Randomised clinical trial: a leucine-metformin-sildenafil combination (NS-0200) vs placebo in patients with non-alcoholic fatty liver disease.

BACKGROUND: Sirtuin 1 (Sirt1) is suppressed in non-alcoholic fatty liver disease (NAFLD), while its' stimulation or overexpression results in reduced disease severity in pre-clinical NAFLD models. Leucine allosterically activates Sirt1 and synergise with other Sirt/AMPK/NO pathway activators. We developed a triple combination of leucine, metformin and sildenafil (NS-0200), which was effective in a mouse model of non-alcoholic steatohepatitis (NASH). AIM: To report the results from a Phase 2, randomised clinical trial of of NS-0200 in 91 subjects with NAFLD (liver fat ≥15% by magnetic resonance imaging-proton-density fat fraction (MRI-PDFF)). METHODS: Subjects were randomised to placebo, low-dose (1.1 g leucine/0.5 g metformin/0.5 mg sildenafil) or high-dose NS-0200 (1.1 g leucine/0.5 g metformin/1.0 mg sildenafil) b.d. for 16 weeks; change in hepatic fat was assessed via MRI-PDFF, and lipid metabolism was assessed via changes in the lipidomic signature. Seventy subjects completed the trial and met a priori compliance criteria. Analyses were conducted on the full cohort and on those with alanine aminotransferase (ALT) values above median (50 U/L; n = 35). RESULTS: In the full cohort, active treatments did not separate from placebo. High dose NS-0200 reduced hepatic fat by 15.7% (relative change from baseline) in the high ALT group (P < 0.005) while low dose NS-0200 and placebo did not significantly change hepatic fat. Lipidomic analysis showed dose-responsive treatment effects in both overall and high ALT cohorts, with significant decreases in metabolically active lipids and up-regulation of fatty acid oxidation. CONCLUSION: These data support further evaluation of high-dose NS-0200 for treating NASH, especially in those with elevated ALT (NCT 02546609).

Functional incorporation of P-glycoprotein into Xenopus oocyte plasma membrane fails to elicit a swelling-evoked conductance.

Microinjecton of Xenopus oocytes with P-glycoprotein-containing membranes from multidrug resistant cells following a recently published procedure resulted in the transplantation of the protein to the plasma membrane of the oocytes and was confirmed by Western blot analysis. These oocytes showed a reduced intracellular accumulation of daunomycin, when compared to uninjected oocytes or to those injected with membrane vesicles lacking P-glycoprotein, thus indicating that the protein had been incorporated in a transport-competent form. On the other hand, transplantation of P-glycoprotein to the oocyte membrane did not significantly change either the appearance or the properties of swelling-elicited membrane conductance with respect to those determined in oocytes either uninjected or injected with membranes lacking P-glycoprotein. These results do not support a role for P-glycoprotein as a swelling-activated chloride channel.

Specific serological response by active immunization with GD3-bearing liposomes.

GD3 is the most prominent ganglioside on the surface of human melanoma cells, and therefore it has been considered by several investigators as a potential tool for active immunotherapy of melanoma. The main obstacle to this goal is that GD3 is poorly immunogenic in mice and in humans. Several approaches have been described for increasing the GD3 immunogenicity. Here, the immunogenicity of GD3 ganglioside was investigated by vaccination of Balb/c x C57B1/6 F1 mice with several types of GD3-bearing liposomes. The humoral immune response was analyzed by ELISA and tumor cell recognition. Several liposome formulations were assayed in order to increase the immunogenicity of GD3. We also tested vaccinations with GD3-Salmonella minnesota, Freund's complete adjuvant and Bordetella pertussis antigen. Immunization of mice with sphingomyelin:cholesterol:dicetyl-phosphate:GD3, molar ratio 40:40:10:10, liposomes resulted in good IgM and IgG3 anti-GD3 response, with a maximum titer of 1:1200 and absence of significant cross-reactivity with other gangliosides. In immunofluorescence assays, the antisera induced showed high capacity of recognition of melanoma cells with no reactivity against other tumor cells. The results clearly showed a high positive correlation between liposomes with sphingomyelin and GD3 immunoreactivity. The incorporation of muramyl-dipeptide or Lipid A in the liposome formulation increased the secretion of IgM and IgG as well as the nonspecificity of the response.

