Regional mild hypothermia in the protection of the ischemic brain

Over the last 50 years deep hypothermia (23(0) C) has demonstrated to be an excellent neuroprotective agent in cerebral ischemic injury. Mild hypothermia (31-33(0) C) has proven to have the same neuroprotective properties without the detrimental effects of deep hypothermia. Mechanisms of injury that are exaggerated by moderate hyperthermia and ameliorated by hypothermia include, reduction of oxygen radical production, with peroxidase damage to lipids, proteins and DNA, microglial activation and ischemic depolarization, decrease in cerebral metabolic demand for oxygen and reduction of glycerin and excitatory amino acid (EAA) release. Studies have demonstrated that inflammation potentiates cerebral ischemic injury and that hypothermia can reduce neutrophil infiltration in ischemic regions. To further elucidate the mechanisms by which mild hypothermia produces neuroprotection in ischemia by attenuating the inflammatory response, we provoked inflammatory reaction, in brains of rats, dropping a substance that provokes a heavy inflammatory reaction. Two groups of ten animals underwent the same surgical procedure: the skull bone was partially removed, the duramater was opened and an inflammatory substance (5% carrageenin) was topically dropped. The scalp was sutured and, for the group that underwent neuroprotection, an ice bag was placed covering the entire skull surface, in order to maintain the brain temperature between 29,5-31(0) C during 120 minutes. After three days the animals were sacrificed and their brains were examined. The group protected by hypothermia demonstrated a remarkable reduction of polymorphonuclear leukocytes (PMNL) infiltration, indicating that mild hypothermia can have neuroprotective effects by reducing the inflammatory reaction.

Section: R O S O M M O Ffmentioning

confidence: 99%

Mild hypothermia reduces polymorphonuclear leukocytes infiltration in induced brain inflammation

Prandini

Filho

Lapa

et al. 2005

“…The effects of hypothermia described in medical literature include its effects on excitatory amino acids, free radicals, decline in vascular permeability, nitric oxide, cerebral blood flow, (due to the decline in the regional oxygen flow and oxygen consumption), decline of the inflammatory reaction and decrease in the genic expression and apoptosis 21,22,[25][26][27][28] .…”

Section: Discussionmentioning

confidence: 99%

“…These studies demonstrated encouraging results, and so did the studies published by Prandini et al on ischemic brain lesions 21 and Prandini et al on treatment of brain inflammatory lesions 22 . The aforementioned promising results for hypo-Traumatic brain injury: selective hypothermia dvilevicius and Prandini thermia gave rise to this study.…”

mentioning

confidence: 84%

Selective hypothermia: an experimental study on traumatic brain injury in rats

Dvilevicius

Prandini

2008

Self Cite

-Objective:To evaluate the efficiency of selective hypothermia in the treatment of the traumatic brain injury in rats. Method: After the trauma produced for the model of cortical impact, a small craniectomy in the right frontoparietal region was carried through; after the procedure the animals had been divided in two groups of 15 each. Group A, without treatment with hypothermia (control group) and group B, treated with selective hypothermia for a period to 5 to 6 hours. After this time all the animals were sacrificed, their brains had been removed and histopathological analysis was carried through. Results: Comparison between both groups was done using the counting of neurons injured for field. Counting in the control group n=15 had an average of 70.80 neurons injured for field against an average of 21.33 neurons injured for field in group B (submitted to the treatment with hypothermia), with n=15 also. The difference was statiscally significant. Conclusion: Based in the quantification of the neurons injured for field, the effectiveness of the treatment with selective hypothermia was demonstrated.Key Words: selective hypothermia, hypothermia, neuroprotection, traumatic brain injury. Hipotermia seletiva: estudo experimental de traumatismo crânio-encefálico em ratosResumo -Objetivo: Avaliar a eficiência da hipotermia seletiva no tratamento do traumatismo crânio-encefálico (TCe) em ratos. o trauma foi produzido por um modelo de impacto cortical desenvolvido exclusivamente para o estudo. Método: Após o TCe produzido pelo modelo de impacto cortical, foi realizada pequena craniectomia na região fronto-parietal direita; após o procedimento os animais foram divididos em dois grupos de 15 cada um. o grupo A, sem tratamento com hipotermia (grupo controle) e grupo B, tratado com hipotermia seletiva por período de 5 a 6 horas. depois deste tempo todos os animais foram sacrificados, seus encéfalos foram removidos e realizada a análise anatomopatológica. Resultados: Na comparação entre o grupo tratado com hipotermia e o grupo controle utilizou-se a contagem de neurônios lesados por campo. Tal contagem no grupo A (controle/sem tratamento) com n=15 teve media de 70,80 neurônios lesados por campo contra a media de 21,33 nerônios lesados por campo no grupo B (submetido ao tratamento com hipotermia), com n=15 também. diferença estatísticamente significativa pôde ser demonstrada. Conclusão: A análise anatomopatológica dos encéfalos dos animais estudados, baseada na quantificação dos neurônios lesados por campo demonstrou efetividade do tratamento com hipotermia seletiva com diferença estatística significativa.PAlAvrAs-ChAve: hipotermia seletiva, hipotermia, neuroproteção, traumatismo crânio-encefálico.

