Abstract

Host-derived lipids undergoing enzymatic or nonenzymatic oxidation play critical roles in regulating inflammation. Polyunsaturated fatty acids, cholesterol, and cholesterol intermediates can be enzymatically oxidized and serve as signaling mediators controlling tissue homeostasis and immunity. Spontaneously generated oxidized lipids, including nonenzymatically oxidized phospholipids (oxPLs), result from oxidative stress and accumulate during inflammation, affecting cellular metabolism, immune cell functions, and cell fate. These distinct classes of oxidized lipids not only share overlapping inflammatory roles but also exhibit divergent effects depending on their molecular structures and cellular targets. This Review highlights the double-edged nature of oxPLs: Although their transient production triggers protective responses, their accumulation sustains inflammation, contributing to tissue damage. We also discuss the emerging roles of oxPLs in cell death programs, immune cell activation, and stromal cell functions, which are critical processes favoring tumor growth. Overall, we highlight how oxidized lipids orchestrate immune responses and explore their contribution to infectious diseases and cancer.

Highlight

• CTSB promotes ox-LDL-induced foam cell formation and ferroptosis.

• CTSB interacts with NRF2, thereby enhancing the transcriptional upregulation of HMOX1.

• CTSB serves as a potential biomarker for assessing atherosclerotic progression.

Abstract
Atherosclerosis is a chronic inflammatory vascular disease characterized by lipid accumulation and plaque formation, representing a leading cause of life-threatening cardiovascular events. Ferroptosis, an iron-dependent form of cell death driven by lipid peroxidation, has been implicated in atherosclerotic progression; however, the exact mechanism remains elusive. Here, we identified cathepsin B (CTSB) as a novel ferroptosis-related gene through bioinformatic screening and investigated its functional role in macrophage-derived foam cells and plaque instability using both in vitro and in vivo models. Mechanistically, CTSB bound to and stabilized nuclear factor erythroid 2-related factor 2 (NRF2), facilitating its nuclear translocation and subsequent transcriptional activation of heme oxygenase-1 (HMOX1), a pivotal regulator of iron homeostasis and oxidative stress. Consequently, CTSB-driven HMOX1 upregulation promoted ferroptosis and exacerbated plaque vulnerability, whereas CTSB knockdown or pharmacological inhibition reversed these effects. Collectively, our findings uncover a CTSB/NRF2/HMOX1 signaling cascade that drives ferroptosis in macrophage-derived foam cells and promotes plaque instability, positioning CTSB as a promising therapeutic target for stabilizing high-risk atherosclerotic plaques.

Keyword
Atherosclerosis; Foam cells; Plaque instability; Cathepsin B; Ferroptosis

Introduction

Atherosclerosis is a progressive vascular disease that poses a severe threat to human health [1], [2]. After vascular endothelial damage occurs, oxidized low-density lipoprotein (ox-LDL) accumulates in the subendothelial layer, accompanied by macrophage infiltration, smooth muscle cell proliferation, and other processes. These processes lead to the formation of fatty streaks, fibrous plaques, and atheromatous plaques, ultimately resulting in vascular stenosis and triggering life-threatening cardiovascular and cerebrovascular events such as myocardial infarction and ischemic stroke [3], [4], [5]. In the complex pathological process of atherosclerosis, foam cells play an indispensable and crucial role, serving as the core driving factor for the early initiation and subsequent progression of the disease [6], [7]. In the early stage of the disease, lipid streaks formed by the accumulation of a large number of foam cells represent the initial pathological manifestation of atherosclerosis. As the disease progresses, foam cells undergo necrosis and disintegration due to excessive lipid phagocytosis, releasing a large amount of cholesterol crystals, inflammatory factors, and cellular debris. This exacerbates inflammation, stimulates smooth muscle cells to form a fibrous cap, and promotes the transformation of lipid streaks into fibrous plaques [8], [9]. In the later stage, inflammatory factors and proteases released by foam cells weaken the fibrous cap of the plaque and destroy its structural stability, making the plaque prone to rupture [10], [11]. However, the molecular mechanisms that regulate foam cell formation and affect the progression of arteriosclerosis remain incompletely elucidated. Therefore, it is essential to conduct a thorough investigation of the biomarkers and regulatory networks of foam cells in order to identify effective prevention and treatment targets for atherosclerosis.
Ferroptosis is a type of iron-dependent cell death triggered by the excessive accumulation of lipid peroxides. It exhibits significant differences from traditional cell death types such as apoptosis and necrosis in terms of morphology, biochemical characteristics, and molecular mechanisms[12], [13], [14]. In the pathological microenvironment of atherosclerosis, the triggering conditions for ferroptosis are widely present. On one hand, a large amount of ox-LDL exists in atherosclerotic lesions. Ox-LDL can deplete intracellular glutathione and inhibit GPX4 activity, disrupting the intracellular antioxidant balance and creating conditions for the occurrence of ferroptosis. On the other hand, iron accumulation occurs in lesion areas. Iron ions within cells such as macrophages can accelerate the ferroptosis process by promoting lipid peroxidation [15], [16], [17]. It has shown that foam cells and vascular smooth muscle cells in atherosclerotic lesions are susceptible to ferroptosis. The ferroptosis of these cells further exacerbates the inflammatory response, promotes the expansion of the necrotic core of the plaque, impairs plaque stability, and accelerates the progression of atherosclerosis [18], [19]. Additionally, ferroptosis may further promote disease development by affecting the function of vascular endothelial cells and exacerbating endothelial damage [20]. Therefore, the association between ferroptosis and atherosclerosis warrants further investigation .

