Dog-specific hemorrhagic changes induced by liposomal formulations, in the liver and the gallbladder.

Although several liposomal drugs, including liposomal doxorubicin, have been approved, the etiology of the pathological responses caused by their physicochemical properties remains unknown. Herein, we investigated the pathological changes in the liver and the gallbladder of dogs following a single injection of liposomal doxorubicin (1 or 2.5 mg/kg) or an empty liposomal formulation (i.e., liposomal formulation without doxorubicin, ca. 21 mg/kg as lipid content). Injection of liposomal doxorubicin or the empty liposomal formulation induced hemorrhagic changes in the liver and the gallbladder. These changes were accompanied by minimal cellular infiltration with no obvious changes in the blood vessels. As there were no differences in the incidence and severity of hemorrhage between the groups administered comparable amounts of total lipid, the physicochemical properties of the liposomal formulation rather than an active pharmacological ingredient, doxorubicin, were associated with the hemorrhagic changes. Furthermore, decreased cytoplasmic granules with low electron density in mast cells beneath the endothelium of the hepatic vein were observed in the liver of dogs treated with liposomal doxorubicin or empty liposomal formulation. Injection of compound 48/80, a histamine releaser induced comparable hemorrhage in dogs, implying that hemorrhage caused by injection of liposomal doxorubicin or the empty liposomal formulation could be attributed to the histamine released from mast cells. The absence of similar hemorrhagic lesions in other species commonly used in toxicology studies (i.e., rats and monkeys), as well as humans, is due to the lack of mast cells beneath the endothelium of the hepatic vein in these species.

[Clinical study of the combination of small amount of nedaplatin (CDGP)/5-FU with radiation for the treatment of esophageal cancer].

Recently chemoradiotherapy for esophageal cancer has been drawing public attention to the issue of quality of life maintenance for patients. Although the standard method of chemoradiotherapy is CDDP/5FU, it has been claimed that CDGP (a derivative of CDDP) alone is more effective than CDDP for the treatment of esophageal cancer due to its low nephro- and digestive toxicity. We used a small amount of CDGP/5-FU in combination with radiation instead of CDDP, for the treatment of esophageal cancer and performed clinical examination of patients. The partial response rate was 80% and the complete response rate was 50%. Major side-effects were leukopenia, neutropenia, thrombocytopenia and anemia. Further study of dosage and schedule is necessary, however, CDGP/5-FU combined with radiation therapy could be used as choices of chemoradiotherapy for esophageal cancer in the future.