Hypothesis

Intermittent high-dose vitamin K2 (MK-7) pulses preferentially increase the ucOCN/cOCN ratio, thereby attenuating NF‑κB‑driven SSPC senescence and rescuing brain‑bone endocrine signaling in aged humans.

Rationale

• Vitamin K2 is a cofactor for γ‑glutamyl carboxylase, which converts glutamate residues to γ‑carboxyglutamate (Gla) in osteocalcin, determining its carboxylation state 3.
• In rodent models, high ucOCN levels enhance insulin secretion, muscle metabolism, and neuroprotection via GPRC6A and GPR158 2.
• Age‑related systemic inflammation activates NF‑κB in skeletal stem/progenitor cells (SSPCs), driving senescence and suppressing ucOCN production 45.
• Emerging data suggest that vitamin K2 can also inhibit NF‑κB signaling in mesenchymal cells by reducing intracellular ROS, independent of its carboxylase activity (hypothesized from in‑vitro studies of MK‑7 on TNF‑α stimulated fibroblasts).

Mechanistic Insight

We propose that pulsatile, supra‑physiological doses of vitamin K2 create a transient surplus of reduced vitamin K2 (hydroquinone) that:

1. Competes with oxidized vitamin K for the carboxylase active site, momentarily decreasing carboxylation efficiency and favoring synthesis of ucOCN.
2. Scavenges ROS in the bone marrow niche, lowering NF‑κB activation in SSPCs, thereby alleviating senescence‑associated secretory phenotype (SASP) and restoring osteoblast differentiation.
3. The resulting rise in circulating ucOCN amplifies GPRC6A/GPR158 signaling in pancreas, muscle, testes, and brain, improving metabolic homeostasis and neuroprotection.

Testable Predictions

1. Human crossover trial – Older adults (≥65 y) receive either:

   • Arm A: Daily low‑dose MK‑7 (45 µg) for 12 weeks (control).
   • Arm B: Same low‑dose background plus weekly intermittent high‑dose MK‑7 pulses (5 mg) for 12 weeks.
   • Primary outcome: change in plasma ucOCN/cOCN ratio (ELISA) at week 6 and week 12.
   • Secondary outcomes: serum NF‑κB activity (p‑p65 levels in circulating monocytes), SSPC senescence markers (p16^INK4a^, SASP cytokines) in bone marrow aspirates, cognitive composite score, and insulin sensitivity (HOMA-IR).

2. Mechanistic substudy – Ex vivo bone marrow cultures from participants treated with serum from Arm B will show:

   • Reduced NF‑κB nuclear translocation (immunofluorescence) and decreased SA‑β‑gal positivity.
   • Increased osteocalcin secretion and higher ucOCN proportion.

3. Falsification – If intermittent high‑dose vitamin K2 fails to raise the ucOCN/cOCN ratio or does not reduce SSPC senescence markers relative to control, the hypothesis is refuted.

Implications

Confirming this mechanism would define a dosing strategy that uncouples the bone‑mineralizing function of cOCN from the endocrine benefits of ucOCN, offering a translational route to counteract age‑related metabolic decline and cognitive loss via bone‑targeted nutrition.