Three Major Causes of Metabolic Retinal Degenerations and Three Ways to Avoid Them

Abstract

An imbalance of homeostasis in the retina leads to neuron loss and this eventually results in a deterioration of vision. If the stress threshold is exceeded, different protective/survival mechanisms are activated. Numerous key molecular actors contribute to prevalent metabolically induced retinal diseases—the three major challenges are age-related alterations, diabetic retinopathy and glaucoma. These diseases have complex dysregulation of glucose-, lipid-, amino acid or purine metabolism. In this review, we summarize current knowledge on possible ways of preventing or circumventing retinal degeneration by available methods. We intend to provide a unified background, common prevention and treatment rationale for these disorders and identify the mechanisms through which these actions protect the retina. We suggest a role for herbal medicines, internal neuroprotective substances and synthetic drugs targeting four processes: parainflammation and/or glial cell activation, ischemia and related reactive oxygen species and vascular endothelial growth factor accumulation, apoptosis and/or autophagy of nerve cells and an elevation of ocular perfusion pressure and/or intraocular pressure. We conclude that in order to achieve substantial preventive or therapeutic effects, at least two of the mentioned pathways should be targeted synergistically. A repositioning of some drugs is considered to use them for the cure of the other related conditions.

Complementary Practices in Pharmacy and Their Relation to Glaucoma—Classification, Definitions, and Limitations

“…The heterogenous disease group of glaucoma is a progressive optic neuropathy causing vision loss; in 2022, it was the second leading cause of vision loss after cataracts [4]. The degeneration of retinal ganglion cells accelerates in the retinal nerve fiber layer, and its effect influences the visual pathway up to the visual cortex, causing visual field deficits.…”

“…The growing global trend of complementary treatments for glaucoma can be further explained by the IOP-independent mechanisms, focusing on herbal remedies and diet. These molecular mechanisms create a cascade, rather than discrete events, and include the withdrawal of neurotrophic factors, oxidative stress, mitochondrial dysfunction, glutamate excitotoxicity, autophagy, protein misfolding, ischemia, and hypoxia [4,7].…”

“…Phytotherapy generally uses the chemical composition and pharmacological activity of the source plant (either the entire herb, or a processed portion, e.g., buds, leaves, sprouts, flowers, fruits, seeds, bark, and/or roots) for therapeutic purposes [6,15]. According to Bürgi's law, plant-derived remedies have combined synergistic effects, rather than just one useful molecule, so they cannot be simplified to a single pharmacologic mechanism [4]. Herb-based therapies are widely applied in all existing medical traditions, including anthroposophic medicine, Traditional Chinese Medicine (TCM), Ayurvedic medicine, Tibetan-Mongolian medicine, etc., including evidence-based medicine (EBM).…”

“…Further, according to Bürgi's law of herbal synergism, one extracted useful molecule cannot always to be reduced to the same pharmacological effect that it has in synergism with other plant substances. Therefore, it is more difficult to produce evidence-based standardized herbal pharmacotherapy [4]. However, the rapid growth of the herbal product industry and the lack of corresponding regulations and legislation have caused the WHO and other regulatory bodies to be increasingly concerned with the safety and efficacy of herbal medicines.…”

“…and D. purpurea L.), pilocarpine (Pilocarpus jaborandi Holmes), quinine (Cinchona officinalis L.), etc. [3,4]. The evolution of medicine is based upon empirical experience and prescientific observations leading to the construction of systematic therapy methods and practices.…”