Table 1.
Unique Age-Dependent Findings in Select Recent Publications
| Species, strain, and age | Major macrophage findings | Additional comments | Reference |
|---|---|---|---|
| Mouse C57BL/6 20–24 months |
In aged mice: ↑ percentage of circulating monocytes and macrophages in the spleen ↓ percentage of macrophages in the peritoneum ↑ number of mitochondria and mitochondrial reactive oxygen species after LPS stimulation ↓ autophagy |
Showed that autophagy deficient macrophages (Atg7 knockout) have similar phenotype to aged macs in their studies | (85) |
| Mouse C57BL/6 18–24 months |
↓ percentage of peritoneal macrophages in aged animals with ↓ phagocytosis of necrotic cells. | Decreased necrotic cell clearance in vivo (peritoneum) lead to elevated peritoneal MIP-2 Prolonged inflammation in aged mice |
(87) |
| Mouse C57BL/6 21 months |
↑ A20 expression in alveolar macrophages from healthy aged mice ↓ NFκB and MAPK signaling A20 can be induced by TNFα but not IL-6. |
Dietary fish oil lowers A20 levels and protects aged mice from Streptococcus pneumoniae infection | (46) |
| Mouse Swiss Albino 12 and 16 months |
↓TLR2 and TLR4 expression in resident peritoneal macrophages from aged mice | (79) | |
| Mouse BALB/c 19–21 months |
Response to infection by alveolar macrophages from aged mice: ↓ TNFα and IL-6 production ↓ NFκB, JNK, and p38 activation ↑ ERK activation |
Aged lung lower levels of IL-6 and IL-1β after infectious challenge | (16) |
| Mouse BALB/c 17–18 months |
↓ number of marginal zone macrophages in the spleen of aged mice No age-dependent difference in phagocytosis |
Anatomical breakdown of the marginal zone with age. | (10) |
| Mouse BALB/c 18–20 months |
↓ splenic macrophages, pro-inflammatory response after LPS stimulation and other pro-inflammatory stimuli ↓ anti-inflammatory response after incubation with IL-4 No difference in pro-and anti-inflammatory phenotype markers between bone marrow-derived macrophages from young and aged mice |
From primary macrophages: global suppression of macrophage function. From bone marrow-derived macrophages: age-dependent differences in macrophage phenotype lost after prolonged cell culture |
(58) |
| Mouse/C57BL/6 and B6.SJL-Ptprca Pepcb/BoyJ 15–20 months |
↓ phagocytosis by peritoneal macrophages from aged mice both in vivo and in vitro. No difference in phagocytosis by bone marrow-derived macrophages or bone marrow monocytes |
(57) |
IL, interleukin; JNK, c-Jun N-terminal kinase; LPS, lipopolysaccharide; MAPK, mitogen-activated protein kinase; MIP-2, macrophage inflammatory protein 2; NFκB, nuclear factor kappa-light-chain-enhancer of activated B cells; TLR, Toll-like receptor; TNFα, tumor necrosis factor alpha.