Steatorrhea and Hyperoxaluria Occur after Gastric Bypass Surgery in Obese Rats Regardless of Dietary Fat or Oxalate
Steatorrhea and Hyperoxaluria Occur after Gastric Bypass Surgery in Obese Rats Regardless of Dietary Fat or Oxalate
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DOI：
10.1016/j.juro.2013.02.3229
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发表时间：
2013-09-01
影响因子：
6.6
通讯作者：
Hatch, Marguerite
中科院分区：
文献类型：
--
作者：
Canales, Benjamin K.;Ellen, Joseph;Hatch, Marguerite
目的：我们在Roux-en-Y胃旁路手术的大鼠模型中确定了饮食脂肪和草酸盐对粪便脂肪排泄和尿液参数的影响。材料和方法：饮食诱导的肥胖Sprague-Dawley（R）大鼠作为对照进行假手术（16），或Roux-en-Y胃旁路手术（19）。恢复后，大鼠自由进食正常钙、高脂肪（40%）饮食（含或不含1.5%草酸钾）5周，然后进食正常（10%）脂肪饮食2周。每个周期后收集粪便和尿液。粪便脂肪测定气相色谱法和尿液代谢产物进行了评估，通过测定分光光度法。结果：每日粪便脂肪排泄量保持在控制低的饮食。然而，Roux-en-Y胃旁路大鼠摄入的食物量与对照组相似，但粪便脂肪排泄量高8倍（p < 0.001），粪便更重（p = 0.02）。与对照组相比，高脂饮食加草酸钾的胃旁路大鼠尿草酸排泄量增加了5倍（p < 0.001），而不加草酸钾的胃旁路大鼠尿钙增加了2倍（p < 0.01）。用草酸钾降低胃旁路大鼠的膳食脂肪导致草酸排泄减少50%（p < 0.01），尿钙降低30%，尿pH升高0.3 U（p < 0.001）。在该Roux-en-Y胃旁路模型中，高脂肪喂养导致脂肪过多、高尿酸和低尿液pH，通过降低膳食脂肪和草酸盐含量可部分逆转。Roux-en-Y胃旁路大鼠正常脂肪和无草酸盐饮食排泄的草酸盐是年龄匹配的假手术对照组的两倍。虽然Roux-en-Y胃旁路术高尿酸血症主要由肠道和饮食介导，但肝脏或其他机制的草酸生成的次要原因值得进一步探讨。
Purpose: We determined the effect of dietary fat and oxalate on fecal fat excretion and urine parameters in a rat model of Roux-en-Y gastric bypass surgery.Materials and Methods: Diet induced obese Sprague-Dawley (R) rats underwent sham surgery as controls (16), or Roux-en-Y gastric bypass surgery (19). After recovery, rats had free access to a normal calcium, high fat (40%) diet with or without 1.5% potassium oxalate for 5 weeks and then a normal (10%) fat diet for 2 weeks. Stool and urine were collected after each period. Fecal fat was determined by gas chromatography and urine metabolites were evaluated by assay spectrophotometry.Results: Daily fecal fat excretion remained low in controls on either diet. However, Roux-en-Y gastric bypass rats ingested a food quantity similar to that of controls but had eightfold higher fecal fat excretion (p < 0.001) and heavier stools (p = 0.02). Compared to controls, gastric bypass rats on the high fat diet with potassium oxalate had a fivefold increase in urine oxalate excretion (p < 0.001), while gastric bypass rats without potassium oxalate had a twofold increase in urine calcium (p < 0.01). Lowering dietary fat in gastric bypass rats with potassium oxalate led to a 50% decrease in oxalate excretion (p < 0.01), a 30% decrease in urine calcium and a 0.3 U increase in urine pH (p < 0.001).Conclusions: In this Roux-en-Y gastric bypass model high fat feeding resulted in steatorrhea, hyperoxaluria and low urine pH, which were partially reversible by lowering the dietary fat and oxalate content. Roux-en-Y gastric bypass rats on normal fat and no oxalate diets excreted twice as much oxalate as age matched, sham operated controls. Although Roux-en-Y gastric bypass hyperoxaluria appears primarily mediated by gut and diet, secondary causes of oxalogenesis from liver or other mechanisms deserve further exploration.