inaugural effort to establish a comprehensive scRNA-Seq transcriptomic profile of corneal immune cells during wound healing in healthy and diabetic mice, which offers a valuable reference for subsequent investigations into the pathological roles of immune cells in DK.

IL-23 Promotes γδT Cell Activity in Dry Eye Disease Progression

Purpose

Conjunctival-resident γδT cells, the predominant ocular source of interleukin-17A (IL-17A), play crucial roles in dry eye disease (DED) pathogenesis. The upstream regulators of these cells are unknown. This study evaluated the role of conjunctival IL-23 expression in mediating γδT cell generation and elucidated its contribution to dry eye inflammatory responses.

Methods

Single-cell RNA sequencing (scRNA-seq) was used to identify and quantify conjunctival mRNA molecules in γδT cells in mice. The IL-23 level increased in wild-type (WT) and decreased in γδT-deficient (TCRδ-/-) mice after dry eye was induced via an intelligently controlled environmental system (ICES). Flow cytometry and transcriptome sequencing were used to investigate the impact of the changes in IL-23 expression on human γδT cells.

Results

The expression of the IL-23 receptor (IL-23R) was greater in γδT cells than in other conjunctival cell types, such as CD4+ T cells, CD8+ T cells and epithelial cells. An increase in IL-23 led to an increase in γδT cell density, which was proportional to dry eye severity. However, in the TCRδ-/- mice, the upregulation of IL-23 failed to increase the expression level of IL-17A and the severity of dry eye. Furthermore, increases in the expression of IL-23 and the number of γδT cells were evident in the ocular surface cells of patients who developed visual display terminal syndrome.

Conclusions

An increase in conjunctival IL-23 expression contributes to the induction of the DED inflammatory response through interactions with its cognate receptor on γδT cells and the promotion of their proliferation. The findings of this study suggest that the suppression of IL-17A through the blockade of IL-23R activation may be a viable target for improving the management of inflammation in DED patients.

Disrupted Mitochondrial Dynamics Impair Corneal Epithelial Healing in Neurotrophic Keratopathy

Neurotrophic keratopathy (NK) is a degenerative corneal disease characterized by impaired corneal sensitivity and epithelial repair that is often linked to sensory nerve dysfunction. To establish a clinically relevant model and explore the mechanisms underlying NK pathogenesis, we developed a novel mouse model through partial transection of the ciliary nerve. This approach mimics the progressive nature of NK, reproducing key clinical features such as corneal epithelial defects, reduced sensitivity, diminished tear secretion, and delayed wound healing. Using this model, we investigated how disruptions in mitochondrial dynamics contribute to corneal epithelial dysfunction and impaired repair in NK. Our findings revealed substantial disruptions in mitochondrial dynamics, including reduced expression of fusion proteins (OPA1), downregulation of fission regulators (FIS1 and MFF), and impaired mitochondrial transport, as evidenced by decreased expression of Rhot1 and Kif5b. Additionally, the downregulation of mitophagy-related genes (Pink1 and Prkn) contributed to the accumulation of dysfunctional mitochondria, leading to DNA damage and impaired corneal epithelial repair. These mitochondrial abnormalities were accompanied by increased γH2AX staining, indicative of DNA double-strand breaks and cellular stress. This study highlights the pivotal role of mitochondrial dynamics in corneal epithelial health and repair, suggesting that therapeutic strategies aimed at restoring mitochondrial function, enhancing mitophagy, and mitigating oxidative stress may offer promising avenues for treating NK.

Correlation between lipoprotein-associated phospholipase A2 and diabetic peripheral neuropathy in patients with type 2 diabetes mellitus: A cross-sectional study

BACKGROUND

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme implicated in inflammation and oxidative stress, and has been associated with cardiovascular conditions and adverse outcomes, particularly in diabetes and its complications. However, no prior studies have examined the relationship between Lp-PLA2 and diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes mellitus (T2DM). This research aims to explore the potential association between Lp-PLA2 and DPN.

METHODS

This retrospective study included 880 hospitalized patients with T2DM treated between March 2024 and August 2024 at Nanjing First Hospital. To assess the relationship between Lp-PLA2 and DPN, multiple logistic regression models were applied. The study also utilized restricted cubic spline (RCS) modeling, segmented regression, stratified analysis, and receiver operating characteristic (ROC) curve assessments.

RESULTS

Patients diagnosed with DPN exhibited elevated Lp-PLA2 levels compared to those without DPN. Even after adjusting for multiple variables, Lp-PLA2 was independently associated with a higher likelihood of DPN (odds ratio [OR] 1.011, 95 % confidence interval [CI] 1.008-1.014, P < 0.001). The RCS analysis revealed a nonlinear association, with an inflection point at 215.8 ng/mL. In ROC curve analysis, the area under the curve (AUC) for Lp-PLA2 was 0.664, while the combined indicator AUC was 0.739.

CONCLUSIONS

Serum Lp-PLA2 levels show a significant correlation with the presence of DPN in patients with T2DM. These findings suggest that Lp-PLA2 could serve as a valuable biomarker for identifying patients at risk for DPN, emphasizing the need for close monitoring of T2DM individuals with elevated Lp-PLA2 to mitigate the risk of developing DPN and associated adverse health outcomes.

Nervous system contributions to small cell lung cancer: Lessons from diverse oncological studies

The nervous system plays a vital role throughout the entire lifecycle and it may regulate the formation, development and metastasis of tumors. Small cell lung cancer is a typical neuroendocrine tumor, and it is naturally equipped with neurotropism. In this review, we firstly summarize current preclinical and clinical evidence to demonstrate the reciprocal crosstalk among the nervous system, tumor, and tumor microenvironment in various ways, including neurotransmitter-receptor pathways, innervations of nerve fibers, different types of synapse formation by neurons, astrocytes, and cancer cells, neoneurogenesis. Futherly, we emphasize how the nervous system interacts with small cell lung cancer and discuss the limitations of current research methods for examining the interactions. We propose that integrating neuroscience, development biology, and tumor biology can be a promising direction to provide new insights into development and metastasis of small cell lung cancer and raise some novel treatment strategies.

