Tissue deposition of gadolinium and development of NSF: a convergence of factors

Lanthanum-Induced Gastrointestinal Histiocytosis

A patient with end-stage renal disease (ESRD) on hemodialysis presented with fever, anorexia, and nausea shortly after starting oral lanthanum carbonate for phosphate control. Gastric and duodenal biopsies demonstrated diffuse histiocytosis with intracellular aggregates of basophilic foreign material. Transmission electron microscopy, an underutilized diagnostic test, revealed the nature of the aggregates as heavy metal particles, consistent with lanthanum. Symptoms and histiocytosis improved after discontinuation of lanthanum. Lanthanum may be an underdiagnosed cause of gastrointestinal histiocytosis.

Measurement of T1 relaxation time of osteochondral specimens using VFA-SWIFT

PURPOSE

To evaluate the feasibility of SWIFT with variable flip angle (VFA) for measurement of T₁ relaxation time in Gd-agarose-phantoms and osteochondral specimens, including regions of very short T₂ *, and compare with T₁ measured using standard methods METHODS: T₁ s of agarose phantoms with variable concentration of Gd-DTPA^2- and nine pairs of native and trypsin-treated bovine cartilage-bone specimens were measured. For specimens, VFA-SWIFT, inversion recovery (IR) fast spin echo (FSE) and saturation recovery FSE were used. For phantoms, additionally spectroscopic IR was used. Differences and agreement between the methods were assessed using nonparametric Wilcoxon and Kruskal-Wallis tests and intraclass correlation.

RESULTS

The different T₁ mapping methods agreed well in the phantoms. VFA-SWIFT allowed reliable measurement of T₁ in the osteochondral specimens, including regions where FSE-based methods failed. The T₁ s measured by VFA-SWIFT were shifted toward shorter values in specimens. However, the measurements correlated significantly (highest correlation VFA-SWIFT versus FSE was r = 0.966). SNR efficiency was generally highest for SWIFT, especially in the subchondral bone.

CONCLUSION

Feasibility of measuring T₁ relaxation time using VFA-SWIFT in osteochondral specimens and phantoms was demonstrated. A shift toward shorter T₁ s was observed for VFA-SWIFT in specimens, reflecting the higher sensitivity of SWIFT to short T₂ * spins. Magn Reson Med 74:175-184, 2015. © 2014 Wiley Periodicals, Inc.

Understanding nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF) is a rare and a debilitating disease noted uncommonly in patients with impaired renal function when exposed to low-stability gadolinium-based contrast agents (Gd-CAs). According to experimental studies, cytokines released by the stimulation of effector cells such as skin macrophages and peripheral blood monocytes activate circulating fibroblasts which play a major role in the development of NSF lesions. The presence of permissive factors, presumably, provides an environment conducive to facilitate the process of fibrosis. Multiple treatment modalities have been tried with variable success rates. More research is necessary to elucidate the underlying pathophysiological mechanisms which could potentially target the initial steps of fibrosis in these patients. This paper attempts to collate the inferences from the in vivo and in vitro experiments to the clinical observations to understand the pathogenesis of NSF. Schematic representations of receptor-mediated molecular pathways of activation of macrophages and fibroblasts by gadolinium and the final pathway to fibrosis are incorporated in the discussion.

Extracellular matrix remodelling properties of human fibrocytes

The fibrocytes are thought to serve as a source of newly deposited collagens I and III during reparative processes and in certain fibrotic disorders, but their matrix remodelling properties are incompletely understood. We evaluated their ability to produce several extracellular matrix (ECM) components, in comparison with fibroblasts, and to participate in collagen turnover. The collagen gene expression profile of fibrocytes differed from that of fibroblasts because fibrocytes constitutively expressed relatively high levels of the mRNA encoding collagen VI and significantly lower levels of the mRNA encoding collagens I, III and V. The proteoglycan (PG) gene expression profile was also different in fibrocytes and fibroblasts because fibrocytes constitutively expressed the mRNA encoding perlecan and versican at relatively high levels and the mRNA encoding biglycan and decorin at low and very low levels, respectively. Moreover, fibrocytes expressed the mRNA for hyaluronan synthase 2 at higher level than fibroblasts. Significant differences between the two cell populations were also demonstrated by metabolic labelling and analysis of the secreted collagenous proteins, PGs and hyaluronan. Fibrocytes constitutively expressed the scavenger receptors CD163 and CD204 as well as the mannose receptors CD206 and Endo180, and internalized and degraded collagen fragments through an Endo180-mediated mechanism. The results of this study demonstrate that human fibrocytes exhibit ECM remodelling properties previously unexplored, including the ability to participate in collagen turnover. The observed differences in collagen and PG expression profile between fibrocytes and fibroblasts suggest that fibrocytes may predominantly have a matrix-stabilizing function.

