We examined changes in skeletal muscle protein lactylation and acetylation in response to acute resistance exercise, chronic resistance training (RT), and a single endurance cycling bout. Additionally, we performed in vitro experiments to determine if different sodium lactate treatments affect myotube protein lactylation and acetylation. The acute and chronic RT study (12 college-aged participants) consisted of 10 weeks of unilateral leg extensor RT with vastus lateralis (VL) biopsies taken at baseline, 24 h following the first RT bout, and the morning of the last day of the RT bout. For the acute cycling study (9 college-aged participants), VL biopsies were obtained before, 2 h after, and 8 h after 60 min of cycling. For in vitro experiments, C2C12 myotubes were treated with varying levels of sodium lactate, including LOW (1 mM for 24 h), HIGH (10 mM for 24 h), and PULSE (10 mM for 30 min followed by 1 mM for 23.5-h). Neither acute nor chronic RT significantly affected nuclear or cytoplasmic protein lactylation. However, cytoplasmic protein acetylation was significantly reduced following one RT bout (−15%, p = 0.002) and chronic RT (−16%, p = 0.006). Cycling did not acutely alter post-exercise global protein lactylation or acetylation patterns. Lastly, varying 24 h lactate treatments did not alter nuclear or cytoplasmic protein lactylation or acetylation, cytoplasmic protein synthesis levels, or myotube diameters. These findings continue to support the idea that exercise induces more dynamic changes in skeletal muscle protein acetylation, but not lactylation. However, further human research with more sampling timepoints and a lactylomics approach are needed to determine if, at all, different exercise modalities affect skeletal muscle protein lactylation.

Background/Objectives: Mood disorders include symptoms of depression, anxiety, and or stress, and have increased in prevalence. Green tea and its bioactive components (epigallocatechin gallate [EGCG] and L-theanine) have been investigated for their health benefits and neuroprotective properties. As adults seek integrative and alternative treatment modalities, it is relevant to determine the effects of natural and non-pharmacological treatments on humans. This study aimed to assess current evidence from published randomized controlled trials testing the effects of green tea, green tea extracts, or its bioactive compounds on mood disorder symptomology and brain-derived neurotrophic factor (BDNF). Methods: We searched PubMed, Cochrane Library, PsycINFO, Embase, Google Scholar, and ClinicalTrials.gov, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and utilizing predetermined inclusion and exclusion criteria. Results: A total of 445 studies were identified, 395 screened, and thirteen met inclusion criteria. Seven used one of the bioactive compounds found in green tea for intervention, while six used green tea extract, matcha, or traditional green tea. Mood disturbance was assessed with several tools, with studies reporting improvements in depressive (n = 4), anxiety (n = 6), stress (n = 5), and sleep (n = 1) symptoms. No studies found a statistically significant effect of green tea or its bioactive compounds on BDNF. Conclusions: Our findings suggest green tea, GTE, L-theanine, and EGCG may improve mood disorder symptomology, particularly symptoms of depression; no evidence to date reports effects on BDNF.

Background: Previous research indicates that gastrointestinal discomfort from milk consumption may be attributable to A1 β-casein, rather than lactose intolerance alone. A2 milk (free of A1 β-casein) consumption may result in fewer symptoms compared to conventional milk containing both A1/A2 β-casein. Objective: In this five-week, double-blind, double-crossover study, we assessed the physiological responses to doses escalating in volume of lactose-free conventional milk (Lactaid), A2 milk, and lactose-free A2 milk in fluid milk-avoiding participants. Methods: Each milk type was consumed over three separate weeks with three increasing doses across five days per week, >one week washout. Gastrointestinal symptoms, blood glucose, and breath gases were monitored for twenty-four, two-, and three-hours post-consumption, respectively. Sensory evaluation was completed for each sample. Results: Fifty-three participants consented and were randomized, with forty-eight participants completing the study. Overall, symptoms were minimal. On Days 1 and 3, lower ratings of bloating and flatulence were observed in A2 compared to lactose-free A2. Breath hydrogen responses reflected lactose content, but were higher in lactose-free A2 than Lactaid on Day 5. Thirty-three participants were deemed lactose-intolerant and had higher fasting and average breath hydrogen for all samples. The only symptom corresponding to the increase in breath hydrogen among these participants was flatulence after A2 consumption. Surprisingly, flatulence was apparently higher for lactose-tolerant individuals when consuming Lactaid compared to A2. Conclusions: These findings suggest that adults who avoid conventional fluid milk consumption may experience minimal GI discomfort from lactose-free and/or A1-free milks.

