Sex difference in brain functional connectivity of hippocampus in Alzheimer's disease

Alzheimer's disease (AD), affecting nearly 6.5 million people, is the fifth leading cause of death in individuals 65 years or older in the USA. Prior research has shown that AD disproportionality affects females; females have a greater incidence rate, perform worse on a variety of neuropsychological tasks, and have greater total brain atrophy. Recent research has linked these sex differences to neuroimaging markers of brain pathology, such as hippocampal volumes. Specifically, research from our lab found that functional connectivity from the hippocampus to the precuneus cortex and brain stem was significantly stronger in males than in females with mild cognitive impairment. The aim of this study was to extend our understanding to individuals with AD and to determine if these potential sex-specific functional connectivity biomarkers extend through different disease stages. The resting state fMRI and T2 MRI of cognitively normal individuals (n = 32, female = 16) and individuals with AD (n = 32, female = 16) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were analyzed using the Functional Connectivity Toolbox (CONN). Our results demonstrate that males had a significantly stronger interhemispheric functional connectivity between the left and right hippocampus compared to females. These results improve our current understanding of the role of the hippocampus in sex differences in AD. Understanding the contribution of impaired functional connectivity sex differences may aid in the development of sex-specific precision medicine for improved AD treatment.

Sex differences in brain functional connectivity of hippocampus in mild cognitive impairment

Mild cognitive impairment (MCI) is the prodromal stage of Alzheimer's Disease (AD). Prior research shows that females are more impacted by MCI than males. On average females have a greater incidence rate of any dementia and current evidence suggests that they suffer greater cognitive deterioration than males in the same disease stage. Recent research has linked these sex differences to neuroimaging markers of brain pathology, such as hippocampal volumes. Specifically, the rate of hippocampal atrophy affects the progression of AD in females more than males. This study was designed to extend our understanding of the sex-related differences in the brain of participants with MCI. Specifically, we investigated the difference in the hippocampal connectivity to different areas of the brain. The Resting State fMRI and T2 MRI of cognitively normal individuals (n = 40, female = 20) and individuals with MCI (n = 40, female = 20) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were analyzed using the Functional Connectivity Toolbox (CONN). Our results demonstrate that connectivity of hippocampus to the precuneus cortex and brain stem was significantly stronger in males than in females. These results improve our current understanding of the role of hippocampus-precuneus cortex and hippocampus-brainstem connectivity in sex differences in MCI. Understanding the contribution of impaired functional connectivity sex differences may aid in the development of sex specific precision medicine to manipulate hippocampal-precuneus cortex and hippocampal-brainstem connectivity to decrease the progression of MCI to AD.

Measuring Behavior in the Home Cage: Study Design, Applications, Challenges, and Perspectives

The reproducibility crisis (or replication crisis) in biomedical research is a particularly existential and under-addressed issue in the field of behavioral neuroscience, where, in spite of efforts to standardize testing and assay protocols, several known and unknown sources of confounding environmental factors add to variance. Human interference is a major contributor to variability both within and across laboratories, as well as novelty-induced anxiety. Attempts to reduce human interference and to measure more "natural" behaviors in subjects has led to the development of automated home-cage monitoring systems. These systems enable prolonged and longitudinal recordings, and provide large continuous measures of spontaneous behavior that can be analyzed across multiple time scales. In this review, a diverse team of neuroscientists and product developers share their experiences using such an automated monitoring system that combines Noldus PhenoTyper® home-cages and the video-based tracking software, EthoVision® XT, to extract digital biomarkers of motor, emotional, social and cognitive behavior. After presenting our working definition of a "home-cage", we compare home-cage testing with more conventional out-of-cage tests (e.g., the open field) and outline the various advantages of the former, including opportunities for within-subject analyses and assessments of circadian and ultradian activity. Next, we address technical issues pertaining to the acquisition of behavioral data, such as the fine-tuning of the tracking software and the potential for integration with biotelemetry and optogenetics. Finally, we provide guidance on which behavioral measures to emphasize, how to filter, segment, and analyze behavior, and how to use analysis scripts. We summarize how the PhenoTyper has applications to study neuropharmacology as well as animal models of neurodegenerative and neuropsychiatric illness. Looking forward, we examine current challenges and the impact of new developments. Examples include the automated recognition of specific behaviors, unambiguous tracking of individuals in a social context, the development of more animal-centered measures of behavior and ways of dealing with large datasets. Together, we advocate that by embracing standardized home-cage monitoring platforms like the PhenoTyper, we are poised to directly assess issues pertaining to reproducibility, and more importantly, measure features of rodent behavior under more ethologically relevant scenarios.

