Potential toxicity evaluation and comparison within multiple mice organs after repeat injections of linear versus macrocyclic gadolinium-based contrast agents: A comprehensive and time course study

Deposition of Gadolinium in the Central and Peripheral Nervous Systems and Its Effects on Sensory, Cognitive, and Athletic Implications after Multiple Injections of Gadolinium-Based Contrast Agents in Rats

BACKGROUND AND PURPOSE

After repeat administration of gadolinium-based contrast agents (GBCAs), the association between gadolinium retention in the central and peripheral nervous systems and the main manifestations of myelopathy and progressive neurologic symptoms remains unclear. We investigated the effects of the repeat administration of GBCAs on gadolinium retention in the central and peripheral nervous systems and the sensory, cognitive, and athletic implications.

MATERIALS AND METHODS

Forty-eight male Wistar rats (6 weeks of age) were randomly divided into 4 experimental groups (12 rats in each group): the gadodiamide group (linear and nonionic GBCAs), the gadopentetate dimeglumine group (linear and ionic GBCAs), the gadoterate meglumine group (macrocyclic and ionic GBCAs), and the control group (0.9% saline solution). The brains of the rats were scanned using 9.4T MRI. Sensory behavioral tests were performed to assess the effect of GBCAs on pain sensitivity function. Gadolinium deposition in the brain, spinal cord, and peripheral nerves was determined by inductively coupled plasma mass-spectrometry. Transmission electron microscopy was used to observe the microscopic distribution of gadolinium after deposition in the spinal cord. The histopathologic features in the spinal cord were analyzed by H&E staining, Nissl staining, glial fibrillary acidic protein staining, and neuron-specific enolase staining after administration of GBCAs.

RESULTS

All GBCAs resulted in gadolinium deposition in the central and peripheral nerve tissues, with the highest deposition in the sciatic nerve tissue (mean, 62.86 [SD, 12.56] nmol/g). Decreased muscle power, impairment of spatial cognitive function power, and pain hypersensitivity to thermal and mechanical stimuli were observed after exposure to gadodiamide. At the spinal cord, transmission electron microscopy found that the region of gadolinium depositions had a spheric structure similar to "sea urchins" and was mainly located near the vascular basement membrane.

CONCLUSIONS

Multiple injections of GBCAs caused gadolinium deposition in the brain, spinal cord, and peripheral nerves, especially in the spinal cords of the gadodiamide group. Gadodiamide led to pain hypersensitivity and decreased muscle power and cognitive ability. For the patients who are hypersensitive to pain and need multiple MRI examinations, we recommend using macrocyclic GBCAs and the lowest dose possible.

Toxicity Mechanisms of Gadolinium and Gadolinium-Based Contrast Agents-A Review

Gadolinium-based contrast agents (GBCAs) have been used for more than 30 years to improve magnetic resonance imaging, a crucial tool for medical diagnosis and treatment monitoring across multiple clinical settings. Studies have shown that exposure to GBCAs is associated with gadolinium release and tissue deposition that may cause short- and long-term toxicity in several organs, including the kidney, the main excretion organ of most GBCAs. Considering the increasing prevalence of chronic kidney disease worldwide and that most of the complications following GBCA exposure are associated with renal dysfunction, the mechanisms underlying GBCA toxicity, especially renal toxicity, are particularly important. A better understanding of the gadolinium mechanisms of toxicity may contribute to clarify the safety and/or potential risks associated with the use of GBCAs. In this work, a review of the recent literature concerning gadolinium and GBCA mechanisms of toxicity was performed.

Acetabular Labral Repair and Selective Labral Debridement Show No Significant Difference in Clinical Outcomes at a Minimum 2-Year Follow-Up

PURPOSE

To compare the outcomes of arthroscopic labral repair using looped type suture with a matched-pair selective labral debridement with a minimum 2-years follow-up.

METHODS

We identified 378 patients undergoing primary arthroscopic labral repair using loop-suture and selective labral debridement from January 2, 2018, to December 28, 2020. The labral repair group was matched 1:1 to a selective labral debridement control group by age, sex, body mass index, follow-up period, lateral center-edge angle, Tönnis grade, and preoperative joint space. Before surgery, 3-Tesla radial magnetic resonance imaging with a 3-dimensional double-echo steady-state sequence was obtained following failed nonoperative treatment lasting more than 3 months. Follow-up imaging was conducted at a minimum of 2 years. In both groups, the ratio of positive slices in which a disrupted chondrolabral junction was observed between the 2 o'clock and 11 o'clock positions was measured. Patient-reported outcome scores included the Harris Hip Score, visual analog score, Hip Outcome Score Activities of Daily Living Subscale, and Hip Outcome Score of Sport-Specific Subscale.

