Compositions for platelet rich plasma (PRP) are provided. Generally, these compositions comprise a higher concentration of platelets than whole blood. Concentrations of lymphocytes, monocytes, and neutrophils may be different from concentrations found in whole blood. These compositions may have depressed concentrations of red blood cells and hemoglobin. In some variations, the compositions may be useful to treat damaged connective tissue, particularly spinal disc, and/or to slow or stop cardiac apoptosis after a heart attack.
