TABLE 1.

Embryoids and stem cell models.

Types	Initial cells	Characteristics	Methods	References
Embryoid bodies (EBs)	Mouse clonal pluripotent	Identical to intraperitoneal teratocarcinomas, which	Cultured without feeder cells	Martin and Evans, (1975)
	Teratocarcinoma cells	Consist of an inner core of embryonal carcinoma cells surrounded by a layer of endodermal cells
Embryoid bodies (EBs)	HESCs	Comprise three embryonic germ layers	Suspension, without LIF, and bFGF	Itskovitz-Eldor et al. (2000)
Blastoids	mESCs, mTSCs	Structures that morphologically and transcriptionally resemble embryonic Day 3.5 blastocysts	Sequential aggregation of ESCs and TSCs in microwells	Rivron et al. (2018)
Blastoids	mEPSCs (LCDM-EPSCs and Liu’s EPSCs)	Mouse blastocyst-like structures in terms of morphological and can be implanted to induce decidua formation	3D differentiation system with 2:1:1 mixture of KSOM, TSC basal and N2B27 basal medium to support the growth both ESC and TSC aggregates	Li et al. (2019)
Blastoids	mEPSCs, mTSCs	All three blastocyst lineages in blastocyst-like structures	Compacted amorphous EPSC aggregates plus TSCs in microwell-based system using sequential changes of different media under hypoxic culture conditions	Sozen et al. (2019)
Blastocyst-like cyst (iBLs)	MPSCs	A blastocoel-like cavity and outer cells expressing trophectoderm lineage markers and inner cells expressing implantation-competent pluripotency markers	Combination of LIF, BMP4, LPA, and AA converts mouse primed PSCs into iBLC PCs and produces iBLCs	Kime et al. (2019)
Human-blastoids	naïve hPSCs	Resemble human blastocysts in terms of morphology, size, cell number, and composition and allocation of different cell lineages	3D culture coupled with sequential treatment of WIBR3 cells with HT or TH method	Yu et al. (2021)
Blastoids	naïve hPSCs	Consist of three tissue layers displaying exclusive lineage markers, which mimics the natural blastocyst	brief induction of TE by modulating PD + A83 treatment	Yanagida et al. (2021)
iBlastoids	HiPSCs	Model the overall architecture and transcriptomic profiles of blastocysts and, ICM-like, Epi-like and PrE-like structures and cells	Transfer of a reprogramed and mixed cell population in 3D culture and a medium that sustains the early developmental signatures	Liu et al. (2021)
Human EPS-blastoids	HEPSCs	Resemble human blastocysts in terms of morphology, the expression of markers specific for 3 cell lineages, and global transcriptome signatures	3D, two-step differentiation protocol	Fan et al. (2021)
Gastruloids	mESCs	Multicellular models of a gastrulating embryo	Small aggregates of mESCs, of approximately 300 cells	van den Brink et al. (2014)
Gastruloids	hESCs	Recapitulate the embryonic arrangement of the mammalian germ layers	Colonies of hESCs grown on micropatterned substrate and differentiated with BMP4	Etoc et al. (2016)
Gastrulation-like	hESCs	Colonies reproducibly differentiated to an outer trophectoderm-like ring, an inner ectodermal circle and a ring of mesendoderm expressing primitive-streak markers in between	Geometric confinement of colonies and response to BMP4	Warmflash et al. (2014)
Human pregastrulating epiblast	hESCs	Display a similar size range, morphology and tissue polarity that match those of epiblasts of in vitro attached Day 10 human embryos	Dispersedly dissociated hESCs as single cells in Matrigel and in culture under pluripotency conditions	Simunovic et al. (2019)