Cathepsin B (CTSB) is a key member of the lysosomal cysteine protease family. Under physiological conditions, it is mainly involved in the degradation and recycling of intracellular proteins, maintaining cellular metabolic balance [21]. CTSB has been shown to be associated with a variety of diseases. For instance, it can promote acute kidney injury by activating mitochondrial apoptosis [22]. In the progression of cancer, CTSB acts as a risk factor for tumor cell migration, proliferation, and apoptosis, influencing cancer angiogenesis and chemoresistance [23], [24]. In recent years, CTSB has also been confirmed to be closely related to the pathological progression of atherosclerosis. Existing studies have demonstrated that the expression level of CTSB is significantly increased in the lesion tissues of atherosclerotic mice, and its expression is positively correlated with the severity and instability of the plaque [25], [26]. This suggests that CTSB may serve as a potential biomarker for evaluating the progression of atherosclerosis. Therefore, in-depth exploration of the regulatory mechanism of CTSB in atherosclerosis is of great significance for the development of new diagnostic and therapeutic strategies.
In this study, we explored the role of CTSB in regulating ferroptosis and plaque stability in atherosclerosis. We demonstrated that CTSB promotes ox-LDL-induced foam cell formation and ferroptosis both in vitro and in vivo. Furthermore, we identified a novel mechanism by which CTSB interacts with and stabilizes NRF2, facilitating its nuclear translocation and transcriptional upregulation of HMOX1, a pro-ferroptosis gene. Our findings provide new insights into the molecular regulation of ferroptosis in atherosclerosis and propose CTSB as a promising target for therapeutic intervention.

Abstract
Denisovans, originally identified from ancient genome from Denisova Cave in Altai, were a sister group to the Neanderthals and were once widely distributed across diverse terrains in the north and south of eastern Asia1–5. Genomic studies suggest that there were multiple events of interbreeding between modern humans (Homo sapiens) and Denisovans somewhere in Asia6. However, little is known about Denisovan living environments, diet, ecological niche, the timing of their disappearance, and the possible coexistence with modern humans in different regions. Here we report the radiocarbon age and stable isotopic signature of Penghu 3, a large Denisovan tibia from Penghu Channel, Taiwan7. The results showed that Penghu 3 dates to approximately 45,000 years ago, the time when modern humans were already widespread in southern parts of Asia. This Denisovan individual inhabited a C4-dominated ecosystem, open environments such as savannahs and floodplains, or a mixture of both, and consumed a high proportion of animal protein similar to some European Neanderthals8–10, with no clear evidence for the use of aquatic resources. These findings have implications for the behavioral flexibility, large body size7, and eventual disappearance of the Denisovans.

Nitrogen isotopes within the tibia match what you’d expect from a highly carnivorous creature with a meat-dominated diet, similar to European Neanderthals. Curiously, the analysis also suggested the individual didn’t eat much fish or other seafood, harboring nitrogen isotopes derived exclusively from terrestrial herbivores, contrasting with H. sapiens that migrated into southeast Asia about 45,000 years ago. Although the data only come from a single individual, they could hint that Denisovans had a less flexible dietary range than newcomers from our own species. 
Another surprise from the new fossils is their age, says Chris Stringer, a paleoanthropologist at the Natural History Museum in London who was one of the researchers to originally date the remains with uranium isotopes. In 2023, his team estimated the bones were about 160,000 years old. But the new radiocarbon dates suggest they’re much younger, only about 45,000 years old, making them “the youngest well-dated Denisovans so far,” Stringer says. The bones fill a long-standing gap in the Denisovan fossil record, he notes, landing them at a time and place when they likely would have interacted and possibly interbred with members of our species rapidly spreading across Asia. 