Effect of 0.05% cyclosporine A eye drops on the healing process of corneal epithelial defects in rats

0.05% cyclosporine A eye drops is a kind of new medication for dry eye after corneal refractive surgeries. However, it is still unclear how this eye drops affect the healing process of corneal epithelial defects caused by operative procedures. In this vivo study, the effect of 0.05% cyclosporine A eye drops on the healing process of the corneal epithelium was assessed in a rat model featuring mechanically induced central corneal epithelial defects. These Sprague-Dawley rats were randomly divided into three groups, the 0.05% cyclosporine A eye drops group (CsA group), the 0.1% sodium hyaluronate eye drops group (HA group), and the model control group (MC group). The epithelial healing, tear secretion, epithelial microvilli, expression of apoptosis markers (TUNEL, p53, and bcl-2 proteins), inflammatory factors (IL-1β, TNF-α, and IL-6), and epidermal growth factor (EGF) were detected in the current study using corneal fluorescein sodium staining, phenol red thread test, transmission electron microscopy (TEM), immunofluorescence, and enzyme-linked immunosorbent assay (ELISA), respectively. Compared to the other two groups, lower expression of apoptosis markers and inflammatory factors were exhibited in the CsA group, along with its faster and better epithelial healing and higher tear secretion (P < 0.05). In conclusion, 0.05% cyclosporine A eye drops effectively promote the healing process for corneal epithelial defects in rats, potentially offering advantages for rapid corneal recovery after refractive surgical procedures.

Novel full-thickness biomimetic corneal model for studying pathogenesis and treatment of diabetic keratopathy

Diabetic keratopathy (DK), a significant complication of diabetes, often leads to corneal damage and vision impairment. Effective models are essential for studying DK pathogenesis and evaluating potential therapeutic interventions. This study developed a novel biomimetic full-thickness corneal model for the first time, incorporating corneal epithelial cells, stromal cells, endothelial cells, and nerves to simulate DK conditions in vitro. By exposing the model to a high-glucose (HG) environment, the pathological characteristics of DK, including nerve bundle disintegration, compromised barrier integrity, increased inflammation, and oxidative stress, were successfully replicated. Transcriptomic analysis revealed that HG downregulated genes associated with axon and synapse formation while upregulating immune response and oxidative stress pathways, with C-C Motif Chemokine Ligand 5 (CCL5) identified as a key hub gene in DK pathogenesis. The therapeutic effects of Lycium barbarum glycopeptide (LBGP) were evaluated using this model and validated in db/db diabetic mice. LBGP promoted nerve regeneration, alleviated inflammation and oxidative stress in both in vitro and in vivo models. Notably, LBGP suppressed the expression of CCL5, highlighting its potential mechanism of action. This study establishes a robust biomimetic platform for investigating DK and other corneal diseases, and identifies LBGP as a promising therapeutic candidate for DK. These findings provide valuable insights into corneal disease mechanisms and pave the way for future translational research and clinical applications.

Advanced dressings based on novel biological targets for diabetic wound healing: A review

The diabetic wound is one of the most common complications of diabetes in clinic. The existing diabetic wound dressings all have bottlenecks in decreasing inflammation, stopping peripheral neuropathy, relieving local ischemia and hypoxia in diabetic wounds. These challenges are intricately linked to the roles of various growth factors, as well as matrix metalloproteinases. Thus, a comprehensive understanding of growth factors-particularly their dynamic interactions with the extracellular matrix (ECM) and cellular components-is essential. Cells and proteins that influence the synthesis of growth factors and matrix metalloproteinases emerge as potential therapeutic targets for diabetic wound management. This review discusses the latest advancements in the pathophysiology of diabetic wound healing, highlights novel biological targets, and evaluates new wound dressing strategies designed for the treatment of diabetic wounds.

Oxidative stress in diabetes mellitus and its complications: From pathophysiology to therapeutic strategies

ABSTRACT

Oxidative stress due to aberrant metabolism is considered as a crucial contributor to diabetes and its complications. Hyperglycemia and hyperlipemia boost excessive reactive oxygen species generation by elevated mitochondrial respiration, increased nicotinamide adenine dinucleotide phosphate oxidase activity, and enhanced pro-oxidative processes, including protein kinase C pathways, hexosamine, polyol, and advanced glycation endproducts, which exacerbate oxidative stress. Oxidative stress plays a significant role in the onset of diabetes and its associated complications by impairing insulin production, increasing insulin resistance, maintaining hyperglycemic memory, and inducing systemic inflammation. A more profound comprehension of the molecular processes that link oxidative stress to diabetes is crucial to new preventive and therapeutic strategies. Therefore, this review discusses the mechanisms underlying how oxidative stress contributes to diabetes mellitus and its complications. We also summarize the current approaches for prevention and treatment by targeting the oxidative stress pathways in diabetes.

Long-term Nerve Regeneration in Diabetic Keratopathy Mediated by a Novel NGF Delivery System

Diabetic keratopathy (DK) is a common chronic metabolic disorder that causes ocular surface complications. Among various therapeutic approaches, local delivery of nerve growth factor (NGF) remains the most effective treatment of DK. However, achieving a sustained therapeutic effect with NGF and the frequent drug delivery burden remain challenging during clinical practice. Here, we developed a novel adeno-associated virus (AAV)-based NGF delivery system that achieved 1-year-long-lasting effects by a single injection. We refined the corneal stromal injection technique, resulting in reduced corneal edema and improved AAV distribution homogeneity. AAV serotype AAV.rh10 exhibited high tropism and specificity to corneal nerves. A dose of 2 × 109 vector genomes was determined to achieve efficient Ngf gene expression without inducing corneal immune responses. Moreover, NGF protein was highly expressed in trigeminal ganglion through a retrograde transport mechanism, indicating the capacity for repairing corneal nerve damage at both the root and corneal nerve endings. In a mouse DK model, a single injection of AAV-Ngf into the corneal stroma led to marked corneal nerve regeneration for over 5 months. Together, we provide a novel therapeutic paradigm for long-term effective treatment of DK, and this therapeutic approach is superior to current DK therapies.

