Effect of serotonin transporter genotype on self-reported efficacy and activity changes of brain prefrontal area in response to placebo

Patients benefit from drug therapy not only through pharmacological mechanisms, but also through non-pharmacological action (placebo effect), which may be mediated in part by the prefrontal area of the brain. We consider that the difference between responders and non-responders to placebo might be related to polymorphisms in the serotonin transporter-linked polymorphic region (5-HTTLPR). To study this idea, we performed a randomized double-blind clinical trial using caffeine and lactose (placebo). Activity in the prefrontal area of the brain was measured in terms of blood flow by means of near-infrared spectroscopy (NIRS) as an objective indicator. Self-reported feelings of drowsiness on established scales were used as subjective indicators. Twenty-one subjects in block A took caffeine on the first day and placebo on the third day, and 21 in block B took placebo on the first day and placebo on the third day. After placebo administration, improvement of sleepiness was significantly enhanced, a similar extent to that after caffeine medication. Among the 42 subjects, 22 showed S/S type polymorphism in the serotonin transporter (52.4 %), 17 showed S/L type (40.5 %) and 3 showed L/L type (7.10 %). Statistical analysis of the results indicate that subjects with L/L genotype showed a significantly greater placebo response in terms of both self-reported feeling of drowsiness and blood flow in the prefrontal area of the brain associated with working memory (46 area). Our results indicate that the L/L genotype of 5-HTTLPR, which is rare in Japanese (3.2 %) but common in Americans (32.2 %), may be associated with a greater placebo effect.

Versatility of HDA19-deficiency in increasing the tolerance of Arabidopsis to different environmental stresses

Histone acetylation is controlled by HATs and HDACs, which are essential epigenetic elements that regulate plant response to environmental stresses. A previous study revealed that a deficiency in an HDAC isoform (HDA19) increases tolerance to high salinity stress in the Arabidopsis wild-type Col-0 background. Here, the increased tolerance of hda19 to drought and heat stresses is demonstrated. Results indicate that hda19 plants have greater tolerance than wild-type plants to stress conditions. The data indicate that the stress response pathway coordinated by HDA19 plays a pivotal role in increasing tolerance to a variety of different abiotic stresses in Arabidopsis, including salinity, drought, and heat. The greater level of tolerance of hda19 plants to several different environmental stresses suggests that HDA19 represents a promising target for pharmacological manipulation in order to enhance abiotic stress tolerance in plants.

ABBREVIATIONS

HAT, histone acetyltransferase; HDAC, histone deacetylase; HSF, heat shock transcription factor; RPD3, reduced potassium dependency 3; SIRT, Silent Information Regulator 2.

Cognitive Dysfunction in Urban-Community Dwelling Prefrail Older Subjects

OBJECTIVES

A number of studies have reported that frailty is cross-sectionally associated with cognitive decline and is also a risk for future cognitive decline or dementia; however, there have been only a few studies that focus on the association between prefrailty and cognitive dysfunction. In the current study, we investigated the association between prefrailty and cognition.

DESIGN

A cross-sectional study of the data obtained at registration in a randomized control trial.

SETTING

Toyota, Japan.

PARTICIPANTS

Community-dwelling older subjects (male 54.6%) who had cognitive complaints.

MEASUREMENTS

A battery of neuropsychological and physical assessments were performed. Prefrailty was defined as exhibiting one or two of the five Fried criteria (weight loss, exhaustion, weakness, slow gait speed and low physical activity). We performed a multiple regression analysis to investigate the associations of cognitive performance with prefrailty, adjusting for the factors that were significantly different between the robust and prefrailty groups. To assess the cognitive attributes that were significantly associated with prefrailty, logistic analysis was performed to see if one specific criterion of the five frailty criteria was associated with cognitive performance.

RESULTS

The study subjects included 183 prefrail and 264 robust individuals. The prefrail subjects with cognitive complaints were older, less educated, more depressive, and more likely to have diabetes mellitus than the robust subjects. The prefrail subjects had lower performance in a wide-range of cognitive domains, and after adjustments for age, education, depressive mood, and diabetes mellitus, prefrailty was associated with a decline in delayed memory and processing speed. Among the components of the Fried criteria, slow gait speed and loss of activity were significantly associated with slow processing speed as assessed by the digit symbol substitution test.

CONCLUSION

The current results demonstrated that prefrailty was associated with worse memory and processing speed performance, but not with other cognitive domains.

Long and Short Sleep Duration and Physical Frailty in Community-Dwelling Older Adults

OBJECTIVE

The objective of this study was to investigate whether older adults who have a particularly long sleep duration are likely to exhibit physical frailty, similar to those with a particularly short sleep duration.

DESIGN

Cross-sectional study.

SETTING

The National Center for Geriatrics and Gerontology - Study of Geriatric Syndromes.

PARTICIPANTS

A total of 9,824 older adults (mean age: 73.6 ± 5.5 years, 4,812 men and 5,012 women) met the entry criteria for this study.

MEASUREMENTS

We divided the participants into three groups according to self-reported sleep duration (Short: ≤6 h, Mid: 6.1-8.9 h (control), Long: ≥ 9 h). Physical frailty was characterized based on the criteria from the Cardiovascular Health Study. Multinomial logistic regression analysis was performed to evaluate the effect of sleep duration on physical frailty by sex.