Comparative in vivo dissociation of gadolinium chelates in renally impaired rats: a relaxometry study

PURPOSE

Investigation of dissociated versus chelated gadolinium (Gd) in plasma, skin, and bone of rats with impaired renal function after administration of ionic macrocyclic (gadoterate or Dotarem) or nonionic linear (gadodiamide or Omniscan) Gd chelates.

MATERIALS AND METHODS

Subtotally nephrectomized Wistar rats were subjected to receive daily injections of 2.5 mmol/kg of Omniscan, gadodiamide without excess ligand caldiamide, Dotarem, or saline (n = 7-10 rats/group) for 5 consecutive days. The Gd concentration was measured by inductively coupled plasma mass spectrometer in skin, femur epiphysis, and plasma on completion of the study (day 11), and dissociated Gd(3+) was measured in the plasma at day 11 (liquid chromatography inductively coupled plasma mass spectrometry). The r(1) relaxivity constant was measured in skin (at day 4 and day 11) and bone (day 11) to investigate the dissociated or chelated form of Gd found in tissue samples. Clinical and skin histopathologic studies were performed.

RESULTS

Subtotal nephrectomy decreased creatinine clearance by 60%. No macroscopic skin lesions were observed in the Dotarem and Omniscan groups in contrast with the gadodiamide group (2 rats survived the study period and 4 of 10 rats showed skin ulcerations and scabs). Skin histopathologic lesions were in the range gadodiamide > Omniscan > Dotarem (similar to control rats). At day 11, the skin Gd concentration was lower in the Dotarem group (161.0 ± 85.5 nmol/g) as compared with the Omniscan (490.5 ± 223.2 nmol/g) and gadodiamide groups (mean value, 776.1 nmol/g; n = 2 survivors). The total Gd concentration in the femur was significantly higher in the Omniscan group than in the Dotarem group. At day 11, the dissociated Gd(3+) concentration in plasma was below the limit of detection in the Dotarem group and was 1.5 ± 0.7 μmol/L in the Omniscan group corresponding to 62% ± 15% of the total Gd concentration. The dissociated Gd(3+) concentration was 1.1 μmol/L in gadodiamide rats (n = 2 survivors). In the skin, the in vivo r1 relaxivity value increased from 4.8 ± 0.7 mM(-1)s(-1) at day 4 to 10.5 ± 3.9 mM(-1)s(-1) at day 11 in the Omniscan group, P < 0.05 (in vitro r(1) in skin, 3.5 mM(-1)s(-1)) and gadodiamide group, whereas no significant change was observed in the Dotarem group (2.8 ± 0.2 and 4.9 ± 2.8 mM(-1)s(-1) at day 4 and 11, respectively, NS) (in vitro value in the skin, 3.2 mM(-1)s(-1)). In the femur, the in vivo r1 relaxivity was higher in the Omniscan group (8.9 ± 2.1 mM(-1)s(-1)) (in vitro relaxivity, 4.5 mM(-1)s(-1)) and gadodiamide group (8.8 mM(-1)s(-1), n = 2 survivors) than in the Dotarem group (3.8 mM(-1)s(-1), n = 1 rat with measurable r(1), since for 7 rats, 1/T(1) - 1/T(1(diamagnetic)) <10% of 1/T(1(diamagnetic)) because of low Gd concentration) (in vitro relaxivity value in the femur matrix, 3.1 mM(-1)s(-1)).

CONCLUSIONS

Unlike Dotarem, Omniscan and gadodiamide induced histologic skin lesions. At day 11, a higher Gd concentration was found in both skin and femur of Omniscan- and gadodiamide-treated rats than in Dotarem-treated rats. Relaxometry results indicate gradual in vivo dechelation and release of dissociated Gd(3+) in a soluble form in renally impaired rats receiving Omniscan and gadodiamide, whereas Dotarem remained stable over the study period.

