Lactate, with a chemical formula of C₃H₆O₃, is an intermediate product of glucose metabolism in the body and a raw material for hepatic gluconeogenesis. Under physiological resting conditions, the body mainly relies on aerobic oxidation of sugar and fat for energy supply, so the blood lactate concentration is lower. However, during exercise, the enhanced glycolysis in skeletal muscles leads to the significant release of lactate into the bloodstream, causing a marked increase in blood lactate concentration. Traditionally, lactate has been regarded as a metabolic waste product of glycolysis and a contributor to exercise-induced fatigue. Nevertheless, recent studies have revealed that, in humans, lactate is a major vehicle for carbohydrate carbon distribution and metabolism, serving not only as an energy substance alongside glucose but also as a vital component in various biological pathways involved in cardiac energetics, muscle adaptation, brain function, growth and development, and inflammation therapy. Two primary pathways can elevate lactate levels in neurons during exercise. One is peripheral skeletal muscle-derived lactate, which can enter the bloodstream and cross the blood-brain barrier into the brain with the assistance of monocarboxylate transporters (MCTs) from the solute carrier family 16 (SLC16). The other is the central brain-derived pathway. During exercise, neuronal activity is enhanced, promoting the secretion of neuroactive substances such as glutamate, norepinephrine, and serotonin in the brain. This activates astrocytes to break down glycogen into lactate and stimulates glutamate from the presynaptic terminal into the synaptic cleft. It upregulates the glucose transport protein-1 (GLUT-1) expression, allowing astrocytes to convert glucose into lactate through glycolysis. The lactate is produced via peripheral pathways and central pathways during exercise are transported by astrocyte membrane monocarboxylate transporters MCT1 and MCT4 to the extracellular space, where neurons take it up through neuronal cell membrane MCT2. The lactate in neurons can serve as an alternative energy source of glucose for neuronal functional activities, meeting the increased energy demands of synaptic activity during exercise, and maintaining energy balance and normal physiological function in the brain. Additionally, acting as a signaling molecule lactate can enhance synaptic plasticity through the SIRT1/PGC-1α/FNDC5 and ERK1/2 signaling pathways, lactate can promote angiogenesis by upregulating VEGF-A expression through the PI3K/Akt and ERK1/2 signaling pathways, stimulate neurogenesis via the Akt/PKB signaling pathway, and reduce neuroinflammation through activation of the “lactate timer”. Overall, lactate contributes to the protection of neurons, the promotion of learning and memory, the enhancement of synaptic plasticity, and the reduction of neuroinflammation in the nervous system. While lactate may serve as a potential mediator for information exchange between the peripheral and central nervous systems during exercise, further experimental research is needed to elucidate its action mechanisms in the nervous system. In addition, future studies should utilize advanced neurophysiological and molecular biology techniques to uncover the importance of lactate in maintaining brain function and preventing neurological diseases. Accordingly, this article first reviews the historical research on lactate, then summarizes the metabolic characteristics and neuronal sources of lactate, and finally explores the role and mechanisms of exercise-induced lactate in the nervous system, aiming to provide new perspectives and targets for understanding the mechanisms underlying exercise promotion of brain health.

ObjectiveObesity has been identified as one of the most important risk factors for cognitive dysfunction. Physical exercise can ameliorate learning and memory deficits by reversing synaptic plasticity in the hippocampus and cortex in diseases such as Alzheimer’s disease. In this study, we aimed to determine whether 8 weeks of treadmill exercise could alleviate hippocampus-dependent memory impairment in high-fat diet-induced obese mice and investigate the potential mechanisms involved. MethodsA total of sixty 6-week-old male C57BL/6 mice, weighing between 20-30 g, were randomly assigned to 3 distinct groups, each consisting of 20 mice. The groups were designated as follows: control (CON), high-fat diet (HFD), and high-fat diet with exercise (HFD-Ex). Prior to the initiation of the treadmill exercise protocol, the HFD and HFD-Ex groups were fed a high-fat diet (60% fat by kcal) for 20 weeks. The mice in the HFD-Ex group underwent treadmill exercise at a speed of 8 m/min for the first 10 min, followed by 12 m/min for the subsequent 50 min, totally 60 min of exercise at a 0° slope, 5 d per week, for 8 weeks. We employed Y-maze and novel object recognition tests to assess hippocampus-dependent memory and utilized immunofluorescence, Western blot, Golgi staining, and ELISA to analyze axon length, dendritic complexity, number of spines, the expression of c-fos, doublecortin (DCX), postsynaptic density-95 (PSD95), synaptophysin (Syn), interleukin-1β (IL-1β), and the number of major histocompatibility complex II (MHC-II) positive cells. ResultsMice with HFD-induced obesity exhibit hippocampus-dependent memory impairment, and treadmill exercise can prevent memory decline in these mice. The expression of DCX was significantly decreased in the HFD-induced obese mice compared to the control group (P<0.001). Treadmill exercise increased the expression of c-fos (P<0.001) and DCX (P=0.001) in the hippocampus of the HFD-induced obese mice. The axon length (P<0.001), dendritic complexity (P<0.001), the number of spines (P<0.001) and the expression of PSD95 (P<0.001) in the hippocampus were significantly decreased in the HFD-induced obese mice compared to the control group. Treadmill exercise increased the axon length (P=0.002), dendritic complexity(P<0.001), the number of spines (P<0.001) and the expression of PSD95 (P=0.001) of the hippocampus in the HFD-induced obese mice. Our study found a significant increase in MHC-II positive cells (P<0.001) and the concentration of IL-1β (P<0.001) in the hippocampus of HFD-induced obese mice compared to the control group. Treadmill exercise was found to reduce the number of MHC-II positive cells (P<0.001) and the concentration of IL-1β (P<0.001) in the hippocampus of obese mice induced by a HFD. ConclusionTreadmill exercise led to enhanced neurogenesis and neuroplasticity by increasing the axon length, dendritic complexity, dendritic spine numbers, and the expression of PSD95 and DCX, decreasing the number of MHC-II positive cells and neuroinflammation in HFD-induced obese mice. Therefore, we speculate that exercise may serve as a non-pharmacologic method that protects against HFD-induced hippocampus-dependent memory dysfunction by enhancing neuroplasticity and neurogenesis in the hippocampus of obese mice.

