Unveiling mechanisms underlying kidney function changes during sex hormone therapy

Abstract

BACKGROUNDMen with chronic kidney disease (CKD) experience faster kidney function decline than women. Studies in individuals undergoing sex hormone therapy suggest a role for sex hormones, as estimated glomerular filtration rate (eGFR) increases with feminizing therapy and decreases with masculinizing therapy. However, effects on measured GFR (mGFR), glomerular and tubular function, and involved molecular mechanisms remain unexplored.METHODSThis prospective, observational study included individuals initiating feminizing (estradiol and antiandrogens; n = 23) or masculinizing (testosterone; n = 21) therapy. Baseline and 3-month assessments included mGFR (iohexol clearance), kidney perfusion (para-aminohippuric acid clearance), tubular injury biomarkers, and plasma proteomics.RESULTSDuring feminizing therapy, mGFR and kidney perfusion increased (+3.6% and +9.1%, respectively; P < 0.05) without increased glomerular pressure. Tubular injury biomarkers, including urine neutrophil gelatinase-associated lipocalin, epidermal growth factor (EGF), monocyte chemoattractant protein-1, and chitinase 3-like protein 1 (YKL-40), decreased significantly (-53%, -42%, -45%, and -58%, respectively). During masculinizing therapy, mGFR and kidney perfusion remained unchanged, but urine YKL-40 and plasma tumor necrosis factor receptor 1 (TNFR-1) increased (+134% and +8%, respectively; P < 0.05). Proteomic analysis revealed differential expression of 49 proteins during feminizing and 356 proteins during masculinizing therapy. Many kidney-protective proteins were positively associated with estradiol and negatively associated with testosterone, including proteins involved in endothelial function (SFRP4, SOD3), inflammation reduction (TSG-6), and maintaining kidney tissue structure (agrin).CONCLUSIONSex hormones influence kidney physiology, with estradiol showing protective effects on glomerular and tubular function, while testosterone predominantly exerts opposing effects. These findings emphasize the role of sex hormones in sexual dimorphism observed in kidney function and physiology and suggest new approaches for sex-specific precision medicine.TRIAL REGISTRATIONDutch Trial Register (ID: NL9517); ClinicalTrials.gov (ID: NCT04482920).

Keywords: Chronic kidney disease; Endocrinology; Nephrology; Sex hormones.

Figure 1. Median with IQR of serum estradiol and serum testosterone before and during 3 months of feminizing and masculinizing hormone therapy.

(A) Total serum estradiol (pmol/L) and (B) total serum testosterone (nmol/L) before and during 3 months of feminizing (n = 23) and masculinizing (n = 21) hormone therapy. The differences between baseline and 3-month values were evaluated using Wilcoxon’s signed-rank test due to nonnormal distribution of the data. One participant had an unusually high serum testosterone concentration (125 nmol/L) during the 3-month study visit, despite reportedly receiving only 40.5 mg of transdermal testosterone per day, possibly due to external contamination of the gel. Consequently, this testosterone measurement was excluded from all subsequent analyses. ***P < 0.001.

Figure 2. mGFR and intrakidney hemodynamic function before and during 3 months of feminizing and masculinizing therapy with percentage changes.

(A) mGRF (ml/min per 1.72 m²). (B) ERPF (ml/min per 1.72 m²). (C) FF (%). (D) RBF (ml/min per 1.72 m²). (E) RVR (mmHg/L/min). (F) P_GLO (mmHg). (G) R_A (dyne x s x cm^–5). (H) R_E (dyne x s x cm^–5). (I) R_A/R_E. Data were collected from 23 individuals receiving feminizing hormone therapy and 21 individuals receiving masculinizing hormone therapy. Data are presented as median (IQR). y axis is in linear scale. *P < 0.05. Percentage changes for P_GLO, R_A, and R_A/R_E, during feminizing hormone therapy were adjusted for Δ total protein. For percentage change, variables were log transformed, and linear mixed models were applied to the log-transformed data, clustering measurements within participants. The resulting ratios, along with 95% confidence intervals, were back transformed and presented as percentage changes for comparison between baseline and 3-month measurements.

Figure 3. Heatmap with correlations between Δ serum estradiol and serum testosterone and Δ mGFR, ERPF and intra-kidney hemodynamic parameters.

Using Spearman rank’s correlation coefficient (ρ), considering masculinizing and feminizing hormone therapy together as 1 group (n = 43 for correlations with serum estradiol and n = 42 for correlations with serum testosterone). *P < 0.05. mGFR (mL/min per 1.73 m²); ERPF (mL/min per 1.73 m²); FF (%); RBF (mL/min per 1.73 m²); RVR (mmHg/L/min; corrected for BSA); P_GLO (mmHg); R_A (dyne × s × cm^-5); R_E (dyne × s × cm^-5).

