See Gratwicke and Foltynie (doi:) for a scientific commentary on this article.Cognitive impairments in Parkinson’s disease show variable onset, severity and progression. Ray et al. demonstrate that the future cognitive status of newly diagnosed patients can be predicted from the volume of the nucleus basalis of Meynert, with implications for the development of interventions for cognitive decline in Parkinson’s disease dementia.

Introduction Increasing imaging evidence supports the role of neuroinflammation in dementia pathogenesis. Despite this, the spatial association within the brain has not been comprehensively meta-analysed. Methods We searched literature databases for case-control studies examining the levels of translocator protein (TSPO) levels, representing neuroinflammation, in region of interest analyses between healthy controls and mild cognitive impairment (MCI) or Alzheimer's disease (AD) subjects. Standardised mean difference effect sizes were calculated and results meta-analysed using randomeffects models. Results The literature search identified 28 studies for inclusion, covering 37 different brain regions of interest. Compared to healthy controls, AD subjects had widespread increased TSPO levels throughout the brain, with the largest effects seen in fronto-temporo-parieto-occipital regions. MCI subjects also had increased TSPO levels, mainly within the neocortex, however, the effects were more modest. Discussion Neuroinflammation effect sizes increases and disperses from MCI to AD, relative to healthy controls.

Background & aims: There is a large body of evidence which supports the role of inflammation in the pathophysiology of mental health disorders, including depression. Dietary patterns have been shown to modulate the inflammatory state, thus highlighting their potential as a therapeutic tool in disorders with an inflammatory basis. Here we conduct a systematic review and meta-analysis of current literature addressing whether there is a link between the inflammatory potential of a diet and risk of depression or depressive symptoms. Methods: A systematic literature search was performed to identify studies that reported an association between the inflammatory potential of the diet and risk of depressive symptoms or diagnosis of depression. Random effect models were used to meta-analyse effect sizes. Quality assessment, publication bias, sensitivity and subgroup analyses were also performed. Results: Eleven studies, with a total of 101,950 participants at baseline (age range: 16e72 years old), were eligible for review. A significant association between a pro-inflammatory diet and increased risk of depression diagnosis or symptoms was evident, relative to those on an anti-inflammatory diet (OR: 1.40, 95% confidence intervals: 1.21e1.62, P < 0.001). No publication bias was detected; however, some study heterogeneity was evident (I 2 ¼ 63%, P < 0.001). Subgroup analyses suggested the main source of study heterogeneity was the study design (cross-sectional or longitudinal) and the effect measure used (odds ratio, hazard ratio or relative risk). Conclusion: These results provide an association between pro-inflammatory diet and risk of depression. Thus, adopting an anti-inflammatory diet may be an effective intervention or preventative means of reducing depression risk and symptoms.

BackgroundThe purpose of this study was to examine whether very short duration, very high intensity sprint interval training (SIT) leads to loss of body fat mass in association with improvements to VO2max and fatty acid oxidation, and to assess the extent of sex dimorphism in these physiological responses.MethodsA total of 24 men and 17 women (mean (SEM) age: 39 (±2) years; body mass index 24.6 (0.6)) completed measurements of the maximal rate of oxygen uptake (VO2max) and fatty acid oxidation (FATmax). Body fat and lean mass were measured by dual emission x-ray absorptiometry, and fasting blood lipid, glucose and insulin profiles were assessed before and after training. SIT consisted of 4×20 s sprints on a cycle ergometer at approximately 175% VO2max, three times per week for 12 weeks.ResultsFat mass decreased by 1.0 kg, although men lost statistically significantly more fat than women both when expressed in Kg and as % body fat. VO2max increased by around 9%, but women improved VO2max significantly more than men. FATmax improved by around 13%, but fasting plasma glucose, insulin, total triglyceride, total cholesterol and high-density lipoprotein (HDL) did not change after training, while low-density lipoprotein decreased by 8% (p=0.028) and the HDL:Total Cholesterol ratio improved by 6%. There were no sex differences in these metabolic responses to training.ConclusionsThese results show lower body fat %, and higher rates of fatty acid oxidation and VO2max after 12 weeks of training for just 4 min per week. Notably, women improved VO2max more than men, while men lost more fat than women.

