An observational study in Sleep, Collagen Turnover and Cell Culture Techniques, sponsored by University of Toronto. Recruiting at 1 site in Canada. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-12.
Sponsored by University of Toronto · Observational
The goal of this observational study is to evaluate the effect of hormones which surge or diminish during different stages of sleep on collagen turnover in tendon cells. The main questions it aims to answer are:
To evaluate the effect of sleep on tendon adaptation, blood will be taken from human participants overnight and used to treat a tendon cell culture model.
Recent clinical evidence has linked poor sleep with increased risk of musculoskeletal injury while evidence from basic biological models indicates that growth hormone and cortisol may regulate the turnover of collagen, a key structural protein in tendons. Growth hormone concentration in the blood surges during deep sleep (\~1-2 hr after sleep onset), while cortisol concentration reaches a nadir at this same time. It remains unclear whether serum containing these hormones, collected during sleep itself, can modulate collagen turnover processes. Therefore, the purpose of this study is to evaluate the effect of hormones which surge or diminish during different stages of sleep on collagen turnover in tendon cells.
This study will use a within-subjects design to collect serum for ex vivo experiments. The total study duration will be \~8 days. Participants will first be screened to ensure compliance with our inclusion and exclusion criteria. Written informed consent will be obtained from participants that pass screening. Twelve participants will be recruited in total (6 male, 6 female). Participants will complete a 7 night sleep diary while wearing two wearable devices (an accelerometer to measure physical activity and basic sleep outcomes, worn on the waist; a Fitbit to estimate sleep stages and sleep onset). After the sleep diary, participants will arrive at the laboratory following an overnight fast for a resting venous blood collection. They will return to the laboratory to sleep overnight in the Nutrition and Metabolism Research Group's Bed Rest Facility. Approximately 95 minutes following sleep onset, participants will be briefly awoken for a venous blood draw (i.e., deep sleep sample), before returning to sleep. Four hours after the deep sleep sample, participants will be briefly woken up for a venous blood draw (i.e., REM sleep sample). Participants will then be allowed to finish their night of sleep in the facility.
Commercially available human tenocytes will be treated with serum from the different timepoints (morning, deep/early sleep, REM/late sleep) for 7 days. Following the 7 day treatment period, tenocytes will be collected and collagen I and III expression will be assessed by immunoblot while stable isotope tracers will be used to quantify collagen synthesis and breakdown.
The primary objective of the study is to evaluate the effect of the nocturnal biochemical milieu on human tenocyte-derived collagen expression in vitro. The secondary objectives of the study is to assess whether changes in collagen expression are due to altered collagen synthesis and/or breakdown.
University of Toronto is the lead sponsor of 404 studies on the registry; 55 are open to participants now.
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Resident of Kingston, Ontario
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Healthy, recreationally active, young adults (18-35) regularly getting \> 7 h of sleep per night are the target population. There is no intervention for this study.
Collagen Expression
Tenocyte-derived collagen expression will be assessed following a 7 day treatment period using daytime, early/deep sleep, and late/REM sleep by immunoblot.
Time frame: Ex vivo experiments and immunoblot analysis will conclude approximately 12 weeks following serum collection.
Collagen Synthesis
On the last day of the 7 day serum incubation, cells will be treated with a stable-isotope tracer for 6hrs to measure incorporation of this tracer into tenocyte collagen and thus collagen synthesis.
Time frame: Ex vivo experiments and immunoblot analysis will conclude approximately 12 weeks following serum collection.
Collagen breakdown
Cells will be treated with a stable isotope tracer during a 7 day serum incubation. Six hours prior to collection, tracer will be withdrawn and tracer release into the media will be measured to estimate collagen breakdown.
Time frame: Ex vivo experiments and immunoblot analysis will conclude approximately 12 weeks following serum collection.
Plan to share: Yes — This study is a collaboration between the McGlory and Moore research groups. Therefore, sleep and activity data will be shared between groups. Serum collected from sleep trials at the McGlory lab will also be shared with the Moore lab where ex vivo experiments will be conducted. However, no identifying information collected by the McGlory lab will be shared with the Moore lab.
Supporting information: Study protocol, Statistical analysis plan
Time frame: IPD collected by the McGlory lab will be made available to collaborators at the Moore lab following completion of data collection (estimated October 2026) until the time of publication (estimated November 2027).
Access criteria: Paul Babits and Dr. Daniel Moore will have access sleep, activity data as well as serum collected during overnight trials. Electronic data will be shared via secure servers. Serum will be shipped between sites following the completion of data collection.
No publications or documents are linked to this record.
Start is estimated for Nov 2026; primary completion for Feb 2027, 3 months later.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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