Estimated GFR Slope Across CKD Stages in Primary Hyperoxaluria Type 1

Efficacy and Safety of Lumasiran in Patients With Primary Hyperoxaluria Type 1: Results from a Phase III Clinical Trial

Introduction

Patients with primary hyperoxaluria type 1 (PH1), a genetic disorder associated with hepatic oxalate overproduction, frequently experience recurrent kidney stones and worsening kidney function. Lumasiran is indicated for the treatment of PH1 to lower urinary and plasma oxalate (POx).

Methods

ILLUMINATE-A (NCT03681184) is a phase III trial in patients aged ≥6 years with PH1 and estimated glomerular filtration rate (eGFR) ≥30 ml/min per 1.73 m2. A 6-month double-blind placebo-controlled period is followed by an extension period (≤54 months; all patients receive lumasiran). We report interim data through month 36.

Results

Of 39 patients enrolled, 24 of 26 (lumasiran/lumasiran group) and 13 of 13 (placebo/lumasiran group) entered and continue in the extension period. At month 36, in the lumasiran/lumasiran group (36 months of lumasiran treatment) and placebo/lumasiran group (30 months of lumasiran treatment), mean 24-hour urinary oxalate (UOx) reductions from baseline were 63% and 58%, respectively; 76% and 92% of patients reached a 24-hour UOx excretion ≤1.5× the upper limit of normal (ULN). eGFR remained stable. Kidney stone event rates decreased from 2.31 (95% confidence interval: 1.88-2.84) per person-year (PY) during the 12 months before consent to 0.60 (0.46-0.77) per PY during lumasiran treatment. Medullary nephrocalcinosis generally remained stable or improved; approximately one-third of patients (both groups) improved to complete resolution. The most common lumasiran-related adverse events (AEs) were mild, transient injection-site reactions.

Conclusion

In patients with PH1, longer-term lumasiran treatment led to sustained reduction in UOx excretion, with an acceptable safety profile and encouraging clinical outcomes.See for Video Abstract.

The protective effect of caffeine against oxalate-induced epithelial-mesenchymal transition in renal tubular cells via mitochondrial preservation

Mitochondrial dysfunction is one of the key mechanisms for developing chronic kidney disease (CKD). Hyperoxaluria and nephrolithiasis are also associated with mitochondrial dysfunction. Increasing evidence has shown that caffeine, the main bioactive compound in coffee, exerts both anti-fibrotic and anti-lithogenic properties but with unclear mechanisms. Herein, we address the protective effect of caffeine against mitochondrial dysfunction during oxalate-induced epithelial-mesenchymal transition (EMT) in renal cells. Analyses revealed that oxalate successfully induced EMT in MDCK renal cells as evidenced by the increased expression of several EMT-related genes (i.e., Snai1, Fn1 and Acta2). Oxalate also suppressed cellular metabolic activity and intracellular ATP level, but increased reactive oxygen species (ROS). Additionally, oxalate reduced abundance of active mitochondria and induced mitochondrial fragmentation (fission). Furthermore, oxalate decreased mitochondrial biogenesis and content as evidenced by decreased expression of sirtuin-1 (SIRT1), peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), cytochrome c oxidase subunit 4 (COX4), and total mitochondrial proteins. Nonetheless, these oxalate-induced deteriorations in MDCK cells and their mitochondria were successfully hampered by caffeine. Knockdown of Snai1 gene by small interfering RNA (siRNA) completely abolished the effects of oxalate on suppression of cellular metabolic activity, intracellular ATP and abundance of active mitochondria, indicating that these oxalate-induced renal cell deteriorations were mediated through the Snai1 EMT-related gene. These data, at least in part, unveil the anti-fibrotic mechanism of caffeine during oxalate-induced EMT in renal cells by preserving mitochondrial biogenesis and function.

Primary Hyperoxaluria Type 1: Clinical, Paraclinical, and Evolutionary Aspects in Adults from One Nephrology Center

Introduction

Primary hyperoxaluria type 1 (PH1) is a rare and inherited condition of urolithiasis. The aim of our study was to analyze clinical, paraclinical, and evolutionary aspects of PH1 in adult patients in our Nephrology department.

Methods

We conducted a retrospective single-center study between 1990 and 2021. We collected patients followed for PH1 confirmed by genetic study and/or histopathological features of renal biopsy and morphoconstitutional analysis of the calculi.

Results

There were 25 patients with a gender ratio of 1.78. The median age at onset of symptoms was 18 years. A delay in diagnosis more than 10 years was noted in 13 cases. The genetic study found the I244T mutation in 17 cases and 33-34 InsC in 4 cases. A kidney biopsy was performed in 5 cases, on a native kidney in 4 cases and on a graft biopsy in one case. The analysis of calculi was done in 10 cases showing type Ic in 2 cases. After a median follow-up of 13 years (1 year-42 years), 14 patients progressed to end-stage chronic renal failure (ESRD). The univariate study demonstrated a remarkable association with progression to ESRD in our population (44% vs. 56%) RR = 13.32 (adjusted ORs (95% CI): 2.82-62.79) (p < 0.01).

Conclusion

Progression to ESRD was frequent in our series. Early diagnosis and adequate management can delay such an evolution.