The kidney injury caused by the onset of acute graft-versus-host disease is associated with down-regulation of αKlotho.

Acute graft-versus-host disease (aGVHD) and kidney injury are the major complications after allogeneic hematopoietic stem cell transplantation (HSCT). Although the underlying mechanisms for the development of these complications are not yet fully understood, it has been proposed that emergence of aGVHD contributes to the development of kidney injury after HSCT. We have shown previously that aGVHD targets the kidney in a biphasic manner: at the onset, inflammatory genes are up-regulated, while when aGVHD becomes established, donor lymphocytes infiltrate the kidney. Here, we characterize renal manifestations at the onset of aGVHD. Mice receiving allogeneic bone marrow and spleen cells displayed symptoms of aGVHD and elevated serum levels of tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) within 4 days. There was concurrent kidney injury with the following characteristics: (1) elevated expression of the kidney injury biomarker, neutrophil gelatinase-associated lipocalin (NGAL), (2) accumulation of hetero-lysosomes in proximal tubule epithelial cells, and (3) reductions in αKlotho mRNA and protein and increased serum levels of fibroblast growth factor 23 (Fgf23), phosphate and urea. This situation resembled acute renal injury caused by bacterial lipopolysaccharide. We conclude that the onset of aGVHD is associated with kidney injury involving down-regulation of αKlotho, a sight that may inspire novel therapeutic approaches.

Sub-acute, moderate-dose, but not short-term, low-dose dietary pre-exposure of mice to perfluorooctanoate aggravates concanavalin A-induced hepatitis.

Exposure of mice to perfluorooctanoate (PFOA) evokes pronounced hepatomegaly along with significant alterations in both the histological structure and immune status of the liver. The present study was designed to evaluate the effects of this perfluorochemical on immune-mediated liver damage. In this connection, the influence of both sub-acute (10 days), moderate-dose (0.002% w/w=3±0.7mg/kg body weight/day) and short-term (28 days), low-dose (0.00005% w/w=70±2µg/kg body weight/day) dietary pretreatment with PFOA on the development of concanavalin A (Con A)-induced liver damage in mice was examined. With sub-acute, moderate, but not short-term, low-dose exposure, PFOA aggravated the acute liver damage caused by Con A, i.e., elevated serum levels of transaminases and led to more pronounced damage of hepatic tissue. This aggravation was associated with significantly enhanced hepatic level of interleukin-6 (IL-6), but unaltered hepatic levels of tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and interleukin-4 (IL-4). Moreover, hepatic DNA fragmentation was not changed by sub-acute exposure to the moderate-dose. Our findings imply that exposure to PFOA may sensitize hepatic parenchymal cells to other toxicants that activate the hepatic immune system and thereby aggravate liver injury during acute inflammation.

Both sub-acute, moderate-dose and short-term, low-dose dietary exposure of mice to perfluorooctane sulfonate exacerbates concanavalin A-induced hepatitis.

Exposure of rodents to perfluorooctane sulfonate (PFOS) induces pronounced hepatomegaly associated with significant alterations in hepatic histophysiology and immune status. The present investigation was designed to evaluate the effects of this perfluorochemical on immune-mediated liver damage. Accordingly, the influence of both sub-acute (10 days), moderate-dose (0.004%, w/w=6±1.3 mg/kg body weight/day) or short-term (28 days), low-dose (0.0001%, w/w=144±4 µg/kg body weight/day) dietary pretreatment with PFOS on the development of concanavalin A (Con A)-induced liver damage in mice was examined. With either regimen of exposure, PFOS exacerbated the acute liver damage caused by Con A, i.e., elevated serum levels of transaminases and led to more pronounced damage of hepatic tissue. This exacerbation was associated with either reduced (moderate dose) or unaltered (low dose) hepatic levels of the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). Moreover, hepatic DNA fragmentation was enhanced, particularly following short-term exposure to a low-dose. Our findings suggest that exposure to PFOS may sensitize hepatic parenchymal cells to other insults that activate the hepatic immune system and thereby exacerbate liver damage during acute inflammation.

