Preliminary study of rabbits as an animal model of mammalian eye transplantation and literature review / Estudo preliminar de coelhos como modelo animal para transplante de olho em mamíferos e revisão da literatura

ABSTRACT Purpose: To describe an innovative animal model of eye transplantation used in rabbits. Methods: six Dutch-belted male rabbits were submitted to lateral orbitotomy in the right eye, wide retrobulbar anatomy exposure, dissection of the structures, identification and distal section of the optic nerve followed by anastomosis either by vicryl (group 1) or fibrin glue (group 2). Electroretinography recording was performed before the section of the optic nerve and every 30 seconds after, to monitor the function of retina. Left eye was used as control group. Results: After optic nerve resection and anastomosis, stable ERG amplitude of the right eye was lost after 302 seconds in group 1 and after 296 seconds on group 2. Left eye kept longer stable ERG amplitude curves. Conclusions: The animal model of whole eye transplantation was effective in describing a novel technique to be used in rabbits, with success of the anatomic procedure. Further studies will clarify the best anastomosis methods and maintenance of function of the receptor organ. Translational relevance: this animal model of whole eye transplantation provides a novel perspective for blind patients and the research models, since we describe a novel mammal animal model. This model can be used as basis of a human model of whole eye transplantation in future studies.

RESUMO Objetivo: Descrever uma técnica cirúrgica inovadora para transplante de olho em um modelo animal em coelhos. Métodos: Seis coelhos machos com Dutch Belted foram submetidos à orbitotomia lateral do olho direito, com ampla exposição da anatomia retrobulbar, dissecção do cone muscular, exposição e secção distal do nervo óptico seguida de anastomose por vicryl (Grupo 1) ou cola de fibrina (Grupo 2). O registro da eletrorretinografia foi realizado antes da secção do nervo óptico e a cada 30 segundos após, para monitorar a função da retina. O olho esquerdo foi usado como grupo controle. Resultados: Após a ressecção do nervo óptico, a estabilidade da amplitude da eletrorretinografia foi perdida no olho direito após 302 segundos no Grupo 1 e após 296 segundos no Grupo 2. O olho esquerdo manteve eletrorretinografia estável por períodos mais longos. Conclusão: O modelo animal de transplante total de olho foi eficaz em descrever uma nova técnica cirúrgica para ser utilizada em laboratório com coelhos, com sucesso do procedimento anatômico. Novos estudos esclarecerão os melhores métodos de anastomose e manutenção da função do órgão receptor.

Vagal impairment in elderly Chagas disease patients: a population-based study (the Bambuí study).

BACKGROUND: Chagas disease (ChD) will become predominantly a disease of the elderly, as a consequence of the effectiveness of control measures in many Latin American countries. The effects of the disease in old age have received little attention. We investigated the effects of ageing in the association between cardiac vagal impairment, a typical feature of ChD, and chronic Trypanosoma cruzi infection. METHODS: The study sample of this cross-sectional study consists of 1014 subjects ≥ 60 years old (mean age = 68.3; SD = 6.9) residing in Bambuí City (Southeast Brazil). ECG was recorded and one-breath sinus arrhythmia test was performed. Maximal expiratory over the minimal inspiratory (E:I) ratio and heart rate variability (HRV) measurements were calculated. Ordinal logistic regression was used to assess the relation between vagal indexes and chronic T. cruzi infection. RESULTS: The prevalence of T. cruzi infection was 32.0% and of major ECG abnormalities, 43.4%. Among individuals aged 60-69 years, T. cruzi infection was significantly and independently associated with reduced SDNN (OR 0.38; 95% CI 0.27-0.53), RMSSD (OR 0.48; 0.34-0.67) and EI: ratio (OR 0.45; 95% CI 0.33-0.63). Among individuals aged >70 years, no significant odds ratios were found in either the unadjusted or the adjusted analysis. The presence of major ECG abnormalities did not affect the association between vagal indexes and T. cruzi infection. CONCLUSIONS: Disease-specific vagal cardiac dysfunction was observed in ChD individuals below 70. However, further ageing interferes significantly with vagal heart modulation, attenuating the difference of HRV indexes between ChD and non-ChD subjects.