Nephrogenic systemic fibrosis: current concepts

Nephrogenic systemic fibrosis (NSF) was first described in 2000 as a scleromyxedema-like illness in patients on chronic hemodialysis. The relationship between NSF and gadolinium contrast during magnetic resonance imaging was postulated in 2006, and subsequently, virtually all published cases of NSF have had documented prior exposure to gadolinium-containing contrast agents. NSF has been reported in patients from a variety of ethnic backgrounds from America, Europe, Asia and Australia. Skin lesions may evolve into poorly demarcated thickened plaques that range from erythematous to hyperpigmented. With time, the skin becomes markedly indurated and tethered to the underlying fascia. Extracutaneous manifestations also occur. The diagnosis of NSF is based on the presence of characteristic clinical features in the setting of chronic kidney disease, and substantiated by skin histology. Differential diagnosis is with scleroderma, scleredema, scleromyxedema, graft-versus-host disease, etc. NSF has a relentlessly progressive course. While there is no consistently successful treatment for NSF, improving renal function seems to slow or arrest the progression of this condition. Because essentially all cases of NSF have developed following exposure to a gadolinium-containing contrast agent, prevention of this devastating condition involves the careful avoidance of administering these agents to individuals at risk.

Clinical, biological, and skin histopathologic effects of ionic macrocyclic and nonionic linear gadolinium chelates in a rat model of nephrogenic systemic fibrosis

OBJECTIVE

the purpose of this study was to compare the clinical, pathologic, and biochemical effects of repeated administrations of ionic macrocyclic or nonionic linear gadolinium chelates (GC) in rats with impaired renal function.

MATERIAL AND METHODS

rats submitted to subtotal nephrectomy were allocated to single injections of 2.5 mmol/kg of gadodiamide (nonionic linear chelate), nonformulated gadodiamide (ie, without the free ligand caldiamide), gadoterate (ionic macrocyclic chelate), or saline for 5 consecutive days. Blinded semi-quantitative histopathologic and immunohistochemical examinations of the skin were performed, as well as clinical, hematological, and biochemical follow-up. Rats were killed at day 11. Long-term (up to day 32) follow-up of rats was also performed in an auxiliary study.

RESULTS

epidermal lesions (ulcerations and scabs) were found in 4 of the 10 rats treated with nonformulated gadodiamide. Two rats survived the study period. Inflammatory signs were observed in this group. No clinical, hematological, or biochemical signs were observed in the saline and gadoterate- or gadodiamide-treated groups. Plasma fibroblast growth factor-23 levels were significantly higher in the gadodiamide group than in the gadoterate group (day 11). Decreased plasma transferrin-bound iron levels were measured in the nonformulated gadodiamide group. Histologic lesions were in the range: nonformulated gadodiamide (superficial epidermal lesions, inflammation, necrosis, and increased cellularity in papillary dermis) > gadodiamide (small superficial epidermal lesions and signs of degradation of collagen fibers in the dermis) > gadoterate (very few pathologic lesions, similar to control rats).

CONCLUSIONS

repeated administration of the nonionic linear GC gadodiamide to renally impaired rats is associated with more severe histologic lesions and higher FGF-23 plasma levels than the macrocyclic GC gadoterate.

Responses of human skin in organ culture and human skin fibroblasts to a gadolinium-based MRI contrast agent: comparison of skin from patients with end-stage renal disease and skin from healthy subjects

OBJECTIVE

Nephrogenic systemic fibrosis is a clinical syndrome occurring in a small subset of patients with end-stage renal disease (ESRD). Exposure to certain of the gadolinium-based contrast agents during magnetic resonance imaging appears to be a trigger. The pathogenesis of the disease is largely unknown. The present study addresses potential pathophysiologic mechanisms.

MATERIALS AND METHODS

We have compared responses in organ-cultured skin and skin fibroblasts from individuals with ESRD to responses of healthy control subjects to Omniscan treatment.

RESULTS

Treatment of skin from ESRD patients with Omniscan stimulated production of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinases-1, but not type I procollagen. The same treatment also stimulated an increase in hyaluronan production. Similar results were seen with skin from normal controls but basal levels were higher in ESRD patients. Fibroblasts in monolayer culture gave the same responses, but there were no differences based on whether the cells were isolated from the skin of healthy subjects or those with ESRD.

CONCLUSION

These data indicate that Omniscan exposure alters an enzyme/inhibitor system responsible for regulating collagen turnover in the skin and directly stimulates hyaluronan production. The higher basal levels of type I procollagen, matrix metalloproteinase-1, tissue inhibitor of metalloproteinases-1, and hyaluronan in the skin from ESRD patients could contribute to the sensitivity of this patient population to fibrotic changes, which might be induced by exposure to some of the gadolinium-based contrast agents.