Background: Elevated biomarkers of systemic inflammation have been reported in individuals with cognitive decline, however, most of the literature concerns cross-sectional analyses that have produced mixed results. This study investigates the etiology of this association by performing meta-analyses on prospective studies investigating the relationship between baseline interleukin-6 (IL-6), an established marker of peripheral inflammation, with cognitive decline risk in non-demented adults at follow-up.Methods: We reviewed studies reporting peripheral IL-6 with future cognitive decline, up to February 2017 by searching the PubMed, Science Direct, Scopus and Google Scholar databases. Studies which contained odds ratios (ORs) for the association between circulating baseline IL-6 and longitudinal cognitive performance in non-demented community dwelling older adults were pooled in random-effects models.Results: The literature search retrieved 5,642 potential articles, of which 7 articles containing 8 independent aging cohorts were eligible for review. Collectively, these studies included 15,828 participants at baseline. Those with high circulating IL-6 were 1.42 times more likely to experience global cognitive decline at follow-up, over a 2–7-year period, compared to those with low IL-6 (OR 1.42, 95% CI 1.18–1.70; p < 0.001). Subgroup and sensitivity analyses suggests that this association is independent of the study sample size, duration of follow-up and cognitive assessments used.Conclusions: These results add further evidence for the association between high peripheral inflammation, as measured by blood IL-6, and global cognitive decline. Measuring circulating IL-6 may be a useful indication for future cognitive health.

Introductioncognitive deterioration and reductions of bone health coincide with increasing age. We examine the relationship between bone composition and plasma markers of bone remodelling with measures of cognitive performance in healthy adults.Methodsthis cross-sectional study included 225 old (52% women, mean age: 74.4 ± 3.3 years) and 134 young (52% women, mean age: 23.4 ± 2.7 years) adult participants from the MyoAge project. Whole body bone mineral density was measured by dual-energy X-ray absorptiometry. Blood analyses included a panel of bone-related peptides (dickkopf-1, osteoprotegerin, osteocalcin (OC), osteopontin, sclerostin, parathyroid hormone and fibroblast growth factor 23), as well as serum calcium and 25-hydroxy vitamin D assays. A selection of cognitive domains (working memory capacity, episodic memory, executive functioning and global cognition) was assessed with a standardised neuropsychological test battery.Resultsadjusting for covariates and multiple testing revealed that plasma OC levels were positively associated with measures of executive functioning (β = 0.444, P < 0.001) and global cognition (β = 0.381, P = 0.001) in the older women.Discussionthese correlative results demonstrate a positive association between OC, a factor known to regulate bone remodelling, with cognitive performance in older non-demented women. Further work should address possible mechanistic interpretations in humans.

Chronic low-grade inflammation during aging (inflammaging) is associated with cognitive decline and neurodegeneration; however, the mechanisms underlying inflammaging are unclear. We studied a population (n = 361) of healthy young and old adults from the MyoAge cohort. Peripheral levels of C-X-C motif chemokine ligand 10 (CXCL10) was found to be higher in older adults, compared with young, and negatively associated with working memory performance. This coincided with an age-related reduction in blood DNA methylation at specific CpGs within the CXCL10 gene promoter. In vitro analysis supported the role of DNA methylation in regulating CXCL10 transcription. A polymorphism (rs56061981) that altered methylation at one of these CpG sites further associated with working memory performance in 2 independent aging cohorts. Studying prefrontal cortex samples, we found higher CXCL10 protein levels in those with Alzheimer's disease, compared with aged controls. These findings support the association of peripheral inflammation, as demonstrated by CXCL10, in aging and cognitive decline. We reveal age-related epigenetic and genetic factors which contribute to the dysregulation of CXCL10.

Depression and anxiety can be severely detrimental to the health of both the affected woman and her offspring. In a rodent model of postpartum depression and anxiety, chronic social stress exposure during lactation induces deficits in maternal care and increases anxiety. Here, we extend previous findings by expanding the behavioral analyses, assessing lactation, and examining several neural systems within amygdalar and hypothalamic regions involved in the control of the stress response and expression of maternal care that may be mediating the behavioral changes in stressed dams. Compared with control dams, those exposed to chronic social stress beginning on day 2 of lactation show impaired maternal care and lactation and increased maternal anxiety on day 9 of lactation. Saccharin-based anhedonia and maternal aggression were increased and lactation was also impaired on day 16 of lactation. These behavioral changes were correlated with a decrease in oxytocin mRNA expression in the medial amygdala, and increases in the expressions of corticotrophin-releasing hormone mRNA in the central nucleus of the amygdala, glucocorticoid receptor mRNA in the paraventricular nucleus, and orexin 2 receptor mRNA in the supraoptic nucleus of stressed compared with control dams. The increase in glucocorticoid receptor mRNA in the paraventricular nucleus was negatively correlated with methylation of a CpG site in the promoter region. In conclusion, the data support the hypothesis that social stress during lactation can have profound effects on maternal care, lactation, and anxiety, and that these behavioral effects are mediated by central changes in stress and maternally relevant neuropeptide systems.