High-dose dietary exposure of mice to perfluorooctanoate or perfluorooctane sulfonate exerts toxic effects on myeloid and B-lymphoid cells in the bone marrow and these effects are partially dependent on reduced food consumption.

It is well established that exposure of mice to perfluorooctanoate (PFOA) or perfluorooctane sulfonate (PFOS) exerts adverse effects on the thymus and spleen. Here, we characterize the effects of a 10-day dietary treatment with these compounds (0.001-0.02%, w/w) on the bone marrow (BM) of mice. At a dose of 0.02%, both compounds reduced food consumption and caused atrophy of the thymus and spleen. At this same dose, histopathological and flow cytometric analysis revealed that (i) the total numbers of BM as well as the numbers of myeloid, pro/pre B, immature B and early mature B cells were all reduced significantly; and (ii) these adverse effects were reversed either partially or completely 10days after withdrawal of these compounds. At the lower dose of 0.002%, only PFOA reduced the B-lymphoid cell population. Finally, mice fed an amount of diet equivalent to that consumed by the animals exposed to 0.02% PFOA also exhibited atrophy of the thymus and spleen, and a reduction in the number of B-lymphoid population, without affecting myeloid cells. Thus, in mice, immunotoxic doses of PFOA or PFOS induce adverse effects on the myeloid and B-lymphoid cells in the BM, in part as a consequence of reduced food consumption.

Radiosynthesis of perfluorooctanesulfonate (PFOS) and perfluorobutanesulfonate (PFBS), including solubility, partition and adhesion studies.

Here, we describe for the first time the synthesis of [(35)S] PFOS and [(35)S] PFBS with sulfur-35 enriched sulfur dioxide as the radiolabelled reagent, resulting in 2.5 and 2.3 mCi of product, respectively. Basic information concerning the physicochemical properties of perfluorooctanesulfonate (PFOS), perfluorobutanesulfonate (PFBS) and perfluorooctanoic acid (PFOA) are still limited. Hence, we utilized these radiolabelled perfluoroalkanesulfonates (PFSAs), as well as carbon-14 labelled perfluorooctanoic acid ([(14)C] PFOA) to determine some basic characteristics of physiological and experimental significance. The solubility of PFOS in buffered aqueous solutions at pH 7.4 was found to be severely reduced in the presence of potassium and sodium ions, which, however, did not reduce the solubility of PFOA or PFBS. PFOS was found to adhere to a small extent to polypropylene and polystyrene, whereas no such adhesion of PFOA or PFBS was detected. The extents of adhesion of PFOS and PFOA to glass were found to be 20% and 10%, respectively. For the first time, the partition coefficients for PFOS, PFBS and PFOA between n-octanol and water were determined experimentally, to be -0.7, -0.3, and 1.4, respectively, reflecting the difference in the amphiphilic natures of these molecules.

Dietary exposure to perfluorooctanoate or perfluorooctane sulfonate induces hypertrophy in centrilobular hepatocytes and alters the hepatic immune status in mice.

It is well established that exposure of mice to perfluorooctanoate (PFOA) or perfluorooctane sulfonate (PFOS) induces hepatomegaly and, concurrently, immunotoxicity. However, the effects of these perfluorochemicals on the histology and immune status of the liver have not been yet investigated and we have examined these issues here. Dietary treatment of male C57BL/6 mice with 0.002% (w/w) PFOA or 0.005% (w/w) PFOS for 10 days resulted in significant reductions in serum levels of cholesterol and triglycerides, a moderate increase in the serum activity of alkaline phosphatase (ALP) and hepatomegaly, without affecting other immune organs. This hepatomegaly was associated with marked hypertrophy of the centrilobular hepatocytes, with elevated numbers of cytoplasmic acidophilic granules and occasional mitosis. Furthermore, dietary exposure to PFOA or PFOS altered the hepatic immune status: whereas exposure to PFOA enhanced the numbers of total, as well as of phenotypically distinct subpopulations of intrahepatic immune cells (IHIC), and in particular the presumptive erythrocyte progenitor cells, treatment with PFOS enhanced only the numbers of hepatic cells that appear immunophenotypically to be erythrocyte progenitors, without affecting other types of IHIC. In addition, exposure to these compounds attenuated hepatic levels of tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and interleukin-4 (IL-4). Furthermore, the exposed animals exhibited a significant increase in hepatic levels of erythropoietin, a hormone required for erythropoiesis. Thus, in mice, PFOA- and PFOS-induced hepatomegaly is associated with significant alterations in hepatic histophysiology and immune status, as well as induction of hepatic erythropoiesis.

