Elevated lactate dehydrogenase predicts poor prognosis of acute ischemic stroke

Integrated analysis of single cell-RNA sequencing and Mendelian randomization identifies lactate dehydrogenase B as a target of melatonin in ischemic stroke

AIMS

Despite the success of single-cell RNA sequencing in identifying cellular heterogeneity in ischemic stroke, clarifying the mechanisms underlying these associations of differently expressed genes remains challenging. Several studies that integrate gene expression and gene expression quantitative trait loci (eQTLs) with genome wide-association study (GWAS) data to determine their causal role have been proposed.

METHODS

Here, we combined Mendelian randomization (MR) framework and single cell (sc) RNA sequencing to study how differently expressed genes (DEGs) mediating the effect of gene expression on ischemic stroke. The hub gene was further validated in the in vitro model.

RESULTS

We identified 2339 DEGs in 10 cell clusters. Among these DEGs, 58 genes were associated with the risk of ischemic stroke. After external validation with eQTL dataset, lactate dehydrogenase B (LDHB) is identified to be positively associated with ischemic stroke. The expression of LDHB has also been validated in sc RNA-seq with dominant expression in microglia and astrocytes, and melatonin is able to reduce the LDHB expression and activity in vitro ischemic models.

CONCLUSION

Our study identifies LDHB as a novel biomarker for ischemic stroke via combining the sc RNA-seq and MR analysis.

High serum lactate dehydrogenase to albumin ratio is associated with increased risk of poor prognosis after ischemic stroke

BACKGROUND

Lactate dehydrogenase to albumin ratio (LAR) is a comprehensive biomarker for anaerobiosis, inflammation, and nutritional status, but its prognostic value for ischemic stroke has rarely been reported. We aimed to prospectively investigate whether serum LAR is associated with the prognosis of ischemic stroke patients in a large-scale cohort study.

MATERIALS AND METHODS

Serum LAR levels were measured among 6634 patients with ischemic stroke admitted at Minhang hospital from January 2018 to December 2022. The primary outcome was the composite of major disability and death (modified Rankin Scale score [mRS] ≥ 3) at 3-month follow up. Secondary outcomes included death and the ordered 7-level category score of mRS. Multivariate logistic regression and restricted cubic splines were adopted to evaluate the associations between serum LAR levels and adverse clinical outcomes of ischemic stroke.

RESULTS

During 3 months of follow-up period, a total of 2125 patients experienced primary outcome. After multivariate adjustment, the highest quartile of serum LAR was associated with an increased risk of primary outcome (odds ratio [OR], 1.52; 95% confidence interval [CI], 1.27-1.83; P for trend < 0.001). Each standard deviation higher log-transformed serum LAR resulted in a 20% (95% CI, 12%-28%) increased risk of primary outcome. Furthermore, multivariable-adjusted restricted cubic spline analyses showed a linear association between the serum LAR level with primary outcome (P for linearity < 0.001). Finally, the addition of serum LAR to conventional risk factors significantly improved risk predictive abilities for the primary outcome (net reclassification improvement [NRI]: 18.35%, P < 0.001; integrated discrimination improvement [IDI]: 0.35%, P < 0.001) at 3-month follow up in patients with ischemic stroke.

CONCLUSION

High serum LAR level was independently associated with an increased risk of adverse clinical outcomes among patients with ischemic stroke, indicating that serum LAR may be a valuable prognostic biomarker for ischemic stroke.

Causal relationship between lactate dehydrogenase and risk of developing ischemic stroke: A Mendelian randomized study

BACKGROUND AND OBJECTIVE

Ischemic stroke (IS) is one of the major global health problems. It is not clear whether there is a causal relationship between lactate dehydrogenase (LDH) and the risk of IS attacks. The purpose of this study was to investigate whether LDH has a causal relationship with the development of IS.

METHODS

The genome-wide association data of LDH and IS were obtained through a Mendelian randomization-based platform. Single nucleotide polymorphisms (SNP) that were significantly associated with LDH were identified and used as instrumental variables, and a two-sample Mendelian randomization study was used to examine the causal relationship between LDH and IS. The statistical methods included Inverse-variance weighted approach, MR-Egger regression, and weighted median estimator.

RESULTS

We selected 15 SNPs of genome-wide significance from Genome-wide association study database with LDH as instrumental variables. A consistent causal association between LDH and IS was observed by different assessment methods. The results of the inverse-variance weighted method suggested an inverse association between LDH and higher genetic predictability of IS risk (OR, 0.997; 95%CI 0.995-0.999). The weighted median estimate showed consistent results with the MR-Egger method (weighted median estimate: OR, 0.995; 95%CI 0.992-0.999; MR-Egger method: OR, 0.996; 95%CI 0.992-0.999). The inverse-variance weighted method indicates a causal association between LDH and IS (β = -0.002563, SE = 0.00128, p = .0453). MR-Egger analysis (β = -0.004498, SE = 0.001877, p = .03) and the weighted median method suggested that LDH and IS also existed causal relationship (β = -0.004861, SE = 0.001801, p = .00695).

CONCLUSIONS

Our Mendelian randomization results suggest that LDH is inversely associated with the risk of developing IS, and are contrary to the results of previous observational studies.

Lactate Dehydrogenase and Hemorrhagic Stroke During Extracorporeal Membrane Oxygenation for COVID-19

PURPOSE

Hemorrhagic stroke (HS) is a devastating complication during extracorporeal membrane oxygenation (ECMO) but markers of risk stratification during COVID-19 are unknown. Lactate dehydrogenase (LDH) is a readily available biomarker of cell injury and permeability. We sought to determine whether an elevated LDH before ECMO placement is related to the occurrence of HS during ECMO for COVID-19.

METHODS

Adult patients with COVID-19 requiring ECMO between March 2020 and February 2022 were included. LDH values prior to ECMO placement were captured. Patients were categorized into high (> 750 U/L) or low (≤ 750 U/L) LDH groups. Multivariable regression modeling was used to determine the association between LDH and HS during ECMO.

RESULTS

There were 520 patients that underwent ECMO placement in 17 centers and 384 had an available LDH. Of whom, 122 (32%) had a high LDH. The overall incidence of HS was 10.9%, and patients with high LDH had a higher incidence of HS than those with low LDH level (17% vs 8%, p = 0.007). At 100 days, the probability of a HS was 40% in the high LDH group and 23% in those with a low LDH, p = 0.002. After adjustment for clinical covariates, high LDH remained associated with subsequent HS (aHR: 2.64, 95% CI 1.39-4.92). Findings were similar when restricting to patients supported by venovenous ECMO only.

CONCLUSION

Elevated LDH prior to ECMO cannulation is associated with a higher incidence of HS during device support. LDH can risk stratify cases for impending cerebral bleeding during ECMO.