Evaluating the Vitamin K2 Status of Calcium-based Stone Formers

It is hypothesized that calcium-based stone formers will have an altered fecal gut microbiota compared to non-stone former controls. This altered microbiota will have a lower abundance of bacteria that produce menaquinones (vitamin K2), thus stone formers will also have a different blood menaquinone profile compared to controls. Ultimately, the different levels of menaquinones will result in increased inactive Matrix Gla protein (dp-ucMGP), which is a key protein that sequesters free calcium. To test this hypothesis, calcium-based stone former and non-stone forming controls will be recruited to a single site, observation study to collect urine, blood, and fecal samples. These samples will be used to determine dp-ucMGP levels, menaquinone profiles, the composition of the gut microbiota, and other parameters of interest.

Inclusion criteria

• Male/Female, 18 - 65 years old
• No self-reported kidney stones during their lifetime (controls)
• Ultrasound examination confirming absence of kidney stones (controls)
• Have had at least 1 incidence of a clinically confirmed calcium-based kidney stone in the last 12 months (stone formers)
• Ability to collect a clean catch urine sample
• Prescription and over-the-counter drugs unchanged for ≥30 days
• Willingness to provide medical information, blood, urine, and fecal samples

Exclusion criteria

• Current, or within 30 days, use of antibiotics or antifungals
• Current, or within 30 days, use of vitamin K antagonists
• Current probiotic use or any use within 14 days of screening sample collection should be recorded
• A history or currently undergoing immunosuppressive drug therapy, chemotherapy, or radiation therapy 2021-06-29 1.0 Page 4 of 6
• Fecal incontinence
• History of disorder with abnormal calcium regulation such as hyperparathyroidism, active malignancy, or osteoporosis.