Cerebral aneurysms: formation, progression, and developmental chronology

Abstract

The prevalence of unruptured intracranial aneurysms (UIAs) in the general population is up to 3%. Existing epidemiological data suggests that only a small fraction of UIAs progress towards rupture over the lifetime of an individual, but the surrogates for subsequent rupture and the natural history of UIAs are discussed very controversially at present. In case of rupture of an UIA, the case fatality is up to 50%, which therefore continues to stimulate interest in the pathogenesis of cerebral aneurysm formation and progression. Actual data on the chronological development of cerebral aneurysm has been especially difficult to obtain and, until recently, the existing knowledge in this respect is mainly derived from animal or mathematical models or short-term observational studies. Here, we review the current data on cerebral aneurysm formation and progression as well as a novel approach to investigate the developmental chronology of cerebral aneurysms.

Figure 1

Original figure from the publication “Exploring the age of intracranial aneurysms using carbon birth dating: Preliminary Results” by Etminan et al. A) Atmospheric ¹⁴CO₂ levels have been essentially stable over the past 2000 years, except for a large increase between 1955–1963 due to above ground nuclear tests.. B, C) The collagen samples of each individual patient were placed on the ¹⁴C record with projected concentrations to 2017 expressed in the F¹⁴C nomenclature, which does not correct for radioactive decay and illustrates above ground ¹⁴C levels over the past 85 years. ^–, The patients’ birth dates (vertical lines) and the aneurysm collagen date ranges (horizontal lines) are illustrated for ruptured (R) and unruptured (U) samples.

Figure 1

Original figure from the publication “Exploring the age of intracranial aneurysms using carbon birth dating: Preliminary Results” by Etminan et al. A) Atmospheric ¹⁴CO₂ levels have been essentially stable over the past 2000 years, except for a large increase between 1955–1963 due to above ground nuclear tests.. B, C) The collagen samples of each individual patient were placed on the ¹⁴C record with projected concentrations to 2017 expressed in the F¹⁴C nomenclature, which does not correct for radioactive decay and illustrates above ground ¹⁴C levels over the past 85 years. ^–, The patients’ birth dates (vertical lines) and the aneurysm collagen date ranges (horizontal lines) are illustrated for ruptured (R) and unruptured (U) samples.

Figure 1

Original figure from the publication “Exploring the age of intracranial aneurysms using carbon birth dating: Preliminary Results” by Etminan et al. A) Atmospheric ¹⁴CO₂ levels have been essentially stable over the past 2000 years, except for a large increase between 1955–1963 due to above ground nuclear tests.. B, C) The collagen samples of each individual patient were placed on the ¹⁴C record with projected concentrations to 2017 expressed in the F¹⁴C nomenclature, which does not correct for radioactive decay and illustrates above ground ¹⁴C levels over the past 85 years. ^–, The patients’ birth dates (vertical lines) and the aneurysm collagen date ranges (horizontal lines) are illustrated for ruptured (R) and unruptured (U) samples.

Figure 2

The average age of cells can be determined from the ¹⁴C/C content of the DNA of the cell population. The age of tissues (red) and specific cell types (orange) are depicted for a human subject who was born in 1973 (vertical line) and died in 2005 based on published turnover rates..^{, –, ,}

Figure 3

Sequence of sample processing for birth dating on aneurysm collagen.