Effects of Dehydration on Brain Perfusion and Infarct Core After Acute Middle Cerebral Artery Occlusion in Rats: Evidence From High-Field Magnetic Resonance Imaging

Tsai, Yuan-Hsiung; Yang, Jen Ming; Lee, I‐Neng; Yang, Jen-Tsung; Lin, Li-Mei; Huang, Yen-Chu; Yeh, Mei-Yu; Weng, Hsu–Huei; Su, Chia‐Hao

doi:10.3389/fneur.2018.00786

Cited by 19 publications

(16 citation statements)

References 20 publications

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“…Unlike SWS and urine osmolality, other physiological markers such as blood pressure, heart rate, and hematocrit as well as cerebral blood flow velocity were not observed to be affected by dehydration. Other studies found a slight decrease in blood pressure and cerebral blood flow ( Trangmar et al, 2014 , 2015 ; Tsai et al, 2018 ; Watso and Farquhar, 2019 ) and an increase in heart rate variability ( Castro-Sepulveda et al, 2014 ) upon mild hypertonic dehydration. However, these studies also measured vessel diameter, which is a critical parameter in assessing cerebral blood flow and could not be reliably assessed in this study.…”

Section: Discussionmentioning

confidence: 90%

Cerebral Ultrasound Time-Harmonic Elastography Reveals Softening of the Human Brain Due to Dehydration

et al. 2021

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Hydration influences blood volume, blood viscosity, and water content in soft tissues – variables that determine the biophysical properties of biological tissues including their stiffness. In the brain, the relationship between hydration and stiffness is largely unknown despite the increasing importance of stiffness as a quantitative imaging marker. In this study, we investigated cerebral stiffness (CS) in 12 healthy volunteers using ultrasound time-harmonic elastography (THE) in different hydration states: (i) during normal hydration, (ii) after overnight fasting, and (iii) within 1 h of drinking 12 ml of water per kg body weight. In addition, we correlated shear wave speed (SWS) with urine osmolality and hematocrit. SWS at normal hydration was 1.64 ± 0.02 m/s and decreased to 1.57 ± 0.04 m/s (p < 0.001) after overnight fasting. SWS increased again to 1.63 ± 0.01 m/s within 30 min of water drinking, returning to values measured during normal hydration (p = 0.85). Urine osmolality at normal hydration (324 ± 148 mOsm/kg) increased to 784 ± 107 mOsm/kg (p < 0.001) after fasting and returned to normal (288 ± 128 mOsm/kg, p = 0.83) after water drinking. SWS and urine osmolality correlated linearly (r = −0.68, p < 0.001), while SWS and hematocrit did not correlate (p = 0.31). Our results suggest that mild dehydration in the range of diurnal fluctuations is associated with significant softening of brain tissue, possibly due to reduced cerebral perfusion. To ensure consistency of results, it is important that cerebral elastography with a standardized protocol is performed during normal hydration.

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Section: Discussionmentioning

confidence: 90%

Cerebral Ultrasound Time-Harmonic Elastography Reveals Softening of the Human Brain Due to Dehydration

et al. 2021

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“…In one study, chronic dehydration was found altering metabolic activity in some regions of the brain, namely a reduced metabolism (Gross et al., 1985). More recently, it was observed how 48‐hr water deprivation prior to middle cerebral artery (MCA) occlusion was associated with a larger volume of the infarction and a larger progression of the infarct volume, as measured with high‐field MRI (Tsai et al., 2018). Such results have been confirmed in humans, showing an association between a BUN/Cr > 15 at admission, cerebral oedema and size of hypodensity at CT in the MCA territory (Bhatia et al., 2015).…”

Section: Discussionmentioning

confidence: 99%

A physiological perspective of the associations between hydration status and CTP neuroimaging parameters in hyper‐acute ischaemic stroke patients

