[Gastrointestinal metabolic surgery improves salt-sensitive hypertension via GLP-1-mediated inhibition of the RAS/NHE3 axis].

摘要

Objective: To investigate the effect of Roux-en-Y gastric bypass (RYGB) on salt-sensitive hypertension and its underlying molecular mechanism. Methods: (1) Clinical study: A total of 57 patients who underwent RYGB at Daping Hospital, Army Medical University between December 2010 and May 2025 were enrolled. According to the diagnostic criteria for hypertension, the patients were divided into normotensive group and hypertensive group. Baseline and postoperative clinical data were collected. Daily sodium intake was calculated based on 24-hour urinary sodium excretion, and the correlation between preoperative sodium intake and the reduction of postoperative systolic blood pressure was analyzed. (2) Animal experiment: Forty-eight 6-week-old male Dahl salt-sensitive hypertensive rats were fed an 8% high-salt diet for 8 weeks to establish the salt-sensitive hypertension models. Thirty modeled rats were randomly divided into the RYGB group (n=15) and the sham operation group (n=15). The remaining 18 rats were randomly divided into control group (n=6), liraglutide group (n=6) and liraglutide+EX9-39 group (n=6), which were treated with normal saline, liraglutide (0.2 mg·kg-1·d-1), and liraglutide combined with EX9-39 (75 μg·kg-1·d-1), respectively. Rat blood pressure was measured via non-invasive tail-cuff method and invasive radiotelemetry method, and isolated vascular function was detected. HE, PAS and Masson staining were used to evaluate mesenteric vascular remodeling, glomerular matrix distribution and renal fibrosis degree, respectively. Enzyme-linked immunosorbent assay was adopted to detect serum levels of glucagon-like peptide-1 (GLP-1) and angiotensin Ⅱ (AngⅡ). Western blot was performed to determine the protein expression of tumor necrosis factor-α, interleukin-6, GLP-1 receptor (GLP-1R), angiotensin-converting enzyme (ACE) 1, ACE2, angiotensin Ⅱ type 1 receptor (AGTR1), phosphorylated Na⁺/H⁺ exchanger 3 (NHE3) and total NHE3 in renal cortex. (3) Cell experiments: Rat renal epithelial NRK-52E cells were used. Four experimental groups were set up: high-salt group (treated with 160 mmol/L NaCl for 24 h), high-salt+liraglutide group (100 nmol/L liraglutide), high-salt+liraglutide+EX9-39 group(100 nmol/L liraglutide+150 nmol/L EX9-39), and control group (equal volume of drug vehicle). Western blotting was performed to detect the expression of ACE1, AGTR1, phosphorylated NHE3 and total NHE3. Results: (1) Clinical study: The enrolled patients had an age of (43.91±10.19) years, including 33 males (58%). There were 24 patients in the normotensive group and 33 in the hypertensive group. Compared with the baseline levels, both systolic blood pressure ((133.26±16.48) mmHg vs. (118.23±15.40) mmHg, 1 mmHg=0.133 kPa) and diastolic blood pressure ((83.16±12.44) mmHg vs. (74.54±8.80) mmHg) were decreased after RYGB (both P<0.05). The median daily preoperative sodium intake of all participants was 10.45 (8.19, 15.58) g/d. A positive correlation was observed between preoperative sodium intake and the reduction in postoperative systolic blood pressure (R=0.326, P=0.013). (2) Animal experiment: At the 8th week after surgery, the tail-cuff systolic blood pressure ((125.33±12.16) mmHg vs. (182.00±11.61) mmHg), 24-hour mean systolic blood pressure ((125.81±12.89) mmHg vs. (182.11±10.21) mmHg) and 24-hour mean diastolic