The donor follicular units are harvested from the donor area and implanted into the recipient area. The time interval between the graft harvested from the body and implanted back is the period in which hair follicular cells are cut off from circulation and supply of oxygen, and various nutrients are on hold. This period is called ‘graft out of body time’ or ‘ischemia time.’
The graft during this period is kept or stored in a solution named graft holding solution. the purpose of graft holding solution is to prevent desiccation of graft and to minimize ischemic injury to hair follicle cells. the most commonly used solutions are extracellular graft holding solutions like normal saline, lactated ringer, and autologous plasma or platelet-rich plasma .the other intracellular graft holding solutions are various cell culture media, and the most commonly used solution is a hypothermal solution with or without ATP. The various studies were done by Ubel, Garg AK, Kim, Limmer, and Beemer concluded the following points about the use of graft holding solutions.
1. The extracellular fluids like normal saline, lactated ringer can be used as a graft holding solution when grafts out of body time are within two hours. These extracellular fluids should not be chilled.
2. When grafts are implanted immediately or within two hours of graft out of body time, the survival of grafts remains the same.
3. Longer ischemia time of more than six hours, use of chilled hypothermic solution with ATP improves graft survival.
Important Point of Graft Holding Solutions
The hair follicles or grafts suffers various injuries during harvesting, storage, and implantation. The injuries are Ischemic injury, cold injury, reperfusion injury, graft desiccation injuries, and microtrauma sustained during graft handling.
The time lag between hair follicle harvesting and implantation is called out of body graft timing or ischemia timing. During this period, the graft is cut off from blood circulation and remains in ischemic condition leading to ‘ischemic injury.
The metabolism of cells depends on temperature. Lower the temperature lower will be oxygen demand and metabolism. At the low temperature, the permeability of cells will increase, which may lead to cell swelling and, finally, cell damage called “cold injury.”
During ischemia, the hypoxanthine formation occurs in graft cells, which, when re-exposed to oxygen after transplant in live tissue, results in the formation of free radicals, which damages the DNA and cell membrane. This is known as ‘Ischemic reperfusion Injury (IRI).’
Hair follicle cells are susceptible to dehydration, if exposed to air, will lead to cellular damage called desiccation injury.
The rough handling of hair follicles/grafts may produce micro-trauma to cells, which will affect the outcome of hair formation.
After extraction of grafts, they are kept in a solution called graft holding solution (GHS).
The extracellular GHS are isotonic solutions and are composed of ingredients similar to plasma and the extracellular environment of cells.
Most Commonly used extracellular GHS are normal saline, lactated ringer, autologous plasma, platelet-rich plasma.
Extracellular GHS should not be chilled. If done, it will cause cellular swelling.
Intracellular GHS are hypertonic solutions with elevated levels of potassium, reduced-sodium levels, and more anions that provide higher osmotic pressure, which protects cells from cold injury.
Intracellular GHS are chilled to lower oxygen demand and cellular metabolism.
The most commonly used Intracellular GHS is Hypothermosol.
When grafts are implanted immediately or within two hours of graft out of body time, the survival of grafts remains unaffected.
Longer graft out body time for more than two hours, the Hypothermosol GHS improves graft survival
The extracellular fluids like normal saline, lactated ringer can be used as a graft holding solution when grafts out of body time are within two hours. These extracellular fluids should not be chilled.
When grafts are implanted immediately or within two hours of graft out of body time, the survival of grafts remains the same.
Longer ischemia time of more than six hours, use of chilled hypothermic solution with ATP improves graft survival.
Use of Plasma & Platelet Rich Plasma as Graft Holding Media
The autologous plasma and PRP having various nutrients, antibodies, and various platelet-derived growth factors. The plasma used by Garg has shown beneficial results in terms of early growth, increased density, and thickness of hair in their studies.
The Prothrombin present in plasma when it comes in contact with tissue collagen, it gets converted to thrombin. Furthermore, thrombin converts fibrinogen into fibrin. The fibrin is a fibrous, non-globular protein. These fibril strands form a network ‘called 3D fibrin scaffold’ in which activated platelets are present. These platelets release various growth factors14. So the 3D fibrin scaffold provides a biological protective three-dimensional covering with platelet growth factor. The PRP and or autologous plasma is extracellular fluid and does not require chilling, and the grafts can be stored at a relatively cold temperature. The standardization of PRP formation and more large sample studies are needed to prove the beneficial effect of PRP as a graft holding solution.
Grafts kept in Platelet Rich Plasma
