Relationship between brain iron dynamics and blood-brain barrier function during childhood: a quantitative magnetic resonance imaging study

BACKGROUND

Mounting evidence suggests that the blood-brain barrier (BBB) plays an important role in the regulation of brain iron homeostasis in normal brain development, but these imaging profiles remain to be elucidated. We aimed to establish a relationship between brain iron dynamics and BBB function during childhood using a combined quantitative magnetic resonance imaging (MRI) to depict both physiological systems along developmental trajectories.

METHODS

In this single-center prospective study, consecutive outpatients, 2-180 months of age, who underwent brain MRI (3.0-T scanner; Ingenia; Philips) between January 2020 and January 2021, were included. Children with histories of preterm birth or birth defects, abnormalities on MRI, and diagnoses that included neurological diseases during follow-up examinations through December 2022 were excluded. In addition to clinical MRI, quantitative susceptibility mapping (QSM; iron deposition measure) and diffusion-prepared pseudo-continuous arterial spin labeling (DP-pCASL; BBB function measure) were acquired. Atlas-based analyses for QSM and DP-pCASL were performed to investigate developmental trajectories of regional brain iron deposition and BBB function and their relationships.

RESULTS

A total of 78 children (mean age, 73.8 months ± 61.5 [SD]; 43 boys) were evaluated. Rapid magnetic susceptibility progression in the brain (Δsusceptibility value) was observed during the first two years (globus pallidus, 1.26 ± 0.18 [× 10- 3 ppm/month]; substantia nigra, 0.68 ± 0.16; thalamus, 0.15 ± 0.04). The scattergram between the Δsusceptibility value and the water exchange rate across the BBB (kw) divided by the cerebral blood flow was well fitted to the sigmoidal curve model, whose inflection point differed among each deep gray-matter nucleus (globus pallidus, 2.96-3.03 [mL/100 g]-1; substantia nigra, 3.12-3.15; thalamus, 3.64-3.67) in accordance with the regional heterogeneity of brain iron accumulation.

CONCLUSIONS

The combined quantitative MRI study of QSM and DP-pCASL for pediatric brains demonstrated the relationship between brain iron dynamics and BBB function during childhood.

TRIAL REGISTRATION

UMIN Clinical Trials Registry identifier: UMIN000039047, registered January 6, 2020.

Future Perspective for ALK-Positive Anaplastic Large Cell Lymphoma with Initial Central Nervous System (CNS) Involvement: Could Next-Generation ALK Inhibitors Replace Brain Radiotherapy for the Prevention of Further CNS Relapse?

Central nervous system (CNS) involvement in anaplastic large cell lymphoma (ALCL) at diagnosis is rare and leads to poor prognosis with the use of the standard ALCL99 protocol alone. CNS-directed intensive chemotherapy, such as an increased dose of intravenous MTX, increased dose of dexamethasone, intensified intrathecal therapy, and high-dose cytarabine, followed by cranial irradiation, has been shown to improve survival in this population. In this paper, the authors describe a 14-year-old male with an intracranial ALCL mass at onset who received CNS-directed chemotherapy followed by 23.4 Gy of whole-brain irradiation. After the first systemic relapse, the CNS-penetrating ALK inhibitor, alectinib, was applied; it has successfully maintained remission for 18 months without any adverse events. CNS-penetrating ALK inhibitor therapy might prevent CNS relapse in pediatric ALK-positive ALCL. Next-generation ALK inhibitors could be introduced as a promising treatment option, even for primary ALCL with CNS involvement, which could lead to the omission of cranial irradiation and avoid radiation-induced sequalae. Further evidence of CNS-penetrating ALK inhibitor combined therapy for primary ALK-positive ALCL is warranted to reduce radiation-induced sequalae in future treatments.

Systemic herpes simplex virus infection in a child with eczema herpeticum

Eczema herpeticum (EH) is a disseminated cutaneous infection with herpes simplex virus (HSV) that develops in patients with atopic dermatitis. The kinetics and clinical significance of HSV viremia in EH are poorly understood. Herein, we report HSV DNAemia in a child with EH 12 months after the completion of chemotherapy for Hodgkin lymphoma.

Lacosamide for children with paroxysmal kinesigenic dyskinesia

OBJECTIVES

This study was performed to evaluate the efficacy and tolerability of lacosamide (LCM) for paroxysmal kinesigenic dyskinesia (PKD) in children.

METHODS

We retrospectively reviewed the medical charts of pediatric PKD patients (aged <16 years) treated with LCM. Data regarding demographic characteristics, proline-rich transmembrane protein 2 (PRRT2) gene variant, clinical features of PKD, dose of LCM, efficacy, and adverse events were recorded.

RESULTS

Four eligible patients (3 males, 1 female) were identified, with an age of onset ranging from 8.3 to 14.7 years. PRRT2 variant was evaluated in three children and a c.649dupC variant was identified in one child with a positive family history. Attacks were bilateral in three children and left-sided in one. Two children had a family history of PKD and one child had a family history of benign infantile epilepsy. Treatment with carbamazepine failed in two children due to drowsiness and auditory disturbance. The initial dose of LCM was 50 mg/day in three children and 100 mg/day in one. All patients were attack-free within a few days. The maintenance dose was mostly similar to the initial dose. No adverse events related to LCM were reported during follow-up.

