Frozen human muscle cells were used to build tissue in another laboratory

Frozen human muscle cells were used to build tissue in another laboratory

In a preprint published on July 16, researchers from the University of Oregon and the University of California, San Diego demonstrated the complete process. They isolated two cell types from human muscle, preserved them in a cryobank, transported them, and used them to grow a three-dimensional muscle model. After thawing, the cells retained features of their respective cell types and several of their functions.

Human muscle is difficult to study across a series of experiments. A biopsy yields few living cells, and only some laboratories have access to surgical procedures and tissue samples. Laboratories without such access usually work with mice or with cell lines that have divided many times in culture.

Muscle contains two related cell populations. Satellite cells serve as muscle stem cells. After an injury, they divide and fuse to form new fibers. Fibro-adipogenic progenitors reside nearby, support repair through signaling, and remodel the surrounding tissue. When repair fails, they give rise to scar tissue and fat. Understanding age-related muscle loss requires observing both populations from the same human sample.

The authors collected cells from one 25-year-old female donor, froze them, stored them in liquid nitrogen, and shipped them to Oregon in a dry nitrogen container. The average temperature inside the container remained near −194 °C. After thawing, the satellite cells again fused into long muscle tubes. The fibro-adipogenic progenitors responded to signals that directed them toward scar-forming or fat-forming states. The team then used the frozen satellite cells to construct three-dimensional muscle with aligned fibers.

One muscle sample completed the full process from biopsy to a model produced in another laboratory. Similar cells had previously been isolated from biopsies and frozen tissue. The new study tested the complete process for two cell types from a single donor, including isolation, storage, transport, and use. BlueRock gave other developers access to its bank of clinical stem cells, so they would not have to create the starting material and establish its quality control from scratch. This cryobank addresses an earlier stage of the same problem by providing researchers with a matched pair of human muscle cell types for reproducible experiments.

The authors tested cells from only one young donor, so the study does not yet measure age-related differences or variation among individuals. It also does not show how storage affects cellular metabolism or communication between the cell types. The next test is to build such a bank using cells from people of different ages and determine which properties of muscle tissue are lost with age and which remain intact after cryopreservation.