The association of low birthweight and prematurity on outcomes in children and adults with nephrotic syndrome-a NEPTUNE cohort study

Preterm birth increases susceptibility to hyperglycemia induced glomerular alterations in male mice

Diabetic kidney disease (DKD) is the leading cause of progressive chronic kidney disease in adults in the United States. However, the impact of preterm birth on the progression of DKD has not been studied. The goal of this project was to determine the effect of preterm birth on kidney health after exposure to hyperglycemia. CD-1 pups born preterm (19 days post conception (dpc)) and term (20 dpc) were studied, and outcomes of the male mice were reported. Preterm and term mice were treated with streptozotocin at six weeks to induce hyperglycemia. Body weight and blood sugar were monitored. Histologic, molecular, and imaging techniques were used to characterize the mice at 18 weeks. The preterm mice with diabetes had a lower podocyte density, lower proximal tubular fraction, and more atubular glomeruli compared to the term mice without diabetes. The preterm mice with diabetes also had a lower podocyte density and lower renin expression compared to term mice with diabetes. Based on single-cell RNA sequencing, the preterm mice with diabetes had increased expression of genes related to the angiogenesis migration pathway-related in endothelial cells and increased expression of genes in the actin adhesion pathway in podocytes compared to term mice with diabetes. Furthermore, the preterm mice with diabetes exhibited a weaker endothelial cell-podocyte interaction compared to term mice with diabetes. These data suggest that preterm birth increases susceptibility to glomerular and tubular damage after a brief "second hit" of hyperglycemia. In conclusion, preterm birth disrupts endothelial-podocyte crosstalk and increases susceptibility to kidney injury induced by hyperglycemia.

Proteinuria as an End Point in Clinical Trials of Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is a characteristic histopathological lesion that is indicative of underlying glomerular dysfunction. It is not a single disease entity but rather a heterogeneous disorder that is an important cause of nephrotic syndrome and kidney failure in children and adults. The aim of this Kidney Health Initiative project was to evaluate potential end points for clinical trials in FSGS. Our focus is on the data supporting proteinuria as a surrogate end point. Available data support the use of complete remission of proteinuria in patients with heavy proteinuria as a surrogate end point for progression to kidney failure. Substantial treatment effects on proteinuria that are short of a complete remission may also predict the effect of a treatment on progression to kidney failure, but further work is needed to determine how such an end point should be defined. Fortunately, efforts are underway to bring together patient-level data from randomized controlled trials, observational studies, and registries to address this issue.

Association of Preterm Birth with Adverse Glomerular Disease Outcomes in Children and Adults

Key Points

Preterm birth was a risk factor for adverse outcomes in this heterogeneous cohort of children and adults with glomerular disease. In analyses adjusted for diagnosis and apolipoprotein L1 risk status, there was less remission and faster progression of kidney disease in those born preterm. A novel finding from this study is that adults born preterm were more likely to have an apolipoprotein L1 high-risk genotype.

Background

While some studies of children with nephrotic syndrome have demonstrated worse outcomes in those born preterm compared with term, little data exist on associations of preterm birth with outcomes in adult-onset glomerular disease. Cardiovascular outcomes in those born preterm with glomerular disease are unknown.

Methods

We performed a cross-sectional and longitudinal analysis of participants in the Cure Glomerulonephropathy cohort. Preterm (<37 weeks' gestation) was compared with term (≥37 weeks' gestation). A survival analysis and adjusted Cox proportional hazards model were used to examine a composite outcome of 40% decline in eGFR or progression to kidney failure. An adjusted logistic regression model was used to examine remission of proteinuria.

Results

There were 2205 term and 235 preterm participants. Apolipoprotein L1 (APOL1 ) risk alleles were more common in those born preterm. More pediatric than adult participants in Cure Glomerulonephropathy were born preterm: 12.8% versus 7.69% (P < 0.001). Adults born preterm compared with term had a higher prevalence of FSGS (35% versus 25%, P = 0.01) and APOL1 high-risk genotype (9.4% versus 4.2%, P = 0.01). Participants born preterm had a shorter time interval to a 40% eGFR decline/kidney failure after biopsy (P = 0.001). In adjusted analysis, preterm participants were 28% more likely to develop 40% eGFR decline/kidney failure (hazard ratio: 1.28 [1.07 to 1.54], P = 0.008) and 38% less likely to attain complete remission of proteinuria (odds ratio: 0.62 [0.45 to 0.87], P = 0.006). There was no significant difference in cardiovascular events.

Conclusions

Preterm birth was a risk factor for adverse outcomes in this heterogeneous cohort of children and adults with glomerular disease. Adults born preterm were more likely to have an APOL1 high-risk genotype and FSGS. In analyses adjusted for FSGS and APOL1 risk status, there was less remission and faster progression of kidney disease in those born preterm.