Cancer treatments are known to have several side effects in patients, such as fatigue, nausea, and hair loss. Now, a study suggests that stem cell transplants may induce the premature aging of certain immune system cells.
The study, “Chemotherapy and Stem Cell Transplantation Increase p16INK4a Expression, a Biomarker of T-cell Aging,” was conducted by Dr. William Wood, MD, and his colleagues from the Lineberger Comprehensive Cancer Center at the University of North Carolina, and published in the journal EBioMedicine.
The objective of the study was to investigate the levels of an aging-related marker, the p16 mRNA (the code that cells use to produce proteins), in 63 myeloma, lymphoma, or leukemia patients after transplant procedures using the stem cells from the patient or stem cells received from a donor. Blood samples were collected from these patients to observe the levels of p16 mRNA in the T-cells (immune cells).
In healthy subjects, the levels of p16 increase in T-cells as people age. However, the researchers observed that in both groups of transplant patients, the levels of p16 mRNA were increased, especially in patients who had been treated with their own stem cells, in which the p16 mRNA was three times more concentrated than before the transplant.
Specifically, the study indicated that this increase in the mRNA levels of p16 was equivalent to 30 years of chronological age – even greater than the impact of chemotherapy, which has been observed to induce an increase in the p16 mRNA expression comparable to 10 years of chronological age.
The authors believe that transplants using stem cells from the patient (autologous stem cell transplant) forced the regeneration of the bone marrow, causing the immune cells to age faster. Also, given that many patients are submitted to chemotherapy before a transplant, the total amount of p16 mRNA may be equivalent to recipients’ cells aging twice.
“We know that transplant is life-prolonging, and in many cases, it’s life-saving, for many patients with blood cancers and other disorders,” Wood said in a news release. “At the same time, we’re increasingly recognizing that survivors of transplant are at risk for long-term health problems, and so there is interest in determining what markers may exist to help predict risk for long-term health problems, or even in helping choose which patients are best candidates for transplantation.”
Because age in years is not always a reliable health indicator, it is important to measure cell aging in a more molecular and functional way. And although p16 mRNA levels may be analyzed as a marker for cell aging, it is important to understand the exact association between increases in the p16 mRNA levels and age-related deterioration of the T-cells.
The authors note that stem cell transplants are an important option in the treatment of blood cancer and hope that future studies help to determine whether the evaluation of the p16 mRNA levels can serve as a solid indicator in the assessment of the risks and benefits associated with this type of treatment.