Gadolinium-promoted precipitation of calcium phosphate is associated with profibrotic activation of RAW 264.7 macrophages

Gadolinium-based contrast agents are now being linked to nephrogenic systemic fibrosis (NSF). The exact mechanism by which gadolinium species act in the pathogenesis of NSF is not fully understood. In this study, we evaluated the effect of gadolinium chloride (GdCl(3)) on the precipitation of calcium phosphate, and examined the role of the gadolinium-containing precipitates in the profibrotic activation of macrophages. In a free-drift system, the induction time was markedly reduced with increasing concentration of GdCl(3), accompanied by alterations of morphology and composition of the precipitates. In complete cell culture medium, the addition of GdCl(3) resulted in formation of particles around 200-300 nm. In an in vitro cellular model with RAW 264.7 macrophages, GdCl(3) increased the production of TGF-beta1 and IL-6 via the activation of PKC and ERK signaling pathway. Our findings demonstrate that GdCl(3) promotes calcium phosphate precipitation and induces profibrotic activation of macrophages.

Gadolinium-containing magnetic resonance image contrast agent promotes fibrocyte differentiation

Gadolinium-containing magnetic resonance imaging (MRI) contrast agents such as Omniscan are associated with nephrogenic systemic fibrosis (NSF). To determine if Omniscan can affect the differentiation of monocytes into fibroblast-like cells called fibrocytes that are found in the fibrotic lesions of NSF, peripheral blood mononuclear cells (PBMCs) from NSF patients, hemodialysis patients without NSF, and healthy, renally sufficient controls were exposed to Omniscan in a standardized in vitro fibrocyte differentiation protocol. When added to PBMCs, the gadolinium-containing MRI contrast agent Omniscan generally had little effect on fibrocyte differentiation. However, 10(-8) to 10(-3) mg/mL Omniscan reduced the ability of the fibrocyte differentiation inhibitor serum amyloid P (SAP) to decrease fibrocyte differentiation in PBMCs from 15 of 17 healthy controls and one of three NSF patients. Omniscan reduced the ability of SAP to decrease fibrocyte differentiation from purified monocytes, indicating that the Omniscan effect does not require the presence of other cells (such as T cells) in the PBMCs. Omniscan also reduced the ability of a different fibrocyte differentiation inhibitor, interleukin-12, to decrease fibrocyte differentiation. These data suggest that Omniscan interferes with the regulatory action of signals that inhibit the differentiation of monocytes to fibrocytes. J. Magn. Reson. Imaging 2009;30:1284-1288. (c) 2009 Wiley-Liss, Inc.

Advanced kidney disease, gadolinium and nephrogenic systemic fibrosis: the perfect storm

PURPOSE OF REVIEW

Studies of a rare systemic fibrosing condition-entitled nephrogenic systemic fibrosis (NSF) are linked to gadolinium-based contrast (GBC) agent exposure in patients with advanced kidney disease. However, many patients with kidney disease are exposed to GBC agents, yet they do not develop this devastating disorder.

RECENT FINDINGS

NSF appears more likely to develop when the combination of advanced kidney disease, linear GBC agent exposure, and the presence of unique patient features converge. Linear GBC agents are more likely to promote NSF, probably due to chelate-Gd binding instability +/- underlying proinflammatory effects. Patients with advanced acute or chronic kidney disease (CKD) are at highest risk, in contrast to those with lower stages of CKD (stages I-III). Finally, whereas exposure to GBC agents in patients with advanced kidney disease is required for NSF to develop, it does not appear sufficient. Additional patient-specific co-factors, such as metabolic disorders, vascular injury, and inflammation, may also be necessary for NSF to occur.

SUMMARY

NSF develops when 'the perfect storm' of factors is present: unstable/pro-inflammatory GBC agent exposure, advanced kidney disease, and unique patient factors. Recognizing this combination of factors will hopefully allow this devastating condition to become of historical interest only.

Involvement of gadolinium chelates in the mechanism of nephrogenic systemic fibrosis: an update

Nephrogenic systemic fibrosis (NSF) is a highly debilitating scleroderma-like disease occurring exclusively in patients with severe or end-stage renal failure. Since the recognition of a link between gadolinium chelates (GCs) used as contrast agents for MR imaging and NSF by two independent European teams in 2006, numerous studies have described the clinical issues and investigated the mechanism of this disease. So far the most commonly reported hypothesis is based on the in vivo dechelation of GCs. The physicochemical properties of GCs, especially their thermodynamic and kinetic stabilities, are described in the present article. High kinetic stability provided by the macrocyclic structure, combined with high thermodynamic stability, minimizes the amount of free gadolinium released in the body. The current hypotheses regarding the pathophysiologic mechanism are critically discussed.

