Functional adaptation after kidney tissue removal in patients is associated with increased plasma atrial natriuretic peptide concentration

Renal MRI: From Nephron to NMR Signal

Renal diseases pose a significant socio-economic burden on healthcare systems. The development of better diagnostics and prognostics is well-recognized as a key strategy to resolve these challenges. Central to these developments are MRI biomarkers, due to their potential for monitoring of early pathophysiological changes, renal disease progression or treatment effects. The surge in renal MRI involves major cross-domain initiatives, large clinical studies, and educational programs. In parallel with these translational efforts, the need for greater (patho)physiological specificity remains, to enable engagement with clinical nephrologists and increase the associated health impact. The ISMRM 2022 Member Initiated Symposium (MIS) on renal MRI spotlighted this issue with the goal of inspiring more solutions from the ISMRM community. This work is a summary of the MIS presentations devoted to: 1) educating imaging scientists and clinicians on renal (patho)physiology and demands from clinical nephrologists, 2) elucidating the connection of MRI parameters with renal physiology, 3) presenting the current state of leading MR surrogates in assessing renal structure and functions as well as their next generation of innovation, and 4) describing the potential of these imaging markers for providing clinically meaningful renal characterization to guide or supplement clinical decision making. We hope to continue momentum of recent years and introduce new entrants to the development process, connecting (patho)physiology with (bio)physics, and conceiving new clinical applications. We envision this process to benefit from cross-disciplinary collaboration and analogous efforts in other body organs, but also to maximally leverage the unique opportunities of renal physiology. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Protective effect of sacubitril/valsartan (Entresto) on kidney function and filtration barrier injury in a porcine model of partial nephrectomy

Kidney surgery often includes organ ischaemia with a risk of acute kidney injury. The present study tested if treatment with the combined angiotensin II-angiotensin II receptor type 1 and neprilysin blocker Entresto (LCZ696, sacubitril/valsartan) protects filtration barrier and kidney function after ischaemia and partial nephrectomy (PN) in pigs. Single kidney glomerular filtration rate (GFR) by technetium-99m diethylene-triamine-pentaacetate clearance was validated (n = 6). Next, four groups of pigs were followed for 15 days (n = 24) after PN (one-third right kidney, 60 min ischaemia) + Entresto (49/51 mg/day; n = 8), PN + vehicle (n = 8), sham + Entresto (49/51 mg/day; n = 4) and sham + vehicle (n = 4). GFR, diuresis and urinary albumin were measured at baseline and from each kidney after 15 days. The sum of single-kidney GFR (right 25 ± 6 mL/min, left 31 ± 7 mL/min) accounted for the total GFR (56 ± 14 mL/min). Entresto had no effect on baseline blood pressure, p-creatinine, mid-regional pro-atrial natriuretic peptide (MR-proANP), heart rate and diuresis. After 15 days, Entresto increased GFR in the uninjured kidney (+23 ± 6 mL/min, P < .05) and reduced albuminuria from both kidneys. In the sham group, plasma MR-proANP was not altered by Entresto; it increased to similar levels 2 h after surgery with and without Entresto. Fractional sodium excretion increased with Entresto. Kidney histology and kidney injury molecule-1 in cortex tissue were not different. In conclusion, Entresto protects the filtration barrier and increases the functional adaptive response of the uninjured kidney.