Sleep a therapeutic target for stroke?

Role of the L-PGDS-PGD2-DP1 receptor axis in sleep regulation and neurologic outcomes

To meet the new challenges of modern lifestyles, we often compromise a good night's sleep. In preclinical models as well as in humans, a chronic lack of sleep is reported to be among the leading causes of various physiologic, psychologic, and neurocognitive deficits. Thus far, various endogenous mediators have been implicated in inter-regulatory networks that collectively influence the sleep-wake cycle. One such mediator is the lipocalin-type prostaglandin D2 synthase (L-PGDS)-Prostaglandin D2 (PGD2)-DP1 receptor (L-PGDS-PGD2-DP1R) axis. Findings in preclinical models confirm that DP1R are predominantly expressed in the sleep-regulating centers. This finding led to the discovery that the L-PGDS-PGD2-DP1R axis is involved in sleep regulation. Furthermore, we showed that the L-PGDS-PGD2-DP1R axis is beneficial in protecting the brain from ischemic stroke. Protein sequence homology was also performed, and it was found that L-PGDS and DP1R share a high degree of homology between humans and rodents. Based on the preclinical and clinical data thus far pertaining to the role of the L-PGDS-PGD2-DP1R axis in sleep regulation and neurologic conditions, there is optimism that this axis may have a high translational potential in human therapeutics. Therefore, here the focus is to review the regulation of the homeostatic component of the sleep process with a special focus on the L-PGDS-PGD2-DP1R axis and the consequences of sleep deprivation on health outcomes. Furthermore, we discuss whether the pharmacological regulation of this axis could represent a tool to prevent sleep disturbances and potentially improve outcomes, especially in patients with acute brain injuries.

Objective Sleep Measures in Inpatients With Subacute Stroke Associated With Levels and Improvements in Activities of Daily Living

OBJECTIVE

To investigate whether objective polysomnographic measures of prevalent sleep problems such as sleep-disordered-breathing (SDB) and insomnia are associated with activities of daily living levels in inpatients at rehabilitation units.

DESIGN

Retrospective and observational study.

SETTING

Single rehabilitation center.

PARTICIPANTS

Inpatients with subacute stroke (N=123) (61.6±13.1 years; 23.8±3.4 kg/m²; 33% women; 90.5±36.7 days post-stroke) underwent a 1-night polysomnographic study and a 1-month inpatient rehabilitation program.

MAIN OUTCOME MEASURES

Admission and discharge Barthel Index (BI) scores and its change scores.

RESULTS

One hundred three (92%) patients had moderate-to-severe SDB (46.7±25.1 events/h in the apnea-hypopnea index), and 24 (19.5%) patients had acceptable continuous positive airway pressure adherence. Diverse values were found for total sleep time (259±71 min), sleep efficiency (69.5%±19.3%), sleep latency (24.3±30.9 min), and wakefulness after sleep onset (93.1±74.2 min). Admission BI scores and the BI change scores were 33.8±23.2 and 10.1±9.2, respectively. The National Institutes of Health Stroke Scale (NIHSS, 10.2±5.6), available in 57 (46%) patients, was negatively associated with admission levels and gains in BI change scores (P<.001, =0.002, respectively) in a univariate analysis. In regression models with backward selection, excluding NIHSS score, both age (P=.025) and wakefulness after sleep onset (P<.001) were negatively associated (adjusted R²=0.260) with admission BI scores. Comorbidity of hypertension; sleep latency percentage of stage 1, non-rapid eye movement sleep; and desaturation events ≥4% (P<.001, 0.001, 0.021, and 0.043, respectively; adjusted R²=0.252) were negatively associated with BI score gains.

CONCLUSIONS

Based on objective sleep measures, insomnia rather than SDB in inpatients with subacute stroke was associated negatively with admission levels of activity of daily living and its improvement after a 1-month rehabilitation course.