IMPACT OF SLEEP RESTRICTION ON LOCAL IMMUNE RESPONSE, SKIN BARRIER RESTORATION, COGNITION, MARKSMANSHIP AND GUT FUNCTION WITH AND WITHOUT ‘MULTI-NUTRIENT’ NUTRITION INTERVENTION

40 Systemic immune function is impaired by sleep restriction. However, the impact of sleep 41 restriction on local immune responses, and to what extent any impairment can be mitigated by 42 nutritional supplementation is unknown. 43 Objectives: We assessed the effect of 72-h sleep restriction (2-h nightly sleep) on local immune 44 function and skin barrier restoration of an experimental wound, and determined the influence of 45 habitual protein intake (1.5 g·kg·d) supplemented with arginine, glutamine, zinc sulfate, 46 vitamin C, vitamin D3 and omega-3 fatty acids compared to lower protein intake (0.8 g·kg·d) 47 without supplemental nutrients on these outcomes. Secondary outcomes included sleepiness, 48 cognition, marksmanship, markers of gut barrier damage, and exploratory analyses to identify 49 predictors of skin barrier recovery. 50 Methods: Wounds were created in healthy adults by removing the top layer of ≤ 8 forearm 51 blisters induced via suction, after adequate sleep (AS) or 48-h of a 72-h sleep restriction period 52 (SR; 2-h nightly sleep). A subset of participants undergoing sleep restriction received 53 supplemental nutrients during and after sleep restriction (SR+). Wound fluid was serially 54 sampled 48-h post-blistering to assess local cytokine responses. Performance on a battery of 55 cognitive assessment and marksmanship tasks were collected throughout the 72-h sleep 56 restriction period. 57 Results: The IL-8 response of wound fluid was higher for AS compared to SR (area-under-the58 curve, AUCi (log10), 5.1±0.2 and 4.9±0.2 pg·mL , respectively (P=0.03); and, both IL-6 and IL59 8 concentrations were higher for SR+ compared to SR (p<0.0001), signifying a potentially 60 enhanced early wound healing response. Skin barrier recovery was shorter for AS (4.2 ± 0.9 61 days) compared to SR (5.0 ± 0.9 days) (P=0.02), but did not differ between SR and SR+ 62 (P=0.18). As expected, participants were tired and experienced cognitive declines in response to 63 the imposed sleep restriction. In linear regression models adjusting for age, BMI, race, ethnicity, 64 energy intake and study group, omega-3 intake was associated with longer healing time ([beta ± 65 SE] per g/d: 0.70 ± 0.33, P=0.04), and protein intake was associated with shorter healing time 66 (per g/d: -0.02 ± 0.01, P=0.01). AUCi of IL-8 (per logged pg/mL: -1.50 ± 0.43, P<0.001) and 67 MIP-1b (per logged pg/mL: -1.42 ± 0.50, P=0.01) sampled from the wound sites were associated 68 with shorter healing time. Participants were also generally slower and less accurate on measures 69 of cognitive performance and marksmanship. No effects on markers of gut barrier damage were 70 observed. 71 Conclusions: Relatively modest sleep disruption induces cognitive declines and delays wound 72 healing. Supplemental nutrition may mitigate some decrements in local immune responses, 73 without detectable effects on wound healing rate. Wound healing time may be influenced by 74 omega-3 and protein intake, as well as wound cytokines (but not serum biomarkers). Additional 75 research is warranted to further elucidate these findings. 76