L-lactate as an indicator for cellular metabolic status: An easy and cost-effective colorimetric L-lactate assay

Lactate level as a predictor of outcomes in patients with acute upper gastrointestinal bleeding: A systematic review and meta‑analysis

There remains no consensus on the prognostic value of lactate in predicting adverse outcomes such as mortality, rebleeding and higher intensive care unit (ICU) admission rates in patients with upper gastrointestinal bleeding (UGIB). The present study aimed to determine the prognostic accuracy of lactate level in predicting adverse clinical outcomes in patients with acute UGIB. Systematic literature search was conducted in PubMed Central, SCOPUS, EMBASE, MEDLINE, Google Scholar and ScienceDirect databases for studies published up to February 2023. Random-effects model was used for the meta-analysis and the results were presented as pooled standardized mean differences or odds ratio (OR) with 95% confidence interval (CIs). A total of 11 studies were included in the present review. Most of the studies had a high risk of bias. Pooled OR were as follows: 1.39 (95% CI: 1.29-1.51; I2=85%) for the prediction of mortality; 1.29 (95% CI: 1.17-1.42; I2=85.9%) for prediction of ICU admission, 1.14 (95% CI: 1.06-1.23; I2=42.4%) for rebleeding and 2.84 (95% CI: 2.14-3.77; I2=8.1%) for the need of packed red blood cell (pRBC) transfusion. Sensitivity and specificity for the mortality prediction were 72% (95% CI: 57-83%) and 75% (95% CI: 61-85%), respectively, with the area under the curve of 0.79 (95% CI: 0.72-0.85). In conclusion, the results showed that lactate level is a moderately accurate early prediction marker of most adverse clinical outcomes such as mortality, rebleeding, ICU admission and the need for pRBC transfusion in acute UGIB patients.

Viability of HepG2 and MCF-7 cells is not correlated with mitochondrial bioenergetics

Alterations in metabolism are a hallmark of cancer. It is unclear if oxidative phosphorylation (OXPHOS) is necessary for tumour cell survival. In this study, we investigated the effects of severe hypoxia, site-specific inhibition of respiratory chain (RC) components, and uncouplers on necrotic and apoptotic markers in 2D-cultured HepG2 and MCF-7 tumour cells. Comparable respiratory complex activities were observed in both cell lines. However, HepG2 cells exhibited significantly higher oxygen consumption rates (OCR) and respiratory capacity than MCF-7 cells. Significant non-mitochondrial OCR was observed in MCF-7 cells, which was insensitive to acute combined inhibition of complexes I and III. Pre-treatment of either cell line with RC inhibitors for 24-72 h resulted in the complete abolition of respective complex activities and OCRs. This was accompanied by a time-dependent decrease in citrate synthase activity, suggesting mitophagy. High-content automated microscopy recordings revealed that the viability of HepG2 cells was mostly unaffected by any pharmacological treatment or severe hypoxia. In contrast, the viability of MCF-7 cells was strongly affected by inhibition of complex IV (CIV) or complex V (CV), severe hypoxia, and uncoupling. However, it was only moderately affected by inhibition of complexes I, II, and III. Cell death in MCF-7 cells induced by inhibition of complexes II, III, and IV was partially abrogated by aspartate. These findings indicate that OXPHOS activity and viability are not correlated in these cell lines, suggesting that the connection between OXPHOS and cancer cell survival is dependent on the specific cell type and conditions.