Acid excretion is impaired in calcium oxalate stone formers

Silva, P. H. I.; Dhayat, N. A.; Fuster, D. G.; Seeger, H.; Ritter, A.; Ernandez, T.; Buchkremer, F.; Roth, B.; Bonny, O.; Rubio-Aliaga, I.; Wagner, C. A.

doi:10.1101/2024.09.30.615797

bioRxiv · 10.1101/2024.09.30.615797

Acid excretion is impaired in calcium oxalate stone formers

Silva, P. H. I.·Dhayat, N. A.·Fuster, D. G.·Seeger, H.·Ritter, A.·Ernandez, T.·Buchkremer, F.·Roth, B.·Bonny, O.·Rubio-Aliaga, I.·Wagner, C. A.

View original source ↗Export metadata ↓

Abstract

BackgroundUrine pH is a key factor in kidney stone formation. We aimed to identify whether acid excretion capacity is disturbed in calcium oxalate (CaOx) or calcium phosphate (CaP) stone formers. MethodUrinary, serum, clinical, and anthropomorphic baseline data were obtained from the Swiss Kidney Stone Cohort, a prospective, longitudinal, and multi-centric observational study. We included in this study 193 non-stone formers (NSF, confirmed by negative CT scan), and 309 CaOx and 28 CaP stone formers. Titratable acids, net acid excretion (NAE), NAE capacity (NAEC) and acid-base (AB) score were calculated. Logistic regression analyses were used to estimate the potential associations of various acid-base variables with the occurrence of CaOx kidney stones. ResultsCaOx stone formers showed a disturbed capacity to excrete acids in comparison to NSF (NAEC NSF = 3.49{+/-}12.6 mmol/24h; CaOx = -1.06{+/-}13.10; CaP = 0.97{+/-}14.70 and AB score NSF = 20.5{+/-}6.36 mmol/24h; CaOx = 17.9{+/-} 6.53; CaP = 18.8{+/-}6.10). The correlation between urine calcium and urine pH was altered in CaOx stone formers and between urine calcium and NAE was stronger in CaP stone formers. Logistic models showed that urinary ammonium was negatively associated with CaOx stone formation (unadjusted model, odds ratio 0.43[0.32-0.58], p< 0.001 for CaOx). Urine calcium was positively associated with CaOx kidney stones (2.85 [2.11-3.92], p<0.001). Similar results were obtained after adjusting for age, sex, and BMI. Replacing urine ammonium, pH, and phosphate with NAEC or ammonium and pH with AB score in our logistic regression models showed that NAEC and AB score are strongly associated with CaOx kidney stone formation. ConclusionAmmonium excretion, NAEC and AB score are associated with the occurrence of CaOx kidney stones suggesting a potential role of proximal tubule dysfunction in their formation. CaP stone formers exhibit a disproportionately higher calcium excretion when acid excretion increases. Key learning pointsO_ST_ABSWhat was knownC_ST_ABSUrine pH is a strong determinant in the formation of various urologically relevant crystals. Impaired urine acidification capacity has been observed in individuals who form calcium phosphate and uric acid stones. This study addsWhen compared to non-stone formers, calcium oxalate stone formers are marked by a reduced capacity of excreting acids when urine pH becomes more acidic. Potential impactThe calculation of net acid excretion capacity and acid-base score are novel tools to identify those under potential higher risk of developing calcium oxalate stones.

Explore related subjects

physiology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Silva, P. H. I., Dhayat, N. A., Fuster, D. G., Seeger, H., Ritter, A., Ernandez, T., Buchkremer, F., Roth, B., Bonny, O., Rubio-Aliaga, I., Wagner, C. A.. 2024-10-01. Acid excretion is impaired in calcium oxalate stone formers. https://doi.org/10.1101/2024.09.30.615797

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Cholinergic impairment in the dorsal motor nucleus of the vagus during experimental Alzheimer's disease

