Daylight linked to lower BMI, artificial night light to higher BMI in 5,000+ Brazilians

Key Findings

🚀 Astronauts age 1.9 years in one week of spaceflight

• 4 astronauts on the Axiom-2 mission showed an average biological age acceleration of 1.91 years by day 7 of spaceflight, measured using 32 DNA methylation-based aging metrics

• Upon return to Earth, all crew members' biological age decreased—older astronauts returned to pre-flight levels while younger astronauts dropped below their original baseline

• Changes in immune cell composition, particularly regulatory and naïve CD4 T-cells, explained a significant portion of the age acceleration in several aging clock models

🦷 Orthodontic forces trigger time-dependent gene responses in teeth

• Human periodontal ligament cells exposed to orthodontic pressure (2 g/cm²) showed rhythmic gene expression changes over 24 hours

• BMAL1 and CLOCK genes peaked at 12 hours (2.31-fold and 2.10-fold increases), while PER1 and CRY1 peaked at 18 hours (2.44-fold and 2.13-fold increases)

• A strong inverse correlation (-0.76) was observed between BMAL1 and PER1 expression, suggesting coordinated circadian regulation

🧠 Sleep neurology review highlights treatment pitfalls

• Chronic insomnia affects approximately 10% of adults, while other sleep disorders including sleep apnea, restless legs syndrome, and narcolepsy are often misdiagnosed

• Cognitive behavioral therapy for insomnia remains the gold-standard first-line treatment, yet medications are frequently started prematurely due to limited access to CBT

• Inappropriate use of dopamine agonists for restless legs syndrome can worsen outcomes, representing a key therapeutic pitfall

💊 Bedtime vs. morning blood pressure medications show no difference

• Meta-analysis of 5 studies with 36,477 patients (42.30% male) found no significant differences in major cardiovascular events between bedtime and morning antihypertensive dosing

• No differences were observed in all-cause mortality, cardiovascular mortality, heart attacks, strokes, or heart failure between timing groups

• Results showed substantial heterogeneity (I² > 90%) across studies, suggesting patient-specific factors may be more important than universal timing

🐟 Endangered fish reveal circadian adaptation mechanisms

• Whole-genome sequencing of 159 endangered Percocypris pingi fish (69 wild, 90 hatchery) revealed low genetic diversity and simple population structure

• Multiple candidate genes including pkc, mapk6, and rorab1 were enriched in circadian entrainment pathways, with 9 key circadian genes showing 24-hour oscillation patterns

• Four populations (Datuo, Woluo wild populations and Jinping, Yaan hatchery populations) showed relatively high genetic diversity compared to 13 other populations

🧴 Skin collagen production follows day-night rhythms

• Human skin fibroblasts showed opposing day-night rhythms: collagen assembly genes (like LOX) peaked during day, while synthesis and degradation genes peaked at night

• Timed application of baicalin during day and palmitoyl tripeptide-1 at night increased collagen fiber density in mice

• Clinical trial in 30 women showed significant improvements: skin luminance increased 16.29%, nasolabial fold depth decreased 36.35%, and firmness improved 24.35%