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Evidence Suggesting a Role of Iron in a Mouse Model of Nephrogenic Systemic Fibrosis.

Bose C, Megyesi JK, Shah SV, Hiatt KM, Hall KA, Karaduta O, Swaminathan S - PLoS ONE (2015)

Bottom Line: The deferiprone-treated group had significantly decreased skin thickness (p<0.05) and significantly decreased dermal fibrosis compared to the Omniscan-only group.Our in vitro experiments demonstrated that exposure to Omniscan resulted in the release of catalytic iron and this was prevented by the iron chelator deferiprone.Our studies support an important role of iron in the pathophysiology of gadolinium chelate toxicity and nephrogenic systemic fibrosis.

View Article: PubMed Central - PubMed

Affiliation: Central Arkansas Veterans Healthcare System, Renal Section, Medicine Service, Little Rock, Arkansas, United States of America; University of Arkansas for Medical Sciences, Department of Internal Medicine, Division of Nephrology, Little Rock, Arkansas, United States of America.

ABSTRACT
Nephrogenic systemic fibrosis is associated with gadolinium contrast exposure in patients with reduced kidney function and carries high morbidity and mortality. We have previously demonstrated that gadolinium contrast agents induce in vivo systemic iron mobilization and in vitro differentiation of peripheral blood mononuclear cells into ferroportin (iron exporter)-expressing fibrocytic cells. In the present study we examined the role of iron in a mouse model of nephrogenic systemic fibrosis. Chronic kidney disease was induced in 8-week-old male Balb/C mice with a two-step 5/6 nephrectomy surgery. Five groups of mice were studied: control (n = 5), sham surgery control (n = 5), chronic kidney disease control (n = 4), chronic kidney disease injected with 0.5 mmol/kg body weight of Omniscan 3 days per week, for a total of 10 injections (n = 8), and chronic kidney disease with Omniscan plus deferiprone, 125 mg/kg, in drinking water (n = 9). Deferiprone was continued for 16 weeks until the end of the experiment. Mice with chronic kidney disease injected with Omniscan developed skin changes characteristic of nephrogenic systemic fibrosis including hair loss, reddening, ulceration, and skin tightening by 10 to 16 weeks. Histopathological sections demonstrated dermal fibrosis with increased skin thickness (0.25±0.06 mm, sham; 0.34±+0.3 mm, Omniscan-injected). Additionally, we observed an increase in tissue infiltration of ferroportin-expressing, fibrocyte-like cells accompanied by tissue iron accumulation in the skin of the Omniscan-treated mice. The deferiprone-treated group had significantly decreased skin thickness (p<0.05) and significantly decreased dermal fibrosis compared to the Omniscan-only group. In addition, iron chelation prevented tissue infiltration of ferroportin-expressing, fibrocyte-like cells. Our in vitro experiments demonstrated that exposure to Omniscan resulted in the release of catalytic iron and this was prevented by the iron chelator deferiprone. Deferiprone inhibited the differentiation of human peripheral blood mononuclear cells into ferroportin-expressing cells by immunohistochemical staining and western blot analysis. Our studies support an important role of iron in the pathophysiology of gadolinium chelate toxicity and nephrogenic systemic fibrosis.

No MeSH data available.


