Strain differences of the effect of enucleation and anophthalmia on the size and growth of sensory cortices in mice

Analysis of the incidence, characteristics, and risk factors of complications during induction chemotherapy in children with high-risk neuroblastoma

Patients with high-risk neuroblastoma (HR-NB) exhibit suboptimal 5-year survival rates, leading to a widespread international preference for high-intensity chemotherapeutic regimens in these children. We analyzed the incidence and risk factors for complications during induction chemotherapy in children with HR-NB and tried to assist clinicians in predicting such complications and optimizing therapeutic strategy. The clinical data of children with HR-NB admitted to our hospital from January 2007 to December 2019 were retrospectively analyzed. The incidence, characteristics, and risk factors of complications (infection, hemorrhage, and chemotherapy-related adverse reactions (CRAR)) requiring hospitalization during induction chemotherapy in these children were explored. (1) A total of 108 patients with HR-NB were included in the final analysis. The overall infection rate was 92.6% (100/108), with the highest incidence of 71.3% observed during the first cycle. FN, bacterial infection, as well as fungal infection were common infectious complications in children with HR-NB during induction chemotherapy. (2) The overall hemorrhage rate was 24.1% (26/108), with the highest incidence of 14.8% also observed in the first cycle. Among the children with hemorrhage, there were 72% with bone marrow involved, while 65.0% of them had a high vanillylmandelic acid (VMA) value. And children with hemorrhage also exhibited neuron-specific enolase (NSE) ≥ 200 µg/L in 88.5% of cases and lactic dehydrogenase (LDH) ≥ 1000U/L in 73.1% of cases. (3) The incidence of CRAR rate was 100%, and 99.1% (107/108) patients experienced myelosuppression. The incidence of myelosuppression peaked in the third cycle, reaching up to 85.2%. Most children suffered severe myelosuppression existed with bone marrow metastases (76.3%), abnormal VMA (67.5%), and LDH ≥ 1000 U/L (60%). (4) Non-myelosuppressive adverse effects were observed in 75.9% children (82/108), with the highest incidence occurring in the third cycle at 42.6%. (5) Patients who experienced three types of complications had a lower median survival time (MST) of 54.4 months, a 3-year event-free survival (EFS) rate of (44.2 ± 10.7)%, and a 3-year overall survival (OS) rate of (75.8 ± 8.6)%, in comparison to those with only one or two complications, who had a higher MST of 59.5 months, a 3-year EFS rate of (73.5 ± 5.2)% (X2 = 10.457, P = 0.001), and a 3-year OS rate of (84.8 ± 4.1)% (X2 = 10.511, P = 0.001).

CONCLUSION

The presence of bone marrow involved and increased VMA were high-risk factors for infection, while NSE ≥ 200 µg/L and LDH ≥ 1000 U/L were high-risk factors for hemorrhage. For those children who had experienced severe myelosuppression, the presence of bone marrow metastases, increased VMA, and LDH ≥ 1000 U/L were their risk factors. The presence of bone involvement was a high-risk factor for children to have non-myelosuppressive adverse effects. Complications that arise during induction chemotherapy could negatively impact the children's prognosis and overall quality of life.

WHAT IS KNOWN

• The high-risk neuroblastoma (HR-NB) had a worse prognosis; there was a general international preference for high-intensity chemotherapeutic regimens in the induction phase to these children.

WHAT IS NEW

• We analyzed the incidence and risk factors of complications during induction chemotherapy in children with HR-NB and tried to help clinicians predict such complications and adopt optimized therapeutic strategy.

