Effect of TPN on bone marrow kinetics--therapeutic implications

Stimulation of tumor and host tissue proliferation occurs with nutritional support of the tumor-bearing host. This study was performed to determine the effect of parenteral nutrition on bone marrow cytokinetics in tumor-bearing animals. Forty-three Lewis/Wistar rats with subcutaneous mammary tumor implants (AC-33) were protein-depleted for 8 days, underwent superior vena cava cannulation and were randomized to receive intravenous saline or total parenteral nutrition (TPN). Animals receiving TPN were sacrificed after 2, 6, 12, 24, and 48 hr and bone marrow cells were harvested for cell cycle analysis by flow cytometry. Compared to control animals, a significant increase in bone marrow cells in S (DNA synthetic) phase was demonstrated after 24 hr of TPN. The ratio of sensitive/resistant bone marrow cells to chemotherapy specific for cells actively synthesizing DNA was increased after 24 hr of TPN. This alteration in bone marrow cytokinetics was transient and distinct from the previously documented stimulation of tumor growth kinetics. The potential therapeutic implications of differentially stimulating host tissue and tumor growth kinetics with TPN are discussed.