Abstract
Human skin pigmentation is a dynamic and highly adaptive trait influenced by genetic, environmental, and cultural factors. It is driven by variation in ultraviolet radiation, governed by a complex polygenic structure, and further modulated through gene-culture interactions. This review synthesizes advances from evolutionary biology, anthropology, molecular genetics, and gene-culture coevolution to provide an integrated framework for understanding global diversity of pigmentation. We take a distinct approach by focusing on the major evolutionary hypotheses and the polygenic architecture underlying pigmentation. We emphasize both large-effect loci, including SLC24A5, SLC45A2, and MC1R, as well as population-specific adaptive variants identified through recent genomic and functional studies. Using evidence from diverse global populations, we examine how natural selection, demographic processes, and convergent evolution have jointly structured present-day variation in human skin pigmentation. We further emphasize how cultural practices, including clothing, diet, and mobility, have generated gene-culture feedback that modulates selective pressures over evolutionary timescales, underscoring the need for integrative, multi-ethnic research approaches that trace the temporal variation of skin pigmentation and advance its broader biomedical and anthropological implications.

Abstract
BackgroundThis study reports a case of recurrent laryngeal leukoplakia, a precancerous lesion, in a female cook with long-term occupational exposure to cooking oil fumes. In 2022, the Korean Epidemiological Investigation and Evaluation Committee determined that substantial scientific evidence supported the work-relatedness of the case.

Case presentationA 55-year-old woman working as a cook in group-catering facilities in long-term care hospitals and general hospitals was referred to an otolaryngology clinic after an abnormal laryngeal finding was incidentally detected during routine upper gastrointestinal endoscopy in April 2018. Subsequent laryngoscopy revealed granulation tissue of the left vocal fold. Histopathological examination following laryngeal microsurgery confirmed high-grade dysplasia, leading to a diagnosis of left vocal fold leukoplakia, and the lesion was excised. During follow-up, persistent voice changes and recurrence of the lesion were identified, and repeat excision again demonstrated low- and high-grade dysplasia. The patient had worked as a cook for approximately 14.6 years and routinely performed oil-intensive cooking tasks, including frying, grilling, stir-frying, and battered-dish preparation, for approximately 2–4.5 hours per day. She reported insufficient ventilation during heavy fume generation. She had no history of smoking, passive smoking from her spouse, alcohol consumption, vocal abuse, gastroesophageal reflux disease, or mechanical trauma to the larynx.

ConclusionsThis case suggests a possible occupational contribution of repeated intermittent exposure to cooking oil fumes and irritant aldehydes to recurrent laryngeal precancerous lesions among cooks. However, because direct historical exposure measurements were unavailable and this is a single case report, definitive causality cannot be established. Improvement of workplace ventilation and other exposure-control measures should be considered, and further studies with direct exposure assessment are needed.

Abstract
Background
Traditional risk factors do not fully account for the residual cardiometabolic risk of major adverse cardiovascular events (MACE) in coronary artery disease (CAD). We aimed to identify circulating metabolic signatures associated with MACE susceptibility and uncover potential pathobiological mechanisms underlying the gut-liver-heart axis.
Methods
In this retrospective case-control study, untargeted high-performance liquid chromatography-mass spectrometry (HPLC-MS) was performed on fasting serum from 200 patients with CAD and MACE, 200 with CAD without MACE, and 400 matched non-CAD controls. Metabolomics data were processed using univariate analysis, multivariate analysis, and eXtreme Gradient Boosting (XGBoost) machine learning. Pathway enrichment was conducted using metabolite set enrichment analysis. Circulating fibroblast growth factor 19 (FGF19) was quantified via enzyme-linked immunosorbent assay to validate enterohepatic endocrine disruption.
Results
The MACE cohort exhibited a pronounced cardiometabolic phenotype, characterized by significantly highest rates of diabetes, hypertension, and dyslipidemia (p < 0.01). The XGBoost model robustly discriminated patients with CAD and MACE from non-CAD controls (area under the curve [AUC] = 0.984) and from patients with CAD without MACE (AUC = 0.932). Pathway analysis revealed marked dysregulation of linoleic acid metabolism and peroxisome proliferator-activated receptor (PPAR) signaling (p < 0.05). Specifically, pro-inflammatory oxidized linoleic acid metabolites, including 9- and 13-hydroxyoctadecadienoic acid (HODE)—which drive plaque instability—were significantly elevated in the MACE cohort. Furthermore, atheroprotective primary bile acids were significantly depleted in patients with CAD (p < 0.001). This depletion was accompanied by an elevated serum FGF19 level (p = 0.003), reflecting a potential disruption of the gut-liver-heart endocrine axis.
Conclusions
In conclusion, dysregulated linoleic acid oxidation, altered PPAR signaling, and disturbed primary bile acid-FGF19 metabolism may represent key metabolic pathways associated with MACE susceptibility. Integrating these gut-liver-heart axis signatures into machine learning models holds significant promise for refining cardiovascular risk stratification and guiding targeted preventive interventions.

