Deceased-donor kidney transplantation: improvement in long-term survival.

BACKGROUND: Despite marked improvement in short-term renal allograft survival rates (GSR) in recent years, improvement in long-term GSR remained elusive. METHODS: We analysed the kidney transplant experience at our centre accrued over four decades to evaluate how short-term and long-term GSR had changed and to identify risk factors affecting graft survival. The study included 1476 adult recipients of a deceased-donor kidney transplant who were transplanted between 1963 and 2006 and who had received one of five distinct immunosuppressive protocols. RESULTS: Five-year actual GSR steadily improved over the years as immunosuppressive therapy evolved (22-86%, P < 0.001) in spite of an increasing trend in the transplantation of higher-risk donor-recipient pairings. For those whose grafts functioned for the first year, subsequent 4-year GSR (5-year conditional GSR) also improved significantly (63-92%, P < 0.001). Acute rejection and delayed graft function (DGF) were the most significant risk factors for actual graft survival, while acute rejection was the only significant risk factor for conditional GSR. Use of kidneys from expanded-criteria donors (ECD) was not a risk factor, compared to the use of standard-criteria donor kidneys for either 5-year actual or conditional GSR. There was an impressive decline in the incidence of acute rejection events (77.4-5.8%, P < 0.001). While the DGF rate had decreased, it still remained high (68.7-38.5%, P < 0.001). CONCLUSIONS: We found a significant improvement in both short-term and long-term GSR of deceased-donor kidney transplants over the last four decades. These improvements are most likely related to the decreased incidence of acute rejection episodes. Minimizing acute rejection events and preventing DGF could result in further improvement in the GSR. Our experience in the judicious use of ECD kidneys suggests that this source of kidneys could be expanded further.

Three-dimensional culture of mouse renal carcinoma cells in agarose macrobeads selects for a subpopulation of cells with cancer stem cell or cancer progenitor properties.

The culture of tumor cell lines in three-dimensional scaffolds is considered to more closely replicate the in vivo tumor microenvironment than the standard method of two-dimensional cell culture. We hypothesized that our method of encapsulating and maintaining viable and functional pancreatic islets in agarose-agarose macrobeads (diameter 6-8 mm) might provide a novel method for the culture of tumor cell lines. In this report we describe and characterize tumor colonies that form within macrobeads seeded with mouse renal adenocarcinoma cells. Approximately 1% of seeded tumor cells survive in the macrobead and over several months form discrete elliptical colonies appearing as tumor cell niches with increasing metabolic activity in parallel to colony size. The tumor colonies demonstrate ongoing cell turnover as shown by BrdU incorporation and activated caspase-3 and TUNEL staining. Genes upregulated in the tumor colonies of the macrobead are likely adaptations to this novel environment, as well as an amplification of G(1)/S cell-cycle checkpoints. The data presented, including SCA-1 and Oct4 positivity and the upregulation of stem cell-like genes such as those associated with the Wnt pathway, support the notion that the macrobead selects for a subpopulation of cells with cancer stem cell or cancer progenitor properties.

Hydrophilic agarose macrobead cultures select for outgrowth of carcinoma cell populations that can restrict tumor growth.

Cancer cells and their associated tumors have long been considered to exhibit unregulated proliferation or growth. However, a substantial body of evidence indicates that tumor growth is subject to both positive and negative regulatory controls. Here, we describe a novel property of tumor growth regulation that is neither species nor tumor-type specific. This property, functionally a type of feedback control, is triggered by the encapsulation of neoplastic cells in a growth-restricting hydrogel composed of an agarose matrix with a second coating of agarose to form 6- to 8-mm diameter macrobeads. In a mouse cell model of renal adenocarcinoma (RENCA cells), this process resulted in selection for a stem cell-like subpopulation which together with at least one other cell subpopulation drove colony formation in the macrobeads. Cells in these colonies produced diffusible substances that markedly inhibited in vitro and in vivo proliferation of epithelial-derived tumor cells outside the macrobeads. RENCA cells in monolayer culture that were exposed to RENCA macrobead-conditioned media exhibited cell-cycle accumulation in S phase due to activation of a G(2)/M checkpoint. At least 10 proteins with known tumor suppression functions were identified by analysis of RENCA macrobead-conditioned media, the properties of which offer opportunities to further dissect the molecular basis for tumor growth control. More generally, macrobead culture may permit the isolation of cancer stem cells and other cells of the stem cell niche, perhaps providing strategies to define more effective biologically based clinical approaches to treat neoplastic disease.

Neutralization of endotoxin by a phospholipid emulsion in healthy volunteers.

BACKGROUND: An approach to endotoxin (lipopolysaccharide [LPS]) blockade makes use of the ability of lipoproteins, via surface phospholipids, to bind and neutralize LPS. The aim of the present study was to determine whether the intravenous administration of a protein-free, phospholipid-rich emulsion is an effective method for neutralizing the effects of LPS in healthy persons. METHODS: This was a double-blind, placebo-controlled study in 20 volunteers. Volunteers received Escherichia coli endotoxin (2 ng/kg) intravenously 2 h into a 6-h infusion of either emulsion (210 mg/kg) or placebo (Intralipid diluted 1 : 64). RESULTS: The volunteers who received emulsion had a lower mean clinical score (P<.01), temperature (P<.05), pulse rate (P<.05), neutrophil count (P<.05), tumor necrosis factor- alpha level (P<.05), and interleukin-6 level (P<.05) than did the volunteers who received placebo. Response was related to serum phospholipid level. The greatest effects were observed in the volunteers achieving phospholipid levels of approximately 500 mg/dL or higher. CONCLUSION: Phospholipid emulsion attenuates the clinical and laboratory effects associated with the administration of LPS in humans, suggesting a novel approach to the treatment of endotoxemia.

Safety and pharmacokinetics of an endotoxin-binding phospholipid emulsion.

BACKGROUND: Lipids and lipoproteins have been shown to bind and neutralize endotoxin and to improve outcomes in animal models of sepsis. OBJECTIVE: To provide safety and pharmacokinetic data for a protein-free, phospholipid-rich emulsion developed as an agent to neutralize endotoxin, and to study the changes in lipids and lipoproteins following emulsion administration. METHODS: Thirty healthy male volunteers (aged 18-45 y) were given an emulsion containing 92.5% soy phospholipid, 7.5% soy triglyceride, and 18 mM sodium cholate using a double-blind, placebo-controlled crossover protocol. Emulsion at 3 escalating doses (75, 150, 300 mg/kg) based on phospholipid content was administered by intravenous infusion over 2 hours in the low- and mid-dose groups and 6 hours in the high-dose group. RESULTS: All subjects completed the protocol without significant toxicities. A slight dose-dependent increase in indirect bilirubin at the 24-hour time point was observed in the emulsion treatment period, with a maximum difference between placebo and emulsion of 0.9 mg/dL. Mean +/- SD peak phospholipid levels were 316 +/- 30, 533 +/- 53, and 709 +/- 86 mg/dL, and phospholipid half-lives were 5.4 +/- 0.6, 5.4 +/- 0.5, and 8.0 +/- 0.8 hours for the low, mid, and high doses, respectively. Increases in total cholesterol, low-density lipoprotein cholesterol and apolipoprotein A-I and B levels were observed. High-density lipoprotein cholesterol decreased immediately following emulsion infusion, but rebounded to above placebo levels by 24 hours. CONCLUSIONS: A unique phospholipid-rich emulsion was shown to have a favorable safety profile and to expand the blood lipid and lipoprotein pool without the use of human-derived blood products. Lipid levels expected to protect against the physiologic effects of bacterial endotoxin were achieved.