ABSTRACT
Abstract The renin-angiotensin-aldosterone system (RAAS) plays a key role in diabetic nephropathy (DN). Angiotensin-II secreted during the RAAS pathway increases nephropathy. It stimulates oxidative stress which can quench nitric oxide. Reduced nitric oxide level aggravates Ang-II-induced vasoconstriction. Ang-II has also emerged as a central mediator of the glomerular hemodynamic changes that are associated with renal injury. Deletion of ACE2 is also noted due to increased Ang-II level which leads to the development of DN. We hypothesize that nephropathy caused by Ang-II in the periphery may be controlled by brain RAAS. ACE inhibitors and ARBs may show the renoprotective effect when administered through ICV without crossing the blood-brain barrier. DN was observed after 8 weeks of diabetes induction through alloxan. Administration of captopril and valsartan once and in combined therapy for 2 weeks, significantly reduced urine output, blood urea nitrogen, total protein in the urine, serum cholesterol, serum creatinine, serum triglycerides, and kidney/body weight ratio as compared to diabetic control rats. Further, combination therapy significantly increased the body weight and serum nitrate level as compared to diabetic control animals. However, increased ACE2 levels in the brain may reduce the sympathetic outflow and might have decreased the peripheral activity of Ang-II which shows beneficial effects in DN.
Subject(s)
Animals , Male , Female , Rats , Renin-Angiotensin System/immunology , Angiotensin II/analysis , Diabetic Nephropathies/pathology , Wounds and Injuries/classification , Angiotensin-Converting Enzyme Inhibitors/administration & dosage , Peptidyl-Dipeptidase A/administration & dosageABSTRACT
Abstract Introduction Diabetes mellitus is a metabolic disease associated with a rise in the level of blood glucose. Individuals with diabetes mellitus are more likely to develop hearing loss, tinnitus, and dizziness due to macro- and microvascular complications. The extent to which auditory and vestibular functions are impaired in individuals with type-2 diabetes mellitus is still under debate. Objective To systematically review studies focusing on auditory and vestibular functions in individuals with type-2 diabetes mellitus. Data Synthesis A search was conducted in the PubMed, MedlinePlus, Ingenta Connect and Google Scholar databases for articles published until June 2019. A total of 15,980 articles were primarily retrieved, 33 of which were shortlisted based on the inclusion criteria set by the investigators for the systematic review. Out of 33 full-length articles, 26 evaluated the functioning of the auditory system, while 7 evaluated the functioning of the vestibular system. Most studies related to auditory functioning reported a significant effect of type-2 diabetes mellitus on the peripheral auditory system, whereas studies on vestibular functioning reported no significant effect of diabetes mellitus on the functioning of the peripheral vestibular end-organ. Conclusion Overall, the results of various audiological and peripheral vestibular tests reveal distinctive peripheral and/or central auditory and vestibular end-organ impairments in individuals with type-2 diabetes mellitus.
ABSTRACT
Abstract Introduction: Calcium is vital for the functioning of the inner ear hair cells as well as for the neurotransmitter release that triggers the generation of a nerve impulse. A reduction in calcium level could therefore impair the peripheric vestibular functioning. However, the outcome of balance assessment has rarely been explored in cases with osteopenia and osteoporosis, the medical conditions associated with reduction in calcium levels. Objective: The present study aimed to investigate the impact of osteopenia and osteoporosis on the outcomes of behavioural and objective vestibular assessment tests. Methods: The study included 12 individuals each in the healthy control group and osteopenia group, and 11 individuals were included in the osteoporosis group. The groups were divided based on the findings of bone mineral density. All the participants underwent behavioural tests (Fukuda stepping, tandem gait and subjective visual vertical) and objective assessment using cervical and ocular vestibular evoked myogenic potentials. Results: A significantly higher proportion of the individuals in the two clinical groups' demonstrated abnormal results on the behavioural balance assessment tests (p < 0.05) than the control group. However, there was no significant difference in latencies or amplitude of cervical vestibular evoked myogenic potential and oVEMP between the groups. The proportion of individuals with absence of ocular vestibular evoked myogenic potential was significantly higher in the osteoporosis group than the other two groups (p < 0.05). Conclusion: The findings of the present study confirm the presence of balance-related deficits in individuals with osteopenia and osteoporosis. Hence the clinical evaluations should include balance assessment as a mandatory aspect of the overall audiological assessment of individuals with osteopenia and osteoporosis.
Resumo: Introdução: O cálcio é vital para o funcionamento das células ciliadas, assim como para a liberação dos neurotransmissores que desencadeiam um impulso nervoso. Uma redução nos níveis de cálcio poderia, portanto, prejudicar o funcionamento vestibular periférico. No entanto, a avaliação do equilíbrio tem sido raramente explorada em casos de osteopenia e osteoporose, condições médicas associadas à redução dos níveis de cálcio. Objetivo: O presente estudo teve como objetivo investigar o impacto da osteopenia e da osteoporose nos resultados dos testes de avaliação comportamental e vestibular objetiva. Método: O estudo incluiu 12 indivíduos nos grupos controle e grupo de osteopenia e 11 indivíduos no grupo da osteoporose. Os grupos foram divididos com base nos achados da densidade mineral óssea. Todos os participantes foram submetidos a testes comportamentais (Prova dos Passos de Fukuda, Marcha em tandem e Vertical Visual Subjetiva) e à avaliação objetiva com o uso de potenciais evocados miogênicos vestibulares cervical e ocular (cVEMP e oVEMP). Resultados: Uma proporção significativamente maior de indivíduos nos dois grupos com condições clínicas mostrou resultados anormais nos testes de avaliação comportamental e do equilíbrio (p < 0,05) do que o grupo controle. Embora não tenha havido diferença significativa nas latências ou na amplitude de cVEMP e oVEMP entre os grupos, a proporção de indivíduos com ausência de oVEMP foi significativamente maior no grupo da osteoporose do que nos outros dois grupos (p < 0,05). Conclusão: Os resultados do presente estudo demonstram a presença de déficits de equilíbrio em indivíduos com osteopenia e osteoporose. Assim, as avaliações clínicas gerais e audiológicas de indivíduos com osteopenia e osteoporose deveriam incluir a avaliação do equilíbrio como um aspecto obrigatório.