Use of platelet lysate for bone regeneration - are we ready for clinical translation?

Table 1 Common methods of platelet lysate preparation

Ref.	Platelet collection	Leucocyte reduction	Freeze and thaw temperature (°C)	Anti-coagulation factors	PDGF level
[15]	Buffy coat	Inline filtration	-30/37	100 IU/mL H	(AA) 7424 ± 1043 pg/mL2
					(BB) 4655 ± 1353 pg/mL
					(AB) 40458 ± 1791 pg/mL
[18]	Buffy coat	Inline filtration	–30/37	2 IU/mL H	Higher than FCS
[38]1	Apheresis	NR	-20/37	NR	NR
[25]1	Apheresis	NR	-80/NR	2 IU/mL H	NR
[36]1	NR	NR	-80/NR	10 IU/mL H	NR
[51]	Apheresis	NR	-80/37	2 IU/mL H	(AB) 530 ± 60 pg/μL
[37]1	Apheresis	NR	-80/NR	NR	(AA) 19596 pg/mL
					(BB) 22329 pg/mL

¹Pre clinical investigation;

²Measured in media containing 10 mL/L platelet lysate. PDGF: Platelet derived growth factor; AA, AB and BB refer to different isotypes of PDGF; H: Heparin; FCS: Fetal calf serum; NR: Not reported.

Table 2 Summary of pre-clinical studies with platelet lysate-expanded bone marrow mesenchymal stem cells aimed at bone regeneration

Ref.	Animal model	MSC source	MSC expansion media (supplements)	Construct type	Scaffold pre-coating before loading with MSCs	Construct in vitro culture before implantation (supplements)
[38]	Mouse	Iliac crest BM	50 mL/L PL	BCP + 2 × 105 MSCs	A	10-8 M DEX
[36]	Sheep	Iliac crest BM	200 mL/L FCS	Rat-tail-derived collagen + 4 × 107 MSCs	PL	NR
[37]	Mouse	Iliac crest BM	100 mL/L FCS	HA (65%) + β-TCP (35%) + 3 × 105 MSCs	PL for 24 h	100 mL/L FCS
[25]1	Mouse	Iliac crest BM	50 mL/L PL	HA (65%) + β-TCP (35%) + MSCs2	PL for 24 h	50 mL/L PL
[35]1	Mouse	Iliac crest BM	50 mL/L PL	BCP + 4 × 106 MSCs	A	80 mL/L PL

¹No FCS was used at any stage of investigation;

²MSC number not reported. MSCs: Mesenchymal stem cells; BM: Bone marrow; PL: Platelet lysate; BCP: Biphasic calcium phosphate; A: Absent; DEX: Dexamethasone; FCS: Fetal calf serum; NR: Not reported; HA + β-TCP: Hydroxyapatite/beta-tricalcium phosphate.