Prevalence of NSF following intravenous gadolinium-contrast media administration in dialysis patients with endstage renal disease

PURPOSE

To evaluate the prevalence of nephrogenic systemic fibrosis (NSF) in a patient population being at highest risk for developing this disease and to evaluate possible risk factors.

MATERIALS AND METHODS

The radiological records of 552 patients with ESRD being on hemodialysis (HD) or peritoneal dialysis (PD) were retrospectively reviewed to identify whether the patients underwent MR-examinations with or without intravenous administration of GBCA. In case of exposure to GBCA, the number of contrast injections, the benchmark and the cumulative doses of GBCA, and possible cofactors regarding pathogenesis of NSF were recorded. Diagnosis of NSF was confirmed either by deep skin biopsy or by review of medical and histopathological records. Data of NSF patients were compared with data of dialysis patients who did not develop NSF after MR-examinations.

RESULTS

146 dialysis patients underwent MRI without i.v.-administration of GBCA. No case of NSF was observed in this patient population. 195/552 patients proved to have a total number of 325 well-documented exposures to GBCA. Seven different types of GBCA were used during these MR-examinations. NSF prevalence rate was 1.6%. One patient died of NSF. Three different types of GBCA were involved in 6 NSF cases. 4/6 proved to be confounded cases. The cumulative dose of GBCA, history of thrombosis, recent surgery, and the combination of HD and PD proved to be significant cofactors for the development of NSF (p<.05). No significant difference regarding residual renal clearance (p=.898) and residual urine volume (p=.083) was found between NSF and non-NSF patients.

CONCLUSION

The prevalence of NSF proved to be much lower in this high risk patient group being exposed to GBCA compared to the literature. NSF was not observed in ESRD patients undergoing MRI without administration of GBCA. Our data support a positive association between cumulative dose of GBCA and development of NSF. No positive association was found between residual renal clearance and residual urine volume and NSF.

Hypercalcemia and overexpression of CYP27B1 in a patient with nephrogenic systemic fibrosis: clinical vignette and literature review

Nephrogenic systemic fibrosis (NSF) is a disease of thickened, hard, hyperpigmented skin lesions with or without systemic fibrosis occurring in patients with renal insufficiency and associated with the administration of gadolinium-containing contrast. The pathogenesis of this disease is unclear, and there is no definitive treatment. We describe a 71-yr-old patient with stable chronic lymphocytic leukemia (CLL), end-stage renal disease (ESRD), and NSF who presented with hypercalcemia in 2006. Before onset of renal insufficiency in 2002, serum calcium, phosphorus, and PTH levels were normal. In 2004, the patient began hemodialysis, and he was diagnosed with NSF in 2005, shortly after undergoing an MRI with gadolinium contrast administration. Over the next 6 mo, albumin-corrected serum total calcium levels rose from 9.9 to 13.1 mg/dl (normal range, 8.5-10.5 mg/dl) with normal serum phosphorus levels. On admission in September 2006, 1,25-dihydroxyvitamin D [1,25(OH)(2)D] levels were elevated at 130.7 pg/ml (normal range, 25.1-66.1 pg/ml). Biopsy of an NSF lesion showed increased 25-hydroxyvitamin D(3)-1-alpha hydroxylase (CYP27B1) immunostaining compared with the biopsy from a normal control. This is the first reported association of NSF with hypercalcemia caused by elevated 1,25(OH)(2)D levels. This metabolic disturbance should be sought in future cases to determine a connection between NSF, 1,25(OH)(2)D metabolism, and CYP27B1 activation in the skin, which may shed light on the pathogenesis of this unusual local and systemic fibrosing disorder.

Adverse renal and metabolic effects associated with oral sodium phosphate bowel preparation

Colorectal cancer can be prevented by the removal of adenomatous polyps during screening colonoscopy, but adequate bowel preparation is required. Oral sodium phosphate (OSP), an effective bowel purgative, is available over the counter and requires a substantially lower volume than polyethylene glycol-based preparative agents. Accumulating reports implicate OSP in electrolyte disturbances as well as acute kidney injury (AKI) in a syndrome termed phosphate nephropathy (a form of nephrocalcinosis). Despite published case reports and case series, the actual incidence, risk factors, and natural history of phosphate nephropathy remain largely undefined. Several recent observational studies have provided new information on these important issues while supporting a link between OSP and acute phosphate nephropathy as well as the development of chronic kidney disease in elderly patients, many of whom had a normal serum creatinine at the time of OSP ingestion. This review summarizes current knowledge about the renal complications of OSP, risk factors for its development, and the pathophysiology of acute and chronic kidney damage in nephrocalcinosis.