title: High-dose chemotherapy shows a dose-dependent toxicity to bone marrow osteoprogenitors: a mechanism for post-bone marrow transplantation osteopenia.
abstract: BACKGROUND
  Osteoporosis is a sequela of hemopoietic cell transplantation with a complex multifactorial pathogenesis in which the relative role of chemotherapy and irradiation is not completely understood. Therefore, the authors investigated the toxicity of chemotherapy-only conditioning regimens on bone homeostasis and bone marrow osteoprogenitors, its dose dependency, and the mechanism of chemotherapy-induced osteopenia.
  
  
  METHODS
  Fifty-one patients with high-grade non-Hodgkin lymphoma or breast carcinoma who had been treated previously with high-dose + peripheral blood progenitor cell or conventional chemotherapy or who had not received any treatment (prechemotherapy) were enrolled. The authors measured the bone marrow colony-forming unit fibroblast (CFU-f) and long-term culture-initiating cell frequency, forearm bone mineral density, serum osteotropic hormones and metabolic markers of bone formation (plasma osteocalcin), and resorption (urinary collagen I C-crosslinks).
  
  
  RESULTS
  Both high-dose chemotherapy regimens caused a 50% reduction in CFU-f frequency, independently of gonadal function status, whereas conventional chemotherapy and prechemotherapy groups were unaffected. Bone mineral density was measured in 26 non-Hodgkin lymphoma patients and again only high-dose chemotherapy caused a 10% loss in cortical bone and 20% in trabecular bone. No endocrine abnormality was found except for the secondary amenorrhea uniformly induced in the high-dose chemotherapy group. In these patients, plasma osteocalcin unexpectedly failed to increase in response to the menopausal increase in bone resorption rate, showing a selective impairment of the osteoblast compartment to cope with increased functional demand.
  
  
  CONCLUSIONS
  Chemotherapy without irradiation shows a dose-dependent toxicity to bone marrow stromal osteoprogenitors and can cause osteopenia by direct damage of the osteoblastic compartment, as a mechanism distinct from and summable to hypogonadism.
authors.affiliation: Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Banfi
authors.forename: M
authors.initials: M
authors.lastname: Podestà
authors.forename: L
authors.initials: L
authors.lastname: Fazzuoli
authors.forename: M R
authors.initials: MR
authors.lastname: Sertoli
authors.forename: M
authors.initials: M
authors.lastname: Venturini
authors.forename: G
authors.initials: G
authors.lastname: Santini
authors.forename: R
authors.initials: R
authors.lastname: Cancedda
authors.forename: R
authors.initials: R
authors.lastname: Quarto
mesh_terms: D000328:Adult; D000568:Amenorrhea / Q000139:chemically induced; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000009:adverse effects*; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000139:chemically induced* / Q000503:physiopathology; D001854:Bone Marrow Cells / Q000187:drug effects; D016026:Bone Marrow Transplantation; D001943:Breast Neoplasms / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006412:Hematopoietic Stem Cells; D006706:Homeostasis; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000139:chemically induced / Q000503:physiopathology; D019172:Transplantation Conditioning / Q000009:adverse effects*