Presbycusis and the Aging of Eye Movement: Common Attention Mechanisms

Presbycusis, physiological age-related hearing loss, is a major health problem because it is the most common cause of hearing impairment, and its impact will grow in the coming years with the aging population. Besides auditory consequences, the literature recently found an association between hearing loss and cognitive decline over the last two decades, emphasizing the importance of the early detection of presbycusis. However, the current hearing tests are not sufficient to detect presbycusis in some cases. Furthermore, the underlying mechanisms of this association are still under discussion, calling for a new field of research on that topic. In that context, this study investigates for the first time the interaction between presbycusis, eye movement latency and Stroop scores for a normal aging population. Hearing abilities, eye movement latency and the Stroop Victoria test were measured for 69 elderly (mean 66.7 ± 8.4) and 30 young (mean 25.3 ± 2.7) participants. The results indicated a significant relationship between saccade latency and speech audiometry in the silence score, independently from age. These promising results suggest common attentional mechanisms between speech processing and saccade latency. The results are discussed regarding the relationship between hearing and cognition, and regarding the perspective of expanding new tools for presbycusis diagnosis.

Borrelia Infections in Ageing Ticks: Relationship with Morphometric Age Ratio in Field-Collected Ixodes ricinus Nymphs

In Europe, Ixodes ricinus plays a major role as a vector of Borrelia burgdorferi sensu lato (s.l.) spirochaetes, the causative agents of Lyme borreliosis, among other pathogens. In unfed ticks, Borrelia spirochaetes experience prolonged nutrient restriction. However, only few studies exist with regard to Borrelia infections in unfed ticks of different physiological ages. Changing body dimensions of unfed ticks, due to the consumption of energy reserves, allow physiological age estimation. The present study investigated the relationship of morphometric age with Borrelia prevalence and spirochaete load in 1882 questing I. ricinus nymphs, collected at two different locations in northern Germany in 2020. In addition, Borrelia species composition was investigated by employing a reverse line blot (RLB) probe panel suitable for the detection of ten different B. burgdorferi s.l. species, as well as the relapsing-fever spirochaete B. miyamotoi. Overall, Borrelia prevalence was 25.8% (485/1882). Whilst there was no statistically significant difference in Borrelia prevalence between the different morphometric age groups, Borrelia infection intensity as determined by probe-based quantitative real-time PCR significantly declined with increasing morphometric age. Borrelia species differentiation by RLB was successful in 29.5% of positive ticks, and revealed B. afzelii as the dominating species (65.0% of the differentiated infections). Additionally, B. garinii, B. valaisiana, B. burgdorferi sensu stricto, B. spielmanii, and B. miyamotoi were detected.

Studies of ticks of the genus Dermacentor (Acari; Ixodidae) on the natural occurrence of tularemia pathogen in the conditions of the Central Pre-Caucasian region

The purpose of the research is the assessment of the Francisella tularensis occurrence in nature in ticks of the genus Dermacentor; understanding the physiological age in terms of tick infection with tularemia pathogen.Materials and methods. For the period from 2015 to 2019, we examined 8449 specimens of Dermacentor marginatus (916 pools), 8674 specimens of D. reticulatus (705 pools), and 109 specimens of D. niveus (40 pools) for tularemia infection. To assess the dependence of tularemia pathogen found in ticks of different physiological ages, we examined 2440 specimens of D. marginatus (360 pools), and 3349 specimens of D. reticulatus (412 pools) for the period from 2016 to 2019. Studies of ixodid ticks infected with tularemia pathogen were performed by the Natural Focal Infection Laboratory of the Stavropol Anti-Plague Institute. Pools of ixodid ticks were examined for the pathogen DNA of tularemia using reagent kits for identifying Francisella tularensis DNA by polymerase chain reaction with fluorescence hybridization of results recorded in real time.Results and discussion. The infection rate of the tularemia pathogen in ticks in the Central Pre-Caucasian region ranged from 0.044–1.127% in D. marginatus and 0.035–1.455% in D. reticulatus in different years. The greatest number of F. tularensis was isolated from the III physiological age ticks. For D. reticulatus ticks, no statistically significant dependence of the detected tularemia pathogen on physiological age was found.

Flight activity and age cause wing damage in house flies

Wing damage attenuates aerial performance in many flying animals such as birds, bats and insects. Especially insect wings are fragile and light in order to reduce inertial power requirements for flight at elevated wing flapping frequencies. There is a continuing debate on the factors causing wing damage in insects including collisions with objects, mechanical stress during flight activity, and aging. This experimental study is engaged with the reasons and significance of wing damage for flight in the house fly Musca domestica. We determined natural wing area loss under two housing conditions and recorded flight activity and flight ability throughout the animals’ lifetime. Our data show that wing damage occurs on average after 6 h of flight, is sex-specific, and depends on housing conditions. Statistical tests show that both physiological age and flight activity have similar significance as predictors for wing damage. Tests on freely flying flies showed that minimum wing area for active flight is approximately 10-34% below the initial area and requires a left-right wing area asymmetry of less than approximately 25%. Our findings broadly confirm predictions from simple aerodynamic theory based on mean wing velocity and area, and are also consistent with previous wing damage measurements in other insect species.