Abstract
Type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) in children and adolescents are characterized by altered lipid metabolism and gut microbiota. Prior untargeted (nonquantitative) lipidomics of the present T2DM and MetS pediatric cohort revealed alterations in plasma lipids. Fatty acids (FAs) bonded to plasma phospholipids (PLs) and cholesterol esters (CEs) reflect endogenous metabolism and exogenous sources. The present study focused on targeted quantification of FAs esterified to plasma PLs and CEs in children and adolescents with T2DM and MetS and healthy controls (n = 60, ages 7 to 17). Regression models and Spearman correlations assessed associations of esterified FA with the disease, metabolic risk factors, pro-inflammatory cytokines, and gut microbiota composition. T2DM and MetS groups featured higher concentrations of saturated FAs esterified to PLs (C17:0) and CEs (C10:0, C12:0, and C24:0) than healthy controls. Also, both groups had higher omega-6 FA levels, including dihomo-γ-linolenic acid (C20:3n-6) in both plasma fractions (PLs and CEs), C22:5n-6 in PLs, and C18:2n-6 and C20:4n-6 in CEs. These FAs were inversely correlated with high-density lipoprotein cholesterol and directly correlated with obesity, triglycerides, and insulin resistance. Also, MetS had a high CE-omega-6/omega-3 ratio. Gut microbial taxa associated with T2DM and MetS after Tanner, sex, and body mass index percentile adjustment were Agathobacter, Dorea, Fusicatenibacter, and Gemmiger, with higher abundances than those in healthy controls, and the genus Faecalimonas at lower abundances. This work contributes to the current knowledge of lipid metabolism and the role of gut microbiota in T2DM and MetS in children and adolescents.

Proteome-wide interaction study of fatty acids and mortality in the UK Biobank

DOI

Circulating fatty acids exhibit marked heterogeneity in their associations with premature mortality, yet the underlying molecular effect modifiers remain largely unexplored. Standard epidemiological approaches fail to capture dynamic physiological differences across populations, overlooking how individual protein networks alter lipid-mediated health risks. This investigation evaluates proteome-wide interactions between plasma fatty acids and circulating proteins to estimate all-cause and cause-specific mortality risks within a massive prospective framework. Analyzing data from 30,190 UK Biobank participants carrying complete metabolomic and proteomic profiles, the project maps biological susceptibility across diverse inflammatory and metabolic states.

Fully adjusted models demonstrate that omega-3 percentage (HR = 0.88, 95 percent CI [0.85-0.92], p = 9.2 x 10^-11) and linoleic acid percentage (HR = 0.91, 95 percent CI [0.88-0.94], p = 1.4 x 10^-7) associate inversely with all-cause mortality, whereas non-linoleic acid omega-6 percentage (HR = 1.13, 95 percent CI [1.09-1.17], p = 4.1 x 10^-12) and the omega-6 to omega-3 ratio (HR = 1.11, 95 percent CI [1.07-1.15], p = 6.1 x 10^-9) drive substantial risk increases. Proteome-wide screening isolates nine robust interaction pairs involving inflammatory proteins such as PLAU, TSPAN8, MMP10, and TNFRSF1B. Stratified analyses reveal that elevated baseline inflammation amplifies both the hazards of monounsaturated fats and the protective efficacy of omega-3 intake.

Study Design and Methodology

This prospective cohort investigation leverages data from the UK Biobank, an initial recruitment pool exceeding 500,000 adults aged 40 to 69 years. Following rigorous exclusions for missing plasma fatty acid or proteomic metrics, the finalized analytical cohort comprises 30,190 individuals with a mean age of 56.91 years, comprising 16,285 females and 13,905 males. Researchers document 3,345 deaths over a median follow-up duration of 13.9 years, ending on January 15, 2023. Plasma metabolomics quantified via nuclear magnetic resonance spectroscopy yields nine distinct fatty acid proportions, while Olink proximity extension assays profile 2,911 unique circulating proteins spanning cardiometabolic, inflammatory, neurological, and oncological axes. The analytical pipeline randomly partitions the cohort into an 80 percent training dataset (N = 24,152) and a 20 percent test dataset (N = 6,038). Multivariable Cox proportional hazards models control for age, sex, ethnicity, smoking status, alcohol intake, body mass index, educational attainment, household income, the Townsend deprivation index, and a baseline healthy diet score. Fine-Gray subdistribution hazard models evaluate competing risks for cardiovascular and cancer mortality.

Key Findings

• Omega-3 percentage exhibits a robust inverse relationship with all-cause mortality (HR = 0.88, 95 percent CI [0.85-0.92], p = 9.2 x 10^-11).
• Linoleic acid percentage demonstrates significant protection against mortality (HR = 0.91, 95 percent CI [0.88-0.94], p = 1.4 x 10^-7).
• Non-linoleic acid omega-6 percentage drives the highest positive association with mortality risk (HR = 1.13, 95 percent CI [1.09-1.17], p = 4.1 x 10^-12).
• The omega-6 to omega-3 ratio scales positively with death risk (HR = 1.11, 95 percent CI [1.07-1.15], p = 6.1 x 10^-9).
• High expression of MMP10 significantly magnifies monounsaturated fatty acid mortality hazards (HR = 1.23, 95 percent CI [1.12-1.36], p = 0.001).
• Elevated PLAU expression strongly enhances the protective association of omega-3 fatty acids (HR = 0.70, 95 percent CI [0.63-0.76], p < 0.001).
• High TSPAN8 levels intensify the mortality risks associated with an elevated omega-6 to omega-3 ratio (HR = 1.35, 95 percent CI [1.22-1.50], p < 0.001).

