Intestinal microbiota play a considerable role in the host’s organism, broadly affecting its organs and tissues. The kidney can also be the target of the microbiome and its metabolites (especially short-chain fatty acids), which can influence renal tissue, both by direct action and through modulation of the immune response. This impact is crucial, especially during kidney injury, because the modulation of inflammation or reparative processes could affect the severity of the resulting damage or recovery of kidney function. In this study, we compared the composition of rat gut microbiota with its outcome, in experimental acute ischemic kidney injury and named the bacterial taxa that play putatively negative or positive roles in the progression of ischemic kidney injury. We investigated the link between serum creatinine, urea, and a number of metabolites (acylcarnitines and amino acids), and the relative abundance of various bacterial taxa in rat feces. Our analysis revealed an increase in levels of 32 acylcarnitines in serum, after renal ischemia/reperfusion and correlation with creatinine and urea, while levels of three amino acids (tyrosine, tryptophan, and proline) had decreased. We detected associations between bacterial abundance and metabolite levels, using a compositionality-aware approach—Rothia and Staphylococcus levels were positively associated with creatinine and urea levels, respectively. Our findings indicate that the gut microbial community contains specific members whose presence might ameliorate or, on the contrary, aggravate ischemic kidney injury. These bacterial taxa could present perspective targets for therapeutical interventions in kidney pathologies, including acute kidney injury.

中文翻译：

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急性肾脏损伤的微生物组-代谢组学签名。

肠道菌群在宿主生物中起着相当重要的作用，广泛影响其器官和组织。肾脏也可以成为微生物组及其代谢产物（特别是短链脂肪酸）的靶标，它们可以通过直接作用和免疫应答调节来影响肾脏组织。这种影响至关重要，尤其是在肾脏受伤期间，因为炎症的调节或修复过程可能会影响所导致的肾脏功能损害或恢复的严重性。在这项研究中，我们将大鼠肠道菌群的组成及其结局在实验性急性缺血性肾损伤中进行了比较，并命名了细菌类群，该细菌类群在缺血性肾损伤的进展中发挥了可能的负性或正性作用。我们调查了血清肌酐，尿素，以及大鼠粪便中的许多代谢物（酰基肉碱和氨基酸）以及各种细菌类群的相对丰度。我们的分析显示，肾脏缺血/再灌注后血清中32种酰基肉碱的含量增加，并与肌酐和尿素相关，而三种氨基酸（酪氨酸，色氨酸和脯氨酸）的含量却降低了。我们使用成分识别方法检测了细菌丰度与代谢物水平之间的关联，Rothia和葡萄球菌的水平分别与肌酐和尿素水平呈正相关。我们的发现表明，肠道微生物群落包含特定的成员，其存在可能会改善或相反加剧缺血性肾脏损伤。这些细菌分类群可以为包括急性肾损伤在内的肾脏疾病的治疗干预提供透视目标。