In diabetic patients, increased magnitude of glycemic variability levels particularly occurring as low blood sugar attacks or unstable glycemic control may be implicated in the development of chronic complications involving multiple organ systems. Diabetic retinopathy is a disease characterized by damage to the small blood vessels inside the retina, in which one of the most vulnerable and sensitive structures; eye has chronic metabolic imbalance.
Recent evidence has implicated glycaemic variability, including cyclical deterioration in blood glucose concentrations as contributory to vascular stress, oxidative injury and endothelial dysfunction. Chronic hyperglycemia is considered a classical inducer of retinopathic sequelae. All these metabolic changes cumulatively shape diabetic eye disease.
Pathophysiology of Retinal Damage in Diabetes
The retina is supported by a highly specialized microvascular network that sustains visual function. In establishing diabetes, this system is disrupted through a combination of overlapping mechanisms:
- Oxidative stress and metabolic imbalance disrupt cellular homeostasis
- Hwa-jin KwonWhy blood vessels are not staying pure?
- Vascular leak and tissue damage are propagated by inflammatory signaling
- Reduced Retinal Tissue Oxygen Delivery due to Capillary Degeneration
These changes can eventually lead to microaneurysms, bleeding and fluid accumulation, resulting in eventual vision loss. Variable glucose levels could potentiate this process by promoting cellular stress and inflammatory responses.
Role of UC-MSCs in Homeostasis of Retina
Umbilical cord-derivative mesenchymal stem cells (UC-MSCs) attract considerable interest in regenerative medicine on account of their immunomodulatory and trophic properties. Rather than replacing damaged retinal cells directly, we investigated whether UC-MSCs primarily exert their effects through secretion of bioactive signaling molecules that promote tissue homeostasis and repair.
Key mechanisms under investigation include:
Anti-Inflammatory Modulation
UC-MSCs secrete several factors including anti-inflammatory cytokines (IL-10) and other immune regulatory molecules that can potentially mitigate chronic inflammation. In the setting of DR, this could help establish a better balanced retinal microenvironment and delay further vasculopathy promotion.
Vascular Support and Angiogenic Signaling
Depending on the physiological environment, these cells secrete certain growth factors (e.g. VEGF) and other angiogenic mediators which might facilitate healing of microvasculature and improve blood perfusion [4]. This is particularly true in ischemic retinal diseases.
Neuroprotective Effects
The retina is part of the central nervous system, after all. This data suggest that UC-MSC derived factors exert a neuroprotective effect against oxidative stress and apoptosis on retinal neurons, promoting the survival of cells in high metabolic stress environments.
Reduction of Oxidative Stress
UC-MSCs can ameliorate retinal degeneration in diabetes by upregulating antioxidant pathways to mitigate excessive production of ROS, a key mediator that contribute to the pathogenesis of DR.
Paracrine and Exosome-Mediated Signaling
UC-MSCs can positively influence gene expression profiles of surrounding cells both by cell–cell contact and through secretion mechanisms including exosomes and soluble factors, likely promoting repair processes and improving tissue resilience.
UC-MSCs May Inhibit the Development of DR: Possible Mechanisms
Image illustrating the potential protective roles of UC-MSCs in the retina through anti-inflammatory signaling, vascular stability and antioxidant/neuroprotective pathways within the retinal microenvironment.
Clinical Perspective and Limitations
It is important to recognize that although UC-MSC–based approaches are being actively researched, the indications in diabetic retinopathy remain investigational. The current standard of care for diabetic eye disease consists of glycemic control, laser therapy, anti-VEGF injections, and ophthalmologic surveillance.
More recently, regenerative strategies are being investigated as adjunctive or future therapeutic approaches. Especially cell-related strategy(s) like UC-MSC such may be a demand where no satisfactory therapy is accessible.
Conclusion
In addition, diabetic retinopathy is a multifactorial disease involving metabolic dysregulation, vascular dysfunction and chronic inflammation. Extended high blood glucose values, but also glycemic variability reflecting extreme variations in blood glucose (including hypoglycemia), may cause bears chronic retinal stress.
UC-MSCs provide a biologically compelling route for retina protection through immunomodulating, angiogenic, and neuroprotection properties. And while far from a mainstream therapeutic strategy at this point in time, this evolving literature may eventually complement current treatment options aimed at the retinal damage microenvironment itself by introducing such cell-based strategies.