ARTICLE HIGHLIGHTS

Targeting tRNA-Derived Non-Coding RNA Alleviates Diabetes-Induced Visual Impairment through Protecting Retinal Neurovascular Unit

Diabetes is a major risk factor for compromised visual health, leading to retinal vasculopathy and neuropathy, both of which are hallmarks of neurovascular unit dysfunction. Despite the critical impact of diabetic retinopathy, the precise mechanism underlying neurovascular coupling and effective strategies to suppress neurovascular dysfunction remain unclear. In this study, the up-regulation of a tRNA-derived stress-induced RNA, 5'tiRNA-His-GTG, in response to diabetic stress is revealed. 5'tiRNA-His-GTG directly regulates Müller glia action and indirectly alters endothelial angiogenic effects and retinal ganglion cell (RGC) survival in vitro. Downregulation of 5'tiRNA-His-GTG alleviates diabetes-induced retinal neurovascular dysfunction, characterized by reduced retinal vascular dysfunction, decreased retinal neurodegeneration, and improved visually-guided behaviors in vivo. Mechanistically, 5'tiRNA-His-GTG acts as a key regulator of retinal neurovascular dysfunction, primarily by modulating arachidonic acid (AA) metabolism via the CYPs pathway. The 5'tiRNA-His-GTG-CYP2E1-19(S)-HETE signaling axis is identified as a key driver of retinal neurovascular dysfunction. Thus, targeting 5'tiRNA-His-GTG presents a promising therapeutic strategy for treating vasculopathy and neuropathy associated with diabetes mellitus. Modulating this novel signaling pathway can open up new avenues for intervention in diabetic retinopathy and its related complications.

Nanoscale Systems for Local Activation of Hypoxia-Inducible Factor-1 Alpha: A New Approach in Diabetic Wound Management

Chronic wounds in diabetic patients experience significant clinical challenges due to compromised healing processes. Hypoxia-inducible factor-1 alpha (HIF-1α) is a critical regulator in the cellular response to hypoxia, enhancing angiogenesis and tissue restoration. Nevertheless, the cellular response to the developed chronic hypoxia within diabetes is impaired, likely due to the destabilization of HIF-1α via degradation by prolyl hydroxylase domain (PHD) enzymes. Researchers have extensively explored HIF-1α activation as a potential pathway for diabetic wound management, focusing mainly on deferoxamine (DFO) as a potent agent to stabilize HIF-1α. This review provides an update of the other recent pharmacological agents managing HIF-1α activation, including novel PHD inhibitors (roxadustat and daprodustat) and Von Hippel-Lindau protein (VHL) antagonists, which could be potential alternatives for the local treatment of diabetic wounds. Furthermore, it highlights how localized delivery via advanced nanostructures can enhance the efficacy of these novel therapies. Importantly, by addressing these points, the current review can offer a promising area for research. Given that, these novel drugs have minimal applications in diabetic wound healing, particularly in the context of local application through nanomaterials. This gap presents an exciting opportunity for further investigation, as combining these drugs with localized nanotechnology could avoid undesired systemic side effects and sustain drug release within wound site, offering a transformative platform for diabetes wound treatment.

CLEC14A facilitates angiogenesis and alleviates inflammation in diabetic wound healing

BACKGROUND

Delayed wound healing is a serious complication of diabetic wounds, posing a significant challenge to the treatment of patients with diabetes. Diabetic wound healing is a complex dynamic process involving angiogenesis and inflammatory responses. Currently, there are limited targeted therapies to promote diabetic wound healing. This study aimed to reveal the role of CLEC14A in the process of diabetic wound healing, with the hope of identifying new therapeutic targets to accelerate the healing of diabetic wounds.

METHODS

In vivo, diabetic mice were generated by combined streptozotocin (STZ) and high-fat diet treatment. The wound healing model was established in wild-type and Clec14a-/- diabetic mice. The degree of wound healing, as well as angiogenesis and inflammation during the healing process, were evaluated through Hematoxylin and Eosin (H&E) staining, immunohistochemical staining, and immunofluorescence staining. In vitro, the angiogenic activities of Human Umbilical Vein Endothelial Cells (HUVECs) were assessed following treatment with high glucose and adenoviruses overexpressing CLEC14A, using scratch assays and tube formation assays. Interleukin-1β (IL-1β) and Tumor Necrosis Factor-α (TNF-α) were utilized to evaluate the levels of inflammation in HUVECs.

RESULTS

CLEC14A expression was suppressed in diabetic wounds. Deletion of the Clec14a inhibited angiogenesis and activated inflammatory responses in vivo. High-glucose treatment led to decreased CLEC14A expression, impaired angiogenic capacity, and elevated inflammatory levels in vitro. However, adenoviral-mediated overexpression of CLEC14A reversed the response induced by high glucose.

CONCLUSION

CLEC14A accelerates diabetic wound healing by promoting angiogenesis and reducing wound inflammation.

Hyperglycemia-depleted glutamine contributes to the pathogenesis of diabetic corneal endothelial dysfunction

Diabetic mellitus (DM) causes various complications, including the corneal endothelial dysfunction that leads to corneal edema and vision loss, especially in the DM patients with intraocular surgeries. However, the pathogenic mechanism of hyperglycemia-caused corneal endothelial dysfunction remains incomplete understood. Here we firstly screened and identified the glutamine contents of aqueous humor (AH) were significantly reduced in the type 2 diabetic patients and type 1 and type 2 diabetic mice. To explore the potential therapeutic effects of glutamine (Gln) supplement on the protection of diabetic corneal endothelial dysfunction, we performed the anterior chamber perfusion with the addition of L-alanyl-L-glutamine (Ala-Gln), and confirmed that Ala-Gln supplement not only accelerated the resolution of corneal edema and recovery of corneal thickness, but also preserved the regular arrangement and barrier-pump function of cornea. Mechanistically, we revealed that the supplements of Ala-Gln protect corneal endothelial cells (CECs) from the deleterious effects of high glucose-induced oxidative stress, mitochondrial dysfunction, and cell apoptosis. Overall, these results indicate the Gln depletion plays an important role in the diabetic corneal endothelial dysfunction, while the Ala-Gln supplement during intraocular surgery provide an effective prevention strategy through regulating the redox homeostasis and mitochondrial function of corneal endothelium.

Corneal subepithelial nerve fibers in type 2 diabetes: potential biomarker of diabetic neuropathy

AIM

To observe the changes in corneal subepithelial nerve fibers (CNFs) and Langerhans cells (LCs) in patients with type 2 diabetes using corneal laser confocal microscopy (CLCM).

