Effect on bone anabolic markers of daily cheese intake with and without vitamin K2: a randomised clinical trial

Background

Daily intake of 57 g Jarlsberg cheese has been shown to increase the total serum osteocalcin (tOC). Is this a general cheese effect or specific for Jarlsberg containing vitamin K₂ and 1,4-dihydroxy-2naphtoic acid (DHNA)?

Methods

66 healthy female volunteers (HV) were recruited. By skewed randomisation (3:2), 41 HV were allocated to daily intake of 57 g Jarlsberg (J-group) and 25-50 g Camembert (C-group) in 6 weeks. After 6 weeks the C-group was switched to Jarlsberg. The study duration was 12 weeks with clinical investigations every 6 weeks. The main variables were procollagen type 1 N-terminal propeptide (PINP), tOC, carboxylated osteocalcin (cOC) and the osteocalcin ratio (R_O) defined as the ratio between cOC and undercarboxylated osteocalcin (ucOC). Serum cross-linked C-telopeptide type I collagen (CTX), vitamin K₂, lipids and clinical chemistry were used as secondary variables.

Results

PINP, tOC, cOC, R_O and vitamin K₂ increased significantly (p<0.01) after 6 weeks in the J-group. PINP remained unchanged in the C-group. The other variables decreased slightly in the C-group but increased significantly (p≤0.05) after switching to Jarlsberg. No CTX-changes detected in neither of the groups.Serum lipids increased slightly in both groups. Switching to Jarlsberg, total cholesterol and low-density lipoprotein-cholesterol were significantly reduced (p≤0.05). Glycated haemoglobin (HbA1c), Ca⁺⁺ and Mg⁺⁺ were significantly reduced in the J-group, but unchanged in the C-group. Switching to Jarlsberg, HbA1c and Ca⁺⁺ decreased significantly.

Conclusion

The effect of daily Jarlsberg intake on increased s-osteocalcin level is not a general cheese effect. Jarlsberg contain vitamin K₂ and DHNA which increases PINP, tOC, cOC and R_O and decreases Ca⁺⁺, Mg⁺⁺ and HbA1c. These effects reflect increased bone anabolism and a possible reduced risk of adverse metabolic outcomes.

Trial registration number

NCT04189796.

Refined experimental design may increase the value of murine models for estimation of bluetongue virus virulence

Bluetongue is a serious non-contagious vector-borne viral disease in ruminants, causing poor animal welfare and economic consequences globally. Concern has been raised about the development of novel bluetongue virus (BTV) strains and their possibly altered virulence through the process of viral reassortment. Virulence is traditionally estimated in lethal dose 50 (LD₅₀) studies in murine models, but agreement with both in vitro and virulence in ruminants is questionable, and a refined experimental design is needed. Specific reassortants between wild-type and vaccine strains of BTV-1, -6 and -8 have previously been developed by reverse genetics. The aim of the present study was to rank the in vivo virulence of these parental and reassortant BTV strains by calculating LD₅₀ in a murine model by using an experimental design that is new to virology: a between-patient optimised three-level response surface pathway design. The inoculation procedure was intracranial. Fifteen suckling mice were used to establish LD₅₀ for each strain. Three parental and five reassortant virus strains were included. The LD₅₀s varied from of 0.1 (95% confidence interval (CI) 0-0.20) to 3.3 (95% CI 2.96-3.72) tissue culture infectious dose 50/ml. The results support the hypothesis that reassortment in BTV may lead to increased virulence in mice with potential negative consequences for the natural ruminant host. The ranking showed low agreement with in vitro properties and virulence in ruminants according to existing literature. Refined design such as response surface pathway design was found suitable for use in virology, and it introduces significant ethical and scientific improvements.