Enhanced maternal behaviors in a mouse model of congenital blindness

In mammals, mothering is one of the most important prosocial female behavior to promote survival, proper sensorimotor, and emotional development of the offspring. Different intrinsic and extrinsic factors can initiate and maintain these behaviors, such as hormonal, cerebral, and sensory changes. Infant cues also stimulate multisensory systems and orchestrate complex maternal responsiveness. To understand the maternal behavior driven by complex sensory interactions, it is necessary to comprehend the individual sensory systems by taking out other senses. An excellent model for investigating sensory regulation of maternal behavior is a murine model of congenital blindness, the ZRDBA mice, where both an anophthalmic and sighted mice are generated from the same litter. Therefore, this study aims to assess whether visual inputs are essential to driving maternal behaviors in mice. Maternal behaviors were assessed using three behavioral tests, including the pup retrieval test, the home cage maternal behavior test, and the maternal aggression test. Our results show that blind mothers (1) took less time to retrieve their offspring inside the nest, (2) spent more time nursing and licking their offspring in the second- and third-week postpartum, and (3) exhibited faster aggressive behaviors when exposed to an intruder male, compared to the sighted counterparts. This study provides evidence that congenitally blind mothers show more motivation to retrieve the pups, care, and protection towards their pups than sighted ones, likely due to a phenomenon of sensory compensation.

Cross-Modal Plasticity in Brains Deprived of Visual Input Before Vision

Unimodal sensory loss leads to structural and functional changes in both deprived and nondeprived brain circuits. This process is broadly known as cross-modal plasticity. The evidence available indicates that cross-modal changes underlie the enhanced performances of the spared sensory modalities in deprived subjects. Sensory experience is a fundamental driver of cross-modal plasticity, yet there is evidence from early-visually deprived models supporting an additional role for experience-independent factors. These experience-independent factors are expected to act early in development and constrain neuronal plasticity at later stages. Here we review the cross-modal adaptations elicited by congenital or induced visual deprivation prior to vision. In most of these studies, cross-modal adaptations have been addressed at the structural and functional levels. Here, we also appraise recent data regarding behavioral performance in early-visually deprived models. However, further research is needed to explore how circuit reorganization affects their function and what brings about enhanced behavioral performance.

Visual deprivation induces transient upregulation of oligodendrocyte progenitor cells in the subcortical white matter of mouse visual cortex

Sensory experience influences proliferation and differentiation of oligodendrocyte progenitor cells (OPCs). Enhanced sensorimotor experience promoted the lineage progression of OPCs and myelination in the gray matter and white matter (WM) of sensorimotor cortex. In the visual cortex, reduced experience reportedly delayed the maturation of myelination in the gray matter, but whether and how such experience alters the subcortical WM is unclear. Here we investigated if binocular enucleation from the onset of eye opening (i.e., P15) affects the cell state of OPCs in mouse primary visual cortex (V1). Proliferative cells in the WM declined nearly half over 3 days from postnatal day (P) 25. A 3-day BrdU-labeling showed gradual decline in proliferation rates from P19 to P28. Binocular enucleation resulted in an increase in the cycling state of the OPCs that were proliferated from P22 to P25 but not before or after this period. This increase in proliferative OPCs was not associated with lineage progression toward differentiated oligodendrocytes. Proliferative OPCs arose mostly due to symmetric cell division but also asymmetric formation of proliferative and quiescent OPCs. By P30, almost all the proliferated cells exited the cell cycle. Maturing oligodendrocytes among the proliferated cells increased at this age, but most of them disappeared over 25 days. The cell density of the maturing oligodendrocytes was unaffected by binocular enucleation, however. These data suggest that binocular enucleation transiently elevates proliferative OPCs in the subcortical WM of V1 during a specific period of the fourth postnatal week without subsequently affecting the number of maturing oligodendrocytes several days later.

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Binocular enucleation increased proliferative OPCs during P22-25 in the V1 WM.

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Proliferative OPCs decrease in half from P25 over 3 days.

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P22-25 proliferated cells nearly all exited the cell cycle by P30.

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Some P22-25 proliferated OPCs matured over 5 days but disappeared over 25 days.

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Visual loss did not influence oligodendrocyte maturation or its disappearance.