Theaflavin 3, 3 ′ -Digallate Delays Ovarian Aging by Improving Oocyte Quality and Regulating Granulosa Cell Function

Ovarian aging refers to the gradual decline of ovarian function with increasing physiological age, manifested as decreased ovarian reserve, elevated aging-related markers, and reduced oocyte quality. With a declining female fertility and a growing aging population, it is urgent to delay ovarian aging to maintain fertility and improve the life quality of women. Theaflavin 3, 3 ′ -digallate (TF3) is a naturally bioactive polyphenol compound extracted from black tea, and its antioxidant properties play an important role in maintaining human health and delaying aging; however, the effects of TF3 on female reproduction and ovarian function are not yet clear. Here, we show that TF3 can preserve primordial follicle pool, partially restore the estrous cycle, and increase the offspring number of aged mice. Meanwhile, TF3 gavage increased the number of oocytes retrieved, decreased the level of reactive oxygen species, increased the level of glutathione, and decreased the abnormal rate of oocyte spindle after ovulation induction. Moreover, TF3 inhibited human granulosa cell apoptosis and improved their antioxidative stress ability. High-throughput sequencing and small-molecule-targeted pharmacological prediction show that TF3 affects multiple pathways and gene expression levels, mainly involved in reproductive and developmental processes. It may also affect cellular function by targeting mTOR to regulate the autophagic pathway, thereby delaying the process of ovarian aging. This study shows that TF3 can be used as a potential dietary supplement to protect ovary function from aging and thereby improving the life quality of advanced-age women.

Cost-effectiveness of dual-mobility components in patients with displaced femoral neck fractures

Aims Total hip arthroplasty (THA) with dual-mobility components (DM-THA) has been shown to decrease the risk of dislocation in the setting of a displaced neck of femur fracture compared to conventional single-bearing THA (SB-THA). This study assesses if the clinical benefit of a reduced dislocation rate can justify the incremental cost increase of DM-THA compared to SB-THA. Methods Costs and benefits were established for patients aged 75 to 79 years over a five-year time period in the base case from the Canadian Health Payer’s perspective. One-way and probabilistic sensitivity analysis assessed the robustness of the base case model conclusions. Results DM-THA was found to be cost-effective, with an estimated incremental cost-effectiveness ratio (ICER) of CAD $46,556 (£27,074) per quality-adjusted life year (QALY). Sensitivity analysis revealed DM-THA was not cost-effective across all age groups in the first two years. DM-THA becomes cost-effective for those aged under 80 years at time periods from five to 15 years, but was not cost-effective for those aged 80 years and over at any timepoint. To be cost-effective at ten years in the base case, DM-THA must reduce the risk of dislocation compared to SB-THA by at least 62%. Probabilistic sensitivity analysis showed DM-THA was 58% likely to be cost-effective in the base case. Conclusion Treating patients with a displaced femoral neck fracture using DM-THA components may be cost-effective compared to SB-THA in patients aged under 80 years. However, future research will help determine if the modelled rates of adverse events hold true. Surgeons should continue to use clinical judgement and consider individual patients’ physiological age and risk factors for dislocation. Cite this article: Bone Joint J 2021;103-B(12):1783–1790.

Biological Aging, Mortality, and Alzheimer’s Disease Related Biomarkers from Midlife to Old Age

People age at different rates and in different biological systems that may differentially contribute to accelerated decline. Better understanding of biological aging may contribute to identification of better targets for intervention. In 1005 VETSA participants we created 3 indicators of biological age: physiological age (PA), frailty, and brain age. PA included hemoglobin, glucose, lipids, height, weight, waist, systolic and diastolic blood pressure, and age. PA was calculated using the Klemera and Doubal (2006) method. The frailty index summed 37 health deficits (Jiang et al. 2017). A machine learning algorithm was used to estimate brain age across cortical and subcortical regions (Liem et al, 2017); predicted brain age subtracted from chronological age comprised the predicted brain age difference score (PBAD). Frailty and PBAD were calculated at waves 1, 2 and 3 when participants were average age 56, 62, and 68, respectively. PA markers were only available at waves 2 and 3. Outcome measures included mortality by wave 3 and scores on AD-related plasma biomarkers—Neurofilament light (NFL), Tau, and AB40 and AB42 at wave 3. Frailty at wave 1 and 2 predicted mortality. Frailty at wave 1 was significantly associated with wave 3 NFL, AB42 and AB40. Wave 2 & 3 frailty was associated with all biomarkers. Neither PA nor PBAD predicted biomarkers or mortality. The results are striking given the relatively young age of the sample. Even as early as one’s 50s, frailty in a community-dwelling sample predicted accelerated decline and mortality when the outcome age was only 66-73.

Evaluation of Maxillary and Mandibular Growth Pattern Based on Cervical Vertebral Maturation in Japanese

Appropriate evaluation of maxillofacial growth and development is important for effective orthodontic treatment. The evaluation of growth is not based on chronological age, but on the physiological age that is evaluated according to individual development. The cervical vertebral bone age is one approach to evaluate physiological age. In the present study, we evaluated the growth pattern of maxilla and mandible in Japanese patients using the age of the cervical vertebrae as an index. Lateral cephalometric radiographs taken before the start of the orthodontic treatment were traced to evaluate the age of the cervical vertebrae and mandible. Altogether, 400 patients were allocated to groups based on the cervical vertebral maturation stages (CVMS), namely, CVMS I to V, with 80 patients in each group. In this study, stratified random sampling was used to obtain the required samples. We measured ANS-PNS as an index of maxillary length, whereas Ar-Go as an index of mandibular height and Go-Pog as an index of mandibular length on the cephalograms. It was found that ANS-PNS increased significantly between CVMS II and CVMS III, while both Ar-Go and Go-Pog increased significantly between CVMS III and CVMS IV in men. On the other hand, such significant increases in consecutive stages were not found in women. Based on these observations, it was suggested that CVMS is effective in evaluating the growth pattern of the maxilla and mandible.