Limitations

Baseline-only plasma protein assessments fail to capture longitudinal proteomic variability over the 13.9-year follow-up period. Granular subtypes within monounsaturated fatty acid pools remain unanalyzed due to metabolomic platform constraints. Participant demographics skew heavily toward Caucasian individuals from high socioeconomic regions, restricting global generalizability. Residual confounding persists despite extensive covariate adjustment, although calculated E-values ranging from 1.74 to 3.71 indicate that substantial unmeasured confounders are required to nullify the observed effects. Observational architecture precludes definitive causal inferences.

Discussion and Implications

Nutritional dogmas surrounding polyunsaturated fats require immediate revision in light of these proteome-wide interaction metrics. Public health debates heavily vilify total omega-6 exposure, yet this investigation proves that lumping linoleic acid with non-linoleic omega-6 fractions obscures distinct biological realities. Linoleic acid acts as a potent protective agent, challenging historical assumptions that seed oils inherently promote systemic pathology. Conversely, non-linoleic omega-6 fractions and an inflated omega-6 to omega-3 ratio drive severe mortality risks, particularly in hosts exhibiting high baseline vascular inflammation governed by proteins like PLAU and TSPAN8. Clinicians must abandon generalized dietary prescriptions because individual inflammatory phenotypes actively modify nutrient handling. Therapeutic interventions targeting cardiovascular and oncological prevention must prioritize lowering systemic inflammatory drivers while optimizing circulating omega-3 levels to alter enzymatic substrate competition.

Clinical nutrition strategies shouldn't rely on population-wide fatty acid targets because baseline inflammatory protein profiles dictate true disease risk. Practitioners must tailor interventions by evaluating vascular stress markers alongside lipid ratios, recognizing that omega-3 efficacy scales directly with the patient's underlying inflammatory burden.

Highlights

• 4-HNE inhibits AMPK alpha 2 via Cys174/Cys200 modification in a dose/time-dependent manner. Antioxidants abolish suppression. Pathological 4-HNE accumulation impairs AMPK alpha 2, yielding a vascular disease therapeutic target.

Abstract
Background

AMP-activated protein kinase (AMPK) is a critical regulator of endothelial function, oxidative stress, and inflammation. Lipid peroxidation products such as 4-hydroxynonenal (4-HNE) accumulate under conditions of oxidative stress and are implicated in vascular dysfunction. However, whether 4-HNE directly reacts with AMPK and alters its activity remains unclear.

Objectives

To explore the effects of 4-HNE on the LKB1-AMPK axis, with a focus on AMPKα1 and AMPKα2 in different cell types (HUVECs, H9c2 cells), a cell-free system, and in vivo (Akita mice), and to understand the underlying mechanisms in human atherosclerotic plaques.

Methods

In HUVECs and H9c2 cells, cells were treated with 4-HNE, and protein levels were detected by Western blots. AMPKα2 activity was measured after enrichment via immunoprecipitation. Cell viability was also examined. In a cell-free system, recombinant AMPK was incubated with 4-HNE. In Akita mice, AMPKα2 activity was measured in aortas after tempol treatment. In human atherosclerotic plaques, immunohistochemistry, co - immunoprecipitation, and mass spectrometry were employed.

Results

In HUVECs, low 4-HNE concentrations (1-15 μM) didn't change LKB1 levels, but higher ones (20-25 μM) reduced them. 4-HNE had a variable impact on AMPKα1 levels, while significantly inhibiting AMPKα2 activity in a dose - and time-dependent manner. In H9c2 cells, 4-HNE (10 μM) selectively decreased AMPKα2 levels. In the cell-free system, 4-HNE dose-dependently inhibited AMPKα2 activity. In Akita mice, oxidative stress reduced aortic AMPKα2 activity, reversed by Tempol. In human plaques, 4-HNE levels correlated with plaque severity and AMPKα2 inhibition. Cys174 and Cys200 were key for 4-HNE-mediated AMPKα2 inactivation 4-HNE modified AMPKα2 at Cys174 and Cys200, and antioxidants blocked 4-HNE-induced inhibition. Finally, pretreatment with N-ethylmaleimide, a cysteine blocker, abolished the binding of 4-HNE and AMPKα2, supporting a primary role for cysteine modification in the binding of 4-HNE with AMPKα2.

Conclusions

We conclude that 4-HNE inhibits AMPKα2 activity through oxidative modification of specific cysteine residues in human atherosclerosis.

