DOES EVOLUTIONARY BIOLOGY HELP THE UNDERSTANDING OF METABOLIC SURGERY? A FOCUSED REVIEW

ABSTRACT Introduction: The wide net of physiological issues involved in metabolic surgery is extremely complex. Nonetheless, compared anatomy and phisiology can provide good clues of how digestive tracts are shaped for more or less caloric food, for more or less fiber, for abundance and for scarcity. Objective: To review data from Compared Anatomy and Physiology, and in the Evolutionary Sciences that could help in the better comprehension of the metabolic surgery. Method: A focused review of the literature selecting information from these three fields of knowledge in databases: Cochrane Library, Medline and SciELO, articles and book chapters in English and Portuguese, between 1955 and 2019, using the headings “GIP, GLP-1, PYY, type 2 diabetes, vertebrates digestive system, hominid evolution, obesity, bariatric surgery “. Results: The digestive tract of superior animals shows highly specialized organs to digest and absorb specific diets. In spite of the wide variations of digestive systems, some general rules are observed. The proximal part of the digestive tract, facing the scarcity of sugars, is basically dedicated to generate sugar from different substrates (gluconeogenesis). Basic proximal gut tasks are to proportionally input free sugars, insulin, other fuels and to generate anabolic elements to the blood, some of them obesogenic. To limit the ingestion by satiety, by gastric emptying diminution and to limit the excessive elevation of major fuels (sugar and fat) in the blood are mostly the metabolict asks of the distal gut. A rapid and profound change in human diet composition added large amounts of high glycemic index foods. They seem to have caused an enhancement in the endocrine and metabolic activities of the proximal gut and a reduction in these activities of the distal gut. The most efficient models of metabolic surgery indeed make adjustments in this proximal/distal balance in the gut metabolic activities. Conclusion: Metabolic surgery works basically by making adjustments to the proximal and distal gut metabolic activities that resemble the action of natural selection in the development the digestive systems of superior animals.摘要 引言：代谢外科所涉及的生理问题范畴极广且极为复杂。比较解剖生理学（Comparative Anatomy and Physiology）可揭示消化系统如何适配不同热量、不同纤维含量的食物，以及食物丰歉的影响。 研究目的：本研究旨在梳理比较解剖生理学与进化科学（Evolutionary Sciences）领域的相关数据，以助力更深入地理解代谢外科（metabolic surgery）的原理。 研究方法：本研究采用聚焦式文献综述法，从考克兰图书馆（Cochrane Library）、MEDLINE及SciELO数据库中筛选1955年至2019年间发表的英文与葡萄牙文文献及图书章节，检索词包括：“葡萄糖依赖性促胰岛素多肽（GIP）”、“胰高血糖素样肽-1（GLP-1）”、“多肽YY（PYY）”、“2型糖尿病”、“脊椎动物消化系统”、“人科演化”、“肥胖”、“减重代谢外科（bariatric surgery）”。 研究结果：高等动物的消化系统拥有高度特化的器官，用于消化与吸收特定膳食。尽管不同物种的消化系统差异巨大，但仍存在一些通用规律。在糖类匮乏的环境下，消化系统的近端区段主要负责通过糖异生途径从不同底物合成葡萄糖。肠道近端的基础功能包括按比例向血液输送游离糖、胰岛素及其他供能物质，并合成合成代谢成分——其中部分成分可诱导肥胖。通过引发饱腹感、减缓胃排空以限制进食，并抑制血液中主要供能物质（糖与脂肪）的过度升高，是肠道远端的核心代谢功能。人类饮食结构发生的快速且深刻的变化，引入了大量高血糖指数食物。这似乎增强了肠道近端的内分泌与代谢活性，同时削弱了肠道远端的同类功能。目前临床应用的高效代谢外科术式，正是通过调整肠道近端与远端的代谢活性平衡来发挥作用。 结论：代谢外科的核心作用机制，是通过调整肠道近端与远端的代谢活性，模拟自然选择在高等动物消化系统演化过程中的调控效应。