糖尿病的外科治疗及机制探讨

1.糖尿病及肥胖流行情况复旦大学附属华山医院普外科姚琪远

糖尿病和肥胖症已经成为全球2大主要健康问题。据统计，全球约有1.71亿人患糖尿病，预计2030年将达到3.66亿；中国糖尿病患者已经超过2000万，到2030预计将超过4200万，其中90%以上为2型糖尿病[1]。体重增加和肥胖导致胰岛素抵抗及β细胞功能受损，与2型糖尿病有着密切关系。与体重成长的人群相比，病态肥胖者

对胰岛素分泌

的影响

手术所引起的变化

BPD

RYGB

LAGB

GLP-1

L细胞

+

+

+

+/N

GIP

K细胞

+

-/N

N

PYY

L细胞

+

+

+

N

Ghrelin

A/X细胞

N

*注：+表示增加；-表示减少；N表示无明显变化。

至于RYGB和BPD手术之后为何会产生这些激素变化，仍不明确。目前认为这与胃肠道解剖结构重排有关。在这方面主要有两个假说：前肠假说和后肠假说[21]。前肠假说认为胃分流手术后的肠道激素改变主要是由于排除了前肠与食物接触。而2型糖尿病的发生与胃及前肠（主要包括十二指肠和近段空肠）所分泌Ghrelin等一系列“抗肠促胰岛素”因子有关。而胃分流手术是食物绕过了大部分的胃及十二指肠，减少了这些“抗肠促胰岛素”因子的分泌，从而达到了增加肠促胰岛素分泌，改善胰岛素抵抗，增加胰岛素分泌。而后肠假说则认为后肠（低位小肠）过早的食物接触有关。无论是RYGB还是BPD，都导致食糜比正常通路更早期地到达远端小肠。食糜刺激末端回肠使之分泌GLP-1，增强胰岛素作用，促进血糖正常化。同时GLP-1也延迟胃的排空和小肠运动，抑制营养物质食物的吸收，有助于使升高的血糖浓度恢复正常。另外，食糜对末端回肠的刺激也增加了PYY的分泌，也帮助了减慢胃肠道运动，同时产生饱胀感，减少了食欲。后肠假说也解释RYGB和BPD术后，GLP-1和PYY水平的上升。但不管是前肠假说还是后肠假说，都不能用来单独解释减肥手术后的一系列复杂的胃肠道内分泌变化。其中的机制仍有待更多的研究探索。

4.小结

通过外科手术来治疗2型糖尿病已经越来越普遍。大量临床实践已经证明手术方式是一种有效治疗方式。通过手术的手段，糖尿病已经不再是不治之症了。就长期利益而言，减肥手术对于肥胖的2型糖尿病患者而言，无疑是一种安全、经济、有效的治疗方式。手术在减轻体重的同时，改善了血糖控制情况，使得肥胖和糖尿病相关并发症的长期死亡率大大降低。尽管目前已有大量研究已经证实了减肥手术在治疗2型糖尿病方面的可行性有效性，也对手术后的内分泌改变做了一部分解释。但是其中机制人需要进一步研究。此外，对于手术方式的选择以及新的手术方式应用也需要更多的研究。

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