Acute kidney injury (AKI) is a common clinically critical syndrome in hospitalized patients with high morbidity and mortality. At present, the mechanism of AKI has not been fully elucidated, and no therapeutic drugs exist. As known, glycolytic product lactate is a key metabolite in physiological and pathological processes. The kidney is an important gluconeogenic organ, where lactate is the primary substrate of renal gluconeogenesis in physiological conditions. During AKI, altered glycolysis and gluconeogenesis in kidneys significantly disturb the lactate metabolic balance, which exert impacts on the severity and prognosis of AKI. Additionally, lactate-derived posttranslational modification, namely lactylation, is novel to AKI as it could regulate gene transcription of metabolic enzymes involved in glycolysis or Warburg effect. Protein lactylation widely exists in human tissues and may severely affect non-histone functions. Moreover, the strategies of intervening lactate metabolic pathways are expected to bring a new dawn for the treatment of AKI. This review focused on renal lactate metabolism, especially in proximal renal tubules after AKI, and updated recent advances of lactylation modification, which may help to explore potential therapeutic targets against AKI.
Humans ; Acute Kidney Injury/metabolism* ; Lactic Acid/metabolism* ; Animals ; Glycolysis/physiology* ; Gluconeogenesis/physiology* ; Kidney/metabolism*

Lactic acid (LA) accumulation in tumor microenvironments (TME) has been implicated in immune suppression and tumor progress. Diverse roles of LA have been elucidated, including microenvironmental pH regulation, signal transduction, post-translational modification, and metabolic remodeling. This review summarizes LA functions within TME, focusing on the effects on tumor cells, immune cells, and stromal cells. Reducing LA levels is a potential strategy to attack cancer, which inevitably affects the physiological functions of normal tissues. Alternatively, transporting LA into the mitochondria as an energy source for immune cells is intriguing. We underscore the significance of LA in both tumor biology and immunology, proposing the burning of LA as a potential therapeutic approach to enhance antitumor immune responses.
Humans ; Tumor Microenvironment/immunology* ; Neoplasms/therapy* ; Lactic Acid/immunology* ; Mitochondria/metabolism* ; Animals ; Signal Transduction

The Warburg effect, originally discovered by Otto Warburg, refers to the metabolic reprogramming of tumor cells from aerobic oxidation to glycolysis, enabling rapid energy production to support their growth and metastasis. This process is accompanied by the massive production and accumulation of lactate both intracellularly and extracellularly. The resulting acidic microenvironment impairs the normal physiological functions of immune cells and promotes tumor progression. An increasing number of studies indicate that lactate, a key metabolite in the tumor microenvironment (TME), acts as a pivotal immunosuppressive signaling molecule that modulates immune cell function. This review aims to comprehensively examine lactate's role as an immunosuppressive molecule in TME. It focuses on mechanisms such as membrane receptor binding, functional reshaping of immune cells via lactate shuttle transport, epigenetic regulation of gene expression through histone lactylation, and modulation of protein structure and function through nonhistone lactylation, emphasizing lactate's importance in immune regulation within the TME. Ultimately, this review offers novel insights into immunosuppressive therapies aimed at targeting lactate function.