Stella

Ajčević

Furlanis

et al. 2021

Clin Physio Funct Imaging

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Hypohydration may be associated with vascular diseases, poor prognosis and worse outcomes in stroke. The underlying mechanisms have not yet been completely investigated, although some studies suggested potential associations with brain perfusion and collaterals status. Despite the potentially different mechanisms promoting serum or urine biomarkers of hypohydration, few studies have investigated both markers separately. A prospective descriptive study was conducted in stroke patients admitted to a stroke unit <4.5 h from symptoms onset. All patients underwent neurological evaluation and whole‐brain computed tomography perfusion (CTP) upon admission. Blood and urine samples were immediately collected at admission, and patients were defined as “hypohydrated” (HYP) if blood urea nitrogen‐to‐creatinine ratio was >15 and “underhydrated” (UND) if urine osmolality was >500 mOsm/kg. CTP images were processed to calculate core, penumbra, their mismatch and total hypoperfused volume. Forty‐six patients were included and were grouped according to hydration status. Despite no different NIHSS at baseline, at CTP HYP was independently associated with core‐penumbra mismatch (β: −0.157, 95% CI: −0.305 to −0.009; p = .04), while UND was independently associated with the total hypoperfused volume (β: 31.502, 95% CI: 8.522‒54.481; p = .01). Using CTP imaging, this study proposes a physiological insight of some possible mechanisms associated with the better outcomes observed in acute stroke patients when properly hydrated. These results suggest different associations between hydration status and CTP parameters depending on serum or urine biomarkers in the hyper‐acute phase and encourage the association between hydration status and stroke characteristics.

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“…Dehydration at the time of stroke has been acknowledged as being associated with early neurological deterioration and poor functional outcome [ 2 , 3 ]. In our previous animal study with a dehydration protocol of water deprivation for 48 h, approximately 50% of the rats died after MCAO surgery [ 6 ]. In the current study, we shifted the dehydration protocol to water deprivation for 24 h and confirmed the status of dehydration with urine analysis, but the mortality rate immediately after MCAO surgery was maintained high (20%) and even slightly higher in the following stages of study.…”

Section: Discussionmentioning

confidence: 99%

“…Dehydration has a high prevalence in ischemic stroke and is associated with stroke-in-evolution and functional outcome [ 1 , 2 , 3 , 4 ]. The reasons for these observations are based on the concept that dehydrated status may reduce brain perfusion, decrease collateral blood flow, and aggravate ischemic brain injury [ 5 , 6 , 7 , 8 ]. Current acute stroke guidelines recommend rehydration for patients who are under dehydrated situations [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of Early Rehydration on Brain Perfusion and Infarct Core after Middle Cerebral Artery Occlusion in Rats

Tsai

Lee

et al. 2021

Brain Sciences

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Imaging evidence for the effect of rehydration on cerebral perfusion and brain ischemia has never been proposed in the literature. This study aimed to test the hypothesis that early rehydration treatment can improve cerebral perfusion and decrease infarct volume, consequently reducing mortality of dehydrated stroke animals. Methods: Thirty dehydrated experimental rats were randomly assigned to either a rehydration or control group after middle cerebral artery occlusion (MCAO). Diffusion-weighted imaging and dynamic contrast enhancement perfusion imaging were performed at 30 min and 6 h after MCAO using a 9.4T MR imaging scanner to measure the infarct volume and brain perfusion. Results: The survival rates after the first MRI scan were 91.7% for the rehydration group and 58.3% for the control group (p = 0.059). The survival rates after the second MRI scan were 66.7% for the rehydration group, and 8.3% of the control group survived (p = 0.003). The infarct volume of the rehydration group was significantly smaller than control group at 30 min after MCAO (p = 0.007). The delay time and time to maximum were significantly shorter in the rehydration group at 30 min (p = 0.004 and 0.035, respectively). Conclusions: The findings suggest that early rehydration therapy can decrease the infarct volume, shorten the delay time of cerebral perfusion, and increase survival of dehydrated ischemic-stroke rats. This preliminary study provided imaging evidence that more intensive early hydration therapies and reperfusion strategies may be necessary for acute stroke patients with dehydrated status.

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Effects of Dehydration on Brain Perfusion and Infarct Core After Acute Middle Cerebral Artery Occlusion in Rats: Evidence From High-Field Magnetic Resonance Imaging

Cited by 19 publications

References 20 publications

Cerebral Ultrasound Time-Harmonic Elastography Reveals Softening of the Human Brain Due to Dehydration

Cerebral Ultrasound Time-Harmonic Elastography Reveals Softening of the Human Brain Due to Dehydration

A physiological perspective of the associations between hydration status and CTP neuroimaging parameters in hyper‐acute ischaemic stroke patients

Effects of Early Rehydration on Brain Perfusion and Infarct Core after Middle Cerebral Artery Occlusion in Rats

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