Reduced mobilisation of hematopoietic stem cells after hepatic resection for malignant liver disease.

Recent studies have demonstrated that hematopoietic stem cells (HSCs) can mobilize following liver resection, thus contributing to the repair of hepatic damage. Aim of this study has been to determine whether the nature of the hepatic lesion (benign vs. malignant disease) can give rise to a different degree of mobilisation of HSCs. Two groups of patients were selected: the first included seven patients undergoing hepatic resection (five major and two minor) for a benign liver disease (focal nodular hyperplasia, hemangioma cavernosa, angioma, biliary adenofibroma) and the second included seven patients undergoing hepatic resection (five major and two minor) for a malignant (either primary or secondary) liver disease. White blood cell count and CD34+ (percentage and total number) at time T(0) (basal value before surgery) and at time T(1) (value on the sixth-eighth day after surgery) have been evaluated by standard methods. In the group undergoing hepatic resection for a benign liver disease, a significant increase of CD34+ cells, both in percentage (0.082 +/- 0.043 vs. 0.048 +/- 0,026, p = 0.041) and in absolute number (8.14 +/- 5.95 vs. 3.26 +/- 2.63, p = 0.018) have been documented, as opposed to the group of patients affected with a malignant liver disease, where no significant variation has been observed (CD34+ %: 0.044 +/- 0.033 vs. 0.041 +/- 0.031, p: n.s.; CD34+ total number: 3.52 +/- 2.56 vs. 2.27 +/- 2.01, p = n.s.) These results show a different bone marrow response to the surgical liver resection depending on the nature of the lesion, thus emphasizing a reduced mobilisation of HSCs in the malignant diseases. Since it has been documented that the type of the hepatic lesion can induce a different regenerative response, it has to be explained how the neoplastic lesions can negatively influence the mobilization of HSCs. It can be hypothesized that a variety of humoral factors, including stromal cell-derived factor, matrix metalloproteinases, hepatocyte growth factor and interleukin-8 can influence the process of mobilization of HSCs after liver resection surgery. These substances are also involved in the mechanisms of development and metastasising of many tumours. It is probably in this context that a reason may be found for the different mobilisation of hematopoietic stem cells, depending on the nature of the hepatic lesion treated, that was encountered in this study.