blood pressure ((97.36±6.59) mmHg vs. (144.85±16.58) mmHg) in the RYGB group were lower than those in the sham group (all P<0.05). Compared with the sham group, the RYGB group presented a lower ratio of vascular wall thickness to outer vessel diameter, higher vasodilation of mesenteric arteries, and less glomerular collagen deposition. Meanwhile, the levels of serum creatinine, blood urea nitrogen and urinary protein, as well as the expression of tumor necrosis factor-α and interleukin-6 in renal cortex were also lower in RYGB group than sham group (all P<0.05). In addition, compared with sham group, the serum GLP-1 level, renal cortical GLP-1 receptor expression and NHE3 phosphorylation level were higher in the RYGB group, while serum AngⅡ and the expression of ACE1 and AGTR1 in renal cortex were lower (all P<0.05). Drug intervention results showed that tail-cuff systolic blood pressure was lower in the liraglutide group than in the control group ((167.00±9.98) mmHg vs. (182.00±6.26) mmHg, P<0.05). No significant difference in tail-cuff systolic blood pressure was found between the liraglutide+EX9-39 group and the control group (P>0.05). (3) Cell experiments: High-salt treatment upregulated the expression of ACE1 and AGTR1 and inhibited NHE3 phosphorylation in NRK-52E cells. Liraglutide reversed the above abnormalities, whereas EX9-39 antagonized the regulatory effects of liraglutide. Statistically significant differences were observed in the expression levels of the above proteins among all groups (all P<0.05). Conclusion: RYGB can effectively ameliorate salt-sensitive hypertension. The underlying mechanism is associated with GLP-1-mediated inhibition of renin-angiotensin system activity and promotion of NHE3 phosphorylation. 目的： 探讨Roux-en-Y胃旁路手术（RYGB）干预盐敏感高血压的疗效及分子机制。 方法： （1）临床研究：回顾性纳入2010年12月至2025年5月于陆军军医大学大坪医院接受RYGB手术的57例患者，参照高血压诊断标准分为正常血压组与高血压组，收集患者基线及术后临床资料，依据24 h尿钠排泄量计算日均钠盐摄入量，分析术前钠盐摄入量与术后收缩压下降幅度的相关性。（2）动物实验：选取48只6周龄雄性Dahl盐敏感高血压大鼠，给予8%高盐饮食8周诱导盐敏感高血压模型。将30只造模大鼠随机分为RYGB组（n=15）和假手术组（n=15）；剩余18只随机分为对照组（n=6）、利拉鲁肽组（n=6）和利拉鲁肽+EX9-39组（n=6），分别给予生理盐水、利拉鲁肽（0.2 mg·kg-1·d-1）、利拉鲁肽联合EX9-39（75 μg·kg-1·d-1）干预。采用无创鼠尾血压法及有创动态遥测血压法检测大鼠血压，并进行离体血管功能检测，通过HE、PAS及Masson染色分别评估大鼠肠系膜血管重构、肾小球基质分布及纤维化程度；采用酶联免疫吸附测定试剂盒检测血清胰高血糖素样肽-1（GLP-1）、血管紧张素Ⅱ（AngⅡ）水平；Western blot法检测肾皮质肿瘤坏死因子-α、白细胞介素-6、GLP-1受体、血管紧张素转换酶（ACE）1、ACE2、血管紧张素Ⅱ1型受体（AGTR1）、磷酸化钠-氢交换体3（NHE3）及NHE3蛋白表达；（3）细胞实验：选取NRK-52E大鼠肾上皮细胞，实验共设4组：高盐组（160 mmol/L NaCl干预24 h）、高盐+利拉鲁肽组（100 nmol/L利拉鲁肽）、高盐+利拉鲁肽+EX9-39组（100 nmol/L利拉鲁肽和150 nmol/L EX9-39）、对照组（加入等体积药物溶剂），采用Western blot法检测ACE1、AGTR1、磷酸化NHE3及NHE3蛋白表达。 结果： （1）临床研究：纳入患者年龄（43.91±10.19）岁，男性33例（58%）。血压正常组24例，高血压组33例。与术前相比，患者RYGB术后收缩压［（133.26±16.48）mmHg比（118.23±15.40）mmHg，1 mmHg=0.133 kPa］、舒张压［（83.16±12.44）mmHg比（74.54±8.80）mmHg］较低（P均<0.05）；总人群的术前日均钠盐摄入量为10.45（8.19，15.58）g/d，且术前摄盐量与RYGB术后收缩压下降幅度呈正相关（R=0.326，P=0.013）。（2）动物实验：术后第8周RYGB组大鼠鼠尾收缩压［（125.33±12.16）mmHg比（182.00±11.61）mmHg］、24 h平均收缩压［（125.81±12.89）mmHg比（182.11±10.21 mmHg）］及24 h平均舒张压［（97.36±6.59）mmHg比（144.85±16.58）mmHg］均低于假手术组（P均<0.05）；与假手术组相比，RYGB组大鼠血管壁厚度/血管外径比值较小、肠系膜动脉舒张功能较高、肾小球胶原纤维沉积较少，血肌酐、尿素氮、尿蛋白及肾皮质肿瘤坏死因子-α和白细胞介素-6表达水平均较低（P均<0.05）。此外，RYGB组大鼠血清GLP-1水平、肾皮质GLP-1受体表达及NHE3磷酸化水平较假手术组高，而血清AngⅡ及肾皮质ACE1、AGTR1表达水平较低（P均<0.05）。药物干预结果显示，利拉鲁肽组大鼠鼠尾收缩压低于对照组［（167.00±9.98）mmHg比（182.00±6.26）mmHg，P<0.05］，利拉鲁肽+EX9-39组与对照组鼠尾收缩压差异无统计学意义（P>0.05）。（3）细胞实验：高盐可上调NRK-52E细胞中ACE1、AGTR1表达水平并抑制NHE3磷酸化；利拉鲁肽可逆转上述改变，而EX9-39可拮抗利拉鲁肽的调控作用，各组间上述蛋白表达水平差异均有统计学意义（P均<0.05）。 结论： RYGB手术可有效改善盐敏感高血压，其作用机制与GLP-1抑制肾素-血管紧张素系统活性、促进NHE3磷酸化有关。.