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Free Radicals and Antioxidants
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Carnosine or L-carnosine is a dipeptide composed of two amino acids: beta-alanine and L-histidine. It is an endogenous nitrogenous water-soluble compound mainly present in the non-protein fraction of skeletal muscle and other tissues (brain, olfactory epithelium) of humans, mammals, and other vertebrates. Carnosine is an endogenous metabolic antioxidant and a non-enzymatic free radical scavenger in humans. It is also able to inactivate reactive oxygen species and chelate pro-oxidative metals (105–106). Moreover, it is a strong immunomodulator, neuroprotector against free radicals, and may be a good neurotransmitter (106). Recent data report that carnosine is able to rejuvenate senescent cells and can delay eyesight impairment for the prevention and treatment of senile cataract by eye drops (105).
The nervous system and the eye
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
James A.R. Nicoll, William Stewart, Fiona Roberts
The biconvex lens substance is formed by cells that contain transparent crystalline lens proteins. A cataract is any opacity of the crystalline lens. The cells of the lens are enclosed in an elastic membrane, the lens capsule. Metabolism of the lens is maintained by diffusion of nutrients from the aqueous. Any change in the biochemical composition of the aqueous fluid, as occurs in metabolic diseases, e.g. diabetes mellitus or hypocalcaemia, may result in the formation of abnormal opaque proteins in the damaged lens cells. Other insults such as uveitis, ionizing radiation, or trauma may also result in opacities. Congenital cataracts may form if there is damage to the developing lens fibres in utero, e.g. as a result of rubella infection. The most common form of cataract, however, is senile cataract, which is due to the degradation of lens proteins in the oldest, central part of the lens. Most cases of cataract are treated by removal of the opaque lens matter by ‘phakoemulsification’ and the insertion of a plastic lens implant into the residue of the lens capsule behind the iris.
Primary care resource centres – a means of supporting general practice?
Published in Pat Gordon, Janet Hadley, Pat Gordon, Diane Plamping, Extending Primary Care, 2018
Jillian Alderwick, Sarah Taylor, Maggie Jee
Two per cent of 60-year-olds and over 40% of those over 80 years of age suffer from senile cataract. In an area of 10-15 GPs with a population of 20-30 000 people, one would expect 700 people with cataracts sufficiently severe to disturb their eyesight, and between 70-90 people developing cataract for the first time each year. Glaucoma probably affects about 70 people in this GP area (0.5% of people aged between 55-60 and over 4% of those over 80 years). About a quarter of these have other affected family members and can therefore be identified as high risk and entitled to free eye testing. The loss of vision caused by glaucoma can be reduced by early detection and treatment. GPs, optometrists and ophthalmologists working together can achieve this.
Anti-cataract therapies: is there a need for a new approach based on targeting of aquaporins?
Published in Expert Opinion on Therapeutic Targets, 2021
Therapies for senile cataract should ideally be prophylactic but will also be needed when cataracts have started to form. In the earliest stages of cataract formation, when aggregation of crystallins begins, water permeability needs to be optimized to prevent any further formation of protein aggregates and consequent water-filled lacunae forming around them; the large difference in refractive index between protein aggregates and water exacerbates light scatter. Where cataracts are liked to glycation, such as in diabetes, water content may need to be decreased [36]. Therapeutics focussed on aquaporin 5 to improve efflux of water [36] should be investigated. Determination of the optimum water transportation for a given age and lens size, as well as for effective regulation of cell volume, requires accurate fluid dynamic modelling. This is needed to inform pharmacokinetics and the extent to which drugs that can modify the function of a particular aquaporin or aquaporins should control permeability and microcirculation.
Biogeographical and Altitudinal Distribution of Cataract: A Nine-Year Experience Using Electronic Medical Record-Driven Big Data Analytics in India
Published in Ophthalmic Epidemiology, 2021
Hannah Garrigan, Cristos Ifantides, Gumpili Sai Prashanthi, Anthony Vipin Das
Out of the 1,127,232 eligible patients over 40 years-old seen over a 9-year period, there was a 48.55% prevalence of senile cataract in at least one eye (N = 547,308). Summary characteristics of patients are included in Table 1, with the corresponding odds ratios and confidence intervals. Figure 3 displays the number of people with and without senile cataracts broken down by age group. The group without lens opacities was eight years younger on average than the group with lens opacification. Most patients seen with cataract were between 61 and 70 years old (41.46%) and the proportion of people with senile cataract increased as the population aged. Older age groups had increased odds of presenting with senile cataract when compared to 40–50 year olds (Table 1). The average age of women with cataracts was 61 years old (SD = 8.93) and men was 63 years old (SD = 9.21). Women had a 34% increased odds of having a senile cataract present on examination when compared to men (OR = 1.33, 95% CI: 1.32–1.34), when adjusting for all listed confounders.
Nutrition knowledge and dietary patterns in ophthalmic patients
Published in Clinical and Experimental Optometry, 2021
Samuel B Boadi‐kusi, Edward Asiamah, Stephen Ocansey, Sampson L Abu
Previous reports suggest that development of senile cataract can be controlled by the intake of diets rich in vitamin C, lutein/zeaxanthin, B vitamins, omega‐3 fatty acids, multivitamins, and carbohydrates.10,22,32 While there is no cogent evidence for or against the role of nutrition in preventing or slowing down glaucoma, Giaconi et al.33 demonstrated that diets rich in vitamins A and C and carotenoids may have a protective trend against glaucoma. The Rotterdam study34 also suggested that increased intake of retinol and vitamin B1 may lower the risk of developing glaucoma. The fact that both cataract and glaucoma patients, in the present study, recorded lower daily intake of all seven ophthalmic nutrients may be indicative of nutritional deficits in patients with chronic eye diseases.