Repeated intravenous infusion of human apolipoprotein(a) kringle V is associated with reversible dose-dependent acute tubulointerstitial nephritis without affecting glomerular filtration function.

Because anti-angiogenic agents have shown various toxicities in clinical applications, the determination of their toxicities and their reversibility is important in the design of clinical trials. This study was performed to investigate the potential toxicities of an angiogenesis inhibitor, apolipoprotein(a) (Apo(a)) kringle V (rhLK8) in rats. Rats administered an intravenous (IV) bolus injection of rhLK8 (200 mg/kg) for 7 days showed significant increases in serum blood urea nitrogen (BUN), creatinine and the BUN/creatinine ratio, which was compatible with acute tubulointerstitial nephritis (TIN) in pathological examination. Because anti-angiogenic therapies are usually based on long-term treatment strategies, rats were administered 200 mg/kg/day of rhLK8 by intravenous infusion for 28 days. Rats receiving 200 mg/kg of rhLK8 showed abnormal serological and histologic findings, but their levels returned to within normal ranges 2 weeks after the cessation of administration. The creatinine clearance rate (CCr) was not affected by rhLK8 treatment. Collectively, our data indicate that the intravenous infusion of rhLK8 at therapeutic doses may induce renal toxicities, such as acute TIN, but these toxicities are clinically tolerable and reversible with close monitoring and a recovery period.

Inhibition of pathologic retinal neovascularization by a small peptide derived from human apolipoprotein(a).

PURPOSE: To evaluate the effect of KV11, a novel 11-mer peptide from human apolipoprotein(a), against retinal neovascularization and to study its penetration and the possible toxicity to the retina. METHODS: Wound-healing, a modified Boyden chamber, and MTS assays were used to evaluate the effect of KV11 on the migration and proliferation of bovine retinal capillary endothelial cells (BRCECs) induced by vascular endothelial growth factor (VEGF) in vitro. The antiangiogenic effect of KV11 was also studied with a mouse model of oxygen-induced retinopathy. Then, FITC-labeled KV11 was injected into the vitreous of normal rabbits, the retinal penetration was determined by confocal laser-scanning microscope, and further confirmed by UPLC/MS analysis of KV11 in tissue extracts. Electrophysiological tests and histologic examinations were used to study the possible toxicity of KV11 against rabbit neuroretina after intravitreal administration. RESULTS: KV11 inhibited VEGF-induced BRCEC migration but not proliferation and reduced the pathologic neovascularization in a mouse model, without affecting normal retinal vasculature. FITC-labeled KV11 appeared in the retina within 30 minutes after injection and diffused to all layers 3 hours later. The transfer of KV11 from the vitreous to the retina was confirmed by UPLC/MS data. Electrophysiologic tests and histologic examinations revealed no evident functional or morphologic abnormalities in rabbit neuroretina after KV11 injection. CONCLUSIONS: It is concluded that the novel peptide KV11 is an effective inhibitor of retinal pathologic angiogenesis with a sufficient retinal penetration and a favorable safety profile and may provide a promising alternative for ocular antiangiogenic therapy.

Reconstitution of the trypanolytic factor from components of a subspecies of human high-density lipoproteins.

Trypanosoma brucei brucei is non-infectious to man due to the sensitivity of these parasites to the lytic activity of normal human serum. Apolipoproteins (apo) have been purified, under non-denaturing conditions, from the subclass of human high-density lipoprotein (HDL), termed trypanosome lytic factor (TLF), which is responsible for the cytotoxicity of human serum to T. b. brucei. The TLF apolipoproteins were purified by anion exchange chromatography in the presence of the nonionic detergent octylglucoside and a reconstitution method was developed which allowed the role of the individual apolipoproteins and different lipids to be assessed. The results suggest that the TLF lipids do not have a direct role in lysis but are necessary for the correct assembly of the lytic HDL particle. Apo A-I, apo L-III and apo L-I contribute to lysis in reconstituted particles but individually they are not cytotoxic. Apo A-II was not required in the reconstituted TLF particle for trypanosome lysis. Formation of a lytic HDL particle required apo L-III suggesting its potential role as a toxin. Thermal inactivation of TLF activity correlated with the amount of denatured apo L-I, indicating that apo L-I was involved in lysis of T. b. brucei by native TLF.