METHODS

A total of 60 patients (64 eyes), including 40 patients with type 2 diabetes (DM group) and 20 subjects without diabetes (control group) were included with CLCM. Neuron J plugin of Image J software were used for quantitative analysis of CNF length (CNFL), CNF density (CNFD), corneal nerve branch fiber density (CNBD), main branch length density, branch length density, corneal nerve fiber tortuosity (NT) score, and LCs density. An independent samples t-test to analyze the variability between the two groups was performed, and Pearson correlation analysis was used to analyze the relationships between CNF and multiple biochemical indicators in the DM group. The predictive power of CNF for type 2 diabetes was assessed using the receiver operating characteristic (ROC) curve.

RESULTS

There were significant differences in the CNFL, CNFD, and main branch length density between two groups. The results of Pearson correlation analysis showed a significant negative correlation between CNFD and the duration of diabetes as well as triglyceride levels and total cholesterol, and a significant positive correlation between CNFD and serum albumin. In addition, the NT score showed a positive correlation and urea nitrogen, similar to the positive correlation observed between LC density and glycosylated hemoglobin (HbA1c) levels. CNFD showed the highest area under the curve (AUC of ROC) value, followed by main branch length density and CNFL. The AUC of the ROC curve under the logistic regression model also demonstrated good predictive values. The cut-off values of CNFD, CNFL, and main branch length density for diabetes showed 31.25, 18.85, and 12.56, respectively.

CONCLUSION

In patients with type 2 diabetes, there is a notable reduction in both CNFL and CNFD. These measurements can be influenced by various blood biochemical factors. However, the compromised nerve fibers can serve as valuable indicators for predicting the onset of type 2 diabetes and also as biomarkers for detecting diabetic neuropathy and its related complications.

Chronobiological and neuroendocrine insights into dry eye

Dry eye, a prevalent ocular surface disease, is significantly influenced by modern lifestyle factors such as night-shift work and extended screen time. Emerging evidence suggests a strong correlation between disturbances in circadian rhythm, sleep disorders, and dry eye. However, the precise underlying mechanisms remain unclear. Recent studies have underscored the crucial role of circadian rhythms and neuroendocrine regulation in maintaining ocular surface health. Advances in treatment strategies targeting neuroendocrine pathways have shown promising developments. This review explores the interplay between circadian rhythms, neuroendocrine regulation, and the ocular surface, examines the impact of circadian disruption on the pathophysiology of dry eye, and proposes intervention strategies to alleviate dry eye associated with disturbances in circadian rhythms.

The ROS/AKT/S6K axis induces corneal epithelial dysfunctions under LED blue light exposure

In recent years, concerns have escalated regarding eye health problems arising from Light-emitting diode (LED), which emits high-energy blue light (BL), potentially causing corneal epithelial dysfunctions (CEpD). Nevertheless, the mechanisms underlying this damage remain poorly comprehended. This study endeavors to explore the specific mechanisms through which BL exposure induces CEpD. The study carried out diverse assays and treatments to investigate the toxicological effects of BL exposure. 48 hours (h) of 440 nm of BL exposure decreased the migration of human corneal epithelial cells (hCEpCs) while augmenting reactive oxygen species (ROS) production and apoptosis. RNA-Sequencing and bioinformatic analysis indicated that cellular oxidation and reduction equilibrium, wound healing, the positive regulation of the apoptotic process, and the Phosphoinositide 3-kinase (PI3K)/AKT pathway were significantly influenced by BL exposure. Treatment with N-acetylcysteine (NAC), a ROS scavenger, restored cell viability and AKT/S6 kinase (S6K) activation, suggesting the involvement of ROS in BL-induced damage. NAC also reversed BL-induced apoptosis and migration. Blocking AKT/S6K replicated detrimental effects, while pre-treatment with SC79 (SC), an AKT activator, alleviated the changes caused by BL exposure in hCEpCs. Furthermore, in mice, the combination of AKT inhibition and BL exposure led to CEpD. However, treatment with SC and NAC restored CEpD caused by BL exposure. These results imply that the regulation of the ROS/PI3K/AKT/S6K axis is implicated in BL-induced CEpD. Collectively, this study offers insights into the molecular mechanisms of BL-induced CEpD and proposes targeting the ROS/PI3K/AKT/S6K cascade as a potential therapeutic approach. The findings contribute to ocular health knowledge and establish the basis for developing interventions to safeguard the cornea from the detrimental effects of excessive BL exposure.

Current insights on mitochondria-associated endoplasmic reticulum membranes (MAMs) and their significance in the pathophysiology of ocular disorders

The intricate interaction network necessary for essential physiological functions underscores the interdependence among eukaryotic cells. Mitochondria-Associated Endoplasmic Reticulum Membranes (MAMs), specialized junctions between mitochondria and the ER, were recently discovered. These junctions participate in various cellular processes, including calcium level regulation, lipid metabolism, mitochondrial integrity maintenance, autophagy, and inflammatory responses via modulating the structure and molecular composition of various cellular components. Therefore, MAMs contribute to the pathophysiology of numerous ocular disorders, including Diabetic Retinopathy (DR), Age-related Macular Degeneration (AMD) and glaucoma. In addition to providing a concise overview of the architectural and functional aspects of MAMs, this review explores the key pathogenetic pathways involving MAMs in the development of several ocular disorders.

Development of a transformer-based deep learning algorithm for diabetic peripheral neuropathy classification using corneal confocal microscopy images

Background

Diabetic peripheral neuropathy (DPN) is common and can go unnoticed until it is firmly developed. This study aims to establish a transformer-based deep learning algorithm (DLA) to classify corneal confocal microscopy (CCM) images, identifying DPN in diabetic patients.

Methods

Our classification model differs from traditional convolutional neural networks (CNNs) using a Swin transformer network with a hierarchical architecture backbone. Participants included those with (DPN+, n = 57) or without (DPN-, n = 37) DPN as determined by the updated Toronto consensus criteria. The CCM image dataset (consisting of 570 DPN+ and 370 DPN- images, with five images selected from each participant's left and right eyes) was randomly divided into training, validation, and test subsets at a 7:1:2 ratio, considering individual participants. The effectiveness of the algorithm was assessed using diagnostic accuracy measures, such as sensitivity, specificity, and accuracy, in conjunction with Grad-CAM visualization techniques to interpret the model's decisions.