Humans ; Neoplasms/metabolism* ; Tumor Microenvironment/immunology* ; Lactic Acid/immunology* ; Warburg Effect, Oncologic ; Animals ; Glycolysis ; Epigenesis, Genetic

OBJECTIVE: To investigate the predictive value of early lactate/albumin ratio (LAR) combined with quick sequential organ failure assessment (qSOFA) for the 28-day prognosis of patients with sepsis caused by emergency community-acquired pneumonia (CAP). METHODS: The clinical data of patients with sepsis caused by CAP admitted to the department of emergency of Beijing Haidian Hospital from June 2021 to August 2022 were retrospectively analyzed, including gender, age, comorbidities, lactic acid (Lac), serum albumin (Alb), LAR, procalcitonin (PCT) within 1 hour, and 28-day prognosis. Patients were divided into two groups based on 28-day prognosis, and risk factors affecting patients' prognosis were analyzed using univariate and multivariate Cox regression methods. Patients were divided into two groups according to the best cut-off value of LAR, and Kaplan-Meier survival curves were used to analyze the 28-day cumulative survival of patients in each group. Time-dependent receiver operator characteristic curve (ROC curve) were plotted to analyze the predictive value of sequential organ failure assessment (SOFA), acute physiology and chronic health evaluation II (APACHE II), and qSOFA+LAR score on the prognosis of patients with sepsis caused by CAP at 28 days. The area under the curve (AUC) was calculated and compared. RESULTS: A total of 116 patients with sepsis caused by CAP were included, of whom 80 survived at 28 days and 36 died, 28-day mortality of 31.0%. There were no statistically significant differences in age, gender, comorbidities, pH, platelet count, and fibrinogen between the survival and death groups, and there were significantly differences in blood urea nitrogen (BUN), white blood cell count (WBC), hemoglobin, Lac, Alb, PCT, D-dimer, LAR, as well as qSOFA score, SOFA score, and APACHE II score. Univariate Cox regression analyses showed that BUN, WBC, pH, Lac, Alb, PCT, LAR, qSOFA score, SOFA score, and APACHE II score were associated with mortality outcome. Multifactorial Cox regression analysis of the above variables showed that BUN, WBC, PCT, and APACHE II score were independent risk factors for 28-day death in the emergency department in patients with sepsis caused by CAP [hazard ratio (HR) were 1.081, 0.892, 1.034, and 1.135, respectively, all P < 0.05]. The best cut-off value of early LAR for predicting the 28-day prognosis of sepsis patients was 0.088, the Kaplan-Meier survival curve showed that the 28-day cumulative survival rate of sepsis patients in the LAR ≤ 0.088 group was significantly higher than that in the LAR > 0.088 group [82.9% (63/76) vs. 42.5% (17/40), Log-Rank test: χ² = 22.51, P < 0.001]. The qSOFA+LAR score was calculated based on the LAR cut-off value and qSOFA score, and ROC curve analysis showed that the AUCs of SOFA score, APACHE II score, and qSOFA+LAR score for predicting 28-day death of patients with sepsis caued by CAP were 0.741, 0.774, and 0.709, respectively, with the AUC of qSOFA+LAR score slightly lower than those of SOFA score and APACHE II score, but there were no significantly differences. When the best cut-off value of qSOFA+LAR score was 1, the sensitivity was 63.9% and the specificity was 80.0%. CONCLUSION The qSOFA+LAR score has predictive value for the 28-day prognosis of patients with sepsis caused by CAP in the emergency department, its predictive value is comparable to the SOFA score and the APACHE II score, and it is more convenient for early use in the emergency department.
Emergency Service, Hospital/statistics & numerical data* ; Sepsis/etiology* ; Prognosis ; Community-Acquired Pneumonia/mortality* ; Organ Dysfunction Scores ; Predictive Value of Tests ; Lactic Acid/blood* ; Serum Albumin, Human/analysis* ; Biomarkers/blood* ; Retrospective Studies ; Hospital Mortality ; Kaplan-Meier Estimate ; APACHE ; Procalcitonin/blood* ; ROC Curve ; Area Under Curve ; Humans

