Assessing How the Body Responds to Increased Phosphate Intake, and How This Response Depends on Age and Sex.

University of Zurich (UZH)

Status: Not yet enrolling

Conditions: Aging; Mineral Metabolism; Kidney Disease

Treatments: Other: Oral phosphate load

Study type: Interventional

Funder types: Other

Identifiers

NCT07149337

2024-02538

Details and patient eligibility

About

Kidney function declines with age and this could affect phosphate balance after an acute phosphate load (increased phosphate intake). In daily life, we regularly experience acute phosphate loads through our diet.

The aim of this clinical study is to determine whether the body's response to increased phosphate intake changes with age and whether there are sex differences in this response.

Full description

Forty subjects (males and females aged 18-25 or 63-70) will ingest an oral phosphate load, after which their body's response will be assessed by collecting blood and urine samples over a period of ten hours.

Enrollment: 40 estimated patients

Sex: All

Ages: 25 to 70 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Healthy volunteers 18-25 and 63-70 years old
• 18.5 ≥ BMI < 26 kg/m2
• 0.84 ≥ phosphate in plasma ≤ 1.45 mM
• 2.20 ≥ calcium in plasma ≤ 2.50 mM
• 15 ≥ PTH in plasma ≤ 65 pg/ml
• eGFR ≥ 60 ml/min/1-73 m2
• 90 ≥ Systolic blood pressure ≤ 140 mmHg
• 60 ≥ Diastolic blood pressure ≤ 85 mmHg
• No hematuria and no acute urinary tract infection
• Ability and willingness to participate in the study
• Voluntary signed inform consent

Exclusion criteria

• Diabetes mellitus
• Pregnancy
• History of kidney stones
• History of parathyroidectomy
• History of anorexia nervosa
• History of bulimia
• History of solid organ transplantation.
• Nephrolithiasis
• Sarcoidosis
• Chronic pancreatitis
• Chronic diarrhea
• Chronic liver disease
• Complete distal renal acidosis (dRTA)
• Cystinuria
• Hypo- or hyperaldosteronism
• Hyper- or hypotension
• Hypernatremia
• Gastrointestinal disorders
• Known hypersensitivity reactions to azoic dyes, acetylsalicylic acid, as well as antirheumatic drugs and painkillers (prostaglandin synthesis inhibitors).

Intake of vitamin D and calcium supplements, phosphate, bisphosphonates, cinacalcet, denusomab, teriparatide, systemic glucocorticoids or mineralcorticoids, antiepileptics, carboanydrase inhibitors or diuretics

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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40 participants in 1 patient group

Oral phosphate load

Experimental group

Description:

Participants will eat a standard phosphate dinner. The next morning, after consuming a standard phosphate breakfast, they will ingest a phosphate load (558 mg phosphorus) and provide blood and urine samples for nine hours.

Treatment:

Other: Oral phosphate load