Aging-related kidney damage is associated with a decrease in klotho expression and an increase in superoxide production

The purpose of this study was to determine changes in klotho, endothelin (ET) receptors, and superoxide production in kidneys of aged rats and whether these changes are exacerbated in aged rats with cognitive impairment. Twenty aged rats (male, 27 months) were divided into an Old Impaired group (n=9) and an Old Intact group (n=11) according to a cognitive function test. A group of 12-month-old rats (n=10) was used as a Young Intact group. Serum creatinine was increased significantly in the Old Impaired group, suggesting impaired renal function. Aged rats showed glomerulosclerosis and tubulointerstitialfibrosis. These pathological changes were markedly aggravated in the old cognitively impaired than in the old cognitively intact animals. Notably, aged rats demonstrated a significant decrease in klotho protein expression in renal cortex and medulla. Protein expression of IL-6, Nox2, ETa receptors and superoxide production were increased whereas mitochondrial SOD (MnSOD) and ETb receptors expression were decreased in kidneys of the aged rats. Interestingly, these changes were more pronounced in the old impaired than in the old intact rats. In conclusion, the aging-related kidney damage was exacerbated in aged rats with cognitive impairment. Klotho, ETB, and MnSOD were downregulated but ETa, IL-6, Nox2, and superoxide production were upregulated in the aging-related kidney damage. These changes were more pronounced in rats with cognitive impairment.

Effects of short-term treadmill exercise training or growth hormone supplementation on diastolic function and exercise tolerance in old rats

Whether the lusitropic potential of short-term exercise in aged rats is linked to an augmentation in the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and an alteration in the cardiac renin angiotensin system (RAS) is unknown. Old (28-month-old) male, Fischer 344xBrown Norway rats were randomized to 4 weeks of GH supplementation (300 microg subcutaneous, twice daily) or 4 weeks of treadmill running, or were used as sedentary controls. Six-month-old rats, sedentary or exercised, were used as young controls. Training improved exercise capacity in old animals. Exercise and GH attenuated age-related declines in myocardial relaxation despite an exercise-induced suppression of IGF-1. The regulatory protein, sarcoplasmic Ca2+ adenosine triphosphatase (SERCA2), increased with exercise but not GH. Among aged rats, the cardiac RAS was not altered by training or GH. Thus, the signaling pathway underlying the lusitropic benefit of short-term habitual exercise in the aged rat may be distinct from GH-mediated benefits and independent of the cardiac RAS.

Plasma growth hormones, P300 event-related potential and test of variables of attention (TOVA) are important neuroendocrinological predictors of early cognitive decline in a clinical setting: evidence supported by structural equation modeling (SEM) parameter estimates

A review of the literature in both animals and humans reveals that changes in sex hormone have often been associated with changes in behavioral and mental abilities. Previously published research from our laboratory, and others, provides strong evidence that P300 (latency) event-related potential (ERP), a marker of neuronal processing speed, is an accurate predictor of early memory impairment in both males and females across a wide age range. It is our hypothesis, given the vast literature on the subject, that coupling growth hormones (insulin-like growth factor-I, (IGF-I) and insulin-like growth factor binding protein 3 (IGF-BP3)), P300 event-related potential and test of variables of attention (TOVA) are important neuroendocrinological predictors of early cognitive decline in a clinical setting. To support this hypothesis, we utilized structural equation modeling (SEM) parameter estimates to determine the relationship between aging and memory, as mediated by growth hormone (GH) levels (indirectly measured through the insulin-like growth factor system), P300 latency and TOVA, putative neurocognitive predictors tested in this study. An SEM was developed hypothesizing a causal directive path, leading from age to memory, mediated by IGF-1 and IGF-BP3, P300 latency (speed), and TOVA decrements. An increase in age was accompanied by a decrease in IGF-1 and IGF-BP3, an increase in P300 latency, a prolongation in TOVA response time, and a decrease in memory functioning. Moreover, independent of age, decreases in IGF-1 and IGF-BP3, were accompanied by increases in P300 latency, and were accompanied by increases in TOVA response time. Finally, increases in P300 latency were accompanied by decreased memory function, both directly and indirectly through mediation of TOVA response time. In summary, this is the first report utilizing SEM to reveal the finding that aging affects memory function negatively through mediation of decreased IGF-1 and IGF-BP3, and increased P300 latency (delayed attention and processing speed).