In human atherosclerotic lesions, elevated 4-HNE levels inversely correlate with AMPKα2 activity, and enhanced 4-HNE–AMPKα2 interaction positively associates with plaque severity. Collectively, these clinical and preclinical data solidify the causal link between lipid peroxidation and AMPK dysfunction in human atherosclerotic vascular disease.

Highlights
•
Vertebral apophyseal ring (AR) is introduced as a novel proxy for reconstructing spinal biomechanics in fossil hominins.

•
Australopithecus afarensis (A.L. 288-1) shows aplike AR proportions suggesting a similar spinal motion segment.

•
Lucy retained an apelike disc structure, suggesting delayed evolution of modern intervertebral disc function.

•
Findings support gradual, mosaic evolution of efficient human-like bipedalism.

•
Reduced apophyseal ring size in Homoenhanced axial load absorption, flexibility, and endurance locomotion.

Abstract
The evolution of human bipedalism has traditionally been reconstructed from the pelvis and lower limb, whereas the contribution of the vertebral motion segment has received far less attention. This study introduces the vertebral apophyseal ring (AR) as a novel proxy for reconstructing spinal biomechanics in fossil hominins. Several vertebrae with complete ARs from Australopithecus afarensis A.L. 288-1 were compared with vertebrae from 240 adult modern humans, a Neanderthal (Kebara), an Upper Paleolithic modern human (Ohalo II), 20 chimpanzees (Pan troglodytes), and 24 gorillas (Gorilla gorilla). Vertebral body and AR dimensions were measured from vertebrae T4–L5 (L4 in apes), and corresponding ratios were calculated. Statistical differences between modern humans and African apes were assessed using Welch’s analysis of variance followed by Games-Howell post hoc tests. Relative AR size in A.L. 288-1 consistently falls within the range of chimpanzees and gorillas rather than modern humans, indicating that A. afarensis spinal motion segments differed functionally from those of modern humans. Because AR reduction is associated with enlargement of the nucleus pulposus, our findings suggest that spinal adaptations necessary for efficient load absorption, torsional flexibility, and endurance locomotion evolved later in human evolution. These results indicate that the evolution of humanlike bipedalism was a gradual and mosaic process. Although Australopithecus possessed the fundamental capacity for upright walking, it retained primitive spinal features indicative of a less optimized locomotor system. The emergence of a fully modern human gait, therefore, involved progressive reorganization of the vertebral motion segment rather than a single evolutionary transition.
Keywords
Bipedal locomotion; Intervertebral disc; Vertebral motion segement; Spinal biomechanics; Hominin evolution; Nucleus pulposus

Editor’s summary
In the face of a cornucopia of food options in the modern world, many commentators have sought to look backwards to human ancestors for diet directions. In recent decades, attention has focused on the increasing consumption of animal foods as a driver of human evolution. Considering the changing requirements of an enlarging brain and the demands of reproduction, Brand-Miller et al. modeled the distribution of macronutrient requirements across four million years of hominid evolution. They concluded that glucose—from fruit and honey early on and later from the pounding and cooking of starch—was essential for the evolution of the human brain. —Sacha Vignieri
Structured Abstract
INTRODUCTION
What foods enabled the evolution of the large human brain? Currently, that diet is usually framed around increasing intake of animal foods: meat, protein, fat, and omega-3 fatty acids. In evolutionary terms, we take an earlier standpoint and reframe hominin diet reconstruction around the need for glycemic carbohydrate as a source of glucose to support brain metabolism and encephalization. Hominins have existed for about 4 million years, their brain size increasing from 300 g in Australopithicus afarensis to 1500 g in Homo sapiens. Weighing only 2% of adult body weight, it now represents 20% of basal metabolic rate, 66% in a 5-year-old. Although the driving force is unknown, we do know that this exorbitantly expensive organ is fueled primarily by glucose. Humans can synthesize glucose from precursors such as gluconeogenic amino acids, but the process is inefficient and finite.
RATIONALE
We started with metabolic and nutritional considerations, including the rate of glucose oxidation by the brain (~5 mg/min per 100 g). We calculated total obligatory glucose demand (g/day) by the brain, red cells, kidneys, and reproductive organs (fetus, placenta, and mammary glands). In six incremental steps based on the ratio of animal food to plant food, we modeled dietary intake and carbohydrate availability against obligatory* *glucose demand according to brain and body size. At step 1, we used the known dietary composition of chimpanzee diets with an animal:plant energy ratio of 5:95. At step 6, we applied two ratios based on contemporary warm-climate hunter-gatherers: 35:65 and 50:50. We integrated multiple lines of evidence, including food composition, metabolism and physiology, fossil isotope ratios, dental morphology, and genetic changes, to corroborate our findings.
RESULTS
In human males, estimated total glucose demand is 150 to 200 g/day, in reproductive females 200 to 250 g/day, and in young children ~125 g/day. Carbohydrate availability in the diet ranges from 400 g/day at step 1 to 230 g/day at step 6. The earliest hominins were likely frugivorous, consuming >65% of energy as sugars in fruit and other sweet products. Once fire was mastered, cooked starch increasingly replaced sugars as the source of glucose. At a ratio of 35:65 animal to plant energy (E), anatomically modern humans consumed 19%E as protein, 25%E as sugars, and 25%E as starch. Carbohydrate balance, the gap between dietary carbohydrate intake and glucose demand, becomes negative with higher ratios, increasing the likelihood of ketosis in reproductive females.
CONCLUSION
Rises and falls in the availability of fruit and honey with seasons, fluctuating climates, and geographic region may have driven foraging behaviors that increased brain growth and complexity, and even extinctions. Although animal foods were clearly instrumental, changes in intake of sugars and starches also shed light on human development, health, and disease. Multiple lines of evidence, including color vision, teeth morphology, dental caries, and stable isotope ratios, suggest that the diet of early hominins was high in sugars. Our modern physiology and anatomy, including sweet taste receptors, smaller teeth, jaw, gut, and genetic variations relating to glucose metabolism, suggest genetic selection driven specifically by dietary carbohydrates.