Results

In the DPN + group (n = 12), the transformer model successfully predicted all participants, while in the DPN- group (n = 7), one participant was misclassified as DPN+, with an area under the curve (AUC) of 0.9405 (95% CI 0.8166, 1.0000). Among the DPN + images (n = 120), 117 were correctly classified, and among the DPN- images (n = 70), 49 were correctly classified, with an AUC of 0.8996 (95% CI 0.8502, 0.9491). For single-image predictions, the transformer model achieved a superior AUC relative to the ResNet50 model (0.8761, 95% CI 0.8155, 0.9366), the Inception_v3 model (0.8802, 95% CI 0.8231, 0.9374), and the DenseNet121 model (0.8965, 95% CI 0.8438, 0.9491).

Conclusion

Transformer-based networks outperform CNN-based networks in rapid binary DPN classification. Transformer-based DLAs have clinical DPN screening potential.

Comparative Analysis of Corneal Wound Healing: Differential Molecular Responses in Tears Following PRK, FS-LASIK, and SMILE Procedures

BACKGROUND/OBJECTIVES

In this study, we aimed to analyze the changes in the expression profiles of selected messenger RNAs (mRNAs) and their encoded proteins in the tears of patients undergoing photorefractive keratectomy (PRK), femtosecond-assisted laser in situ keratomileusis (FS-LASIK), and small-incision lenticule extraction (SMILE) procedures.

METHODS

A total of 120 patients were divided into three groups based on the laser vision correction (LVC) procedure: PRK, FS-LASIK, or SMILE. Tear samples were collected preoperatively and at 1, 7, 30, and 180 days postoperatively. The expression levels of selected messenger RNAs (mRNAs) and proteins were analyzed by using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS

PRK and FS-LASIK elicited significantly stronger biological responses than SMILE. Interleukin-15 (IL-15) expression increased notably in the PRK and FS-LASIK groups, with mRNA levels reaching fold changes of 4.65 ± 0.65 and 4.99 ± 0.28, respectively, on day 1, compared with only 2.09 ± 0.23 in the SMILE group. Vascular endothelial growth factor A (VEGFA) levels were also elevated in the PRK (2.98 ± 0.23 fold change) and FS-LASIK groups (3.45 ± 1.09 fold change) on day 1, while the SMILE group showed minimal fluctuations. The protein concentration analysis based on the ELISA confirmed these trends, with IL-15 levels peaking at 54.2 ± 2.5 pg/mL in the PRK group and 52.8 ± 3.1 pg/mL in the FS-LASIK group, compared with 32.4 ± 1.9 pg/mL in the SMILE group on day 1. Similarly, VEGFA protein concentrations were the highest in the PRK (72.4 ± 4.1 pg/mL) and FS-LASIK patients (69.5 ± 3.8 pg/mL) on day 1 but remained low in the SMILE patients (45.6 ± 2.3 pg/mL). By day 180, gene expression and protein levels in all groups had stabilized, returning to near-preoperative values.

CONCLUSIONS

PRK and FS-LASIK induced more pronounced molecular and protein-level changes during corneal wound healing than the less invasive SMILE procedure, indicating stronger biological responses. These findings suggest that tailored postoperative care based on the specific procedure could optimize healing and patient outcomes. However, further research with larger sample sizes and longer follow-ups is needed to confirm these observations and develop personalized treatment strategies.

Activation of the SST-SSTR5 signaling pathway enhances corneal wound healing in diabetic mice

Corneal wound healing in diabetic patients is usually delayed and accompanied by excessive inflammation. However, the underlying cellular and molecular mechanisms remain poorly understood. Here, we found that somatostatin (SST), an immunosuppressive peptide produced by corneal nerve fibers, was significantly reduced in streptozotocin-induced diabetic mice. In addition, we discovered that topical administration of exogenous SST significantly improved re-epithelialization and nerve regeneration following diabetic corneal epithelial abrasion. Further analysis showed that topical SST significantly reduced the expression of injury inflammation-related genes, inhibited neutrophil infiltration, and shifted macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 in diabetic corneas' healing. Moreover, the application of L-817,818, an agonist of the SST receptor type 5 subtype, significantly reduced the inflammatory response following epithelial injury and markedly improved the process of re-epithelialization and nerve regeneration in mice. Taken together, these data suggest that activation of the SST-SST receptor type 5 pathway significantly ameliorates diabetes-induced abnormalities in corneal wound repair in mice. Targeting this pathway may provide a novel strategy to restore impaired corneal wound closure and nerve regeneration in diabetic patients.

Preventing and treating neurotrophic keratopathy by a single intrastromal injection of AAV-mediated gene therapy

PURPOSE

Neurotrophic keratopathy (NK) is a degenerative corneal condition resulting from corneal nerve injury. Current therapies, including the recombinant human nerve growth factor (rhNGF) therapy, requires continuous administration. This study aims to develop a novel and highly effective gene therapy strategy for the prevention and treatment of NK.

METHODS

Adeno-associated virus (AAV) was transduced into corneal stromal cells by intrastromal injection. Three dimensional corneal wholemount imaging with co-immunostaining of ZO-1 and tubulin was utilized to assess the transduction of AAV.rh10. The efficacy of prevention and treatment of NK by a single intrastromal injection of AAV-Ngf was tested using capsaicin mouse model, herpes simplex keratitis (HSK) model, type Ⅱ diabetes model and alkali burn model. rhNGF eye drops served as the positive control.

RESULTS

Intrastromal injection of AAV.rh10 efficiently transduced the subepithelial nerve plexus and retrogradely transported to the trigeminal ganglion (TG). A single injection of AAV.rh10-Ngf can significantly promote corneal nerve repair, accelerate corneal epithelial repair, reduce corneal stromal edema, and improve corneal sensitivity across the four NK models. The therapeutic effects were consistent with those achieved by continuous administration of rhNGF drops by 6 times daily.

CONCLUSIONS

This proof-of-concept study demonstrates that AAV.rh10-Ngf gene therapy is a promising method for preventing and treating of NK. Our results underline the potential for developing clinical trials to further explore the safety and efficacy of such gene therapy.