Structural brain plasticity induced by early blindness

It is well established that early blindness results in behavioural adaptations. While the functional effects of visual deprivation have been well researched, anatomical studies are scarce. The aim of this study was to investigate whole brain structural plasticity in a mouse model of congenital blindness. Volumetric analyses were conducted on high-resolution MRI images and histological sections from the same brains. These morphometric measurements were compared between anophthalmic and sighted ZRDBA mice obtained by breeding ZRDCT and DBA mice. Results from MRI analyses using the Multiple Automatically Generated Templates (MAGeT) method showed smaller volume for the primary visual cortex and superior colliculi in anophthalmic compared with sighted mice. Deformation-based morphometry revealed smaller volumes within the dorsal lateral geniculate nuclei and the lateral secondary visual cortex and larger volumes within olfactory areas, piriform cortex, orbital areas and the amygdala, in anophthalmic compared with sighted mice. Histological analyses revealed a larger volume for the amygdala and smaller volume for the superior colliculi, primary visual cortex and medial secondary visual cortex, in anophthalmic compared with sighted mice. The absence of superficial visual layers of the superior colliculus and the thinner cortical layer IV of the primary and secondary visual cortices may explain the smaller volume of these areas, although this was observed in a limited sample. The present study shows large-scale brain plasticity in a mouse model of congenital blindness. In addition, the congruence of MRI and histological findings support the use of MRI to investigate structural brain plasticity in the mouse.

The Effect of Onset Age of Visual Deprivation on Visual Cortex Surface Area Across-Species

Blindness early in life induces permanent alterations in brain anatomy, including reduced surface area of primary visual cortex (V1). Bilateral enucleation early in development causes greater reductions in primary visual cortex surface area than at later times. However, the time at which cortical surface area expansion is no longer sensitive to enucleation is not clearly established, despite being an important milestone for cortical development. Using histological and MRI techniques, we investigated how reductions in the surface area of V1 depends on the timing of blindness onset in rats, ferrets and humans. To compare data across species, we translated ages of all species to a common neuro-developmental event-time (ET) scale. Consistently, blindness during early cortical expansion induced large (~40%) reductions in V1 surface area, in rats and ferrets, while blindness occurring later had diminishing effects. Longitudinal measurements on ferrets confirmed that early enucleation disrupted cortical expansion, rather than inducing enhanced pruning. We modeled the ET associated with the conclusion of the effect of blindness on surface area at maturity (ETc), relative to the normal conclusion of visual cortex surface area expansion, (ETdev). A final analysis combining our data with extant published data confirmed that ETc occurred well before ETdev.

Self and the Brain. The Immune Metaphor

One of the fundamental questions in neuroscience is how brain activity relates to conscious experience. Even though self-consciousness is considered an emergent property of the brain network, a quantum physics-based theory assigns a momentum of consciousness to the single neuron level. In this work, we present a brain self theory from an evolutionary biological perspective by analogy with the immune self. In this scheme, perinatal reactivity to self inputs would guide the selection of neocortical neurons within the subplate, similarly to T lymphocytes in the thymus. Such self-driven neuronal selection would enable effective discrimination of external inputs and avoid harmful "autoreactive" responses. Multiple experimental and clinical evidences for this model are provided. Based on this self tenet, we outline the postulates of the so-called autophrenic diseases, to then make the case for schizophrenia, an archetypic disease with rupture of the self. Implications of this model are discussed, along with potential experimental verification.

Structural and functional brain reorganisation due to blindness: The special case of bilateral congenital anophthalmia

Investigating the changes in the brain that result from a loss of sensory input has provided significant insight into the considerable capacity of the brain to reorganise. One of the difficulties in studying sensory-deprived populations is that the time and extent of sensory loss vary significantly. In this review, we consider the changes in the human brain associated with complete absence of visual input resulting from bilateral congenital anophthalmia, in which the eyes fail to develop. We describe the functional reorganisation and associated structural and connectivity changes that occur in the brain of those affected by the condition. By considering animal models of this condition, we investigate the changes that may be occurring on a scale that is not captured by human in vivo imaging techniques. Finally, we lay out a model pathway for taking auditory information to the occipital cortex that may be specific to anophthalmia.