High-dose, short-term exposure of mice to perfluorooctanesulfonate (PFOS) or perfluorooctanoate (PFOA) affects the number of circulating neutrophils differently, but enhances the inflammatory responses of macrophages to lipopolysaccharide (LPS) in a similar fashion.

Having found previously that high-dose, short-term dietary exposure of mice to perfluorooctanesulfonate (PFOS) or perfluorooctanoate (PFOA) suppresses adaptive immunity, in the present study we characterize the effects of these fluorochemicals on the innate immune system. Male C57BL/6 mice receiving 0.02% (w/w) PFOS or PFOA in their diet for 10 days exhibited a significant reduction in the numbers of total white blood cells (WBC), involving lymphopenia in both cases, but neutropenia only in response to treatment with PFOA. Moreover, both compounds also markedly reduced the number of macrophages (CD11b(+) cells) in the bone marrow, but not in the spleen or peritoneal cavity. The ex vivo production of tumor necrosis factor-alpha (TNF-alpha) and interleukin 6 (IL-6) by peritoneal macrophages isolated from animals treated with PFOA or PFOS was increased modestly. Moreover, both fluorochemicals markedly enhanced the ex vivo production of these same cytokines by peritoneal and bone marrow macrophages stimulated either in vitro or in vivo with lipopolysaccharide (LPS); whereas there was no such effect on splenic macrophages. The serum levels of these inflammatory cytokines observed in response to in vivo stimulation with LPS were elevated substantially by prior exposure to PFOA, but not by PFOS. None of these parameters of innate immunity were altered in animals receiving a dietary dose of these compounds that was 20-fold lower (0.001%, w/w). These findings reveal that in addition to suppressing adaptive immunity, high-dose, short-term exposure of mice to either PFOS or PFOA augments inflammatory responses to LPS, a potent activator of innate immunity.

Characterization of the adipose tissue atrophy induced by peroxisome proliferators in mice.

In the present study, we characterized the effects of peroxisome proliferators (PP) on adipose tissue in mice. Treatment with potent PP, such as perfluorooctanoic acid (PFOA), 2-methyl-2-(p(1,2,3,4-tetrahydroxy-naphthyl)-phenoxy)propionic acid, (4-chloro-6-(2,3-xylidino)2-pyrimidinylthio) acetic acid, and di(2-ethylhexyl)phthalate, caused dramatic decreases in adipose tissue weight, whereas the moderately potent PP, acetylsalicylic acid, had a relatively weak effect. This decrease in weight reflects a loss of fat from adipocytes rather than a loss of cells, as demonstrated by constant DNA content. The dose-dependency and time-course experiments indicate that peroxisome proliferation occurs simultaneously with or prior to adipose tissue atrophy. Thus, hepatic peroxisome proliferation might result in the increased mobilization of lipids and lipid utilization in liver. The enhanced adipose tissue hormone-sensitive lipase (HSL) activity and down-regulated lipoprotein lipase (LPL) activity observed upon PP treatment might, at least in part, explain the loss of fat via increased FA release from adipocytes and/or decreased FA uptake from the circulation, respectively. In addition, the possible involvement of the increased tumor necrosis factor alpha expression found upon PFOA treatment in reducing the insulin sensitivity of adipose tissue and thereby altering LPL and HSL activities is discussed.