Altered overnight levels of pro-inflammatory cytokines in men and women with posttraumatic stress disorder

BACKGROUND

Posttraumatic stress disorder (PTSD) is associated with disturbed sleep and elevated levels of pro-inflammatory cytokines, including interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Studies in animals and healthy humans have also shown that disrupted sleep elevates pro-inflammatory cytokines, including IL-6 and TNF-α. A better understanding of overnight cytokine levels and sleep might shed light on possible mechanisms for elevated inflammation in PTSD. Thus, we investigated overnight levels of IL-6 and TNF-α in individuals with and without PTSD while recording sleep polysomnography (PSG).

METHOD

Serum samples were collected from otherwise healthy, medication-free participants with chronic PTSD (n = 44; 50% female; M age = 30.34 ± 8.11) and matched controls (n = 49; 53% female; M age = 30.53 ± 6.57) during laboratory PSG. Levels of IL-6 and TNF-α were measured at hours 0, 2, 4, 6, and 8 after typical sleep onset time using serial serum samples. Plasma IL-6 and TNF-α levels were quantified using enzyme-linked immunosorbent assays.

RESULTS

Growth model analysis indicated a significantgroup by time interaction for IL-6 (t[247] = -2.92, p = .005) and a significant group by sex by time interaction for TNF-α (t[275] = 2.02, p = .04). PTSD positive men and women initially had higher IL-6 and TNF-α at sleep onset, but not at the end of their sleep cycle. Men with PTSD showed a peak of TNF-α at the end of the sleep cycle, whereas male control subjects demonstrated an inverted U-shaped profile. There were no significant differences in TNF-α levels overnight between women with and without PTSD.

CONCLUSION

To our knowledge, this is the largest study to examine IL-6 overnight in a PTSD sample and the first study to examine overnight TNF-α in PTSD. Overnight IL-6 and TNF-α levels may be altered in individuals with PTSD compared to those without PTSD, and TNF-α trajectories also differed by sex. The current findings highlight the need to consider sex, sleep, time of day, and circadian variation when examining inflammation in PTSD. Additional research in broader study samples will be necessary to clarify associations between disrupted sleep, cytokines, and increased risk for disease in PTSD.

DNA methylation profiles of elderly individuals subjected to indentured childhood labor and trauma

Background

Childhood trauma is associated with increased vulnerability to mental and somatic disorders later in life. Epigenetic modifications such as DNA methylation are one potential mechanism through which such long-lasting impairments/consequences can be explained. The aim of the present study was to investigate whether childhood trauma is associated with long-term DNA methylation alterations in old age.

Methods

We assessed genome-wide DNA methylation profiles in a cohort of former indentured child laborers (“Verdingkinder”) who suffered severe childhood adversities (N = 30; M age = 75.9 years), and compared them to control group with similar demographic characteristics (N = 15, M age = 72.8 years). DNA was isolated from epithelial buccal cells and hybridized to the Illumina Infinium 450 k DNA methylation array, which provides coverage of 485,000 methylation sites.

Results

After accounting for batch effects, age, gender and multiple testing, 71 differentially methylated CpG positions were identified between the two groups. They were annotated among others to genes involved in neuronal projections and neuronal development. Some of the identified genes with differential methylation (DLG associated protein 2, mechanistic target of rapamycin) have previously been associated with traumatic stress.

Conclusions

The results indicate specific epigenetic alterations in elderly individuals who were subjected to childhood adversities. Psychiatric and somatic comorbidities as well as differences in buccal epithelial cells proportion may contribute to the observed epigenetic differences.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-017-0370-2) contains supplementary material, which is available to authorized users.

Osseointegration: the slow delivery of BMP-2 enhances osteoinductivity

Although the placement of dental and orthopedic implants is now generally a safe, reliable and successful undertaking, the functional outcome is less assured in patients whose bone-healing capacity is compromised. To enhance peri-implant osteogenesis in these individuals, BMP-2 could be locally administered. However, neither a free suspension nor an implant-adsorbed depot of the agent is capable of triggering sustained bone formation. We hypothesize that this end could be achieved by incorporating BMP-2 into the three-dimensional crystalline latticework of a bone-mineral like, calcium-phosphate implant coating, where from it would be liberated gradually - as the inorganic layer undergoes osteoclast-mediated degradation - not rapidly, as from an implant-adsorbed (two-dimensional) depot. To test this postulate, we compared the osteoinductive efficacies of implant coatings bearing either an incorporated, an adorbed, or an incorporated and an adsorbed depot of BMP-2 at a maxillary site in miniature pigs. The implants were retrieved 1, 2 and 3 weeks after surgery for the histomorphometric analysis of bone formation within a defined 'osteoinductive' space. At each juncture, the volume of newly-formed bone within the osteoinductive space was greatest around implants that bore a coating-incorporated depot of BMP-2, peak osteogenic activity being attained during the first week and sustained thereafter. In the other groups, the temporal course of bone formation was variable, and the peak levels were not sustained. The findings of this study confirm our hypothesis: they demonstrate that we now have at our disposal a means of efficaciously augmenting and expediting peri-implant bone formation. Clinically, this possibility would render the process of implant placement a safer and a more reliable undertaking in patients whose bone-healing capacity is compromised, and would also permit a curtailment of the postoperative recovery period by a forestallment of the mechanical-loading phase.