Samantha Milanesi

Mesenchymal Stromal Cells Prevent Renal Fibrosis in a Rat Model of Unilateral Ureteral Obstruction by Suppressing the Renin-Angiotensin System via HuR

We studied Mesenchymal Stromal Cells (MSC) effects in experimental Unilateral Ureteral Obstruction (UUO), a fibrogenic renal disease. Rats were divided in 5 groups: sham, UUO, MSC treated-UUO, ACEi treated-UUO, MSC+ACEi treated- UUO. Data were collected at 1, 7, 21 days. UUO induced monocyte renal infiltration, tubular cell apoptosis, tubular atrophy, interstitial fibrosis and overexpression of TGFβ, Renin mRNA (RENmRNA), increase of Renin, Angiotensin II (AII) and aldosterone serum levels. Both lisinopril (ACEi) and MSC treatment prevented monocyte infiltration, reduced tubular cell apoptosis, renal fibrosis and TGFβ expression. Combined therapy provided a further suppression of monocyte infiltration and tubular injury. Lisinopril alone caused a rebound activation of Renin-Angiotensin System (RAS), while MSC suppressed RENmRNA and Renin synthesis and induced a decrease of AII and aldosterone serum levels. Furthermore, in in-vitro and in-vivo experiments, MSC inhibit Human antigen R (HuR) trascription, an enhancer of RENmRNA stability by IL10 release. In conclusion, we demonstrate that in UUO MSC prevent fibrosis, by decreasing HuR-dependent RENmRNA stability. Our findings give a clue to understand the molecular mechanism through which MSC may prevent fibrosis in a wide and heterogeneous number of diseases that share RAS activation as common upstream pathogenic mechanism.

Perfusion of isolated rat kidney with Mesenchymal Stromal Cells/Extracellular Vesicles prevents ischaemic injury

Kidney donation after circulatory death (DCD) is a less than ideal option to meet organ shortages. Hypothermic machine perfusion (HMP) with Belzer solution (BS) improves the viability of DCD kidneys, although the graft clinical course remains critical. Mesenchymal stromal cells (MSC) promote tissue repair by releasing extracellular vesicles (EV). We evaluated whether delivering MSC‐/MSC‐derived EV during HMP protects rat DCD kidneys from ischaemic injury and investigated the underlying pathogenic mechanisms. Warm ischaemic isolated kidneys were cold‐perfused (4 hrs) with BS, BS supplemented with MSC or EV. Renal damage was evaluated by histology and renal gene expression by microarray analysis, RT‐PCR. Malondialdehyde, lactate, LDH, glucose and pyruvate were measured in the effluent fluid. MSC‐/EV‐treated kidneys showed significantly less global ischaemic damage. In the MSC/EV groups, there was up‐regulation of three genes encoding enzymes known to improve cell energy metabolism and three genes encoding proteins involved in ion membrane transport. In the effluent fluid, lactate, LDH, MDA and glucose were significantly lower and pyruvate higher in MSC/EV kidneys as compared with BS, suggesting the larger use of energy substrates by MSC/EV kidneys. The addition of MSC/EV to BS during HMP protects the kidney from ischaemic injury by preserving the enzymatic machinery essential for cell viability and protects the kidney from reperfusion damage.

Modulation of Myostatin/Hepatocyte Growth Factor Balance by Different Hemodialysis Modalities

Background. In this study we investigated the relevance of myostatin and Hepatocyte Growth Factor (HGF) in patients undergoing hemodialysis HD and the influence of different HD modalities on their levels. Methods. We performed a prospective crossover study in which HD patients were randomized to undergo 3-month treatment periods with bicarbonate hemodialysis (BHD) followed by online hemodiafiltration (HDF). Clinical data, laboratory parameters, and myostatin and HGF serum levels were collected and compared. Results. Ten patients and six controls (C) were evaluated. In any experimental condition myostatin and HGF levels were higher in HD than in C. At enrollment and after BHD there were not significant correlations, whereas at the end of the HDF treatment period myostatin and HGF were inversely correlated (r  −0.65, p < 0.05), myostatin serum levels inversely correlated with transferrin (r  −0.73, p < 0.05), and HGF levels that resulted positively correlated with BMI (r 0.67, p < 0.05). Moving from BHD to HDF, clinical and laboratory parameters were unchanged, as well as serum HGF, whereas myostatin levels significantly decreased (6.3 ± 4.1 versus 4.3 ± 3.1 ng/ml, p < 0.05). Conclusions. Modulation of myostatin levels and myostatin/HGF balance by the use of different HD modalities might represent a novel approach to the prevention and treatment of HD-related muscle wasting syndrome.

Interorgan handling of fibroblast growth factor-23 in humans

Fibroblast growth factor-23 (FGF-23) accumulates in blood of patients with chronic kidney disease (CKD) and is associated both with cardiovascular complications and disease progression. However, our knowledge of the sites and mechanisms that regulate plasma FGF-23 is still incomplete. We measured plasma intact FGF-23 across the kidney, splanchnic organs, and lung in 11 patients [estimated glomerular filtration rate (eGFR) 60 ± 6 ml/min] during elective diagnostic cardiac catheterizations. In these patients FGF-23 was removed by the kidney, with a fractional extraction (FE) of ∼22%. The FE of FGF-23 across the kidney was similar to that of creatinine (∼17%, P = NS). In addition, the FGF-23 FE by the kidney was significantly directly related to eGFR (r = 0.709 P = 0.018) and to kidney creatinine FE (r = 0.736 P = 0.013) but only as a trend to plasma phosphate levels (r = 0.55, P = 0.18). There was no difference in FGF-23 levels in blood perfusing splanchnic organs and cardiopulmonary bed. However, the arterial-venous difference of FGF-23 across the lung was directly related to FGF-23 pulmonary artery levels, suggesting that the lung, and possibly the heart, participate in the homeostasis of plasma FGF-23 when its systemic levels are increased. Our data show that the human kidney is the only site for FGF-23 removal from blood and suggest that FGF-23 is predominantly removed by glomerular filtration. The kidney ability to remove FGF-23 from the circulation likely accounts for the early increase in blood of FGF-23 in patients with CKD.