FAQ

Frequently Asked Questions

If your question is not answered on this page, please do not hesitate to e-mail us with your question.

Intraperitoneal & intravenous injection: The difference:

• (#26) What about the administration route for depletion of spleen and liver macrophages
  Intravenously injected clodronate liposomes induce depletion of macrophages in spleen and liver within 24 hours (see useful references in website).
  Intraperitoneally injected liposomes take more time before a substantial depletion is reached in liver and spleen, but contrary to intravenous injection, by this route peritoneal macrophages are also depleted
  Liposomes have to be carried from the peritoneal cavity to the circulation by the lymph flow, which is - contrary to the blood flow - a passive form of transport. The implication is that intraperitoneally administered liposomes reach the spleen and the liver after a longer time than intravenously injected liposomes. Also they are arriving more gradually and over a longer period of time.
  Reference: Biewenga,J., Van der Ende,.B., Krist,L.F.G., Borst,A., Ghufron,M. and Van Rooijen,N. 1995. Macrophage depletion and repopulation in the rat after i.p.administration of Cl2MBP- liposomes: Depletion kinetics and accelerated repopulation of peritoneal and omental macrophages by administration of Freund’s adjuvant. Cell Tissue Res. 280; 189-196.
  In mice e.g.: Fraser,C.C., Chen,B.P., Webb,S., Van Rooijen,N. & Kraal,G. 1995. Circulation of human hemopoietic cells in Severe Combined Immunodeficient mice following Cl2MDP-liposome mediated macrophage depletion. Blood, 86; 183-192.
  In general, ca 0.1 ml of the suspension of clodronate liposomes per 10 gram of animal tissue should be injected for depletion of splenic macrophages. For depletion of liver macrophages (Kupffer cells) half of that dose may be used.
  In case of intraperitoneal injection with the intention to deplete splenic and liver macrophages a first injection on day 0 may be followed by a second injection on day 3 (see e.g. Biewenga et al. 1995)



• (#32) What about the difference between intravenous & intraperitoneal administration?
  The complicated answer is as follows:
  *Intravenous injection via the caudal vein depletes macrophages from spleen, liver and bone marrow within 24 hours, since the clodronate liposomes are immediately distributed via the circulation and will arrive in these organs within minutes. Dependent on the subset of macrophages, they will remain depleted for ca. 5 days. After that time new macrophages will replace the depleted ones, since precursors will be formed in the bone marrow, released in the circulation and arrive at their destination where they finally differentiate to mature macrophages. This applies to e.g. Kupffer cells in the liver and red pulp macrophages in the spleen.
  Marginal metallophilic macrophages and marginal zone macrophages in the spleen take more time for their repopulation. See e.g. Van Rooijen, N., Kors, N., Kraal, G. 1989. Macrophage subset repopulation in the spleen: Differential kinetics after liposome- mediated elimination. J. Leuk. Biol. 45, 97-104.
  *Intraperitoneal injection will deplete macrophages in the peritoneal cavity. From there liposomes will be carried to the blood circulation by the lymph flow and finally deplete macrophages in spleen and liver.
  Since the lymph flow is a passive process (in contrast with the active blood circulation) it may last ca. 3 days before depletion in spleen and liver would be complete. Moreover a second injection was given after these 3 days to complete depletion in spleen and liver. A good reference hereabout is: Fraser,C.C., Chen,B.P., Webb,S., Van Rooijen,N. & Kraal,G. 1995. Circulation of human hemopoietic cells in Severe Combined Immunodeficient mice following Cl2MDP-liposome mediated macrophage depletion. Blood, 86; 183-192.
  In the latter reference it is recommended to repeat the intraperitoneal injection every 5 days with a lower dose (ca. 25% of the initial dose of 0.1 ml of the suspension of clodronate liposomes per 10 grams of body weight).