[This corrects the article DOI: 10.1016/j.apsb.2022.05.019.].

OBJECTIVE: This study aimed to explore the association between body mass index (BMI) and mortality based on the 10-year population-based multicenter prospective study. METHODS: A general population-based multicenter prospective study was conducted at four sites in rural China between 2013 and 2023. Multivariate Cox proportional hazards models and restricted cubic spline analyses were used to assess the association between BMI and mortality. Stratified analyses were performed based on the individual characteristics of the participants. RESULTS: Overall, 19,107 participants with a sum of 163,095 person-years were included and 1,910 participants died. The underweight (< 18.5 kg/m ²) presented an increase in all-cause mortality (adjusted hazards ratio [ aHR] = 2.00, 95% confidence interval [ CI]: 1.66-2.41), while overweight (≥ 24.0 to < 28.0 kg/m ²) and obesity (≥ 28.0 kg/m ²) presented a decrease with an aHR of 0.61 (95% CI: 0.52-0.73) and 0.51 (95% CI: 0.37-0.70), respectively. Overweight ( aHR = 0.76, 95% CI: 0.67-0.86) and mild obesity ( aHR = 0.72, 95% CI: 0.59-0.87) had a positive impact on mortality in people older than 60 years. All-cause mortality decreased rapidly until reaching a BMI of 25.7 kg/m ² ( aHR = 0.95, 95% CI: 0.92-0.98) and increased slightly above that value, indicating a U-shaped association. The beneficial impact of being overweight on mortality was robust in most subgroups and sensitivity analyses. CONCLUSION This study provides additional evidence that overweight and mild obesity may be inversely related to the risk of death in individuals older than 60 years. Therefore, it is essential to consider age differences when formulating health and weight management strategies.
Humans ; Body Mass Index ; China/epidemiology* ; Male ; Female ; Middle Aged ; Prospective Studies ; Rural Population/statistics & numerical data* ; Aged ; Follow-Up Studies ; Adult ; Mortality ; Cause of Death ; Obesity/mortality* ; Overweight/mortality*

OBJECTIVES: To characterize fine particulate matter (PM _2.5)-bound polycyclic aromatic hydrocarbons (PAHs) emitted from different cooking fumes and their exposure routes and assess their health-associated impact to provide a reference for health risk prevention from PAH exposure across different age and sex groups. METHODS: Sixteen PM _2.5-bound PAHs emitted from 11 cooking styles were analyzed using GC-MS/MS. The health hazards of these PAHs in the Handan City population (stratified by age and sex) were predicted using the incremental lifetime cancer risk ( ILCR) model. The respiratory deposition doses ( RDDs) of the PAHs in children and adults were calculated using the PM _2.5 deposition rates in the upper airway, tracheobronchial, and alveolar regions. RESULTS: The total concentrations of PM _2.5-bound PAHs ranged from 61.10 to 403.80 ng/m ³. Regardless of cooking styles, the ILCR _total values for adults (1.23 × 10 ^-6 to 3.70 × 10 ^-6) and older adults (1.28 × 10 ^-6 to 3.88 × 10 ^-6) exceeded the acceptable limit of 1.00 × 10 ^-6. With increasing age, the ILCR _total value first declined and then increased, varying substantially among the population groups. Cancer risk exhibited particularly high sensitivity to short exposure to barbecue-derived PAHs under equivalent body weights. Furthermore, barbecue, Sichuan and Hunan cuisine, Chinese cuisine, and Chinese fast food were associated with higher RDDs for both adults and children. CONCLUSION ILCR _total values exceeded the acceptable limit for both females and males of adults, with all cooking styles showing a potentially high cancer risk. Our findings serve as an important reference for refining regulatory strategies related to catering emissions and mitigating health risks associated with cooking styles.
Humans ; Polycyclic Aromatic Hydrocarbons/analysis* ; Cooking/methods* ; Male ; Female ; Particulate Matter/analysis* ; Adult ; Child ; Middle Aged ; Air Pollutants/analysis* ; Adolescent ; Air Pollution, Indoor/analysis* ; Young Adult ; Child, Preschool ; Aged ; China ; Inhalation Exposure ; Age Factors ; Sex Factors ; Cities ; Infant

