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Updated: Feb 5, 2026
Modeling Age-Associated Neurodegenerative Diseases in Caenorhabditis elegans
Published on: August 15, 2020
Age does not influence the disease course in a mouse model of
Anja Manig1,2, Sandra Ribes1, Catharina Diesselberg1
11Institute of Neuropathology, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
Abstract:
In order to elucidate the causes for the increased mortality of aged patients with bacterial central nervous system (CNS) infections, we compared the course of Streptococcus pneumoniae (S. pneumoniae) meningitis in aged and young mice. Aged (21.2 ± 3.1 months, n = 40) and young (3.2 ± 0.9 months, n = 42) C57BL/6N and B6/SJL mice were infected by intracerebral injection of 50-70 CFU S. pneumoniae serotype 3 and monitored for 15 days. Aged and young mice did not differ concerning mortality (35% versus 38%), weight loss, development of clinical symptoms, bacterial concentrations in cerebellum and spleen as well as the number of leukocytes infiltrating the CNS. In contrast to results from our geriatric mouse model of Escherichia coli (E. coli) meningitis, where aged mice showed a higher mortality and an impaired elimination of bacteria, we did not find any differences between aged and young mice after intracerebral infection with S. pneumoniae serotype 3. This indicates that the increased susceptibility of aged mice to bacterial CNS infections is pathogen-specific: It appears less prominent in infections caused by hardly phagocytable pathogens with thick capsules like S. pneumoniae serotype 3, where the age-related decline of the phagocytic capacity of microglia and macrophages has a minor influence on the disease course.
Insights
Aging does not increase mortality in Streptococcus pneumoniae meningitis. This pathogen-specific finding suggests age-related immune decline impacts bacterial central nervous system infections differently based on pathogen characteristics.
Area of Science:
- Neuroscience
- Immunology
- Infectious Diseases
Background:
- Bacterial central nervous system (CNS) infections pose a higher mortality risk in aged individuals.
- The specific mechanisms underlying this increased susceptibility in the elderly remain incompletely understood.
Purpose of the Study:
- To investigate the impact of aging on the course of Streptococcus pneumoniae meningitis.
- To compare the outcomes of S. pneumoniae meningitis in aged versus young mice.
Main Methods:
- Aged and young mice were intracerebrally infected with Streptococcus pneumoniae serotype 3.
- Mortality, weight loss, clinical symptoms, bacterial loads, and CNS leukocyte infiltration were monitored for 15 days.
Main Results:
- No significant differences in mortality rates were observed between aged (35%) and young (38%) mice.
- Key parameters including weight loss, clinical signs, bacterial concentrations, and CNS immune cell infiltration showed no age-related disparities.
Conclusions:
- The increased susceptibility of aged individuals to bacterial CNS infections is pathogen-specific.
- For pathogens like S. pneumoniae serotype 3, which are difficult to phagocytose due to their capsules, the age-related decline in immune cell function has a minimal impact on disease severity.
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