Calcium Oxalate Kidney Stones: Pathogenesis of Obesity-associated Hyperoxaluria

草酸钙肾结石：肥胖相关高草酸尿症的发病机制

• 批准号: 8673535
• 负责人: HATIM A HASSAN
• 金额: $ 34.37万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8673535
• 关键词: Affect; Anions; Apical; Bathing; Body Size; Calcium Oxalate; Calculi; Celiac Disease; Cells; Creatinine; Diet; Dose; Excretory function; GCG gene; GLP-2; Glycolates; Goals; Human; Hyperoxaluria; Hyperphagia; Inbred BALB C Mice; Incidence; Interferons; Interleukin-6; Intestines; Kidney Calculi; Knockout Mice; Leptin; Life; Ligands; Mannitol; Mediating; Messenger RNA; Minor; Modeling; Molecular; Mus; Obesity; Oral; Oxalates; Pathogenesis; Peptides; Permeability; Play; Prevalence; Reporting; Risk; Risk Factors; Role; TNF gene; Testing; Therapeutic; Therapeutic Effect; Tissues; Urine; absorption; base; cost; cytokine; db/db mouse; feeding; improved; in vivo; intestinal epithelium; neutralizing antibody; nonalcoholic steatohepatitis; protein expression; public health relevance; uptake; urinary

DESCRIPTION (provided by applicant): 70-80% of kidney stones (KS) are composed of calcium oxalate, and minor changes in urine oxalate affect the stone risk. Obesity is a risk factor for KS and obese stone formers often have mild hyperoxaluria. A positive correlation between increased body size and elevated urinary oxalate excretion was reported; however, the underlying mechanism(s) remain(s) unknown. Therefore, we initiated studies in the obese ob/ob (ob) mice to define the pathogenesis of the obesity-associated hyperoxaluria (OAH). ob mice were found to have significantly higher urine oxalate (adjusted for creatinine) compared to controls (>2.9-fold), which is not due to overeating using pair-feeding. Significant hyperoxaluria was also seen in the obese db/db mice (> 2.3-fold). We observed significantly higher jejunal (> 46%) and ileal (>30%) 14C-oxalate and 3H-mannitol (a paracellular marker) absorptive fluxes in ob mice compared to controls ex vivo. Importantly, a significantly higher (>35%) urine 13C-oxalate was observed in ob mice compared to controls following an oral gavage with 13C-oxalate. The proinflammatory cytokines (PCs) IFN-? [IFN] and TNF-¿ [TNF], which are elevated in obesity, caused > 3- fold increase in apical to basolateral 14C-oxalate and 3H-mannitol fluxes in human intestinal Caco2-BBE (C2) cells. The PC-induced increased absorptive fluxes were completed blocked by pretreatment with AMP-18 and GLP-2, peptides known to improve intestinal barrier function. Pretreatment of BALB/c mice with TNF before isolating and mounting jejunal segments in Ussing chambers led to > 1.9-fold increase in 14C -oxalate and 3H- mannitol absorptive fluxes, an effect completely blocked by pretreatment with AMP or GLP. IFN, TNF, and IL-6 also significantly inhibited apical 14C-oxalate uptake by C2 cells through mechanisms involving reduced SLC26A6 (A6), an anion exchanger with essential role in intestinal oxalate secretion, mRNA/total protein expression. In addition, ob mice have significantly reduced jejunal A6 mRNA (>65%) and total protein expression. while a small net oxalate secretory flux was observed in control jejunal tissues, a large net absorptive flux was seen in ob tissues, due to significantly reduced secretory flux and an increased absorptive flux . Based on these findings, I will test the hypothesis that PCs play an important role in the OAH, and that anti-TNF, anti-IFN, and/or anti-IL-6 will normalize and/or ameliorate the observed hyperoxaluria. The following specific aims will be pursued: 1a. Evaluate the therapeutic effects of anti-TNF, anti-IFN, and anti-IL-6 on the observed hyperoxaluria.1b. Evaluate the effects of crossing the ob mice with the TNF, IFN, and/or IL-6 null mice on the observed hyperoxaluria to confirm their roles in the OAH. 2a. Assess small and large intestinal paracellular permeability in vivo in ob mice and their controls. 2b. Examine the therapeutic effects of AMP and GLP on the observed hyperoxaluria. 2c. Elucidate the in vivo mechanisms by which AMP, GLP, anti-TNF, anti- IFN, and/or anti-IL-6 normalize and/or ameliorate the observed hyperoxaluria. 3. Evaluate the effects of crossing the ob mice with the A6 null mice on the observed hyperoxaluria to confirm the role of A6 in the OAH.

描述（由应用提供）：70-80％的肾结石（KS）由草酸钙钙组成，草酸尿液的少量变化会影响石材风险。肥胖是危险因素 对于KS和肥胖的石材，通常患有温和的高黄油尿症。据报道，人体大小增加与草酸尿升高之间存在正相关。但是，基本机制仍然未知。因此，我们在肥胖的OB/OB（OB）小鼠中启动了研究，以定义与肥胖相关的高黄油（OAH）的发病机理。与对照组（> 2.9倍）相比，发现OB小鼠的草酸盐（针对肌酐调节）明显更高，这并不是由于使用配对喂养而暴饮暴食。在肥胖的DB/DB小鼠（> 2.3倍）中也观察到明显的高黄油尿症。我们观察到与对照组相比，与对照组相比，OB小鼠中的空肠（> 46％）和回肠（> 30％）14c-氧甲酸盐和3H-甘露醇（一种细胞细胞标记）吸收通量。重要的是，与口服13c-氧甲酸盐的口服后的对照组相比，OB小鼠中观察到的尿液13c-氧盐的明显更高（> 35％）。促炎细胞因子（PC）IFN-？ [IFN]和TNF-¿ PC诱导的增加的吸收通量通过用AMP-18和GLP-2预处理（已知可以改善肠屏障功能的肽）预处理完成。在隔离和安装ussing室中的空肠段之前对BALB/C小鼠进行预处理，导致14c-氧化和3H-甘露醇吸收性通量的增长> 1.9倍，这一效果完全被AMP或GLP预处理所阻断。 IFN，TNF和IL-6还通过涉及降低的SLC26A6（A6）的机制显着抑制了C2细胞的顶端14C-氧化，这是一种在肠道草酸盐分泌，mRNA/总蛋白质表达中具有重要作用的阴离子交换器。此外，OB小鼠的空肠A6 mRNA（> 65％）和总蛋白表达显着降低。虽然在对照空肠组织中观察到小小的草酸盐分泌通量，但由于秘密通量显着降低和吸收通量增加，在OB组织中看到了较大的净吸收通量。基于这些发现，我将检验以下假设：PC在OAH中起重要作用，抗TNF，抗IFN和/或抗IL-6将正常化和/或改善观察到的高氧化尿症。将追求以下特定目标：1a。评估抗TNF，抗IFN和抗IL-6对观察到的高氧甲尿的治疗作用。1b。评估将OB小鼠与TNF，IFN和/或IL-6 NULL小鼠对观察到的高黄油尿症的影响以确认其在OAH中的作用。 2a。评估OB小鼠体内体内的小肠副细胞细胞渗透性及其对照。 2b。检查AMP和GLP对观察到的高黄油尿症的治疗作用。 2C。阐明了放大器，GLP，抗TNF，抗IFN和/或抗IL-6的体内机制，并改善观察到的高氧化尿症。 3。评估将OB小鼠与A6 NULL小鼠对观察到的Hyperoxaluria杂交以确认A6在OAH中的作用的影响。