Comparison of In Vitro and In Situ Methods for Studying Lipolysis

Table 1

Advantages and limitations of some experimental methods for studying lipolysis.

Method	Advantages	Limitations
Culture of preadipocyte cell lines and differentiated stroma-vascular cells	Provides abundant supply of homogeneous cells; Suitable for screening agents for their possible lipolytic or antilipolytic activities; Appropriate for long-term in vitro studies; Suitable for studying molecular mechanisms and transcription factors involved in lipolysis process	It takes several days until the cells become ready for study; The cells may not fully differentiate to adipocytes; Differentiation capacity decreases with increasing number of passages; Excludes nervous system and endocrine system effects, therefore results may not fully reflect in vivo condition; Glycerol reagent should be highly sensitive
Primary culture of adipocyte	Most of isolated adipocytes are fully differentiated; A rapid method for testing acute effect of compounds; Suitable for screening agents for their possible lipolytic or antilipolytic activities; Comparative use of adipocytes from different depots	Need to high n number to resolve interindividual variations; Need for enzymatic digestion; Loss of hormone sensitivity and gene expression in long-term culture; High variability in results obtained from freshly isolated cells; Excludes nervous system and endocrine system effects; Glycerol reagent should be highly sensitive
Organ culture of adipose tissue	Preserves extracellular matrix and paracrine interactions; Good correlation with in vivo studies; Useful for chronic lipolysis studies; Suitable for assessing the long-term regulation of gen involved in the lipolysis pathways; Comparative use of adipocytes from different depots	Presence of multiple cell types in tissue complicates interpretation of molecular mechanisms of tested drug; Excludes nervous system and endocrine system effects
Microdialysis of adipose tissue	Preserves extracellular matrix and paracrine interactions; Preserves nervous system and endocrine system effects; Enables continuous monitoring of lipolysis; Allows study of adipose tissue response during systemic drug administration	Its application on human is restricted to subcutaneous fat depot; It is time consuming and uncomfortable for the patients