Biomarkers of aging: from primitive organisms to humans

Leading biologists and clinicians interested in aging convened to discuss biomarkers of aging. The goals were to come to a consensus, construct an agenda for future research, and make appropriate recommendations to policy makers and the public-at-large. While there was not total agreement on all issues, they addressed a number of questions, among them whether biomarkers can be identified and used to measure the physiological age of any individual within a population, given emerging information about aging and new technological advances. The hurdles to establishing informative biomarkers include the biological variation between individuals that makes generalizations difficult; the overlapping of aging and disease processes; uncertainty regarding benign versus pathogenic age-related changes; the point at which a process begins to do damage to the organism, and, if so, when does it occur; and when to distinguish critical damage from noncritical damage. Finally, and significantly, it is difficult to obtain funding for this research.

Chronic caloric restriction alters muscle membrane fatty acid content

Chronic caloric restriction (CR) has been demonstrated to increase longevity in lower species and studies are ongoing to evaluate its effect in higher species. A consistent metabolic feature of CR is improved insulin sensitivity and lowered lifetime glycemia, yet the mechanism responsible is currently unknown. However, the membrane's physiochemical properties, as determined by phospholipid composition, have been related to insulin action in animal and human studies and CR has been reported to alter membrane lipid content. We evaluated muscle membrane fatty acid content in rodents randomized to CR versus control diets for up to 29 months. CR was observed to increase the membrane content of C22:6 (docosahexaenoate) and to decrease C18:2 content. The membrane lipid content was related to insulin levels but not to parameters assessing glycemic control. This study suggests that membrane lipids, in particular 22:6, may contribute to the variation in insulin sensitivity seen with age.

Effect of age and caloric restriction on insulin receptor binding and glucose transporter levels in aging rats

We report on the effect of age and chronic caloric restriction (CR) on insulin binding and glucose transporter content in both diaphragm and heart muscle membrane of young (11 months), mid-age (17 months), and old (29 month) ad libitum fed and CR Brown-Norway rats. The control animals received rat chow ad lib and CR animals were allowed 60% of ad libitum food. The CR regimen was initiated at four months of age and the animals were maintained on their respective diets until necropsy. There was no effect of age on insulin binding for either ad libitum or CR animals at each age evaluated. Caloric restriction significantly lowered insulin levels at each age studied when compared to the ad libitum-fed rats. However, CR animals were noted to have increased insulin binding (p < 0.001) compared to ad libitum-fed animals at each age for diaphragm muscle. For the heart, there appeared to be a decreased binding, particularly at higher insulin concentrations, in CR-fed animals. There was no net change in Glut-1 or Glut-4 levels for heart muscle membrane, or Glut-4 levels for diaphragm muscle membrane between ad libitum or CR animals. This data indicates that caloric restriction may have tissue-specific effects for insulin receptor binding, and that the improved insulin sensitivity in CR states is not a result of altered glucose transporter protein content.

[The basis for ultrasonic phenomena during the injection of x-ray contrast media]

During the injection of contrast media for cerebral angiography, high-intensity ultrasound reflections can be recorded by Doppler sonography and B-mode scanning. This phenomenon was examined during carotid angiography and by in vitro experiments in tube models. Our results show that these high-intensity reflections are caused by: (1) transient interfaces of impedance between small compartments of contrast medium and blood and (2) small gas bubbles, which are always present in freshly aspirated contrast medium. Therefore, intraarterially injected contrast medium acts as an ultrasound contrast medium as well.

[The effect of cisplatin on the healing of intestinal anastomosis in the rat. Microangiography and light microscopy studies]

The influence of a single dose cisplatin on wound healing of enterostomies in rats was investigated by measurement of the wound-breaking strength, microangiographically and histologically. Cisplatin (5 mg/kg body weight) was given on day-1 or day-5 preoperatively. Cisplatin led to a significant reduction of the wound-breaking strength, mostly marked on day +14 after operation. The reasons are: a reduced induction of connective tissue proliferation; an inhibition of proliferation of fibroblasts and endothelial cells, and a retardation of vessel proliferation.

Cell fusion as a mechanism for the formation of giant cells (Langhans' type). Autoradiographic findings in autoimmune tubulo-interstitial nephritis of the rat

The formation of multinuclear giant cells of the Langhans' type in tubulo-interstitial auto-immune nephritis in the rat has been investigated by means of autoradiography. While in the majority of giant cells all nuclei were radiolabeled, in a few both labeled and unlabeled nuclei were present. This latter finding represents strong evidence in favour of the hypothesis that giant cells do not form by endomitotic processes but rather through fusion of certain precursor cells. According to previous studies this precursor cell population consists mainly of epitheloid cells, i.e. modified monocytes.