Related in: MedlinePlus

Expression of Omniscan-induced macrophage (CD163) and fibrotic markers (CD34) are iron-regulated, as shown by PBMC in vitro.Expression of CD163 and fibrotic markers are iron-regulated, as shown by immunofluorescence staining of human PBMC treated with 0.5 mM Omniscan plus deferiprone for 8 days. (A) Representative images show CD163 and CD34 expression by Omniscan, and 25 μM of deferiprone effectively inhibited differentiation of the cells and expression of these markers. (Scale bars 100 μm for all). Western blot and quantitative analysis for western blots are shown in Figs (B) and (C). GAPDH was used as loading control. Values are means ±SD, obtained from 3 separate experiments. Significance of the data was determined by ANOVA, followed by paired-group comparisons. (*p <0.05, for CD163, **p <0.01 for CD34 for Omniscan-treated compared with Omniscan plus deferiprone, **p <0.01, compared with Omniscan alone and control).
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pone.0136563.g013: Expression of Omniscan-induced macrophage (CD163) and fibrotic markers (CD34) are iron-regulated, as shown by PBMC in vitro.Expression of CD163 and fibrotic markers are iron-regulated, as shown by immunofluorescence staining of human PBMC treated with 0.5 mM Omniscan plus deferiprone for 8 days. (A) Representative images show CD163 and CD34 expression by Omniscan, and 25 μM of deferiprone effectively inhibited differentiation of the cells and expression of these markers. (Scale bars 100 μm for all). Western blot and quantitative analysis for western blots are shown in Figs (B) and (C). GAPDH was used as loading control. Values are means ±SD, obtained from 3 separate experiments. Significance of the data was determined by ANOVA, followed by paired-group comparisons. (*p <0.05, for CD163, **p <0.01 for CD34 for Omniscan-treated compared with Omniscan plus deferiprone, **p <0.01, compared with Omniscan alone and control).

Mentions: We performed immunofluorescence staining of Omniscan and deferiprone-treated PBMC. As shown in Figs 13A and 14A, treatment of PBMC with Omniscan led to higher expression of CD163, CD34, procollagen-1, and prolyl 4-hydroxylase. Moreover, preincubation of PBMC with 25 μM of deferiprone for 24 hours inhibited most of the Omniscan-induced fibrotic markers. Expression of the iron regulator protein ferroportin was increased in Omniscan-treated cells, as detected by immunostaining (Fig 15A, upper panels). Deferiprone treatment markedly decreased Omniscan-induced, ferroportin-expressing cells. Omniscan treatment reduced hepcidin expression by fibrocyte-like cells, and deferiprone pretreatment partially ameliorated Omniscan-induced reduction in hepcidin expression (Fig 15A, lower panels). Western blot analysis further confirmed our immunostaining results (Figs 13–15, B panels). Panel C of Figs 13–15 demonstrate the quantitative data for western blot analysis.


Evidence Suggesting a Role of Iron in a Mouse Model of Nephrogenic Systemic Fibrosis.

Bose C, Megyesi JK, Shah SV, Hiatt KM, Hall KA, Karaduta O, Swaminathan S - PLoS ONE (2015)

Expression of Omniscan-induced macrophage (CD163) and fibrotic markers (CD34) are iron-regulated, as shown by PBMC in vitro.Expression of CD163 and fibrotic markers are iron-regulated, as shown by immunofluorescence staining of human PBMC treated with 0.5 mM Omniscan plus deferiprone for 8 days. (A) Representative images show CD163 and CD34 expression by Omniscan, and 25 μM of deferiprone effectively inhibited differentiation of the cells and expression of these markers. (Scale bars 100 μm for all). Western blot and quantitative analysis for western blots are shown in Figs (B) and (C). GAPDH was used as loading control. Values are means ±SD, obtained from 3 separate experiments. Significance of the data was determined by ANOVA, followed by paired-group comparisons. (*p <0.05, for CD163, **p <0.01 for CD34 for Omniscan-treated compared with Omniscan plus deferiprone, **p <0.01, compared with Omniscan alone and control).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4549214&req=5