RESULTS

In total, 76 patients of the repair group were matched to 76 controls with a minimum 2-years follow-up (repair vs control: 2.6 ± 0.4 vs 2.6 ± 0.4 years, P = .775). The repair group experienced a 2-fold improvement (0.6 ± 0.1 to 0.3 ± 0.1, P＜.001). Although the selective debridement group experienced a 3-fold improvement (0.3 ± 0.1 to 0.1 ± 0.1, P＜.001). Significant improvement of the patient-reported outcome was shown in both groups at final follow-up without significant difference between the 2 groups.

CONCLUSIONS

The mid-term clinical outcomes are comparable between the labral repair using looped type suture and selective labral debridement group. Although a gap between the labrum and articular cartilage may appear in 3-dimensional double-echo steady-state magnetic resonance imaging results after labral repair, it does not correspond with clinical outcomes.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Gadolinium retention in a rat model of subtotal renal failure: are there differences among macrocyclic GBCAs?

BACKGROUND

Gd levels are higher in tissues of animals with compromised renal function, but studies to compare levels after exposure to different macrocyclic gadolinium-based contrast agents (GBCAs) are lacking. We compared Gd levels in tissues of subtotally nephrectomised (SN) rats after repeated exposure to macrocyclic GBCAs.

METHODS

Sprague-Dawley SN male rats (19 per group) received 16 injections of gadoteridol, gadobutrol, or gadoterate meglumine at 0.6 mmol Gd/kg 4 times/weeks over 4 weeks. A control group of healthy male rats (n = 10) received gadoteridol at the same dosage. Plasma urea and creatinine levels were monitored. Blood, cerebrum, cerebellum, liver, femur, kidney(s), skin and peripheral nerves were harvested for Gd determination by inductively coupled plasma-mass spectrometry at 28 and 56 days after the end of treatment.

RESULTS

Plasma urea and creatinine levels were roughly twofold higher in SN rats than in healthy rats at all timepoints. At day 28, Gd levels in the peripheral nerves of gadobutrol- or gadoterate-treated SN animals were 5.4 or 7.2 times higher than in gadoteridol-treated animals (p < 0.001). Higher Gd levels after administration of gadobutrol or gadoterate versus gadoteridol were also determined in kidneys (p ≤ 0.002), cerebrum (p ≤ 0.001), cerebellum (p ≤ 0.003), skin (p ≥ 0.244), liver (p ≥ 0.053), and femur (p ≥ 0.271). At day 56, lower Gd levels were determined both in SN and healthy rats for all GBCAs and tissues, except the femur.

CONCLUSIONS

Gd tissue levels were lower following gadoteridol exposure than following gadobutrol or gadoterate exposure.

Gadolinium Retention in the Brain of Mother and Pup Mouse: Effect of Pregnancy and Repeated Administration of Gadolinium‐Based Contrast Agents

Background

The association of repeated administration of gadolinium‐based contrast agents (GBCAs) with the gadolinium (Gd) retention in the brains of mother and fetus remains unclear.

Purpose

To investigate the effects of pregnancy and repeated administration of GBCAs on Gd retention in the brains of mother and pup mice.

Study type

Cross‐sectional cohort toxicity study.

Animal Model

From gestational days 16–19, pregnant (n = 48) BALB/c mice.

Field Strength

A 9.4 T and fast spin echo sequence.

Assessment

Half of the mother mice (n = 24) were killed at postnatal day 1 (P1) for inductively coupled plasma mass spectrometry (ICP‐MS) and transmission electron microscopy (TEM). Besides the ICP‐MS and TEM, four pups were randomly selected from each mother and killed at P1 for ultraperformance liquid chromatography mass spectrometry (UPLC‐MS) and Nissl staining.

Statistical Tests

One‐way analysis of variance and unpaired t‐test.

Results

In the group of gadodiamide, retention of Gd in the brains of pregnant mice was significantly lower than that of nonpregnant mice in the area of the deep cerebellar nuclei (DCN) (10.35 ± 2.16 nmol/g vs. 18.74 ± 3.65 nmol/g). Retention of Gd in the DCN of pups whose mothers were administered gadoterate meglumine was significantly lower than that of pups whose mothers were administered gadodiamide (0.21 ± 0.09 nmol/g vs. 6.15 ± 3.21 nmol/g) at P1. In mice treated with gadodiamide, most of the retained Gd in the brain tissue was insoluble (19.5% ± 9.5% of the recovered amount corresponded to the intact complex in the DCN).

Data Conclusion

In different brain areas of the mother and pup mice, the retention of Gd after gadoterate meglumine administration was lower than that of gadodiamide and gadopentetate dimeglumine administration, and almost all the detected Gd in pups' brains was intact soluble GBCAs.

Evidence Level

1

Technical Efficacy

Stage 2