Impact of Obesity, Chronic Kidney Disease and Type 2 Diabetes on Human Urinary Stem Cells

Obesity is at risk for the development of chronic kidney disease but the involved mechanisms are not known (Navarro et al. 2015). Establishing the link between obesity and kidney damage is difficult. Indeed, kidney function measurement lacks precision in obese people (Lemoine et al. 2014) and requires expensive methods such as measurement of 99mTc-DTPA clearance. Biopsies are too invasive for the detection of emerging kidney damage or for the following of the kidney function. Therefore new tools are required for the early identification of at risk individuals for the kidney damage complication. Mesenchymal stem cells may represent such a relevant tool. These cells are present in a large number of organs, including kidney (Costa et al. 2020). In addition to be differentiated cells progenitors (Dominici et al. 2006), they also support immunosuppressive, anti-fibrotic and pro-angiogenic functions that have been used for the treatment of kidney fibrosis (Usunier et al. 2014). Therefore, mesenchymal stem cells contribute to tissue homeostasis and their alterations may reflect organ dysfunctions. Indeed, mesenchymal stem cells from obese adipose tissue lose their immunosuppressive (Serena et al. 2016) and differentiation (Gustafson et al. 2009) functions and contribute to fibrosis (Keophiphath et al. 2009) and inflammation (Lee et al. 2010; Gustafson, Nerstedt, et Smith 2019). It is thus probable that kidney dysfunctions are associated with functional alterations of kidney mesenchymal stem cells. The collection of mesenchymal stem cells from kidney can easily be performed from urine and next cultivated for amplification. They are called urine stem cells (USC). From our experience with obese mouse adipose stem cells, we observed that functional changes of stem cells preceded adipose tissue dysfunctions. Functional signatures of mesenchymal stem cells are thus representative of changes occuring in the function of the tissue notably in answer to obesity. These features c