D-penicillamine in Wilson's disease presenting as acute liver failure with hemolysis

Wilson's disease in a young woman presenting with an acute course is described. The clinical manifestations were fulminant hepatic failure associated with marked intravascular hemolysis. Immediate D-penicillamine and high-dose steroid therapy did not influence the course of the disease. Necropsy revealed an increased hepatic copper content and cirrhosis with extensive necrosis of the liver.

[A combined allogenic implant for the dorsum of the nose (author's transl)]

Report of three patients with small bony defects on the lateral bony wall or the bridge of the nose. Reconstruction was performed with a combined cushion like implant of lyodura polsted with merthiolate preserved allongene crashed cartilage. Over a follow up time period of two years the cosmetic results are good. The histological behavior of these implants was studied in animals.

[Polyploidisation - a phenomenon of aging? (author's transl)]

By means of cytophotometric determination of DNA in different cellular systems an increase in polyploidisation correlated to age could be demonstrated. The latter is well demonstrable if compensatory hyperplasia or hypertrophy occurs. It is discussed that cellular systems of older individuals can increase their DNA - content, but they are not able to carry out a caryo-and cytocinesis.

[The vascularisation of the granulation tissue in different ages. - Its importance for wound healing (author's transl)]

The part of capillaries of a plastic sponge granuloma was determined in rats of different ages. It was found that granulation tissue of older rats contains significantly fewer capillaries than that of young animals. The diminished vascularisation of granulation tissue may be responsible for the deterioration of wound healing in aged individuals.

[Investigations regarding the pathogenesis of fibromatosis of the palmar fascia (Dupuytren's contracture) (author's transl)]

The palmar aponeuroses of five patients suffering from Duputyren's disease were examined by means of light and electron microscopy. In all cases myofibroblasts could be found in the alterated regions of the palmar aponeuroses. The role of the fibroblasts for the pathogenesis of the disease is discussed.

The effect of complete Freund--adjuvant on chronic proliferating inflammation in an experimental granuloma model

Histometric, biochemical, radiochemical and autoradiographic studies were undertaken to investigate the influence of complete Freund-adjuvant (CFA) on a defined chronic proliferating inflammation of a granuloma model in two different experimental situations. Where as the percentage fraction of the fibroblasts, 3H-thymidine marking index of the fibroblasts and the impulse rate of the fibroblasts and endothelial cells do not differ from the values found for the control animals, both the protein and DNA content of the implanted sponges, as well as the DNA content of the individual fibroblasts in the implants increased, independent of the stage of the chronic proliferating inflammation at which the CFA was administered. Surprisingly the quantity of the fibroblast specific synthetic product, collagen, did not increase in proportion to the absolute number of fibroblasts, but remained either constant or even significantly decreased. A possible inhibition of collagen synthesis after CFA administration during chronic proliferating inflammation is discussed.

Veränderungen des RHS der Ratte nach parenteraler Gabe yon Dextran (Mw 40000) und Hydroxyäthylstärke (Mw 40000). Chemische, licht- und elektronenmikroskopische Untersuchungen

Im Tierversuch wurde nach mehrmaliger parenteraler Gabe die Wirkung von Dextran (Mw 40000) und HAS (Mw 40000) auf die Zellen des RHS (retikulohistiozytäres System) am Beispiel verschiedener Lymphknotenstationen mit chemischen, licht- und elektronenmikroskopischen Methoden untersucht. Offensichtlich werden beide Plasmaexpander teilweise in den Zellen des RHS gespeichert. Als wesentlicher Unterschied findet sich jedoch nur nach Dextran-40-Gabe eine so exzessive Speicherung, daβ einzelne Zellen zerstört werden. Gleichartige Veränderungen können nach HÄS-40 nicht beobachtet werden. Eine Blockade des RHS scheint nach Gabe beider Plasma-expander nicht aufzutreten.

The development of the rolling texture in copper measured by neutron diffraction

Three-dimensional orientation distribution functions of the crystallites in copper sheets, cold rolled to different degrees of reduction, have been determined using neutron diffraction pole figures. The main features of the textures may be represented by the orientation `tube' already described in prior publications. Two ranges of rolling reduction can be distinguished, a lower one (30 to 50%) and a higher one (70 to 95%) the texture changes of which correspond to those calculated after the Taylor theory. In an intermediate range (50 to 70%) a different deformation mechanism occurs which leads to an intermediate (001) [110] texture component. It is supposed that anisotropic hardening may have occurred in this range.