“…The removal of bone and durotomy facilitate heat transfer from the brain parenchyma, allowing for more effective neural cooling. Prandini et al 33 , using a rabbitt model of middle cerebral artery occlusion, demonstrated that mild regional hypothermia induced by craniectomy and ice pack surface cooling reduced stroke volume after sacrifice. Forte et al, applied this cooling technique to human subjects who had undergone hemicraniectomy for varying indications.…”

Section: Non Invasive Techniques Of Coolingmentioning

confidence: 99%

Selective therapeutic hypothermia: A review of invasive and noninvasive techniques

Straus

Prasad

Munoz

2011

Objective: Therapeutic hypothermia is a promising treatment to prevent secondary neurologic injury. Clinical utility is limited by systemic complications of global hypothermia. Selective brain cooling remains a largely uninvestigated application. We review techniques of inducing selective brain cooling. Method: Literature review. Results: Strategies of inducing selective brain cooling were divided between non-invasive and invasive techniques. Non-invasive techniques were surface cooling and cooling via the upper airway. Invasive cooling methods include transvascular and compartmental (epidural, subdural, subarachnoid and intraventricular) cooling methods to remove heat from the brain. Conclusion: Selective brain cooling may offer the best strategy for achieving hypothermic neuroprotection. Non-invasive strategies have proven disappointing in human trials. There is a paucity of human experiments using invasive methods of selective brain cooling. Further application of invasive cooling strategies is needed. Key words: therapeutic hypothermia, selective brain cooling, neuroprotection, isolated cerebral hypothermia.Hipotermia terapêutica seletiva: uma revisão de técnicas invasivas e não invasivas RESUMO Objetivo: A hipotermia terapêutica é uma estratégia promissora para prevenção do dano neurológico secundário. Sua utilidade clínica é limitada por complicações sistêmicas da hipotermia global. Resfriamento cerebral seletivo (RCS), entretanto, permanece uma técnica pouco estudada. Revisamos aqui as diferentes técnicas de indução de RCS. Método: Revisão de literatura. Resultados: As estratégias de indução de RCS foram divididas em invasivas e não-invasivas. Métodos de remoção de calor do cérebro não-invasivos incluem o resfriamento de superfície e o de vias aéreas superiores; as técnicas invasivas incluem resfriamento transvascular e compartimental (epidural, subdural, subaracnóideo e intraventricular). Conclusão: RCS pode oferecer a melhor estratégia para alcançar neuroproteção hipotérmica. Estratégias não-invasivas têm se mostrado ineficazes em estudos clínicos. Técnicas invasivas foram raramente estudadas em humanos e necessitam ser mais investigadas para tornarem-se úteis. Palavras-Chave: hipotermia terapêutica, resfriamento cerebral seletivo, neuroproteção, hipotermia cerebral isolada.