Abstract
What did our ancestors eat? Current understanding of diet in human evolution is predicated on abundant animal foods and mastery of fire, both unlikely for early hominins. Using multiple lines of evidence, including the metabolic requirements of an enlarging brain and reproduction, we model macronutrient distribution across 4 million years of evolution. Before cooking made starch easily digestible, the sugars in fruit and honey provided glucose, the brain’s preferred fuel. Modeling suggests that sugars provided >25% of dietary energy, fulfilling obligatory glucose demand. Pounding and cooking released glucose specifically, not merely energy. The evolution of a bigger brain is therefore a story of carbohydrate foods as much as animal foods: from sweet sugars to cooked starch, from chewing to processing, and from wadging to advanced nutrient extraction.

ABSTRACT
Objectives
Recent studies of Paranthropus robustus crania identified temporal trends in features associated with increased bite force production, coinciding with environmental shifts toward more arid conditions. To test whether the evolution of postcanine teeth also reflects increasing mechanical demands associated with hard food consumption, we analyzed trends in the architecture of P. robustus postcanine teeth, including crown area, tooth shape, and average (AET) and relative (RET) enamel thickness.
Materials and Methods
2D mesial sections were created from microCT scans of upper premolars (n = 24), upper molars (n = 14), and lower molars (n = 16) from multiple South African sites. Descriptive statistics, Mann–Whitney U tests, and Jonckheere-Terpstra tests were used to identify significant differences over time, with Holm-Bonferroni corrections applied for multiple comparisons.
Results
Significant temporal trends existed in premolar morphology with increased crown area (CA), absolute crown strength (ACS), overall enamel thickness (AET and RET), and increased enamel thickness over the occlusal half of the tooth. Upper molars increased in CA but no other measured variable. Lower molars showed no significant temporal trends in any measured variable.
Discussion
These results suggest rapid dental evolution in response to dietary pressures, with varying and independent rates of change between different tooth types. These findings support the hypothesis that selection resulted in shifts to P. robustus dental morphology to increase mechanical resistance, consistent with an expanding dietary niche that incorporated increasingly challenging foods.
Summary

Upper premolar enamel thickness in Paranthropus robustus increased significantly over time, consistent with selective pressure for hard-object feeding.
Premolars showed more changes than upper or lower molars, suggesting mosaic rather than uniform dental evolution in the P. robustuslineage.

Omega-3 polyunsaturated fatty acids (PUFAs) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), possess anti-inflammatory properties, yet their association with obesity-depression comorbidity remains unclear. This study investigated the association among US adults and explored underlying mechanisms. We performed a cross-sectional analysis of 4,423 individuals participating in the National Health and Nutrition Examination Survey (NHANES) 2003–2004 & 2011–2014. Serum fatty acids were quantified by gas chromatography. Obesity was defined using anthropometric criteria, and depression was assessed using the PHQ-9 or antidepressant use. Multivariable logistic regression estimated odds ratios (ORs) per standard deviation (SD) increase in PUFA levels. Mechanistic explore through network pharmacology identified potential pathways, which were examined using correlation analyses with inflammatory indices. Higher omega-3 PUFA levels were associated with lower odds of central obesity comorbid depression in females (OR: 0.82, 95% CI: 0.69–0.96) and older adults (OR: 0.79, 95% CI: 0.64–0.97). DHA was significantly associated with lower odds of central obesity (OR: 0.83, 95% CI: 0.73–0.95), depressive symptoms (OR: 0.88, 95% CI: 0.77–1.00), and their comorbidity (OR: 0.85, 95% CI: 0.74–0.98), whereas no significant associations were found for EPA. Mechanistic exploration implicated DHA in TNF and IL-17 signaling pathways, supported by inverse correlations with monocyte-to-HDL ratio (r: −0.138, P < 0.001) and lymphocyte-to-HDL ratio (r: −0.108, P < 0.001). In conclusion, serum DHA is inversely associated with obesity-depression comorbidity, with potential involvement of anti-inflammatory pathways. These findings underscore the potential of DHA for the management of obesity comorbid depression and the need for further interventional trials.