CONCLUSIONS

LCM is an effective and well-tolerated treatment for PKD in children, and low-dose treatment may be viable.

Postprandial changes in plasma GH and insulin concentrations, and responses to stimulation with GH-releasing hormone (GHRH) and GHRP-6 in calves around weaning

Changes in plasma concentrations of GH and insulin in response to feeding and stimulation with GH-releasing hormone (GHRH) or GH-releasing peptide (GHRP-6, a ligand for endogenous GH secretagogue receptors) were compared between 3-week-old (milk-fed) and 12-week-old (concentrate and hay-fed) calves. Feeding of a milk-replacer diet in 3-week-old animals significantly increased the basal (prefeeding) concentrations of GH, insulin and glucose in plasma, whereas feeding of concentrate and hay in 12-week-old animals did not cause a significant change in these traits. However, in the animals maintained on a milk-replacer diet until 12 weeks of age, postprandial plasma GH concentrations and AUC (area under the curve) were not different from those in the age-matched weaned group. The venous injection of either GHRH (0.25 microg/kg) or GHRP-6 (2.5 microg/kg) significantly increased plasma GH concentrations in both 3- and 12-week-old animals, but GH AUC was significantly greater in 3-week-old than in 12-week-old animals. Insulin concentration was transiently but significantly increased by the injection of GHRP-6 only in 12-week-old animals, the AUC being greater in 12-week-old than 3-week-old animals. From these results, we conclude that postprandial levels of plasma GH and insulin concentrations are altered after weaning and by aging, and that the quality of diets or development of the neuroendocrine functions in the digestive-pituitary system may be involved in this alteration.

Effects of nutritional conditions around weaning on carbonic anhydrase activity in the parotid gland and ruminal and abomasal epithelia of Holstein calves

Thirty-two male Holstein calves were used to investigate the effects of nutritional conditions around weaning and aging on carbonic anhydrase (CA) activity in the parotid gland and epithelium from the rumen and abomasum. We fed calf starter and lucerne hay as well as milk replacer (group N) or fed milk replacer either with (group S) or without (group M) administration of short-chain fatty acids (SCFA) through polypropylene tubing into the forestomach until 13 weeks of age. The diets were fed at 1000 hours and 1600 hours, and SCFA were administrated after milk replacer feeding at 1600 hours. Slaughter and tissue sampling were carried out between 1300 hours and 1430 hours at 1, 3, 7, 13, and 18 weeks of age. Tissue samples from five adult (1.5-2.0 years-old) Holstein steers were obtained from a local abattoir. In group N, CA activity in the parotid gland gradually and significantly increased toward the adult value, whilst in the epithelium from the rumen and abomasum, adult values were reached at 3 and 7 weeks of age, respectively. At 13 weeks, the activity for group N was significantly higher than that for the other two groups in the parotid gland, but there was no significant difference in the epithelium from the rumen and abomasum. The concentration of the carbonic isozyme VI in the parotid gland also changed with age but, in contrast to CA activity, had not reached adult levels by 13 weeks of age. In groups M and S, parotid saliva did not show any change toward an alkaline pH or toward a reciprocal change in the concentrations between Cl(-) and HCO(3)(-), even at 13 weeks of age. From these results we conclude that a concentrate-hay based diet around weaning has a crucial role in CA development in the parotid gland, but not in the epithelium of the rumen and abomasum.

Effects of aging and weaning on mRNA expression of leptin and CCK receptors in the calf rumen and abomasum

In order to know the effects of weaning and volatile fatty acid feeding on gastric leptin expression, we investigated the expression of leptin and CCK receptor mRNA in the bovine rumen, abomasum and duodenum using RT-PCR in 3-week-old pre-weaning, 13-week-old post-weaning and adult animals. Leptin mRNA was expressed in the rumen and abomasum of 3-week-old pre-weaning animals, but it was abolished in 13-week-old and adult animals. In the duodenum, leptin expression was observed in the 3-, 13-week-old and adult animals. In the rumen, CCK(A) receptor mRNA was expressed in 3-week-old animals, but not in 13-week-old and adult animals. In the abomasum, CCK(B) receptor expression gradually decreased from 3-week-old to adult animals. Expression of CCK(B) receptor and of CCK(A) receptor was slight in the rumen and abomasum, respectively. In the next study, we examined the effect of weaning of 6 weeks or non-weaning (fed on milk replacer alone (milk) or milk replacer with volatile fatty acids (milk+VFA) until 13 weeks old) on leptin mRNA expression in the rumen and abomasum. In 13-week-old calf rumen and abomasum, leptin mRNA expression was detected in non-weaning milk-fed animals at 13 weeks old, although it was not observed in weaning and non-weaned milk+VFA-fed animals. The change in CCK(A) receptor expression in the rumen was similar to those of leptin mRNA expression. CCK(B) receptor transcription in the abomasum of milk-fed animals was higher than that of the weaning and milk+VFA-fed animals. These results indicate that leptin expression is coincident with CCK receptor expression in calf stomachs, and that leptin and CCK receptor mRNA expression are affected by the change in the physiological status brought about by weaning and VFA feeding.