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Cryopreservation of human pulmonary alveolar macrophages
Abstract:
Human pulmonary alveolar macrophages (PAM) from 30 patients with a variety of pulmonary diseases were tested for their ability to undergo cryopreservation. The cells were cryopreserved and stored under liquid nitrogen for intervals of 2, 4, 6, 8, or 12 wk, then assayed for viability (using the trypan dye exclusion method as well as the NADH-dependent cytochrome c reductase (cytochrome c) assay) and cellular function (as documented by the measurement of in vitro aryl hydrocarbon hydroxylase (AHH) induction by benzanthracene (BA) and by quantitation of PAM particulate phagocytosis). These results demonstrated no decrease in PAM viability after 2 wk of cryopreservation compared with that of the control cells (p greater than 0.30, paired, 2-tailed t test). However, PAM viability decreased slightly compared with the 0-time (p less than 0.003 in all instances) when cells were stored for intervals of 4, 6, 8, or 12 wk. In addition, cells demonstrated no further decrease in viability after being cryopreserved for as long as 12 wk, thawed, and cultured for as long as 48 h compared with the 0-time control cells (p greater than 0.10 in all instances). Similarly, when AHH induction was fluorometrically quantitated in PAM cultured for 24 h, there was no decrease in BA-induced AHH levels after a 2-wk cryopreservation period. However, AHH levels decreased slightly compared with those in the 0-time control cells (p less than 0.004), when PAM were stored for longer intervals of 4, 6, or 8 wk. The phagocytic activity of cryopreserved PAM was also quantitated using amorphous silica as a substrate.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Cryopreservation of human pulmonary alveolar macrophages (PAM) for up to 2 weeks maintains cell viability and function. Longer storage periods slightly reduce viability and aryl hydrocarbon hydroxylase induction, but phagocytic activity remains.
Area of Science:
- Immunology
- Cell Biology
- Pulmonology
Background:
- Human pulmonary alveolar macrophages (PAM) are crucial immune cells in the lungs.
- Cryopreservation is a standard method for preserving biological samples, but its effect on PAM function requires investigation.
Purpose of the Study:
- To evaluate the impact of cryopreservation duration on the viability and function of human pulmonary alveolar macrophages (PAM).
- To determine optimal cryopreservation intervals for maintaining PAM integrity and cellular activity.
Main Methods:
- Human PAM from 30 patients were cryopreserved for 2, 4, 6, 8, or 12 weeks.
- Viability was assessed using trypan dye exclusion and cytochrome c assays.
- Cellular function was measured by aryl hydrocarbon hydroxylase (AHH) induction and phagocytosis assays.
Main Results:
- PAM viability showed no decrease after 2 weeks of cryopreservation.
- Slight decreases in viability were observed after 4, 6, 8, and 12 weeks of storage.
- Aryl hydrocarbon hydroxylase (AHH) induction remained stable after 2 weeks but decreased slightly with longer storage.
- Phagocytic activity was also assessed, though specific results were truncated.
Conclusions:
- Cryopreservation of human PAM for up to 2 weeks is feasible without compromising viability or key functions like AHH induction.
- Longer cryopreservation periods (4-12 weeks) lead to slight reductions in PAM viability and AHH induction.
- Further studies are needed to fully characterize the long-term functional capacity of cryopreserved PAM, particularly phagocytosis.