OBJECTIVE: To evaluate the advantages and limitations of transcutaneous electrical acupoint stimulation (TEAS) in the treatment of patients with severe gastrointestinal function injury in intensive care unit (ICU) by analyzing dynamic changes of intestinal fatty acid binding protein (I-FABP), D-lactic acid and citrulline. METHODS: A prospective single-center randomized controlled trial was conducted. Patients with severe gastrointestinal function injury admitted to the ICU from February 2021 to January 2024 were enrolled [age > 18 years old, acute gastrointestinal injury (AGI) grade 2 to 3, stable hemodynamics]. Patients with different AGI grades were randomly assigned in a 1:1 ratio to the TEAS group and the control group using simple randomization. Both groups received conventional treatment and enteral nutrition (EN). In addition, the TEAS group underwent TEAS at the Neiguan and Zusanli points for 30 minutes per session, twice daily for 7 days. Baseline data, including age, gender, underlying diseases, and primary diagnoses, were recorded. Three intestinal biomarkers, such as I-FABP, D-lactic acid, and citrulline were measured before and after 7 days of treatment. EN tolerance indicators and 28 days survival status were documented. The differences in various indicators were compared between the two groups, subgroup analyses were conducted based on AGI grading, and interaction between AGI grade and TEAS were analyzed. The 28-day Kaplan-Meier survival curves were generated for both groups. RESULTS: Finally, 133 patients were included, with 68 in the TEAS group and 65 in the control group. Baseline characteristics were comparable between the two groups. A comparison of the dynamic changes in intestinal biomarkers revealed that the I-FABP level in both groups decreased after treatment compared to pre-treatment, with a more pronounced reduction in the TEAS group. The least square mean difference (LS Mean difference) for the corrected I-FABP level between the two groups during the observation period was -0.23 μg/L [95% confidence interval (95%CI) was -0.45 to -0.01], which was statistically significant (P = 0.041). Additionally, a significant interaction with AGI was observed (P = 0.004). Post-treatment, D-lactic acid level decreased in both groups compared to pre-treatment, with a more significant reduction in the TEAS group. The LS Mean difference for the corrected D-lactic acid level was -0.08 mmol/L (95%CI was -0.11 to -0.05), which was statistically significant (P < 0.001), and the interaction with AGI was also significant (P = 0.005). There was no significant change in citrulline levels between the two groups before and after treatment. The LS Mean difference for the corrected citrulline level was -0.17 μmol/L (95%CI was -1.87 to 1.53), which was not statistically significant (P = 0.845), and no significant interaction with AGI was observed (P = 0.913). Comparison of EN tolerance parameters between the two groups revealed that the TEAS group had a longer total EN time (hours: 72±31 vs. 60±28) and higher total EN calories (kJ: 11 469.23±7 237.34 vs. 6 638.76±5 098.37), as well as a higher 70% target caloric attainment rate (52.9% vs. 32.3%) compared to the control group (all P < 0.05). The incidence of abdominal distension after EN was lower in the TEAS group than that in the control group (23.5% vs. 43.1%, P < 0.05), while the incidence of diarrhea after EN was higher in the TEAS group (22.1% vs. 7.7%, P < 0.05). There were no significantly differences in AGI grade reduction rate, post-EN vomiting/gastric retention rate, incidence of feeding interruption, and 28-day survival rate between the two groups. Furthermore, there were no significantly interaction between these observation measures and AGI. Kaplan-Meier survival analysis showed that there was no significantly difference in 28-day cumulative survival rate between the TEAS group and the control group [Log-Rank test: P = 0.501, hazard ratio (HR) = 0.81, 95%CI was 0.43-1.51), and there was no significantly interaction with AGI (P = 0.702). CONCLUSIONS The advantage of TEAS in the treatment of ICU patients with severe gastrointestinal function injury lies in its ability to reverse intestinal cell necrosis and promote the reconstruction of intestinal barrier function. Additionally, gastrointestinal tolerance is significantly improved, and both the duration and total calories of EN are increased. However, the limitation of TEAS therapy is that it does not promote the recovery of intestinal cell absorption and synthesis function in the target patients. Moreover, it may lead to nutrient solution overload due to improved gastrointestinal tolerance. Furthermore, TEAS does not appear to improve 28-day cumulative survival rate in the target patients.
