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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

Study design and treatment schedule for Omniscan injections and deferiprone treatment.As mentioned in Materials and Methods, after one week of establishment of CKD, one group of mice was administered deferiprone in drinking water (125mg/kg) two days before starting Omniscan injections. Three injections of Omniscan (0.5 mmol/kg, tail IV, 100 μl volume) per week on alternate days were given to two groups of mice (one received deferiprone and the other received Omniscan only) excluding weekends. A total of 10 injections were given. Control mice (one group of CKD and other was sham) animals received 10 injections of an equivalent volume (100 μl) of saline. After 16 weeks at the endpoint, animals were sacrificed and blood and tissues were collected.
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pone.0136563.g001: Study design and treatment schedule for Omniscan injections and deferiprone treatment.As mentioned in Materials and Methods, after one week of establishment of CKD, one group of mice was administered deferiprone in drinking water (125mg/kg) two days before starting Omniscan injections. Three injections of Omniscan (0.5 mmol/kg, tail IV, 100 μl volume) per week on alternate days were given to two groups of mice (one received deferiprone and the other received Omniscan only) excluding weekends. A total of 10 injections were given. Control mice (one group of CKD and other was sham) animals received 10 injections of an equivalent volume (100 μl) of saline. After 16 weeks at the endpoint, animals were sacrificed and blood and tissues were collected.

Mentions: The dose of Omniscan and time were titrated to establish the optimum required to consistently induce NSF. After one week of nephrectomy, CKD mice were divided into 5 groups, i.e. injected with either normal saline (0.9%) or those treated with various doses (0.1, 0.3, 0.5 and 1 mmol/kg body weight) of gadodiamide (Omniscan, GE Healthcare, Princeton, NJ), for three days per week (days 1, 3, 5, days of the week, tail vein, IV, in 100 μl volume) and a total of 10 injections were given. Mice were monitored every day for any skin changes including hair loss, reddening, ulceration, and skin lesions and skin tightening. Dorsal skin biopsies were taken weekly after Omniscan treatment and at sacrifice. Mice that received 1mmol/kg Omniscan developed early tail necrosis from the 2nd week after injections and manifested tail degeneration by 3–4 weeks. Mice that were moribund or showing obvious signs of distress were removed from the study and euthanized. In view of overt early toxicity with 1 mmol/kg dose and recommendations by our animal use committee, we conducted our further experiments in mice treated with 0.1, 0.3, and 0.5 mmol/kg doses of Omniscan and these mice were monitored for longer periods. There were no such overt early toxic skin changes in the mice that received other doses of Omniscan. Dorsal skin biopsies were taken weekly. The samples were analyzed histopathologically and by immunohistochemistry in the dermatopathology lab by a qualified dermatopathologist (KMH) with extensive expertise in reading NSF. Mice treated with lower doses of Omniscan (0.1 and 0.3 mmol/kg bw) developed NSF-like skin changes by 18 to 20 weeks; in comparison, mice treated with 0.5 mmol/kg bw developed skin changes suggestive of NSF by 10 to 16 weeks. Mice treated with 0.5 mmol/kg bw started developing changes in skin from the 10th week (presence of CD34+ and procollagen+ positive and fibroblast-like cells). By the 16th week more clinically visible changes of NSF were evident including hair loss, indurations, and skin tightening. Skin biopsy samples showed a significant increase in CD34, CD163+ dermal spindle cells, and thick collagen bundles with skin thickness, as determined by immunohistochemical and histopathological analysis. Thus, for our intervention studies we used 10 injections of 0.5 mmol/kg Omniscan, three injections per week, for three consecutive weeks. Mice were sacrificed 13 weeks after last injection. The total duration of the study was 16 weeks after the first Omniscan injection (Fig 1).


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)

Study design and treatment schedule for Omniscan injections and deferiprone treatment.As mentioned in Materials and Methods, after one week of establishment of CKD, one group of mice was administered deferiprone in drinking water (125mg/kg) two days before starting Omniscan injections. Three injections of Omniscan (0.5 mmol/kg, tail IV, 100 μl volume) per week on alternate days were given to two groups of mice (one received deferiprone and the other received Omniscan only) excluding weekends. A total of 10 injections were given. Control mice (one group of CKD and other was sham) animals received 10 injections of an equivalent volume (100 μl) of saline. After 16 weeks at the endpoint, animals were sacrificed and blood and tissues were collected.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4549214&req=5

pone.0136563.g001: Study design and treatment schedule for Omniscan injections and deferiprone treatment.As mentioned in Materials and Methods, after one week of establishment of CKD, one group of mice was administered deferiprone in drinking water (125mg/kg) two days before starting Omniscan injections. Three injections of Omniscan (0.5 mmol/kg, tail IV, 100 μl volume) per week on alternate days were given to two groups of mice (one received deferiprone and the other received Omniscan only) excluding weekends. A total of 10 injections were given. Control mice (one group of CKD and other was sham) animals received 10 injections of an equivalent volume (100 μl) of saline. After 16 weeks at the endpoint, animals were sacrificed and blood and tissues were collected.
Mentions: The dose of Omniscan and time were titrated to establish the optimum required to consistently induce NSF. After one week of nephrectomy, CKD mice were divided into 5 groups, i.e. injected with either normal saline (0.9%) or those treated with various doses (0.1, 0.3, 0.5 and 1 mmol/kg body weight) of gadodiamide (Omniscan, GE Healthcare, Princeton, NJ), for three days per week (days 1, 3, 5, days of the week, tail vein, IV, in 100 μl volume) and a total of 10 injections were given. Mice were monitored every day for any skin changes including hair loss, reddening, ulceration, and skin lesions and skin tightening. Dorsal skin biopsies were taken weekly after Omniscan treatment and at sacrifice. Mice that received 1mmol/kg Omniscan developed early tail necrosis from the 2nd week after injections and manifested tail degeneration by 3–4 weeks. Mice that were moribund or showing obvious signs of distress were removed from the study and euthanized. In view of overt early toxicity with 1 mmol/kg dose and recommendations by our animal use committee, we conducted our further experiments in mice treated with 0.1, 0.3, and 0.5 mmol/kg doses of Omniscan and these mice were monitored for longer periods. There were no such overt early toxic skin changes in the mice that received other doses of Omniscan. Dorsal skin biopsies were taken weekly. The samples were analyzed histopathologically and by immunohistochemistry in the dermatopathology lab by a qualified dermatopathologist (KMH) with extensive expertise in reading NSF. Mice treated with lower doses of Omniscan (0.1 and 0.3 mmol/kg bw) developed NSF-like skin changes by 18 to 20 weeks; in comparison, mice treated with 0.5 mmol/kg bw developed skin changes suggestive of NSF by 10 to 16 weeks. Mice treated with 0.5 mmol/kg bw started developing changes in skin from the 10th week (presence of CD34+ and procollagen+ positive and fibroblast-like cells). By the 16th week more clinically visible changes of NSF were evident including hair loss, indurations, and skin tightening. Skin biopsy samples showed a significant increase in CD34, CD163+ dermal spindle cells, and thick collagen bundles with skin thickness, as determined by immunohistochemical and histopathological analysis. Thus, for our intervention studies we used 10 injections of 0.5 mmol/kg Omniscan, three injections per week, for three consecutive weeks. Mice were sacrificed 13 weeks after last injection. The total duration of the study was 16 weeks after the first Omniscan injection (Fig 1).

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