Role of gasotransmitters in necroptosis

Gasotransmitters are endogenous gaseous signaling molecules that can freely pass through cell membranes and transmit signals between cells, playing multiple roles in cell signal transduction. Due to extensive and ongoing research in this field, we have successfully identified many gasotransmitters so far, among which nitric oxide, carbon monoxide, and hydrogen sulfide are best studied. Gasotransmitters are implicated in various diseases related to necroptosis, such as cardiovascular diseases, inflammation, ischemia-reperfusion, infectious diseases, and neurological diseases. However, the mechanisms of their effects on necroptosis are not fully understood. This review focuses on endogenous gasotransmitter synthesis and metabolism and discusses their roles in necroptosis, aiming to offer new insights for the therapeutic approaches to necroptosis-associated diseases.

Bioinspired Collagen Scaffold Loaded with bFGF-Overexpressing Human Mesenchymal Stromal Cells Accelerating Diabetic Skin Wound Healing via HIF-1 Signal Pathway Regulated Neovascularization

The healing of severe chronic skin wounds in chronic diabetic patients is still a huge clinical challenge due to complex regeneration processes and control signals. Therefore, a single approach is difficult in obtaining satisfactory therapeutic efficacy for severe diabetic skin wounds. In this study, we adopted a composite strategy for diabetic skin wound healing. First, we fabricated a collagen-based biomimetic skin scaffold. The human basic fibroblast growth factor (bFGF) gene was electrically transduced into human umbilical cord mesenchymal stromal cells (UC-MSCs), and the stable bFGF-overexpressing UC-MSCs (bFGF-MSCs) clones were screened out. Then, an inspired collagen scaffold loaded with bFGF-MSCs was applied to treat full-thickness skin incision wounds in a streptozotocin-induced diabetic rat model. The mechanism of skin damage repair in diabetes mellitus was investigated using RNA-Seq and Western blot assays. The bioinspired collagen scaffold demonstrated good biocompatibility for skin-regeneration-associated cells such as human fibroblast (HFs) and endothelial cells (ECs). The bioinspired collagen scaffold loaded with bFGF-MSCs accelerated the diabetic full-thickness incision wound healing including cell proliferation enhancement, collagen deposition, and re-epithelialization, compared with other treatments. We also showed that the inspired skin scaffold could enhance the in vitro tube formation of ECs and the early angiogenesis process of the wound tissue in vivo. Further findings revealed enhanced angiogenic potential in ECs stimulated by bFGF-MSCs, evidenced by increased AKT phosphorylation and elevated HIF-1α and HIF-1β levels, indicating the activation of HIF-1 pathways in diabetic wound healing. Based on the superior biocompatibility and bioactivity, the novel bioinspired skin healing materials composed of the collagen scaffold and bFGF-MSCs will be promising for healing diabetic skin wounds and even other refractory tissue regenerations. The bioinspired collagen scaffold loaded with bFGF-MSCs could accelerate diabetic wound healing via neovascularization by activating HIF-1 pathways.

RTP4 Enhances Corneal HSV-1 Infection in Mice With Type 2 Diabetes Mellitus

Purpose

The purpose of this study was to investigate whether corneal lesions in mice with type 2 diabetes mellitus (T2D) infected with herpes simplex virus (HSV)-1 are more severe, and to elucidate the specific underlying mechanism.

Methods

The corneas of control mice and T2D mice induced by a high-fat diet combined with streptozotocin were infected with the HSV-1 Mckrae strain to assess corneal infection, opacity, and HSV-1 replication. RNA sequencing of the corneal epithelium from wild-type and db/db mice (a genetic T2D mouse model) was conducted to identify the key gene affecting T2D infection. Immunofluorescence staining was performed on corneal sections from T2D mice and patients with T2D. The effect of small interfering RNA (siRNA) knockdown on corneal HSV-1 infection was evaluated in both in vitro and in vivo models.

Results

T2D mice exhibited a more severe infection phenotype following HSV-1 infection, characterized by augmented corneal opacity scores, elevated viral titers, and transcripts compared to control mice. Transcriptome analysis of corneal epithelium revealed a hyperactive viral response in T2D mice, highlighting the differentially expressed gene Rtp4 (encoding receptor transporter protein 4). Receptor transporter protein 4 (RTP4) expression was enhanced in the corneal epithelium of T2D mice and patients with T2D. Virus binding assays demonstrated that RTP4 facilitated HSV-1 binding to human corneal epithelial cells. Silencing RTP4 alleviated HSV-1 infection in both in vitro and in vivo T2D models.

Conclusions

The findings indicate that elevated RTP4 exacerbates HSV-1 infection by enhancing its binding to corneal epithelial cells, whereas Rtp4 knockdown mitigated corneal lesions in T2D mice. This implies RTP4 as a potential target for intervention in diabetic HSV-1 infection.

Chinese patent medicine Tongxinluo: A review on chemical constituents, pharmacological activities, quality control, and clinical applications

BACKGROUND

Cardiovascular and cerebrovascular disease (CCVD) is the leading cause of morbidity and mortality worldwide, imposing a significant economic burden on individuals and societies. For the past few years, Traditional Chinese Medicine (TCM) has attracted much attention due to its advantages such as fewer side effects in the treatment of CCVD. TXL has shown great promise in the treatment of CCVD.

PURPOSE

This paper aims to provide a comprehensive introduction to TXL, covering its chemical constituents, quality control, pharmacological properties, adverse reactions, and clinical applications through an extensive search of relevant electronic databases while discussing its current challenges and provides opinions for future study.

METHODS

The following electronic databases were searched up to 2023: "TXL", "CCVD", "Chemical constituents", "Quality control" and "Pharmacological properties" were entered as keywords in PubMed, Web of Science, Google Scholar and China National Knowledge Infrastructure Database and WANFANG DATA databases. The PRISMA guidelines were followed in this review process.

RESULTS

Studies have confirmed that TXL is effective in treating patients with CCVD and has fewer adverse effects. The aim of this review is to explore TXL anti-CCVD effects in relation to oxidative stress, lipid metabolism and enhanced cardiac function. This review also provides additional information on safety issues.

CONCLUSION

TXL plays a key role in the treatment of CCVD by regulating various pathways such as lipid metabolism, oxidative stress and inflammation. However, further clinical trials and animal experiments are needed to provide more evidence and recommendations for its clinical application. This article provides an overview of TXL research to inform and inspire future studies.

