Oxysterols as promising small molecules for bone tissue engineering: Systematic review

Table 4 Summary of unique oxysterols investigated for in vivo bone tissue engineering in animal models

Oxysterol name	Change from cholesterol1	Effect on in vivo bone formation (defect model)	Ref.
20(S)-OHC	OH group at C20(S)	Increase2 (alveolar and calvarial)	Aghaloo et al[17], 2007; Hokugo et al[30], 2014; Lee et al[35], 2017; Cui et al[34], 2017; Bakshi et al[37], 2019; Huang et al[38], 2019
22(R)-OHC	OH group at C22(R)	Increase2,3 (alveolar)	Bakshi et al[37], 2019
22(S)-OHC	OH group at C22(S)	Increase2,3 (calvarial)	Aghaloo et al[17], 2007
Oxy4/Oxy34	OH group at C20(S), single bond between C5 and C6, OH group at C6(S)	Increase2 (spinal fusion)	Johnson et al[21], 2011; Stappenbeck et al[20], 2012
Oxy18	OH group at C20(S), single bond between C5 and C6, OH group at C6(S), deuterated carbons at C22 and C23	Increase4 (spinal fusion)	Stappenbeck et al[20], 2012
Oxy21/Oxy133	OH group at C20(S), single bond between C5 and C6, OH group at C6(S), n-hexane at C20(S)	Increase2 (spinal fusion, calvarial)	Stappenbeck et al[20], 2012; Montgomery et al[19], 2014; Scott et al[31], 2015; Li et al[36], 2015; Buser et al[33], 2017
Oxy49	OH group at C20(S), single bond between C5 and C6, OH group at C6(S), double bond between C25 and C27	Increase2 (spinal fusion, calvarial)	Johnson et al[21], 2011; Hokugo et al[32], 2016

¹(S) and (R) denote stereoisomerism. Refer to Figure 3 for molecular structures.

²Statistically significant relative to control.

³Used in combination with 20(S)-OHC.

⁴Significantly greater bone formation relative to Oxy4/Oxy34 (internal positive control). OHC: Hydroxycholesterol.