Lactate Contents From Cerebrospinal Fluid in Experimental Subarachnoid Hemorrhage, Well Correlate With Vasospasm

Hydrogen inhalation therapy regulates lactic acid metabolism following subarachnoid hemorrhage through the HIF-1α pathway

The neuroprotective effects of hydrogen have been demonstrated, but the mechanism is still poorly understood. In a clinical trial of inhaled hydrogen in patients with subarachnoid hemorrhage (SAH), we found that hydrogen reduced the accumulation of lactic acid in the nervous system. There are no studies demonstrating the regulatory effect of hydrogen on lactate and in this study we hope to further clarify the mechanism by which hydrogen regulates lactate metabolism. In cell experiments, PCR and Western Blot showed that HIF-1α was the target related to lactic acid metabolism that changed the most before and after hydrogen intervention. HIF-1α levels were suppressed by hydrogen intervention treatment. Activation of HIF-1α inhibited the lactic acid-lowering effect of hydrogen. We have also demonstrated the lactic acid-lowering effect of hydrogen in animal studies. Our work clarifies that hydrogen can regulate lactate metabolism via the HIF-1αpathway, providing new insights into the neuroprotective mechanisms of hydrogen.

Cerebrospinal Fluid Lactate and Glucose Levels as Predictors of Symptomatic Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is a complex neurovascular syndrome with profound systemic effects associated with high rates of disability and mortality. Delayed cerebral ischemia (DCI), which encompasses all neurobiological events occurring in the subacute-late stage after aSAH, has a complex pathogenesis and can occur in the absence of instrumental vasospasm. Our aim was to assess the correlation between cerebrospinal fluid (CSF) lactate and glucose levels measured on the second or third day after aSAH with clinical deterioration caused by DCI and with 3-month functional outcome.

METHODS

This prospective study included all aSAH patients admitted between January 2020 and December 2021 who underwent external ventricular drain placement and CSF lactate and glucose measurement.

RESULTS

Among 133 aSAH patients, 48 had an external ventricular drain placed and early CSF lactate and glucose assessment. Independent predictors of symptomatic DCI were World Federation of Neurosurgical Societies grade IV-V (adjusted odds ratio [aOR] 25.8, 95% confidence interval [CI] 2.9-649.2, P = 0.012), elevated CSF glucose (aOR 28.8, 95% CI 3.3-775.2, P = 0.010), and elevated CSF lactate (aOR 14.7, 95% CI 1.9-205.7, P = 0.018). The only independent predictor of 3-month functional outcome was occurrence of symptomatic DCI (aOR 0.02, 95% CI 0.0-0.2, P = 0.01).

CONCLUSIONS

Elevated CSF lactate and glucose levels in the first 3 days following aSAH were independent predictors of subsequent DCI-related neurological impairment; the presence of instrumental vasospasm was not significantly correlated with DCI after multivariate adjustment. CSF lactate and glucose monitoring may represent a point-of-care test, which could potentially improve prediction of subacute neurological worsening and guide therapeutic choices. Further research with larger prospective cohorts is warranted.

Intrathecal lactate predicting hydrocephalus after aneurysmal subarachnoid hemorrhage

BACKGROUND

Evidence shows possible benefits from continuous drainage by lumbar drain after aneurysmal subarachnoid hemorrhage (SAH). Under the hypothesis that compartmentalization occurs between the ventricle and subarachnoid space after massive SAH, this study aimed to evaluate the biochemical differences between ventricular and intrathecal cerebrospinal fluid (CSF) and assess the role of CSF lactate in shunt-dependent hydrocephalus (SDHC) after aneurysmal SAH.

MATERIALS AND METHODS

Patients with modified Fisher grade III/IV aneurysmal SAH who underwent early obliteration were evaluated. Intrathecal and intraventricular CSF were obtained on day 7 post-SAH to measure their biochemical composition in terms of total protein, glucose, ferritin, and lactate. The associations of SDHC with the clinical parameters and CSF data were analyzed.

RESULTS

There were 28 patients (mean age, 55.4 y; males, 46.6%), including 18 (64.3%) with SDHC. Intrathecal CSF had significantly higher levels of total protein, ferritin, hemoglobin, and lactate but lower glucose level than intraventricular CSF (all P < 0.0001). By multivariate analysis of clinical and CSF parameters, elevated intrathecal CSF lactate (P = 0.036) and the presence of intraventricular hemorrhage (P = 0.05) were independent factors associated with SDHC. Moreover, intrathecal lactate >5.5 μM effectively predicted the occurrence of SDHC (odds ratio: 32, 95% confidence interval: 3.8-270.8; P = 0.0015).

CONCLUSIONS

By compartmentalization of the subarachnoid space after SAH, intrathecal lactate level is a useful predictive parameter for long-term SDHC in patients with aneurysmal SAH patients.

Biomarkers as outcome predictors in subarachnoid hemorrhage--a systematic review

CONTEXT

Subarachnoid hemorrhage (SAH) has a high fatality rate and many suffer from delayed neurological deficits. Biomarkers may aid in the identification of high-risk patients, guide treatment/management and improve outcome.

OBJECTIVE

The aim of this review was to summarize biomarkers of SAH associated with outcome.

METHODS

An electronic database query was completed, including an additional review of reference lists to include all potential human studies.

RESULTS

A total of 298 articles were identified; 112 were reviewed; 55 studies were included.

CONCLUSION

This review details biomarkers of SAH that correlate with outcome. It provides the basis for research investigating their possible translation into the management of SAH patients.