Human alpha 1-antitrypsin gene transfer to in vivo mouse hepatocytes.

The in vivo gene transfer to mouse hepatocytes of pTG 7101, a plasmid containing the full-length gene encoding human alpha 1-antitrypsin (alpha 1-AT) DNA, has been studied by iv administration of recombinant DNA (100 ng/mouse) encapsulated in large and small liposomes. Our results from immunohistochemical liver sections and cytophotometric analysis of hepatocyte chromophore absorbance indicate that human alpha 1-AT was expressed in liver parenchymal cells from mice treated (48 hr before) with DNA encapsulated in small liposomes, and this effect remained for at least 2 weeks. In contrast, the efficiency was greatly limited when large liposomes were used as a vehicle for gene transfer. Additional experiments were performed to study using an ELISA procedure the presence in mouse plasma of human alpha 1-AT from mice treated with encapsulated plasmid in small liposomes or small empty liposomes plus free DNA. According to the immunohistochemical data, the results indicate that detectable alpha 1-AT can only be observed in plasma from mice treated with encapsulated plasmid in small liposomes.

Antimetastatic effect of immunization with liposome-encapsulated tumor cell-membrane proteins obtained from experimental tumors.

Immunization of C57BL/6 mice with tumor-derived membrane-proteins encapsulated in sized liposomes (0.2 microgram/mouse) and composed by phosphatidylcholine or sphingomyelin, significantly reduced the mean values of spontaneous lung metastasis from both B16 (0.7 +/- 0.5 and 1.2 +/- 0.6, respectively) and 3LL (4.8 +/- 2.5 and 7.2 +/- 4.1, respectively) tumors, with respect to control (HEPES) groups (4.8 +/- 1.1 and 19.0 +/- 4.4, respectively). However, no significant antimetastatic effect was observed using free tumor-derived proteins (2 micrograms/mouse) or liposome vehicle alone. Specific humoral immune response after the vaccination was studied by flow cytometry of tumor cells incubated with a pooled sample from each group of immunized mice and FITC-conjugate antimouse immunoglobulins. The results showed that the highest number of positive tumor cells was identified using sera from immunized mice with sized liposomes encapsulating tumor-derived proteins whereas the immunization with the protein fraction in free form failed to induce this effect. In addition, an increased cytotoxicity towards 3LL and B16 tumor cells can also be observed when tumor cells were incubated with spleen effector cells plus specific immunosera. In conclusion, our results show that antitumor active vaccination, using sized liposomes as adjuvants, induces an antitumor host response and a significant inhibition of tumor progression.

Expression of human alpha 1-antitrypsin in mouse after in vivo gene transfer to hepatocytes by small liposomes.

A plasmid (pTG7101) containing the full-length human alpha 1-antitrypsin gene was encapsulated in small liposomes and used for "in vivo" gene transfer to mouse hepatocytes, by i.v. injection (100 ng DNA/mouse and dose). The expression of human protein was evaluated by microspectrophotometry after human alpha 1-antitrypsin immunoperoxidase reaction on liver cryosections and the presence in mouse plasma of de novo synthesized protein was detected by ELISA analysis. Our results indicate that a single dose of encapsulated plasmid induces the expression of human alpha 1-antitrypsin in mouse hepatocytes and a large effect (70%) remains two weeks after treatment. However, no effect was observed when mice were treated with buffer or free plasmid (100 ng/mouse) plus an equivalent lipid dose of empty liposomes. In addition, whereas no additive effect was observed after repetitive treatment-doses, the partial hepatectomy three hours after a single treatment-dose, significantly increased the presence of human alpha 1-antitrypsin in mice plasma.

