増田 貴博

We previously demonstrated that combining a sodium-glucose cotransporter 2 (SGLT2) inhibitor with diuretics significantly reduces interstitial fluid volume without excessive depletion of circulating plasma volume or activation of the renin-angiotensin-aldosterone system (RAAS). However, the differential effects of SGLT2 inhibitor monotherapy versus combination therapy with diuretics on fluid dynamics in patients with pre-existing fluid retention remain unclear. This study included patients with fluid retention, defined by an extracellular water to total body water (ECW/TBW) ratio > 0.400, as measured by bioimpedance analysis. We evaluated 6-month changes in body fluid status and serum copeptin levels, a surrogate marker for vasopressin, between two groups: patients receiving SGLT2 inhibitor dapagliflozin monotherapy (SGLT2i group, n = 13; estimated glomerular filtration rate [eGFR] 25.0 ± 8.5 mL/min/1.73 m2) and those receiving dapagliflozin in combination with loop or thiazide diuretics (SGLT2i + diuretic group, n = 18; eGFR 29.8 ± 15.2 mL/min/1.73 m2). Changes in systolic blood pressure and estimated plasma volume did not significantly differ between groups. However, reductions in ECW/TBW, TBW, and interstitial fluid were significantly greater in the combination group than in the monotherapy group. Moreover, the increase in serum copeptin was significantly suppressed in the SGLT2i + diuretic group. No significant intergroup differences were observed in renin and aldosterone changes. These findings suggest that co-administration of SGLT2 inhibitor with diuretics can more effectively reduce interstitial fluid retention without inducing excessive plasma volume reduction or RAAS activation.

This case report describes an 80-year-old man with severe immunoglobulin G4-related tubulointerstitial nephritis (IgG4-TIN), characterized by storiform fibrosis with diffuse lymphocytic and plasma cell infiltration observed on a renal biopsy. Steroid pulse therapy administered immediately after confirming a remarkable increase in urinary β2-microglobulin (100,948 μg/L) along with no evidence of malignancy significantly improved the renal function and reduced the urinary β2-microglobulin levels. This study highlights the potential utility of urinary β2-microglobulin as a biomarker for early treatment selection in severe IgG4-TIN and emphasizes the need for timely intervention to prevent irreversible kidney damage.

INTRODUCTION: Managing pregnancy in patients with end-stage kidney disease (ESKD) undergoing dialysis is challenging, with hypoalbuminemia significantly increasing risks to both maternal and neonatal outcomes. Intensive hemodialysis regimens are recommended; however, individualized and adaptive dialysis strategies, such as sequential online hemodiafiltration (OL-HDF) and intermittent HDF (i-HDF), may be required to optimize care in complex cases. CASE PRESENTATION: We report the case of a 27-year-old Japanese woman with ESKD who transitioned from OL-HDF to i-HDF during pregnancy due to progressive hypoalbuminemia at 30 + 5 weeks of gestation. Dry weight adjustments were guided by human atrial natriuretic peptide (hANP) levels, blood pressure measurements, and bioimpedance analysis. i-HDF reduced albumin loss compared to OL-HDF, stabilized maternal hemodynamics, and enabled term delivery at 39 + 1 weeks with a healthy neonate weighing 2,774 g. Bioimpedance analysis and hANP-guided adjustments allowed for precise fluid management, resulting in a total gestational weight gain of 6.4 kg. The patient developed superimposed preeclampsia during labor, which was successfully managed. CONCLUSION: This case demonstrates that sequential OL-HDF and i-HDF can effectively address hypoalbuminemia and fluid imbalances, contributing to successful maternal and neonatal outcomes in ESKD pregnancies.