Fundamental research progress of mild hypothermia in cerebral protection

Value of Ventricular Intracranial Pressure Monitoring for Traumatic Bifrontal Contusions

OBJECTIVE

To investigate clinical efficacy of and optimal therapeutic strategy for ventricular intracranial pressure monitoring (V-ICPM) in patients with traumatic bifrontal contusions (TBCs).

METHODS

From 8760 patients with traumatic brain injury treated between January 2010 and January 2016, a retrospective analysis was performed on 105 patients with TBCs who underwent V-ICPM and 282 patients with TBCs who did not. All patients underwent treatment at the 101st Hospital of PLA, Wuxi, China. Rates of successful conservative treatment, decompressive craniectomy, and bifrontal craniotomy; incidence of neurologic dysfunction; length of stay; and medical expenses were compared between groups.

RESULTS

Glasgow Outcome Scale was used to assess all patients during follow-up (range, 6 months to 5.5 years). There were no significant differences in prognosis between the 2 groups (P = 0.100). Compared with the patients who did not undergo V-ICPM, the V-ICPM group had a significantly better successful conservative treatment rate (64.8% vs. 47.2%, P = 0.002), decompressive craniectomy rate (8.1% vs. 22.1%, P = 0.008), and bifrontal craniotomy rate (5.7% vs. 15.6%, P = 0.01); shorter length of stay (P = 0.000); and lower medical expenses (P = 0.004).

CONCLUSIONS

Patients with TBCs should be strictly, closely, and dynamically observed by neurosurgery intensive care unit physicians and nurses. Patients should undergo ventricular intracranial pressure probe implantation in a timely manner. V-ICPM can help optimize treatment. Although V-ICPM did not significantly improve the prognosis of patients, it had many other advantages. V-ICPM warrants further clinical research and may be beneficial for patients with TBCs.

Impact of novel N-aryl piperamide NO donors on NF-κB translocation in neuroinflammation: rational drug-designing synthesis and biological evaluation

NO donor drugs showed a significant therapeutic effect in the treatment of many diseases, such as arteriopathies, various acute and chronic inflammatory conditions, and several degenerative diseases. NO-releasing anti-inflammatory drugs are the prototypes of a novel class of compounds, combining the pharmacological activities of anti-inflammatory and anti-nociceptive of drugs with those of NO, thus possessing potential therapeutic applications in a great variety of diseases. In this study, we designed and predicted biological activity by targeting cyclooxygenase type 2 (COX-2) and NF-κB subunits and pharmacological profiling along with toxicity predictions of various N-aryl piperamides linked via an ester bond to a spacer that is bound to a NO-releasing moiety (-ONO2). The result of absorption, distribution, metabolism and excretion and Docking studies indicated that among 51 designed molecules PA-3′K showed the best binding potential in both the substrate and inhibitory binding pocket of the COX-2 enzyme with affinity values of –9.33 and –5.12 for PDB ID 1CVU and 3LN1, respectively, thereby having the potential to be developed as a therapeutic agent. The results of cell viabilities indicated that PA-3′k possesses the best cell viability property with respect to its dose (17.33 ng/ml), with 67.76% and 67.93% viable cells for CHME3 and SVG cell lines, respectively.

Therapeutic Hypothermia for Asphyxial Out-of-Hospital Cardiac Arrest Due to Drowning: A Systematic Review of Case Series and Case Reports

The objective of this review was to summarize published evidence of the effectiveness of therapeutic hypothermia in patients with drowning-associated asphyxial out-of-hospital cardiac arrest (OHCA) and to explore any preliminary favorable factors in the management of therapeutic hypothermia to improve survival and neurological outcome. Drowning may result in asphyxial OHCA or hypothermic OHCA, but the former does not provide any potential neuroprotective effect as the latter may do. Electronic literature searches of Ovid Medline, Embase, Cochrane Library, and Scopus were performed for all years from inception to July 2016. Primary studies in the form of case reports, letters to the editor, and others with higher quality are included, but guidelines, reviews, editorials, textbook chapters, conference abstracts, and nonhuman studies are excluded. Non-English articles are excluded. Relevant studies are then deemed eligible if the drowning OHCA patient's initial temperature was above 28°C, which implies asphyxial cardiac arrest, and intentional therapeutic hypothermia was instituted. Because of the narrow scope of interest and strict definition of the condition, limited studies addressed it, and no randomized controlled trials (RCT) could be selected. Thirteen studies covering 35 patients are included. No quantitative synthesis, assessment of study quality, or assessment of bias was performed. It is conjectured that extended therapeutic hypothermia of 48-72 hours might help prevent reperfusion injury during the intermediate phase of postcardiac arrest care to benefit patients of drowning-associated asphyxial OHCA, but this finding only serves as preliminary observation for future research. No conclusive recommendation could be made regarding the duration of and the time of onset of therapeutic hypothermia. Future research should put effort on RCT, particularly the effect of extended duration of 48-72 hours. Important parameters should be reported in detail. Asphyxial and hypothermic OHCA should be differentiated.

Hypothermia after cranial irradiation protects neural progenitor cells in the subventricular zone but not in the hippocampus

PURPOSE

To explore if hypothermia can reduce the harmful effects of ionizing radiation on the neurogenic regions of the brain in young rats.

MATERIALS AND METHODS

Postnatal day 9 rats were randomized into two treatment groups, hypo- and normothermia, or a control group. Treatment groups were placed in chambers submerged in temperature-controlled water baths (30 °C and 36 °C) for 8 h, after receiving a single fraction of 8 Gy to the left hemisphere. Seven days' post-irradiation, we measured the sizes of the subventricular zone (SVZ) and the granule cell layer (GCL) of the hippocampus, and counted the number of proliferating (phospho-histone H3+) cells and microglia (Iba1 + cells).

