Temperature variability in the day–night cycle is associated with further intracranial pressure during therapeutic hypothermia

Nogueira, Adriano Barreto; Annen, Eva; Boss, Oliver; Farokhzad, Faraneh; Sikorski, Christopher; Keller, Emanuela

doi:10.1186/s12967-017-1272-y

Cited by 6 publications

(15 citation statements)

References 13 publications

(13 reference statements)

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“…A stronger indication that the circadian rhythm is a primary factor to predict brain injury is being unveiled by our ongoing research showing that the pattern of oscillation of core body temperature in the day–night cycle in high-grade SAH patients correlates with further intracranial pressure ( 2 ). The patients analyzed in this study underwent sedation and targeted temperature management (33–33.9°C) using intravascular catheter.…”

Section: Rationale Of the Hypothesismentioning

confidence: 99%

“…Specifically, the ratio between the coefficient of variation of the nocturnal (starting at 18:00) and the preceding diurnal periods (starting at 6:00) [temperature variability (TV)] correlated with ICP 24 ( p < 0.001). The formula derived from regression analysis is ICP 24 = 6 (4 − TV) mmHg ( 2 ).…”

Section: Rationale Of the Hypothesismentioning

confidence: 99%

“…Due to potential therapeutic implications of the hypothesis (as detailed below), a crucial analysis is the correlation between CRY n/d and TV and ICP 24 . A caveat of this analysis is that TV has been shown to correlate with ICP 24 only under strict control of temperature, with daily mean <35°C ( 2 ).…”

Section: Hypothesis Testingmentioning

confidence: 99%

“…Following this rationale, we discovered that the ratio between the mean temperature during the sleep and the preceding wake period correlates with the likelihood of seizure occurrence in the following 24 h in epileptic patients ( 1 , 3 ). We have recently showed that this concept works even with high-grade subarachnoid hemorrhage (SAH) patients under sedation and therapeutic hypothermia induced by intravascular catheter ( 2 ). In this case, the ratio between the coefficient of variation of temperature during the nocturnal and the preceding diurnal periods correlates with the mean intracranial pressure in the following 24 h (ICP 24 ) ( 2 ).…”

Section: Introductionmentioning

confidence: 99%

“…We have recently showed that this concept works even with high-grade subarachnoid hemorrhage (SAH) patients under sedation and therapeutic hypothermia induced by intravascular catheter ( 2 ). In this case, the ratio between the coefficient of variation of temperature during the nocturnal and the preceding diurnal periods correlates with the mean intracranial pressure in the following 24 h (ICP 24 ) ( 2 ). Collectively, these findings open the possibility to reduce brain injury through circadian rhythm modulation.…”

Section: Introductionmentioning

confidence: 99%

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Hypothesis on the Role of Cryptochromes in Inflammation and Subarachnoid Hemorrhage Outcome

Nogueira

Veiga

et al. 2017

Front. Neurol.

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We have recently found that the temperature variability (TV) in the day–night cycle may predict the mean intracranial pressure in the following 24 h (ICP24) in subarachnoid hemorrhage (SAH) patients under multimodality monitoring, sedation, and hypothermia (<35°C). Specifically, we found that ICP24 = 6 (4 − TV) mmHg. TV is the ratio between the coefficient of variation of temperature during the nocturnal and the preceding diurnal periods. This result suggests that the circadian clock reflects brain plasticity mechanisms and its malfunctioning leads to deterioration of the neurologic status. The sleep–wake cycle is absent in these patients and their circadian clock can function properly only by environment light-independent mechanisms. One mechanism involves the circadian clock proteins named cryptochromes (CRYs). CRYs are highly preserved and widespread in the evolutionary tree, are expressed in different cell types in humans [type II CRYs, in two forms: human cryptochrome 1 and 2 (hCRY1 and hCRY2)], and in certain species, respond to blue light and play role in magnetoreception. Interestingly, SAH outcome seems to correlate with inflammation, and CRYs decrease inflammatory activity. Our hypothesis derived from these observations is that CRYs modulate the circadian oscillation of temperature even during therapeutic hypothermia and improve outcome in SAH through decrease in inflammation. A strategy to test this hypothesis is to measure periodically during the acute phase of high-grade SAH the level of CRYs in cerebrospinal fluid (CSF) and circulating white blood cells, and to correlate these levels with outcome, TV, ICP24, and pro- and anti-inflammatory markers in CSF and blood. If this hypothesis is true, the development of therapies targeting inflammation in SAH could take advantage of cryptochrome properties. It has been shown that blue light phototherapy increases the expression of CRYs in blood mononuclear cells in jaundiced neonates. Likewise, visual stimulus with flashing light improves Alzheimer’s disease features in experimental model and there is a prominent expression of CRYs in the retina. Remarkably, recent evidence showed that hCRY2 responds to electromagnetic fields, which could be one elusive mechanism of action of transcranial magnetic stimulation and a reason for its use in SAH.

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Section: Rationale Of the Hypothesismentioning

confidence: 99%

Section: Rationale Of the Hypothesismentioning

confidence: 99%

Section: Hypothesis Testingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hypothesis on the Role of Cryptochromes in Inflammation and Subarachnoid Hemorrhage Outcome

Nogueira

Veiga

et al. 2017

Front. Neurol.

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Adult human neurogenesis: early studies clarify recent controversies and go further

et al. 2021

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Adult Human Neurogenesis: Early Studies Clarify Recent Controversies and Go Further

Nogueira

Hoshino

Ortega

et al. 2021

Preprint

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Evidence on adult mammalian neurogenesis and scarce studies with human brains led to the idea that adult human neurogenesis occurs in the subgranular zone (SGZ) of the dentate gyrus and in the subventricular zone (SVZ). However, findings published from 2018 rekindled controversies on adult human SGZ neurogenesis. We systematically reviewed studies published during the first decade of characterization of adult human neurogenesis (1994–2004) – when the two-neurogenic-niche concept in humans was consolidated – and compared with further studies. The synthesis of both periods is that adult human neurogenesis occurs in an intensity ranging from practically zero to a level comparable to adult mammalian neurogenesis in general, which is the prevailing conclusion. Nonetheless, Bernier and colleagues showed in 2000 intriguing indications of adult human neurogenesis in a broad area including the limbic system. Likewise, we later showed evidence that limbic and hypothalamic structures surrounding the circumventricular organs form a continuous zone expressing neurogenesis markers encompassing the SGZ and SVZ. The conclusion is that publications from 2018 on adult human neurogenesis did not bring novel findings on location of neurogenic niches. Rather, we expect that the search of neurogenesis beyond the canonical adult mammalian neurogenic niches will confirm our indications that adult human neurogenesis is orchestrated in a broad brain area. We predict that this approach may, for example, clarify that human hippocampal neurogenesis occurs mostly in the CA1-subiculum zone and that the previously identified human rostral migratory stream arising from the SVZ is indeed the column of the fornix expressing neurogenesis markers.

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Temperature variability in the day–night cycle is associated with further intracranial pressure during therapeutic hypothermia

Cited by 6 publications

References 13 publications

Hypothesis on the Role of Cryptochromes in Inflammation and Subarachnoid Hemorrhage Outcome

Hypothesis on the Role of Cryptochromes in Inflammation and Subarachnoid Hemorrhage Outcome

Adult human neurogenesis: early studies clarify recent controversies and go further

Adult Human Neurogenesis: Early Studies Clarify Recent Controversies and Go Further

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