Recombinant cDNA encapsulation in small liposomes with hepatocyte access ability.

Liposomal encapsulation efficiency of a recombinant cDNA was studied by several procedures. We observed that supernatant fraction of ultracentrifuged liposomes prepared by extrusion through polycarbonate filters of 400 nm pore size yielded a very homogeneous suspension of small (50 nm diameter) unilamellar liposomes with highest DNA/lipid ratio and great ability to access to hepatocytes.

In vivo delivery of human alpha 1-antitrypsin gene to mouse hepatocytes by liposomes.

The pTG7101 plasmid containing the full length human alpha 1-Antitrypsin was encapsulated in large (142 +/- 15 nm of diameter) and small (54 +/- 11 nm of diameter) liposomes and administered i.v. to mice (80 ng/mouse). Control animals were treated with empty (small and large) liposomes plus free DNA and with the liposome solvent buffer. The immunohistochemical results on liver cryosections and cytophotometric analysis of hepatocyte chromophore absorbance, after peroxidase reaction, indicated that significant presence of immunoreactive human alpha 1-antitrypsin was present 7 days after mice treatment with encapsulated DNA in small liposomes but not when large liposomes were used. This effect was observed in a great number of liver parenchymal cells. These results agree with the observation that only small liposomes have easy access to hepatocytes and support the idea that small liposomes are appropriate vehicles for in vivo delivery of specific genetic material to liver parenchymal cells, with high efficiency.

Efficacy of liposome-encapsulated indomethacin in response against metastatic 3LL and B16F1 tumor cells.

The ability of large liposomes to be taken up by tissue phagocytic cells, e.g., macrophages, has made it possible to increase the efficacy of several drugs as immunomodulating agents. In the present work, we have evaluated the effect of indomethacin, a prostaglandin synthesis inhibitor, both free and encapsulated in liposomes, on the spontaneous metastatic potential of 3LL and B16F1 tumor cells. Liposomes containing either carboxyfluorescein, indomethacin, or carboxyfluorescein plus indomethacin, were made in order to evaluate their in vitro plasma stability and in vivo clearance from the blood. The liposomes showed a high stability after 6 hours of plasma incubation and they were rapidly cleared in vivo. Liposomes encapsulating propidium iodide, a fluorescent DNA binding dye, were mainly taken up in vivo by hepatic and spleen macrophages 1 hour after intravenous injection, but not by lung macrophages. When C57BL/6 mice were intravenously inoculated with 10(5) 3LL or B16F1 tumor cells previously incubated with indomethacin (10(-7) M) for 48 hours, the number of experimental lung metastatic foci was increased with respect to their respective control groups. Also, in 3LL or B16F1 tumor-bearing mice, treatment with indomethacin (0.5 mg/kg weight/day) for 10 days enhanced the number of lung metastases, but not significantly. However, when mice received indomethacin encapsulated in liposomes, the number of metastases was significantly reduced. In addition, encapsulated indomethacin (0.5 mg/kg weight/day) inhibits prostaglandin E2 production by peritoneal and spleen macrophages, whereas no significant inhibitory effect was observed with control-liposomes or equivalent doses of free indomethacin. We conclude that intravenous administration of liposome-encapsulated indomethacin has an antimetastatic effect on tumor-bearing mice. Use of indomethacin in liposomes may avoid the stimulation of metastases observed when the drug is administered alone.

Antimetastatic effects of liposome entrapped indomethacin.

The "in vivo"administration of sized liposomes encapsulating indomethacin to mice bearing 3LL tumor, significantly reduced the incidence and/or number of superficial lung metastases. Also liposomes encapsulating indomethacin had significant inhibitory effects on the experimentally induced lung metastases. We conclude: i) indomethacin encapsulated in liposomes is more efficient than the free drug in mediating the antimetastatic effects and ii) liposomes are an valuable vehicle in evading the side metastatic effects of this drug during indomethacin treatment of tumor bearing mice.