Association of white blood cell count to mean platelet volume ratio with type 2 diabetic peripheral neuropathy in a Chinese population: a cross-sectional study

BACKGROUND

The white blood cell count to mean platelet volume ratio (WMR) is considered a promising inflammatory marker, and its recognition is increasing. Inflammation is closely related to metabolic diseases such as diabetes and its complications. However, there are currently no reports on the correlation between WMR and type 2 diabetic peripheral neuropathy (DPN). This study aims to explore the correlation between WMR and DPN in type 2 diabetes patients. By understanding this association, we hope to provide a theoretical basis for preventing DPN through the improvement of inflammatory responses.

METHODS

This was a cross-sectional study involving 2515 patients with T2DM. Logistic regression analysis was conducted to assess the associations between WMR and DPN. Finally, the receiver operating characteristic curve (ROC curve) was employed to evaluate the predictive efficacy of WMR for DPN.

RESULTS

Patients in higher WMR quartiles exhibited increased presence of DPN. Additionally, WMR remained significantly associated with a higher odds ratio (OR) of DPN (OR 4.777, 95% confidence interval [CI] 1.296-17.610, P < 0.05) after multivariate adjustment. Moreover, receiver operating characteristic curve analysis indicated that the optimal cutoff value for WMR in predicting DPN presence was 0.5395 (sensitivity: 65.40%; specificity: 41.80%; and area under the curve [AUC]: 0.540).

CONCLUSIONS

In patients with T2DM, WMR was significantly increased in DPN and independently associated with an increased risk of DPN presence in Chinese patients. This suggests that WMR may serve as a useful and reliable biomarker of DPN, highlighting the importance of paying more attention to T2DM patients with high WMR to further prevent and reduce the development of DPN and related unfavorable health outcomes.

Tear Fluid Progranulin as a Noninvasive Biomarker for the Monitoring of Corneal Innervation Changes in Patients With Type 2 Diabetes Mellitus

Purpose

This study aimed to investigate the expression levels of progranulin (PGRN) in the tears of patients with diabetic retinopathy (DR) versus healthy controls. Additionally, we sought to explore the correlation between PGRN levels and the severity of ocular surface complications in patients with diabetes.

Methods

In this prospective, single-visit, cross-sectional study, patients with DR (n = 48) and age-matched healthy controls (n = 22) were included and underwent dry eye examinations. Tear fluid was collected, and its components were analyzed using the Luminex assay. The subbasal nerve plexus of all participants was evaluated by in vivo confocal microscopy.

Results

Patients with DR exhibited more severe dry eye symptoms, along with a reduction in nerve fiber density, length, and branch density within the subbasal nerve plexus, accompanied by an increase in the number of dendritic cells. Tear PGRN levels were also significantly lower in patients with diabetes than in normal controls, and the levels of some inflammatory factors (TNF-α, IL-6, and MMP-9) were higher in patients with DR. Remarkably, the PGRN level significantly correlated with nerve fiber density (R = 0.48, P < 0.001), nerve fiber length (R = 0.65, P < 0.001), and nerve branch density (R = 0.69, P < 0.001).

Conclusions

Tear PGRN levels might reflect morphological changes in the corneal nerve plexus under diabetic conditions, suggesting that PGRN itself is a reliable indicator for predicting the advancement of neurotrophic keratopathy in patients with diabetes.

Translational Relevance

PGRN insufficiency on the ocular surface under diabetic conditions was found to be closely associated with nerve impairment, providing a novel perspective to discover the pathogenesis of diabetic complications, which could help in developing innovative therapeutic strategies.

Immune-Mediated Ocular Surface Disease in Diabetes Mellitus-Clinical Perspectives and Treatment: A Narrative Review

Diabetes mellitus (DM) is a chronic metabolic disorder marked by hyperglycemia due to defects in insulin secretion, action, or both, with a global prevalence that has tripled in recent decades. This condition poses significant public health challenges, affecting individuals, healthcare systems, and economies worldwide. Among its numerous complications, ocular surface disease (OSD) is a significant concern, yet understanding its pathophysiology, diagnosis, and management remains challenging. This review aims to explore the epidemiology, pathophysiology, clinical manifestations, diagnostic approaches, and management strategies of diabetes-related OSD. The ocular surface, including the cornea, conjunctiva, and associated structures, is vital for maintaining eye health, with the lacrimal functional unit (LFU) playing a crucial role in tear film regulation. In DM, changes in glycosaminoglycan metabolism, collagen synthesis, oxygen consumption, and LFU dysfunction contribute to ocular complications. Persistent hyperglycemia leads to the expression of cytokines, chemokines, and cell adhesion molecules, resulting in neuropathy, tear film abnormalities, and epithelial lesions. Recent advances in molecular research and therapeutic modalities, such as gene and stem cell therapies, show promise for managing diabetic ocular complications. Future research should focus on pathogenetically oriented therapies for diabetic neuropathy and keratopathy, transitioning from animal models to clinical trials to improve patient outcomes.

Potential Risk Factors for Ocular Pain in Patients Undergoing Multiple Intravitreal Injections of Anti-Vascular Endothelial Growth Factor

Purpose

To assess ocular pain in patients undergoing multiple intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) who have previous factors that may influence pain sensitivity.

Methodology

This is a prospective, observational, case series study involving patients who underwent multiple (≥3) pro re nata intravitreal injections of ranibizumab or aflibercept to treat any cause of chorioretinal vascular disease. Ocular pain was assessed by the numerical analog scale during intravitreal injection. For this study, the main variable was ocular pain and the secondary variables included age, sex, previous history of glaucoma, primary retinal vascular disease, severe dry eye history, trigeminal pain, scleral buckle surgery, collagen diseases, fibromyalgia, severe migraine history, pars plana vitrectomy, scleral thickness measurements, and type of anti-VEGF.

Results

In a total of 894 patients, 948 eyes (4822 intravitreal injections), 793 patients (88.6%) had ocular pain sensitivity between no pain to mild pain, 80 patients (8.9%) had moderate ocular pain, 15 patients (1.6%) had severe ocular pain, and 6 patients (0.7%) had extremely severe ocular pain. Patients with severe dry eye (p = 0.01) and previous history of scleral buckle surgery (p = 0.01) showed a significant correlation with ocular pain during intravitreal injection. Pars plana scleral thickness (>550 um) and diabetic neuropathy were associated with ocular pain but did not meet the criteria for statistical significance (p = 0.09 and p = 0.06, respectively).