Cholinergic neurons in the dorsal motor nucleus of the vagus (DMN) in the brainstem are a key source of efferent vagus nerve fibers that regulate vital functions, including heart rate and inflammation. Whether the integrity of DMN cholinergic neurons is affected during Alzheimer's disease (AD) remains unknown. Here, in female and male mice with experimental AD (5xFAD), which exhibit age-dependent memory impairment, basal forebrain cholinergic neurodegeneration, and microglial alterations, we observe a reduction in cholinergic neuron density in the DMN at 6 and 10 months of age. Furthermore, while an important physiological function of DMN cholinergic signaling, such as suppression of heart rate, is preserved in control mice upon electrical DMN stimulation, the extent of suppression diminishes with age in both female and male 5xFAD mice. In addition, while electrical DMN stimulation lowers pro-inflammatory cytokine levels in control mice subjected to endotoxemia, this anti-inflammatory effect is diminished with age in 5xFAD mice, with females showing earlier dysfunction at 6 months. These results reveal previously unrecognized age-dependent cholinergic deficits in the DMN and disrupted brain - to - periphery vagus nerve circuits in experimental AD. These findings advance our understanding of AD mechanisms and are of interest for the development of conceptually novel therapies.

physiology↗

bioRxiv2026

Ketogenic diet is protective during endotoxin-induced lung injury through the elevation of BHB

Acute respiratory distress syndrome (ARDS) is marked by severe pulmonary edema and concomitant hypoxia, affecting hundreds of thousands of people a year, especially those in critical care conditions or suffering from septic shock. Previous studies have implicated that the ketogenic diet, a high-fat and low-carbohydrate diet, modulates inflammatory responses. However, the impact of the ketogenic diet on septic ARDS outcomes is unknown. Here, we demonstrated that mice on a ketogenic diet showed strikingly reduced lung injury and inflammation compared to those on a control diet during a murine model of endotoxin-induced lung injury, induced by intratracheal lipopolysaccharide (LPS) injection. Immune mass cytometry studies on lung tissue indicated that the ketogenic diet reduces immune cell infiltration. Treating mice with beta-hydroxybutyrate (BHB), the primary metabolite of ketogenesis, after the onset of ARDS reduced pulmonary edema and lung inflammation, as well as NF-kB activity, suggesting strong therapeutic potential. By multiplex analysis in bronchial alveolar lavage fluid, we observed that the ketogenic diet or BHB administration attenuates the chemotaxis and activation of immune cells. Altogether, our findings reveal that the ketogenic diet provides lung protection during endotoxin-induced lung injury through BHB.

physiology↗

bioRxiv2026

Efficacy of postmenopausal estrogen replacement in SIV-infected female macaques on antiretroviral therapy.

The success of modern antiretroviral therapy (ART) has increased the life expectancy of people living with HIV to levels approaching that of uninfected individuals. For women living with HIV (WLWH), this means that more will survive to undergo menopause and experience the consequences of decreased ovarian hormone levels, particularly estrogen (E2). The recent change in federal guidance for use of postmenopausal hormone therapy is increasing demand for both E2-alone and E2+progestogen formulations to control adverse symptoms of menopause. The consequences and efficacy of hormone therapy in WLWH are thus an important issue for WLWH and their healthcare providers. The role of E2 replacement in postmenopausal WLWH is a significant issue because of its potential effects on control the viral reservoir and its demonstrated beneficial metabolic effects in uninfected postmenopausal women. To address these questions, we employed a novel nonhuman primate model of postmenopausal WLWH undergoing E2 replacement. Reproductively competent female rhesus macaques were infected with simian immunodeficiency virus (SIV) and then subjected to a daily ART regimen. After complete suppression of plasma viremia, all animals were ovariectomized (OVX) and then implanted with Silastic capsules containing either cholesterol vehicle or sufficient E2 to restore pre-OVX plasma levels. Plasma and cell-associated viral dynamics, immune responses, body composition, systemic and tissue-specific metabolic parameters, cytokine profiles, and parameters of bone health were followed longitudinally from baseline through 34 weeks of E2 deficiency or replacement. We found that E2 status did not significantly affect plasma or tissue viral dynamics or overall metabolic homeostasis. However, E2 replacement exerted beneficial effects on several aspects of bone health in spite of a chronic inflammatory state that persisted following effective ART suppression of the SIV reservoir. Our findings suggest that hormone therapy, specifically E2 replacement, offers benefit to WLWH, particularly with respect to bone loss.

physiology↗