Caloric restriction (CR) without malnutrition extends lifespan and delays the onset of age-related disorders in most species but its impact in nonhuman primates has been controversial. In the late 1980s two parallel studies were initiated to determine the effect of CR in rhesus monkeys. The University of Wisconsin study reported a significant positive impact of CR on survival, but the National Institute on Aging study detected no significant survival effect. Here we present a direct comparison of longitudinal data from both studies including survival, bodyweight, food intake, fasting glucose levels and age-related morbidity. We describe differences in study design that could contribute to differences in outcomes, and we report species specificity in the impact of CR in terms of optimal onset and diet. Taken together these data confirm that health benefits of CR are conserved in monkeys and suggest that CR mechanisms are likely translatable to human health. Caloric restriction (CR) delays ageing of model organisms, but whether it works in nonhuman primates has been controversial. Here, the authors pool and reanalyse data from two long-running CR primate studies, concluding that moderate CR indeed improves health and survival of rhesus monkeys.

/pdf/caloric-restriction-improves-health-and-survival-of-rhesus-5csfk1ifkm.pdf

Caloric restriction improves health and survival of rhesus monkeys.

Experimental models of Alzheimer's disease (AD) are critical to gaining a better understanding of pathogenesis and to assess the potential of novel therapeutic approaches. The most commonly used experimental animal models are transgenic mice that overexpress human genes associated with familial AD (FAD) that result in the formation of amyloid plaques. However, AD is defined by the presence and interplay of both amyloid plaques and neurofibrillary tangle pathology. The track record of success in AD clinical trials thus far has been very poor. In part, this high failure rate has been related to the premature translation of highly successful results in animal models that mirror only limited aspects of AD pathology to humans. A greater understanding of the strengths and weakness of each of the various models and the use of more than one model to evaluate potential therapies would help enhance the success of therapy translation from preclinical studies to patients. In this review, we summarize the pathological features and limitations of the major experimental models of AD, including transgenic mice, transgenic rats, various physiological models of sporadic AD and in vitro human cell culture models.

/pdf/alzheimer-s-disease-experimental-models-and-reality-jycywklibs.pdf

Alzheimer's disease: experimental models and reality.

The common marmoset (Callithrix jacchus) is poised to become a standard nonhuman primate aging model. With an average lifespan of 5 to 7 years and a maximum lifespan of 16½ years, marmosets are the shortest-lived anthropoid primates. They display age-related changes in pathologies that mirror those seen in humans, such as cancer, amyloidosis, diabetes, and chronic renal disease. They also display predictable age-related differences in lean mass, calf circumference, circulating albumin, hemoglobin, and hematocrit. Features of spontaneous sensory and neurodegenerative change--for example, reduced neurogenesis, s-amyloid deposition in the cerebral cortex, loss of calbindin D(28k) binding, and evidence of presbycusis--appear between the ages of 7 and 10 years. Variation among colonies in the age at which neurodegenerative change occurs suggests the interesting possibility that marmosets could be specifically managed to produce earlier versus later occurrence of degenerative conditions associated with differing rates of damage accumulation. In addition to the established value of the marmoset as a model of age-related neurodegenerative change, this primate can serve as a model of the integrated effects of aging and obesity on metabolic dysfunction, as it displays evidence of such dysfunction associated with high body weight as early as 6 to 8 years of age.

The marmoset as a model of aging and age-related diseases

Nonhuman primates are useful for the study of age-associated changes in the brain and behavior in a model that is biologically proximal to humans. The Aβ and tau proteins, two key players in the pathogenesis of Alzheimer's disease (AD), are highly homologous among primates. With age, all nonhuman primates analyzed to date develop senile (Aβ) plaques and cerebral β-amyloid angiopathy. In contrast, significant tauopathy is unusual in simians, and only humans manifest the profound tauopathy, neuronal degeneration and cognitive impairment that characterize Alzheimer's disease. Primates thus are somewhat paradoxical models of AD-like pathology; on the one hand, they are excellent models of normal aging and naturally occurring Aβ lesions, and they can be useful for testing diagnostic and therapeutic agents targeting aggregated forms of Aβ. On the other hand, the resistance of monkeys and apes to tauopathy and AD-related neurodegeneration, in the presence of substantial cerebral Aβ deposition, suggests that a comparative analysis of human and nonhuman primates could yield informative clues to the uniquely human predisposition to Alzheimer's disease.

Nonhuman Primate Models of Alzheimer-Like Cerebral Proteopathy

Aluminum is a ubiquitously abundant nonessential element. Aluminum has been associated with neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis, and dialysis encephalopathy. Many continue to regard aluminum as controversial although increasing evidence supports the implications of aluminum in the pathogenesis of AD. Aluminum causes the accumulation of tau protein and Aβ protein in the brain of experimental animals. Aluminum induces neuronal apoptosis in vivo and in vitro, either by endoplasmic stress from the unfolded protein response, by mitochondrial dysfunction, or a combination of them. Some, people who are exposed chronically to aluminum, either from through water and/or food, have not shown any AD pathology, apparently because their gastrointestinal barrier is more effective. This article is written keeping in mind mechanisms of action of aluminum neurotoxicity with respect to AD.

Understanding Aspects of aluminum exposure in Alzheimer's disease development

Cerebral amyloid angiopathy and plaques, and visceral amyloidosis in aged macaques.

The age-related incidence of malignant neoplasia was surveyed from a total of 301 necropsy cases of rhesus monkeys ranging in age from 13-37 years performed in the Pathology Service Unit of the Wisconsin Regional Primate Research Center during the past 15 years. All our aged monkeys lived in indoor cages and were fed with monkey chow and supplemental fruits during the past decades. In this survey, we found a total of 51 malignant neoplasms, and among them 25 cases were colon cancer. The incidence of colon cancer increased with advancing age: 3.2% at 13-19 years, 9.2% at 20-25 years, 13.5% at 26-29 years, and 20.7% at 30-37 years. Most cancers were located in the cecum and transverse regions with a unicentric origin. Two multicentric cases were associated with chronic hypertrophic colitis. Precancerous polypous lesions were not found in all cases. Histologically, all cases were mucinous adenocarcinoma and had local invasion to the muscular wall. Metastasis to the mesenteric lymph nodes was found in only two cases. As in humans, colon cancer is a common outcome of aging in nonhuman primates.

Colon cancer in aged captive rhesus monkeys (Macaca mulatta).

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Wallace D. Houser

Author Tools

Chat about Author

Papers

Cerebral amyloid angiopathy and plaques, and visceral amyloidosis in aged macaques.

Colon cancer in aged captive rhesus monkeys (Macaca mulatta).