Increasing dietary nitrate (NO3-) through beetroot juice (BRJ) supplementation elicits acute ergogenic benefits. However, it is unknown whether chronic NO3- supplementation can enhance resistance training (RT) adaptations in middle-aged and older individuals. Therefore, we sought to determine whether 12 weeks of combined RT and NO3- supplementation enhanced hypertrophic, vascular, strength, and skeletal muscle angiogenesis adaptations in this population. Twenty-eight apparently healthy, untrained men and women (56±7 years old, 29.1±5.3 kg/m2 body mass index) completed 12 weeks of supervised full-body RT (2x/week) while ingesting either BRJ (140 mL daily, providing 800 mg NO3-; n=14 with 7M/7W) or NO3--depleted BRJ placebo (PLA; n=14 with 7M/7W). Participants underwent a whole-body dual-energy x-ray absorptiometry scan, right mid-thigh ultrasonography for muscle imaging, right leg popliteal artery flow-mediated dilation (FMD) assessments, a biopsy of the right mid-thigh vastus lateralis, and strength testing prior to and following the 12-week intervention. Biopsy analyses included a NO3-/nitrite (NOx) fluorometric assay, immunoblotting for proteins involved in angiogenesis, and immunohistochemistry to quantify fiber type-specific capillaries and cross-sectional areas. Muscle NOx values did not significantly change: +15.4% in BRJ (p=0.073) and +7.8% (p=0.514) in PLA. Both groups significantly improved measures related to muscle hypertrophy, strength, and FMD. However, no significant group × time interactions were observed for whole-body lean mass, mid-thigh muscle cross-sectional area, popliteal artery FMD outcomes, or histological or molecular markers. In conclusion, BRJ supplementation does not enhance RT adaptations in middle-aged and older adults.

We examined changes in skeletal muscle protein lactylation and acetylation in response to acute resistance exercise, chronic resistance training (RT), and a single endurance cycling bout. Additionally, we performed in vitro experiments to determine if different sodium lactate treatments affect myotube protein lactylation and acetylation. The acute and chronic RT study (n=12 college-aged participants) consisted of 10 weeks of unilateral leg extensor RT with vastus lateralis (VL) biopsies taken at baseline, 24-hours following the first RT bout, and the morning of the last day of the RT bout. For the acute cycling study (n=9 college-aged participants), VL biopsies were obtained before, 2 hours, and 8 hours after 60 minutes of cycling. For in vitro experiments, C2C12 myotubes were treated with varying levels of sodium lactate including LOW (1mM for 24-hours), HIGH (10mM for 24 hours), and PULSE (10mM for 30 minutes followed by 1 mM for 23.5-hours). Neither acute nor chronic RT significantly affected nuclear or cytoplasmic protein lactylation. However, cytoplasmic protein acetylation was significantly reduced following one RT bout (-15%, p=0.002) and chronic RT (-16%, p=0.006). Cycling did not acutely alter post-exercise global protein lactylation or acetylation patterns. Lastly, varying 24-hour lactate treatments did not alter nuclear or cytoplasmic protein lactylation or acetylation, cytoplasmic protein synthesis levels, or myotube diameters. These findings continue to support that exercise induces changes in skeletal muscle protein acetylation but not lactylation.

Recent enthusiasm has surrounded the homeostatic roles that polyamines have in a variety of cell types. Thus, the purpose of this exploratory in vitro study was to determine how spermidine (SPD), a polyamine commonly consumed as a nutritional supplement, affected general markers of cellular health and function in human primary epidermal keratinocytes. Commercial HEKa cells were seeded onto either six-well (transcriptomics and immunoblotting) or 96-well culture plates (viability, ATP, and JC-1 assays) and cultured to ~90+% confluency through complete growth media (CGM) changes every 48 h. Once cells reached this level of growth, treatments included either CGM + phosphate-buffered saline (PBS control, or CTL), CGM + 1 µM SPD, and CGM + 10 µM SPD for either 6 or 24 h depending upon the outcome being assessed. Cellular ATP levels were not significantly affected by 1 µM or 10 µM SPD treatments lasting 24 h. However, cell counts were 9% greater (p = 0.007) when comparing 24 h 10 µM versus CTL treatments indicating increased cell viability. Transcriptomic analyses indicated that 6 h treatments with 10 µM SPD significantly altered 162 transcripts versus non-treated CTL cells (65 up-regulated and 97 down-regulated, p < 0.01). Four pathways were predicted to be enriched based on differential gene expression including protein deubiquitination (GO:0016579), membrane lipid biosynthesis (GO:0046467), DNA metabolic process (GO:0006259), and cell cycle process (GO:0022402). Additionally, the HR gene (essential for keratinocyte hair follicle formation) was significantly up-regulated at the mRNA level with 6 h 10 µM SPD, and immunoblotting confirmed a 96% increase in protein levels with 24 h 10 µM SPD treatments, albeit this did not reach statistical significance (p = 0.102). Pan-keratin protein content was also 60% greater in the 1 µM and 10 µM 24 h treatments than CTL (p ≤ 0.029). Finally, although select markers of mitochondrial content and biogenesis were not significantly altered with 6 h and 24 h treatments, mitochondrial membrane potential (an aspect of mitochondrial function) was 84% greater with 24 h 1 µM versus CTL (p < 0.001). In conclusion, these preliminary screening experiments in unperturbed human keratinocytes suggest that exogenous SPD positively affects various aspects of homeostasis by stimulating transcriptomic and functional alterations (e.g., increased cell viability and enhanced keratinocyte protein levels).