Growth and Behavior of Congenitally Anophthalmic Lee-Sung Pigs

Circadian rhythm is usually regulated by the environmental light-dark cycle. Congenitally anophthalmic miniature pigs provide a valuable model for the study of factors affecting circadian rhythms in the absence of visual exposure to the light-dark cycle. This study investigated the growth and daily behavior patterns of Lee-Sung pigs with congenital anophthalmia. Growth in 5 Lee-Sung pigs (LSP) with congenital anophthalmia (LSP-A) and 10 normally developed pigs (LSP-N) was assessed when they were 1 through 6 mo old. Behavioral studies using digital video recording were completed in 6 sexually mature LSP (3 LSP-A and 3 LSP-N). MRI showed that LSP-A lose their vision because of a lack of retinal input and optic chiasm development. LSP-N and LSP-A did not differ in body weight or size at 2, 4, and 6 mo of age. Behavior and activity pattern studies showed that both LSP-A and LSP-N were active mainly during daylight, but LSP-A spent significantly more time exploring their environment during the day (28%) and night (10%) than did LSP-N. This study revealed that growth performance was similar between LSP-A and normal pigs, but their behavior and activity patterns differed. LSP-A showed circadian rhythm abnormalities similar to those in blind humans. This study provides basic data on LSP-A as a model for studying compensatory cross-modal brain plasticity and hormone regulation in the absence of retinal input is deficient and for understanding the role of circadian rhythm regulation.

Alterations in cortical and thalamic connections of somatosensory cortex following early loss of vision

Early loss of vision produces dramatic changes in the functional organization and connectivity of the neocortex in cortical areas that normally process visual inputs, such as the primary and second visual area. This loss also results in alterations in the size, functional organization, and neural response properties of the primary somatosensory area, S1. However, the anatomical substrate for these functional changes in S1 has never been described. In the present investigation, we quantified the cortical and subcortical connections of S1 in animals that were bilaterally enucleated very early in development, prior to the formation of retino-geniculate and thalamocortical pathways. We found that S1 receives dense inputs from novel cortical fields, and that the density of existing cortical and thalamocortical connections was altered. Our results demonstrate that sensory systems develop in tandem and that alterations in sensory input in one system can affect the connections and organization of other sensory systems. Thus, therapeutic intervention following early loss of vision should focus not only on restoring vision, but also on augmenting the natural plasticity of the spared systems.

Congenital Anophthalmia and Binocular Neonatal Enucleation Differently Affect the Proteome of Primary and Secondary Visual Cortices in Mice

In blind individuals, visually deprived occipital areas are activated by non-visual stimuli. The extent of this cross-modal activation depends on the age at onset of blindness. Cross-modal inputs have access to several anatomical pathways to reactivate deprived visual areas. Ectopic cross-modal subcortical connections have been shown in anophthalmic animals but not in animals deprived of sight at a later age. Direct and indirect cross-modal cortical connections toward visual areas could also be involved, yet the number of neurons implicated is similar between blind mice and sighted controls. Changes at the axon terminal, dendritic spine or synaptic level are therefore expected upon loss of visual inputs. Here, the proteome of V1, V2M and V2L from P0-enucleated, anophthalmic and sighted mice, sharing a common genetic background (C57BL/6J x ZRDCT/An), was investigated by 2-D DIGE and Western analyses to identify molecular adaptations to enucleation and/or anophthalmia. Few proteins were differentially expressed in enucleated or anophthalmic mice in comparison to sighted mice. The loss of sight affected three pathways: metabolism, synaptic transmission and morphogenesis. Most changes were detected in V1, followed by V2M. Overall, cross-modal adaptations could be promoted in both models of early blindness but not through the exact same molecular strategy. A lower metabolic activity observed in visual areas of blind mice suggests that even if cross-modal inputs reactivate visual areas, they could remain suboptimally processed.