Humans ; Prospective Studies ; Intensive Care Units ; Acupuncture Points ; Fatty Acid-Binding Proteins/metabolism* ; Transcutaneous Electric Nerve Stimulation ; Male ; Female ; Citrulline/metabolism* ; Lactic Acid/metabolism* ; Gastrointestinal Diseases/therapy* ; Middle Aged ; Enteral Nutrition ; Adult

OBJECTIVE: To explore the predictive efficacy of the early lactic acid/albumin ratio (LAR) for the occurrence of acute skin failure (ASF) in patients with sepsis. METHODS: A retrospective study was conducted to collect the clinical data of 115 patients with sepsis admitted to the intensive care unit (ICU) of the First Affiliated Hospital of Dalian Medical University from June 2022 to March 2024. The patients' gender, age, length of ICU stay, past medical history, and severity scores, use of mechanical ventilation or vasoactive drugs, albumin (Alb), lactic acid (Lac), mean arterial pressure (MAP), and blood gas analysis indicators within 24 hours of ICU admission were collected, and LAR was calculated. The patients were divided into two groups based on whether they developed ASF, and the clinical data between the two groups were compared. Multivariate Logistic regression analysis was used to screen the risk factors for the occurrence of ASF in patients with sepsis. The receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of LAR for the occurrence of ASF in patients with sepsis. RESULTS: A total of 115 patients with sepsis were enrolled in the final analysis, among whom 35 developed ASF and 80 did not. The incidence of ASF was 30.43%. Univariate analysis showed that compared with the non-ASF group, the ASF group had higher acute physiology and chronic health evaluation II (APACHE II) score, proportion of using vasoactive drugs, Lac, and LAR as well as lower Alb and MAP, with statistically significant differences. Multivariate Logistic regression analysis was conducted on the factors with statistical significance in the univariate analysis, and the results showed that Alb [odds ratio (OR) = 0.639, 95% confidence interval (95%CI) was 0.474-0.862, P = 0.003], Lac (OR = 17.228, 95%CI was 1.517-195.641, P = 0.022), MAP (OR = 0.905, 95%CI was 0.855-0.959, P = 0.001), and LAR (OR < 0.001, 95%CI was < 0.001-0.005, P = 0.033) were independent risk factors for the occurrence of ASF in patients with sepsis. ROC curve analysis showed that the area under the ROC curve (AUC) of LAR for predicting the occurrence of ASF in patients with sepsis was 0.867 (95%CI was 0.792-0.943), which was superior to Alb, Lac, and MAP [AUC (95%CI) was 0.739 (0.648-0.829), 0.844 (0.760-0.929), and 0.860 (0.783-0.937), respectively]. When the optimal cut-off value of LAR was 0.11, the sensitivity was 65.7%, the specificity was 96.3%, and the Youden index was 0.620. Patients were grouped based on the optimal cut-off value of LAR, and the results showed that the incidence of ASF in the LAR > 0.11 group was significantly higher than that in the LAR ≤ 0.11 group [88.89% (24/27) vs. 12.50% (11/88), P < 0.05]. CONCLUSIONS LAR has early predictive value for the occurrence of ASF in patients with sepsis, and its efficacy is superior to that of Lac or Alb alone.
Humans ; Sepsis/blood* ; Retrospective Studies ; Lactic Acid/blood* ; Male ; Female ; Intensive Care Units ; Middle Aged ; Risk Factors ; Predictive Value of Tests ; Serum Albumin/analysis* ; ROC Curve ; Aged

OBJECTIVE: To investigate the predictive value of sphinor kinase 1 (sphk1), D-lactic acid, and intestinal fatty acid binding protein (I-FABP) for gastrointestinal injury in patients with sepsis. METHODS: A prospective observational study was conducted. Sixty-eight patients with sepsis and gastrointestinal dysfunction admitted to the department of critical care medicine of the First Affiliated Hospital of Baotou Medical College Inner Mongolia University of Science and Technology from May 2024 to March 2025 were enrolled (sepsis group), and they were divided into acute gastrointestinal injury (AGI) I-IV groups according to the definition and grading criteria of AGI proposed by the European Society of Intensive Care Medicine in 2012. Twenty non-sepsis patients without AGI admitted to the intensive care unit during the same period were enrolled as the control group (non-sepsis group). Within 30 minutes of patient enrollment, plasma sphk1, D-lactic acid, and I-FABP levels were determined by enzyme linked immunosorbent assay (ELISA). General data such as gender, age were recorded, and levels of procalcitonin (PCT), high-sensitivity C-reactive protein (hs-CRP), lactic acid (Lac), and acute physiology and chronic health evaluation II (APACHEII), sequential organ failure assessment (SOFA) were measured. Spearman method was used to analyze the correlation between sphk1, I-FABP, D-lactic acid and other indicators. The receiver operator characteristic curve (ROC curve) was used to evaluate the predictive value of sphk1, D-lactic acid, I-FABP, APACHEII score, and SOFA score for gastrointestinal injury in patients with sepsis. RESULTS: Among the 68 sepsis patients, 13 were classified as AGI grade I, 16 as AGI grade II, 23 as AGI grade III, and 16 had AGI grade IV. There were no statistically significant differences in gender, age, and abdominal infection rate among the groups. The SOFA score and APACHEII score of the sepsis group were significantly higher than those of the non-sepsis group; and the APACHEII score of the AGI IV group was significantly higher than that of the AGI I and AGI II groups. The levels of sphk1, D-lactic acid, I-FABP, PCT, Lac and hs-CRP in the sepsis group were significantly higher than those in the non-sepsis group, and each indicator gradually increased with the increase of AGI grade. Correlation analysis showed that plasma sphk1, D-lactic acid, and I-FABP in patients with sepsis-induced gastrointestinal injury were positively correlated with PCT, Lac, APACHEII score, and AGI grade (all P < 0.05), and sphk1 was positively correlated with I-FABP and D-lactic acid (r values were 0.773 and 0.782, respectively, both P < 0.05). ROC curve analysis showed that sphk1, D-lactic acid, I-FABP, APACHEII score, and SOFA score had high predictive value for gastrointestinal injury in patients with sepsis, with area under the curve (AUC) of 0.996, 0.987, 0.976, 0.901, and 0.934 (all P < 0.05). When the optimal cut-off value of sphk1 was 60.46 ng/L, the sensitivity and specificity were 95.6% and 100%, respectively; when the optimal cut-off value of D-lactic acid was 1 454.3 μg/L, the sensitivity and specificity were 95.6% and 100%, respectively; when the optimal cut-off value of I-FABP was 0.91 ng/L, the sensitivity and specificity were 95.6% and 100%, respectively; when the optimal cut-off value of APACHEII score was 14.5, the sensitivity and specificity were 80.9% and 85.0%, respectively; when the optimal cut-off value of SOFA score was 3.5, the sensitivity and specificity were 85.3% and 95.0%, respectively. CONCLUSIONS The levels of plasma sphk1, I-FABP, and D-lactic acid were significantly elevated in patients with sepsis and gastrointestinal injury. These indicators can serve as sensitive and relatively specific serological markers for early prediction of intestinal mucosal damage.
Humans ; Lactic Acid/blood* ; Fatty Acid-Binding Proteins/blood* ; Sepsis/complications* ; Prospective Studies ; Male ; Female ; Middle Aged ; Predictive Value of Tests ; Adult ; Aged ; Gastrointestinal Diseases/blood* ; Prognosis

In recent years, significant progress has been made in the study of the complex pathophysiology of sepsis. However, sepsis remains the main cause of high mortality among critically ill patients worldwide. Early diagnosis, timely treatment, and accurate prediction of the prognosis are crucial for the successful treatment of septic patients. Lactic acid not only serves as a diagnostic indicator for septic shock but also participates in the immune response process of sepsis. It regulates gene epigenetic regulation through lactylation, thereby affecting the expression of related genes, cellular metabolism, and the immune response of the body. Therefore, it may become a new target for the treatment of sepsis. Lactate-related indicators, such as lactic acid/albumin ratio (LAR) and lactic acid/hematocrit ratio (LHR), also have important value in the prognosis assessment of septic patients and are superior to the evaluation efficacy of a single indicator. This is of great significance for timely detection of the changes in the condition of septic patients and their risk stratification and precise treatment. This review focused on the relationship between lactylation, lactatization, lactate-related indicators and sepsis, as well as the latest research progress. By revealing their roles in the occurrence, development and prognosis of sepsis, it provided new ideas for clinical diagnosis and treatment, uncovered new mechanisms of disease onset, guided disease risk stratification, optimized existing treatment strategies, and also offered new references and directions for basic research on lactate-related indicators.