Abstract
Background
Although numerous studies have separately examined the fish and shellfish intakes, fish types, and n-3 polyunsaturated fatty acids (n-3 PUFAs) in relation to mortality, few studies have concurrently evaluated these factors, and findings in Asia including in the Japanese population with high fish consumption, remain inconsistent.
Objective
This study investigated the associations of unsalted fish and shellfish, n-3 PUFAs-rich fish, and marine-derived n-3 PUFA consumption with all-cause and cause-specific mortality in a Japanese population.
Methods
We analyzed 90,944 individuals (42,150 men and 48,794 women) from the Japan Public Health Centre-based Prospective Study who completed a validated food frequency questionnaire between 1995 and 1998. Energy-adjusted intakes were categorized into quintiles. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for all-cause and cause-specific mortality using Cox proportional hazards regression models adjusted for potential confounders.
Results
After adjusting for covariates, a nonlinear association was observed between fish and shellfish intake and all-cause mortality in women, with the lowest mortality observed in Q4 [HR=0.92 (95% CI, 0.86, 0.98), P for nonlinearity=0.022]. In men, higher intake of unsalted fish and shellfish was associated with a lower risk of cerebrovascular disease mortality in all quintiles except Q3 [Q2: HR=0.78 (95% CI, 0.66, 0.92), Q4: HR=0.77 (95% CI, 0.65, 0.91), Q5: HR=0.84 (95% CI, 0.71, 0.99), P for nonlinearity=0.017]. For n-3 PUFA-rich fish consumption, women had lower risks of all-cause (P for linear trend=0.012) and cerebrovascular disease (P for linear trend=0.005) mortality.
Conclusions
A moderate fish and shellfish intake was associated with lower all-cause mortality in women. Higher n-3 PUFA-rich fish intake was also associated with lower cerebrovascular disease mortality in women. Among men, higher unsalted fish and shellfish intake was associated with lower cerebrovascular disease mortality. These findings suggest that different fish types may differentially associated with mortality outcomes.

Abstract
Faunal extinctions correlate with human colonization worldwide during the Quaternary, yet the extent to which human hunting drove these losses remains debated. Resolving these debates depends on accurately dating both human arrival and animal extinction events. Herein I present a simulated overkill scenario modeling interaction between a founding human population and a single prey species. The simulation evaluates expected age offsets, the differences between the actual and observed dates, for extinction and colonization as functions of sample size and human population growth rate. Results show that when extinction is driven by human hunting, age offsets for extinction are expected to be smaller than those for colonization. This difference in age offset is expected because overkill produces a rapid demographic collapse of prey populations and taphonomic processes concentrate late-surviving individuals in the fossil record. In contrast, colonization dates are more offset because human populations are smallest immediately after arrival, and archaeological rarity is compounded by taphonomic effects. Although colonization age offsets are consistently larger than extinction age offsets across sample sizes, they are not extreme, such that archaeological sites should be detectable within five centuries of initial human settlement under modest rates of human population growth.

ABSTRACT
The oral microbiome is implicated in a wide diversity of fundamental biological functions, with the oral cavity serving as a connection between the host and the external environment. Dental calculus, a mineralized form of dental plaque, preserves the diversity of biomolecules found in the oral cavity through time, serving as a rich source of historical microbiota. Despite its potential, dental calculus has rarely been explored outside of humans and non‐human primates. Hence, it remains unclear how ubiquitous it is across mammals. Using natural history museum collections, we surveyed > 1600 specimens belonging to 142 species, representative of almost all mammalian orders, to investigate the taxonomic distribution of dental calculus, and to identify factors that most strongly contribute to its formation. We found dental calculus to be abundant across mammalian taxa, with 104 surveyed species showing calculus. High‐fiber diets were most strongly associated with calculus abundance, whereas species with high protein and fat diets showed little to no calculus deposits. We found evidence of phylogenetic signal in calculus formation, pointing to the effects of oral/dental morphology. In addition, captivity strongly affected dental calculus formation in almost all dietary categories. Using this information, we made predictions about the likelihood of finding dental calculus in unsurveyed mammalian species, opening doors for its utilization for the study of oral microbiota, past and present. Our study found that dental calculus is well‐preserved and readily available in natural history museum collections, making it an easily accessible source of oral microbiota from wild animals. We highlight the taxonomic diversity of species presenting dental calculus and provide information and suggestions for its use to researchers and curators alike.