RESULTS

Irradiation caused a 53% reduction in SVZ size in the normothermia group compared to controls, as well as a reduction of proliferating cell numbers by >50%. These effects were abrogated in the hypothermia group. Irradiation reduced the number of microglia in both treatment groups, but resulted in a lower cell density of Iba1 + cells in the SVZs of the hypothermia group. In the GCL, irradiation decreased both GCL size and the proliferating cell numbers, but with no difference between the treatment groups. The number of microglia in the GCL did not change.

CONCLUSIONS

Hypothermia immediately after irradiation protects the SVZ and its proliferative cell population but the GCL is not protected, one week post-irradiation.

Cerebral Effects of Targeted Temperature Management Methods Assessed by Diffusion-Weighted Magnetic Resonance Imaging

The aim of this randomized porcine study was to compare surface targeted temperature management (TTM) to endovascular TTM evaluated by cerebral diffusion-weighted magnetic resonance imaging (MRI): apparent diffusion coefficient (ADC), and by intracerebral/intramuscular microdialysis. It is well known that alteration in the temperature affects ADC, but the relationship between cerebral ADC values and the cooling method per se has not been established. Eighteen anesthetized 60-kg female swine were hemodynamically and intracerebrally monitored and subsequently subjected to a baseline MRI. The animals were then randomized into three groups: (1) surface cooling (n = 6) at 33.5°C using EMCOOLSpad^®, (2) endovascular cooling (n = 6) at 33.5°C using an Icy^® cooling catheter with the CoolGard 3000^®, or (3) control (n = 6) at 38.5°C using a Bair Hugger™. The swine were treated with TTM for 6 hours followed by a second MRI examination, including ADC. Blood and microdialysate were sampled regularly throughout the experiment, and glucose, lactate, pyruvate, glycerol, and the lactate/pyruvate ratio did not differ among groups, neither intracerebrally nor intramuscularly. Surface cooling yielded a significantly lower median ADC than endovascular cooling: 714 (634; 804) × 10^-6 mm²/s versus 866 (828; 927) × 10^-6 mm²/s, (p < 0.05). The surface cooling ADC was lowered to a range usually attributed to cytotoxic edema and these low values could not be explained solely by the temperature effect per se. To what extent the ADC is fully reversible at rewarming is unknown and the clinical implications should be further investigated in clinical studies.

Effects of Sex and Mild Intrainsult Hypothermia on Neuropathology and Neural Reorganization following Neonatal Hypoxic Ischemic Brain Injury in Rats

Hypoxia ischemia (HI) is a recognized risk factor among late-preterm infants, with HI events leading to varied neuropathology and cognitive/behavioral deficits. Studies suggest a sex difference in the incidence of HI and in the severity of subsequent behavioral deficits (with better outcomes in females). Mechanisms of a female advantage remain unknown but could involve sex-specific patterns of compensation to injury. Neuroprotective hypothermia is also used to ameliorate HI damage and attenuate behavioral deficits. Though currently prescribed only for HI in term infants, cooling has potential intrainsult applications to high-risk late-preterm infants as well. To address this important clinical issue, we conducted a study using male and female rats with a postnatal (P) day 7 HI injury induced under normothermic and hypothermic conditions. The current study reports patterns of neuropathology evident in postmortem tissue. Results showed a potent benefit of intrainsult hypothermia that was comparable for both sexes. Findings also show surprisingly different patterns of compensation in the contralateral hemisphere, with increases in hippocampal thickness in HI females contrasting reduced thickness in HI males. Findings provide a framework for future research to compare and contrast mechanisms of neuroprotection and postinjury plasticity in both sexes following a late-preterm HI insult.

Lost in translation: rethinking approaches to stroke recovery

Stroke is the second leading cause of death and the preeminent cause of neurological disability. Attempts to limit brain injury after ischemic stroke with clot-dissolving drugs have met with great success but their use remains limited due to a narrow therapeutic time window and concern over serious side effects. Unfortunately, the neuroprotective strategy failed in clinical trials. A more promising approach is to promote recovery of function in people affected by stroke. Following stroke, there is a heightened critical period of plasticity that appears to be receptive to exogenous interventions (e.g., delivery of growth factors) designed to enhance neuroplasticity processes important for recovery. An emerging concept is that combinational therapies appear much more effective than single interventions in improving stroke recovery. One of the most promising interventions, with clinical feasibility, is enriched rehabilitation, a combination of environmental enrichment and task-specific therapy.

Principles of neuroanesthesia in aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage is associated with high mortality. Understanding of the underlying pathophysiology is important as early intervention can improve outcome. Increasing age, altered sensorium and poor Hunt and Hess grade are independent predictors of adverse outcome. Early operative interventions imposes an onus on anesthesiologists to provide brain relaxation. Coiling and clipping are the two treatment options with increasing trends toward coiling. Intraoperatively, tight control of blood pressure and adequate brain relaxation is desirable, so that accidental aneurysm rupture can be averted. Patients with poor grades tolerate higher blood pressures, but are prone to ischemia whereas patients with lower grades tolerate lower blood pressure, but are prone to aneurysm rupture if blood pressure increases. Patients with Hunt and Hess Grade I or II with uneventful intraoperative course are extubated in operation theater, whereas, higher grades are kept electively ventilated. Postoperative management includes attention toward fluid status and early management of vasospasm.