Vitamin C Partially Restored Lymphoid Balance in the Bone Marrow of Aged Macaques

Vitamin C partially restored lymphoid balance in the bone marrow of aged macaques

On July 16, Cell Stem Cell published a study of aged cynomolgus macaques that received oral vitamin C for 40 months. The pool of lymphocyte progenitors in their bone marrow increased, and two molecular measures of age shifted toward younger values.

Bone marrow continuously produces blood cells. Its stem cells direct their descendants into two lineages. The lymphoid lineage produces B- and T-lymphocytes, which recognize specific threats. The myeloid lineage produces monocytes, macrophages, and other innate immune cells.

With age, common lymphoid progenitors become less abundant, while blood cell production shifts toward the myeloid lineage. This shift begins in the bone marrow, before newly produced immune cells enter the blood and tissues.

In the study, the authors compared bone marrow from aged macaques that received vitamin C with bone marrow from a control group. Single-cell analysis found more common lymphoid progenitors and a more balanced allocation between the two lineages. The tissue age estimated from gene activity was approximately four years younger. Epigenetic clocks, which measure chemical marks on DNA, showed the same shift.

The authors also identified progranulin (GRN) as a possible mediator between vitamin C and the changes in bone marrow. In cultured human cells, recombinant progranulin reproduced some of the molecular changes associated with vitamin C. This protein can now be tested as a specific mechanism involved in age-related changes at the source of immune cell production.