Selective Brain Hypothermia Augmenting Neuroprotective Effects of Decompressive Craniectomy for Permanent Middle Cerebral Artery Infarction in a Rat Model

Adjuvant therapeutic potential of moderate hypothermia for glioblastoma

PURPOSE

Glioblastoma is the most common malignant brain tumor, currently treated by surgery followed by concomitant radiotherapy and temozolomide-based chemotherapy. Despite these treatments, median survival is only 15 months as a result of tumor recurrence in the resection margins. Here, we propose therapeutic hypothermia - known to have neuroprotective effects - as an adjuvant treatment to maintain residual glioblastoma cells in a dormant state, and thus prevent tumor recurrence.

METHODS

In vitro experiments were performed on healthy tissue with primary human astrocytes, and four human glioblastoma cell lines: A172, U251, U87, and T98G. We explored the adjuvant potential of moderate hypothermia (28 °C) by studying the reversibility of its inhibitory effects on cell proliferation and comparing them to currently used temozolomide.

RESULTS

Moderate hypothermia reduced healthy cell growth, but also inhibited glioblastoma cell proliferation even after rewarming. Indeed, hypothermic preconditioning duration strongly enhanced inhibitory effects from 35% after 3 days to 100% after 30 days. In contrast, moderate (28 °C) and severe (23 °C) preconditioning induced similar results. Finally, moderate hypothermia had more uniform inhibitory effects than temozolomide, which reduced proliferation by between 15% and 95%, and also potentiated the effects of the latter.

CONCLUSION

Moderate hypothermia shows promise as an adjuvant therapy for glioblastoma through its inhibition of cell proliferation beyond direct conditioning and potentiation of the effects of chemotherapy. If in vivo preclinical results corroborate our findings, therapeutic hypothermia applied at the resection margins could probably inhibit tumor growth, delay tumor recurrence and reduce inter-patient variability.

Decompressive craniectomy combined with mild hypothermia in patients with large hemispheric infarction: a randomized controlled trial

Background

The effect of hypothermia on large hemispheric infarction (LHI) remains controversial. Our study aimed to explore the therapeutic outcomes of decompressive craniectomy (DC) combined with hypothermia on LHI.

Methods

Patients were randomly divided into three groups: the DC group, the DC plus head surface cooling (DCSC) group and the DC plus endovascular hypothermia (DCEH) group. The DC group was maintained normothermia. The DCSC group received 24-h ice cap on the head for 7 days. While the DCEH group were given endovascular hypothermia (34 °C). Mortality and modified Rankin Scale (mRS) score at 6 months were evaluated.

Results

Thirty-four patients were included in the study. Mortality of the DC, DCSC and DCEH groups at discharge were 22.2% (2/9), 0% (0/14) and 9.1% (1/11), respectively. However, it increased to 44.4% (4/9), 21.4% (3/14) and 45.5% (5/11) at 6 months, respectively (p = 0.367). Pneumonia (8 cases) was the leading cause of death after discharge. Twelve cases (35.3%) achieved good neurological outcome (mRS 0–3) at 6 months. The proportions of good neurological outcome in the DC, DCSC and DCEH groups were 22.2% (2/9 cases), 42.9% (6/14 cases) and 36.4% (4/11), respectively. The DCSC group seemed to have higher proportion of good outcomes, but there was no significant difference between groups (p = 0.598). Among survivors, endovascular hypothermia had a higher proportion of good outcome (DC group, 2/5 cases, 40.0%; DCSC group, 6/11 cases, 54.5%; DCEH group, 4/6 cases, 66.7%; p = 0.696). The incidence of complications in the DCEH group was higher than those of the DC and DCSC groups (18.9%, 12.0%, and 12.1%, respectively; p = 0.025).

Conclusions

There is still no evidence to confirm that hypothermia further reduces long-term mortality and improves neurological outcomes in LHI patients with DC. However, there is a trend to benefit survivors from hypothermia. A local cooling method may be a better option for DC patients, which has little impact on systematic complications.

Trial registration

Decompressive Hemicraniectomy Combined Hypothermia in Malignant Middle Cerebral Artery Infarct, ChiCTR-TRC-12002698. Registered 11 Oct 2012- Retrospectively registered, URL: http://www.chictr.org.cn/showproj.aspx?proj=6854.