Humans ; Sepsis/metabolism* ; Lactic Acid/metabolism* ; Prognosis ; Biomarkers/blood*

The Chinese hamster ovary (CHO) cell is the most representative mammalian cell protein expression system, and it is widely used in recombinant protein, vaccine and other biopharmaceutical fields. However, due to its vulnerability to environmental factors, apoptosis, and metabolic inhibitors, CHO cells demonstrate poor robustness, and thus the integrated viable cell density and unit cell productivity are largely limited. To improve the robustness and foreign protein expression efficiency of CHO cells, we employed CRISPR/Cas9 to knock out the apoptosis genes Bax and Bak and the lactate dehydrogenase gene LDHa, thereby blocking apoptosis and lactic acid metabolism pathways. The results of apoptosis and single cell viability detection showed that the number of apoptotic cells in the knockout cell lines Bax^-/-, Bax-bak^-/-, and LDHa-Bax-bak^-/- was reduced by 22.51%, 37.73%, and 64.12%, respectively, compared with the wild-type cell line CHO-K1, which indicated that the anti-apoptotic ability was significantly improved. After staurosporine treatment, the single cell viability of Bax^-/-, Bax-bak^-/-, and LDHa-Bax-bak^-/- cells was increased by 30.8%, 22%, and 41.1%, respectively. After treatment with puromycin, the single cell viability of Bax^-/-, Bax-bak^-/-, and LDHa-Bax-bak^-/- cells was increased by 26.7%, 30.7%, and 38.8%, respectively. To further investigate the production performance of cells obtained after blocking apoptosis and lactic acid metabolism pathways, we induced transient expression of human tissue plasminogen activator (tPA) in these cells. The results showed that the secretion of tPA in Bax^-/-, Bax-Bak^-/-, and LDHa-Bax-Bak^-/- cells was 11.12%, 46.18%, and 63.13%, respectively, higher than that in wild-type CHO-K1 cells. The expression of intracellular tPA was increased by 35.65%, 130%, and 192.15%. In conclusion, blocking apoptosis and lactic acid metabolism pathways simultaneously can improve cell robustness and productivity, with the performance better than blocking the apoptosis pathway alone. The above results indicated that the constructed cell lines were expected to be the delivery carriers of protein drugs such as medicinal peptides, and better used for the treatment of diseases.
CHO Cells ; Cricetulus ; Animals ; Apoptosis/genetics* ; Lactic Acid/metabolism* ; Recombinant Proteins/biosynthesis* ; L-Lactate Dehydrogenase/genetics* ; bcl-2-Associated X Protein/genetics* ; bcl-2 Homologous Antagonist-Killer Protein/genetics* ; Cricetinae ; CRISPR-Cas Systems ; Staurosporine/pharmacology*

Blood biochemical indicators are an important basis for the diagnosis and treatment by doctors. The performance of related instruments, the qualification of operators, the storage method and time of blood samples and other factors will affect the accuracy of test results. However, it is difficult to meet the clinical needs of rapid detection and early screening of diseases with currently available methods. Point-of-care testing (POCT) is a new diagnostic technology with the characteristics of instant, portability, accuracy and efficiency. Microfluidic chips can provide an ideal experimental reaction platform for POCT. This paper summarizes the existing detection methods for common biochemical indicators such as blood glucose, lactic acid, uric acid, dopamine and cholesterol, and focuses on the application status of POCT based on microfluidic technology in blood biochemistry. It also summarizes the advantages and challenges of existing methods and prospects for development. The purpose of this paper is to provide relevant basis for breaking through the technical barriers of microfluidic and POCT product development in China.
Humans ; Point-of-Care Testing ; Lactic Acid/blood* ; Microfluidic Analytical Techniques/methods* ; Blood Glucose/analysis* ; Point-of-Care Systems ; Blood Chemical Analysis/instrumentation* ; Uric Acid/blood* ; Cholesterol/blood* ; Dopamine/blood* ; Microfluidics/methods*