pone.0136563.g013: Expression of Omniscan-induced macrophage (CD163) and fibrotic markers (CD34) are iron-regulated, as shown by PBMC in vitro.Expression of CD163 and fibrotic markers are iron-regulated, as shown by immunofluorescence staining of human PBMC treated with 0.5 mM Omniscan plus deferiprone for 8 days. (A) Representative images show CD163 and CD34 expression by Omniscan, and 25 μM of deferiprone effectively inhibited differentiation of the cells and expression of these markers. (Scale bars 100 μm for all). Western blot and quantitative analysis for western blots are shown in Figs (B) and (C). GAPDH was used as loading control. Values are means ±SD, obtained from 3 separate experiments. Significance of the data was determined by ANOVA, followed by paired-group comparisons. (*p <0.05, for CD163, **p <0.01 for CD34 for Omniscan-treated compared with Omniscan plus deferiprone, **p <0.01, compared with Omniscan alone and control).
Mentions: We performed immunofluorescence staining of Omniscan and deferiprone-treated PBMC. As shown in Figs 13A and 14A, treatment of PBMC with Omniscan led to higher expression of CD163, CD34, procollagen-1, and prolyl 4-hydroxylase. Moreover, preincubation of PBMC with 25 μM of deferiprone for 24 hours inhibited most of the Omniscan-induced fibrotic markers. Expression of the iron regulator protein ferroportin was increased in Omniscan-treated cells, as detected by immunostaining (Fig 15A, upper panels). Deferiprone treatment markedly decreased Omniscan-induced, ferroportin-expressing cells. Omniscan treatment reduced hepcidin expression by fibrocyte-like cells, and deferiprone pretreatment partially ameliorated Omniscan-induced reduction in hepcidin expression (Fig 15A, lower panels). Western blot analysis further confirmed our immunostaining results (Figs 13–15, B panels). Panel C of Figs 13–15 demonstrate the quantitative data for western blot analysis.

Bottom Line: The deferiprone-treated group had significantly decreased skin thickness (p<0.05) and significantly decreased dermal fibrosis compared to the Omniscan-only group.Our in vitro experiments demonstrated that exposure to Omniscan resulted in the release of catalytic iron and this was prevented by the iron chelator deferiprone.Our studies support an important role of iron in the pathophysiology of gadolinium chelate toxicity and nephrogenic systemic fibrosis.

View Article: PubMed Central - PubMed

Affiliation: Central Arkansas Veterans Healthcare System, Renal Section, Medicine Service, Little Rock, Arkansas, United States of America; University of Arkansas for Medical Sciences, Department of Internal Medicine, Division of Nephrology, Little Rock, Arkansas, United States of America.

ABSTRACT
Nephrogenic systemic fibrosis is associated with gadolinium contrast exposure in patients with reduced kidney function and carries high morbidity and mortality. We have previously demonstrated that gadolinium contrast agents induce in vivo systemic iron mobilization and in vitro differentiation of peripheral blood mononuclear cells into ferroportin (iron exporter)-expressing fibrocytic cells. In the present study we examined the role of iron in a mouse model of nephrogenic systemic fibrosis. Chronic kidney disease was induced in 8-week-old male Balb/C mice with a two-step 5/6 nephrectomy surgery. Five groups of mice were studied: control (n = 5), sham surgery control (n = 5), chronic kidney disease control (n = 4), chronic kidney disease injected with 0.5 mmol/kg body weight of Omniscan 3 days per week, for a total of 10 injections (n = 8), and chronic kidney disease with Omniscan plus deferiprone, 125 mg/kg, in drinking water (n = 9). Deferiprone was continued for 16 weeks until the end of the experiment. Mice with chronic kidney disease injected with Omniscan developed skin changes characteristic of nephrogenic systemic fibrosis including hair loss, reddening, ulceration, and skin tightening by 10 to 16 weeks. Histopathological sections demonstrated dermal fibrosis with increased skin thickness (0.25±0.06 mm, sham; 0.34±+0.3 mm, Omniscan-injected). Additionally, we observed an increase in tissue infiltration of ferroportin-expressing, fibrocyte-like cells accompanied by tissue iron accumulation in the skin of the Omniscan-treated mice. The deferiprone-treated group had significantly decreased skin thickness (p<0.05) and significantly decreased dermal fibrosis compared to the Omniscan-only group. In addition, iron chelation prevented tissue infiltration of ferroportin-expressing, fibrocyte-like cells. Our in vitro experiments demonstrated that exposure to Omniscan resulted in the release of catalytic iron and this was prevented by the iron chelator deferiprone. Deferiprone inhibited the differentiation of human peripheral blood mononuclear cells into ferroportin-expressing cells by immunohistochemical staining and western blot analysis. Our studies support an important role of iron in the pathophysiology of gadolinium chelate toxicity and nephrogenic systemic fibrosis.

No MeSH data available.


Related in: MedlinePlus