In patients with chronic kidney disease(CKD),the incidence of cardiovascular events and the mortality rate are significantly higher than those in the general population.Approximately 85% of end-stage CKD patients develop hyperhomocysteinemia(HHcy)due to impaired renal function.It is not yet fully determined whether HHcy merely acts as a biomarker of CKD or plays a role in the pathogenesis.Although supplementation with folic acid and other B vitamins(B6 and B12)has been proven to lower the plasma level of total homocysteine,their effectiveness in slowing CKD progression or reducing cardiovascular complications remains uncertain.This article reviews the latest research progress in the relationship between HHcy and CKD,aiming to give new insights into the prevention and treatment of CKD and its complications.
Humans ; Hyperhomocysteinemia/complications* ; Renal Insufficiency, Chronic/complications*

The introduction of non-vitamin K antagonist oral anticoagulant (NOAC) into clinical use heralds a new age for anticoagulation therapy in patients with atrial fibrillation (AF).However,anticoagulation-related bleeding is currently a major challenge in the anticoagulation process.Assessing the risk of anticoagulation-related bleeding is an important part for the management of patients with AF.Clinical risk factor scores have moderate ability to predict the risk of anticoagulation-related bleeding.To improve the anticoagulation safety of NOACs,additional clinical and biological markers and genetic polymorphisms should be considered to enhance the predictive capability for anticoagulation-related bleeding.This review summarizes the challenges in the management of anticoagulation therapy,with emphases on the bleeding risk scores,biomarkers,clinical indicators,and genetic loci currently used to guide the risk assessment of anticoagulation-related bleeding in AF patients.This review is expected to provide research insights and reference frameworks for predicting and evaluating the bleeding risk associated with NOACs.
Humans ; Atrial Fibrillation/drug therapy* ; Anticoagulants/therapeutic use* ; Hemorrhage/chemically induced* ; Risk Assessment ; Administration, Oral ; Risk Factors

Objective To explore the relationships of cognitive impairment with cardiovascular death and all-cause death in menopausal women with hypertension.Methods A total of 4 595 natural-menopausal women with hypertension screened in Wuyuan County of Jiangxi Province from July to August 2018 were selected as the research subjects,and a follow-up investigation of death information was completed from June to August 2022.According to the baseline mini-mental state examination(MMSE)score,all subjects were allocated into a normal cognitive function group and a cognitive impairment group.The basic characteristics and the cumulative risk of death evaluated by the Kaplan-Meier curve were compared between two groups.The multivariate Cox regression model was adopted to analyze the effect of cognitive function on death,and the relationship between MMSE score and death was fitted by the restricted cubic spline.Results A total of 4 595 subjects with the mean age of(65.1±8.4)years were included in this study,in which and 1 859(40.5%)patients with cognitive impairment were detected.During a mean follow-up period of(3.9±0.4)years,199 all-cause deaths were collected,including 102 cardiovascular deaths.The normal cognitive function group and the cognitive impairment group had the cumulative all-cause death rates of 2.6%and 6.9%and the cumulative cardiovascular death rates of 1.0%and 4.0%,respectively.The Kaplan-Meier curve showed that the cumulative risks of all-cause death(χ²=47.287,P<0.001)and cardiovascular death(χ²=45.169,P<0.001)in the cognitive impairment group were higher than those in the normal cognitive function group.The results of multivariate Cox regression analysis indicated that compared with the normal cognitive function group,the cognitive impairment group had increased risks of all-cause death(HR=1.75,95%CI=1.28-2.39,P<0.001)and cardiovascular death(HR=2.56,95%CI=1.61-4.09,P<0.001).The results of the restricted cubic spline curve fitting showed that the MMSE score had linearly negative correlations with the risk of all-cause death(P_all<0.001, P n o n - l i n e a r i t y=0.519)and cardiovascular death(P_all<0.001, P n o n - l i n e a r i t y=0.195).Conclusion Cognitive impairment is an independent risk factor for all-cause death and cardiovascular death in menopausal women with hypertension,and early identification of cognitive impairment in this population is essential for timely intervention.
Humans ; Female ; Cognitive Dysfunction ; Hypertension/complications* ; Aged ; Middle Aged ; Menopause ; Proportional Hazards Models ; Risk Factors ; Cardiovascular Diseases/mortality* ; Cause of Death ; Kaplan-Meier Estimate