Figure 4. Tubular injury biomarkers before and during 3 months of feminizing and masculinizing therapy with the percentage changes.

Urinary tubular injury biomarkers were collected from 21 individuals receiving feminizing hormone therapy, while plasma tubular injury biomarkers were collected from 23 individuals receiving feminizing hormone therapy. In the masculinizing hormone therapy group, urinary NGAL and YKL-40 were collected from 18 individuals, whereas other urinary tubular injury biomarkers were collected from 19 individuals. Plasma tubular injury biomarkers were obtained from 20 individuals receiving masculinizing hormone therapy. Data are presented as median (IQR). For urine tubular injury biomarkers (A–F), the y axis is in log scale, and for plasma tubular injury biomarkers (G and H), the y axis is in linear scale. Percentage changes were adjusted for Δ mGFR. For percentage change, variables were log transformed, and linear mixed models were applied to the log-transformed data, clustering measurements within participants. The resulting ratios, along with 95% confidence intervals, were back transformed and presented as percentage changes for comparison between baseline and 3-month measurements. *P < 0.05; **P < 0.01.

Figure 5. Heatmap with correlations between Δ serum estradiol and serum testosterone and Δ tubular injury biomarkers.

Using Spearman’s rank correlation coefficient (ρ), considering masculinizing and feminizing hormone therapy together as 1 group (n = 39 for NGAL and YKL-40, n = 40 for EGF, UMOD, KIM-1, and MCP-1, and n = 43 for TNFR-1 and TNFR-2 in correlations with serum estradiol; each sample size is reduced by 1 for correlations with serum testosterone). *P < 0.05.

Figure 6. Volcano plot describing the DEPs during feminizing hormone therapy and masculinizing hormone therapy.

Data were collected from 23 individuals receiving feminizing hormone therapy (A) and 20 individuals receiving masculinizing hormone therapy (B). Each dot represents an individual protein, with significantly different proteins highlighted in blue. P values were adjusted to maintain a false discovery rate of 5%. The top 10 proteins in each group are labeled by name. Some duplicates are present due to the use of different aptamers targeting the same or similar proteins.

Figure 7. log fold changes of the identified DEPs that associated with Δ mGFR during feminizing and masculinizing hormone therapy.

Data were collected from 23 individuals receiving feminizing hormone therapy (A) and 20 individuals receiving masculinizing hormone therapy (B). The listed proteins are the DEPs during feminizing or masculinizing hormone therapy, whose changes were associated with Δ mGFR. Refer to Supplemental Figure 2 for a Venn diagram summarizing the identification of these proteins. SPA11, Serpin A11; CLC4C, C-type lectin domain family 4 member C; MXRA8:ECD, matrix-remodeling-associated protein 8:extracellular domain; α1ACT-complex, α-1-antichymotrypsin complex; SPIT3, kunitz-type protease inhibitor 3; FPRP, prostaglandin F2 receptor negative regulator; SCN2B, sodium channel subunit β -2; OAF, out at first protein homolog; ALCAM, CD166 antigen; MDGA1, MAM domain-containing glycosylphosphatidylinositol anchor protein 1; sCD14, monocyte differentiation antigen CD14, soluble; TXD12, thioredoxin domain-containing protein 12; VEGF SR3, vascular endothelial growth factor receptor 3; PIGR, polymeric immunoglobulin receptor; IGF-II:Pro form, insulin-like growth factor II:Pro form.

Figure 8. log fold changes of the identified DEPs that associated with ERPF during feminizing and masculinizing hormone therapy.

Data were collected from 23 individuals receiving feminizing hormone therapy (A) and 20 individuals receiving masculinizing hormone therapy (B). The listed proteins are the DEPs during feminizing or masculinizing hormone therapy, whose changes were associated with Δ ERPF. Refer to Supplemental Figure 2 for a Venn diagram summarizing the identification of these proteins. NMB, neuromedin-B; TR:ECD, transferrin receptor protein 1:extracellular domain; HBD-4, β-defensin 104; CA6, carbonic anhydrase 6; NOE2, noelin-2; MSR:ECD, macrophage scavenger receptor: extracellular domain; RP9, retinitis pigmentosa 9 protein; CA2D3, voltage-dependent calcium channel subunit α-2/δ-3; AGRD1, adhesion G protein–coupled receptor D1; GHC2, mitochondrial glutamate carrier 2; ST1C4, sulfotransferase 1C4; SIM13, small integral membrane protein 13; PRAX, periaxin; GNAS, guanine nucleotide-binding protein G(s) subunit α isoforms; H6ST3, heparan-sulfate 6-O-sulfotransferase 3.