In many ways what's most interesting about this from a biological standpoint is that it explains why stem cells have been found all over the body in previous experiments. This "stress-induced" pluripotency suggests a general mechanism that the body uses to deal with stress. In effect cells are made with the intrinsic capability to respond to injury, by simply turning into stem cells.
From a short glance at the paper it seems that they don't know yet what the mechanism is that triggers the conversion. It might be that it is not triggered specifically by low pH, but by some downstream mechanism that can also be triggered by other kinds of stress.