Conclusion

Dry eye and prior scleral buckle surgery may contribute to pain associated with intravitreal injection. These issues should be taken into consideration in patients undergoing multiple intravitreal injections.

Fosfenopril Attenuates Inflammatory Response in Diabetic Dry Eye Models by Inhibiting the TLR4/NF-κB/NLRP3 Signaling Pathway

Purpose

The purpose of this study was to investigate the involvement of the TLR4/NF-κB/NLRP3 signaling pathway and its underlying mechanism in diabetic dry eye.

Methods

Two models of diabetic dry eye were established in high glucose-induced human corneal epithelial (HCE-T) cells and streptozotocin (STZ)-induced C57BL/6 mice, and the TLR4 inhibitor fosfenopril (FOS) was utilized to suppress the TLR4/NF-κB/NLRP3 signaling pathway. The expression changes in TLR4, NF-κB, NLRP3, and IL-1β, and other factors were detected by Western blot and RT‒qPCR, the wound healing rate was evaluated by cell scratch assay, and the symptoms of diabetic mice were evaluated by corneal sodium fluorescein staining and tear secretion assay.

Results

In the diabetic dry eye model, the transcript levels of TLR4, NF-κB, NLRP3, and IL-1β were raised, and further application of FOS, a TLR4 inhibitor, downregulated the levels of these pathway factors. In addition, FOS was found to be effective in increasing the wound healing rate of high glucose-induced HCE-T cells, increasing tear production, and decreasing corneal fluorescence staining scores in diabetic mice, as measured by cell scratch assay, corneal sodium fluorescein staining assay, and tear production.

Conclusions

The current study found that the TLR4/NF-κB/NLRP3 signaling pathway regulates diabetic dry eye in an in vitro and in vivo model, and that FOS reduces the signs of dry eye in diabetic mice, providing a new treatment option for diabetic dry eye.

Limbal stem cells carried by a four-dimensional -printed chitosan-based scaffold for corneal epithelium injury in diabetic rabbits

Methods: Herein, we obtained and characterized deltaN p63- and adenosine triphosphate-binding cassette subfamily G member 2-expressing limbal stem cells (LSCs). Chitosan and carboxymethyl chitosan (CTH) were cross-linked to be an in situ thermosensitive hydrogel (ACH), which was printed through four-dimensional (4D) printing to obtain a porous carrier with uniform pore diameter (4D-CTH). Rabbits were injected with alloxan to induce diabetes mellitus (DM). Following this, the LSC-carrying hydrogel was spread on the surface of the cornea of the diabetic rabbits to cure corneal epithelium injury. Results: Compared with the control group (LSCs only), rapid wound healing was observed in rabbits treated with LSC-carrying 4D-CTH. Furthermore, the test group also showed better corneal nerve repair ability. The results indicated the potential of LSC-carrying 4D-CTH in curing corneal epithelium injury. Conclusion: 4D-CTH holds potential as a useful tool for studying regenerative processes occurring during the treatment of various diabetic corneal epithelium pathologies with the use of stem cell-based technologies.

Stress systems exacerbate the inflammatory response after corneal abrasion in sleep-deprived mice via the IL-17 signaling pathway

Sleep deprivation (SD) has a wide range of adverse health effects. However, the mechanisms by which SD influences corneal pathophysiology and its post-wound healing remain unclear. This study aimed to examine the basic physiological characteristics of the cornea in mice subjected to SD and determine the pathophysiological response to injury after corneal abrasion. Using a multi-platform water environment method as an SD model, we found that SD leads to disturbances of corneal proliferative, sensory, and immune homeostasis as well as excessive inflammatory response and delayed repair after corneal abrasion by inducing hyperactivation of the sympathetic nervous system and hypothalamic-pituitary-adrenal axis. Pathophysiological changes in the cornea mainly occurred through the activation of the IL-17 signaling pathway. Blocking both adrenergic and glucocorticoid synthesis and locally neutralizing IL-17A significantly improved corneal homeostasis and the excessive inflammatory response and delay in wound repair following corneal injury in SD-treated mice. These results indicate that optimal sleep quality is essential for the physiological homeostasis of the cornea and its well-established repair process after injury. Additionally, these observations provide potential therapeutic targets to ameliorate SD-induced delays in corneal wound repair by inhibiting or blocking the activation of the stress system and its associated IL-17 signaling pathway.

The Role of SLIT3-ROBO4 Signaling in Endoplasmic Reticulum Stress-Induced Delayed Corneal Epithelial and Nerve Regeneration

Purpose

In the present study, we aim to elucidate the underlying molecular mechanism of endoplasmic reticulum (ER) stress induced delayed corneal epithelial wound healing and nerve regeneration.

Methods

Human limbal epithelial cells (HLECs) were treated with thapsigargin to induce excessive ER stress and then RNA sequencing was performed. Immunofluorescence, qPCR, Western blot, and ELISA were used to detect the expression changes of SLIT3 and its receptors ROBO1-4. The role of recombinant SLIT3 protein in corneal epithelial proliferation and migration were assessed by CCK8 and cell scratch assay, respectively. Thapsigargin, exogenous SLIT3 protein, SLIT3-specific siRNA, and ROBO4-specific siRNA was injected subconjunctivally to evaluate the effects of different intervention on corneal epithelial and nerve regeneration. In addition, Ki67 staining was performed to evaluate the proliferation ability of epithelial cells.

Results

Thapsigargin suppressed normal corneal epithelial and nerve regeneration significantly. RNA sequencing genes related to development and regeneration revealed that thapsigargin induced ER stress significantly upregulated the expression of SLIT3 and ROBO4 in corneal epithelial cells. Exogenous SLIT3 inhibited normal corneal epithelial injury repair and nerve regeneration, and significantly suppressed the proliferation and migration ability of cultured mouse corneal epithelial cells. SLIT3 siRNA inhibited ROBO4 expression and promoted epithelial wound healing under thapsigargin treatment. ROBO4 siRNA significantly attenuated the delayed corneal epithelial injury repair and nerve regeneration induced by SLIT3 treatment or thapsigargin treatment.

Conclusions

ER stress inhibits corneal epithelial injury repair and nerve regeneration may be related with the upregulation of SLIT3-ROBO4 pathway.