Functional Magnetic Resonance Imaging to Monitor Disease Progression: a prospective study in Patients with Primary Membranoproliferative Glomerulonephritis.

INTRODUCTION: Primary membranoproliferative glomerulonephritis (MPGN) is a rare kidney disease with poor prognosis and no specific therapies. The disease heterogeneity and the difficulty of performing repeated kidney biopsies poses big challenges. This study investigates the correlation between non-contrast enhanced magnetic resonance imaging (MRI) and histologic and clinical findings in patients with primary MPGN. METHODS: Patients with primary MPGN underwent baseline and 1-year kidney MRI in addition to biopsy and laboratory testing as part of a prospective MRI subproject of a clinical trial (ClinicalTrials.gov identifier NCT03723512). Diffusion-weighted and phase-contrast MRI were used to investigate kidney diffusivity and perfusion. Peritubular interstitial volume and fibrosis were quantified on kidney biopsies. RESULTS: Seven patients with primary MPGN (18[17-21] years, 43% females) were included. Kidney biopsies showed variable degree of global and segmental glomerular sclerosis ([5-30]% and [10-60]%), mild interstitial fibrosis (<10%), and increased peritubular interstitial volume ([19-40]%). MRI and laboratory parameters changed very differently from patient to patient over 1 year. Peritubular interstitial volume and glomerular sclerosis negatively associated with renal blood flow (RBF)(rho = -0.81 and -0.77), and positively with renal vascular resistance (RVR)(rho = 0.65 and 0.73). Urinary albumin to creatinine ratio (uACR) negatively associated with RBF and filtration fraction (FF)(rho = -0.86 and -0.6), while positively with RVR (rho = 0.88). uACR decrease was associated with kidney diffusivity increase (rho = -0.5). Measured glomerular filtration rate (GFR) positively associated with kidney diffusivity, RBF, and FF (rho = 0.87, 0.85 and 0.59), while negatively with RVR (rho = -0.89); GFR increase was associated with kidney diffusivity, RBF, and FF increase (rho = 0.77, 0.7, and 0.7) and RVR decrease (rho = -0.7). DISCUSSION/CONCLUSION: The strong correlation found between MRI and histologic and clinical findings, despite the rather limited number of patients, highlights MRI potential to monitor disease progression in patients with rare kidney disease.

Effects of Octreotide-Long-Acting Release Added-on Tolvaptan in Patients with Autosomal Dominant Polycystic Kidney Disease: Pilot, Randomized, Placebo-Controlled, Cross-Over Trial.

BACKGROUND: Tolvaptan and octreotide-long-acting release (LAR) have renoprotective effects in autosomal dominant polycystic kidney disease (ADPKD) that are partially mediated by amelioration of compensatory glomerular hyperfiltration. We compared the effects of tolvaptan and octreotide-LAR combination therapy versus those of tolvaptan monotherapy in patients with ADPKD. METHODS: This pilot, randomized, placebo-controlled, cross-over trial primarily compared the effects of 1- and 4-week treatments with octreotide-LAR (two 20-mg i.m. injections) or placebo (two i.m. 0.9% saline solution injections) added-on tolvaptan (up to 90 and 30 mg/d) on GFR (iohexol plasma clearance) in 19 consenting patients with ADPKD referred to a clinical research center in Italy. Analyses were intention-to-treat. The local ethical committee approved the study. RESULTS: At 4 weeks, GFR significantly decreased by a median (interquartile range) of 3 (-1 to 5) ml/min per 1.73 m2 with tolvaptan and placebo (P=0.01) and by 7 (3-14) ml/min per 1.73 m2 with tolvaptan and octreotide-LAR (P=0.03). GFR changes during the two treatment periods differed by 2 (-5 to 14) ml/min per 1.73 m2 (P=0.28). At 1 week, GFR significantly decreased by 3 (0-7) ml/min per 1.73 m2 with tolvaptan and placebo (P=0.006) and by 10 (-6 to 16) ml/min per 1.73 m2 with tolvaptan and octreotide-LAR add-on therapy (P<0.001). GFR changes during the two treatment periods significantly differed by 3 (0-12) ml/min per 1.73 m2 (P=0.012). Total kidney volume nonsignificantly changed by 4 (-48 to 23) ml with tolvaptan and placebo (P=0.74), whereas it decreased significantly by 41 (25-77) ml with tolvaptan and octreotide-LAR (P=0.001). Changes during the two treatment periods differed by 36 (0-65) ml (P=0.01). Octreotide-LAR also attenuated (P=0.02) the aquaretic effect of tolvaptan. Treatments were well tolerated. CONCLUSIONS: In patients with ADPKD, octreotide-LAR added-on tolvaptan reduced GFR more effectively than octreotide-LAR and placebo. Octreotide-LAR also reduced total and cystic kidney volumes and attenuated the acquaretic effect of tolvaptan. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Tolvaptan-Octreotide LAR Combination in ADPKD (TOOL), NCT03541447.

Case Report: Tackling Complement Hyperactivation With Eculizumab in Atypical Hemolytic Uremic Syndrome Triggered by COVID-19.

Hemolytic uremic syndrome (HUS) is a rare life-threatening disease of unrestrained complement system dysregulation, microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure in genetically predisposed individuals. In this report, we describe two cases of SARS-CoV-2-associated HUS treated with eculizumab, a C5-blocking monoclonal antibody reported to be remarkably effective in the treatment of HUS. Detailed biochemical and genetic complement system analysis is reported, and the prompt clinical response after C5 pharmacological blockade is documented. Our report provides the rationale and supports the use of terminal complement pathway inhibition for the treatment of SARS-CoV-2-associated HUS.