RESULTS

Among all participants, the prevalence of physical frailty was higher in the Short (10.5%) and Long (17.9%) groups than in the Mid (7.4%) group (p < 0.001). Multinomial logistic regression analysis showed that both Short and Long groups had a significantly higher odds ratio (OR) for physical frailty than the Mid group [Short: OR 1.53, 95% confidence interval (CI) 1.26-1.87; Long: OR 2.39, 95% CI 1.90-3.00], even after adjusting for age, educational level, number of medications, body mass index, Mini Mental State Examination score, current smoking and alcohol habits, self-perceived health, and medical history.

CONCLUSION

Both long and short sleep durations were associated with physical frailty. Further studies are required to confirm the effect of sleep duration on the incidence or worsening of physical frailty in older adults.

Cognitive Frailty is Associated with Fall-Related Fracture among Older People

OBJECTIVE

Cognitive frailty refers to cognitive impairment and physical frailty. Both cognitive impairment and physical frailty include risks of falling. The purpose of the study is to examine cognitive frailty and falling with/without a fracture.

DESIGN

Cross-sectional observation study.

SETTING

General communities in Japan.

PARTICIPANTS

Data of 10,202 older adults aged ≥ 65 years were collected.

MEASUREMENTS

Physical frailty was characterized as slow walking speed and/or muscle weakness. Assessment of cognitive function included word lists memory, attention, executive function, and processing speed. Cognitive impairment refers to one or more cognitive decline indicated by at least 1.5 standard deviations below the threshold after adjusting for age and education. We operationally defined cognitive frailty as having both cognitive impairment and physical frailty. Participants were interviewed about their falling, history of fall-related fractures, and several potentially confounding factors such as demographic characteristics.

RESULTS

Multinomial logistic regression analysis revealed that functional decline in all groups, as compared to the robust group, was significantly associated with falling without fractures, after adjusting for the covariates; cognitive impairment group (P = .017), physical frailty group (P = .002), and cognitive frailty group (P < .001). Only the cognitive frailty group had a significant association with fall-related fracture after adjusting for the covariates (OR 1.92, 95% CI: 1.20-3.08, P = .007).

CONCLUSION

Cognitive frailty is associated with not only falling but also fall-related fractures. Cognitive frailty may have a greater risk for fall-related fractures than cognitive impairment or physical frailty alone. Future research should examine causal the relationship between fall-related fractures and cognitive frailty.

Association between Insulin-Like Growth Factor-1 and Frailty among Older Adults

OBJECTIVES

Frailty is a course experienced in advanced aging. Identification of a biological factor associated with frailty is required. Although serum insulin-like growth factor-1 (IGF-1) is a potential factor related with frailty, consensus has not been reached regarding this relationship. This study aimed to investigate the association between IGF-1 and frailty in older adults.

DESIGN

Cross-sectional study.

SETTING

Cohort study that was part of the "National Center for Geriatrics and Gerontology - Study of Geriatric Syndromes."

PARTICIPANTS

The study participants were 4133 older adults (mean age, 71.8 ± 5.4 years).

MEASUREMENTS

We assessed serum IGF-1 levels and frailty status and collected demographic variables, including cognitive function, as covariates.

RESULTS

Frailty and pre-frailty were present in 274 subjects (7%) and 1930 subjects (47%), respectively. Subjects were divided into four groups based on quartiles of IGF-1 levels. Multinomial logistic analysis showed that the lowest group had significant odds of pre-frailty (crude model: odds ratio [OR] 1.58, 95% confidence interval [CI] 1.30-1.90, p < .001; adjusted model: OR 1.38, 95% CI 1.13-1.68, p = .002) and frailty (crude model: OR 3.42, 95% CI 2.38-4.92, p < .001; adjusted model: OR 1.54, 95% CI 1.02-2.32, p = .039), compared with the highest group.

CONCLUSION

Lower serum IGF-1 levels were independently related with frailty in older adults.

A Randomized, Double-Blind, Crossover Pilot Trial of Rice Endosperm Protein Supplementation in Maintenance Hemodialysis Patients

In maintenance hemodialysis (MHD) patients, low protein intake is associated with protein-energy wasting, a risk factor that affects outcome. However, increased protein intake may lead to hyperphosphatemia and hyperkalemia, which are also mortality risk factors. Here, we evaluated the safety and effects of purified rice endosperm protein (REP), which contains less phosphorus and potassium than soy and casein proteins, as a supplemental protein source for MHD patients. This randomized, double-blind, placebo-controlled, crossover pilot study of REP supplementation (5 g/day × 4 weeks) was carried out in 50 Japanese adult MHD patients (1 dropped out); the primary outcome was the change in the urea kinetic-based normalized protein catabolic rate (nPCR), an indicator of protein intake in MHD patients. Intention-to-treat analyses of 24 patients in the REP-first group and 25 in the placebo-first group showed that REP supplementation increased nPCR significantly by 0.07 g/kg/day (95% confidence interval, 0.03–0.11), whereas changes in serum phosphorus and potassium concentrations were not different from the placebo. REP supplementation did not show a significant effect on other nutritional or metabolic parameters and no specific complications. In conclusion, purified REP with efficient bioavailability may be safe and useful for dietary supplementation in MHD patients.