TABLE 8.

Methodology of studies investigating the association between RBP4 and TNF-α¹

Cytokine	Study design	Study population	Sex	Age,2 y	Study size, n	Cytokine measurement method	RBP4 measurement method	Analysis	Relation	RBP4 specimen	Authors, year (ref)
TNF-α	CC	Patients with T2D	62 M; 75 F	30–60	137	ELISA	ELISA	Correlation	+	Serum	Al-Daghri et al., 2009 (35)
TNF-α	CS	Obese and nonobese T2D patients with NIGT	164 M; 69 F	48.3 ± 1.8 to 63.2 ± 3.1	233	ELISA	Gene expression	Multivariant regression	+	Adipose biopsy	Erikstrup et al., 2009 (71)
TNF-α	CS	Obese and nonobese T2D patients with NIGT	164 M; 69 F	48.3 ± 1.8 to 63.2 ± 3.1	233	Muscle gene expression	Gene expression	Multivariant regression	+	Adipose biopsy	Erikstrup et al., 2009 (71)
TNF-α	CS	Obese and nonobese T2D patients with NIGT	164 M; 69 F	48.3 ± 1.8 to 63.2 ± 3.1	233	Adipose gene expression	Gene expression	Multivariant regression	None	Adipose biopsy	Erikstrup et al., 2009 (71)
TNF-α	CS	Obese and nonobese T2D patients with NIGT	164 M; 69 F	48.3 ± 1.8 to 63.2 ± 3.1	233	Muscle gene expression	RBP or retinol or the RBP-to-retinol ratio (ELISA)	Multivariant regression	None	Plasma	Erikstrup et al., 2009(71)
TNF-α	CS	Chinese	910 M; 838 F	50–70	1748	Milliplex (Millipore) human cytokine panel	ELISA	Correlation	+	Plasma	Liu et al., 2014 (50)
TNF-α	CS	Nonobese, nondiabetic patients with CKD	165 M; 69 F	44–80	15	mRNA level	ELISA	Correlation	+	Plasma	Barazzoni et al., 2011 (66)
TNF-α/IL-10	CS	Nonobese nondiabetic CKD patients undergoing MHD treatment	910 M; 838 F	44–80	15	mRNA level	ELISA	Correlation	+	Plasma	Barazzoni et al., 2011 (66)
sTNFR1,2	CS	Healthy obese subjects	29 M; 18 F	45 ± 9.3	63	Sandwich ELISA	Nephelometry	NM	None	Serum	Broch et al., 2010 (67)
TNF-α	CS	Healthy Swedish men	M	58	100	ELISA	Western blot	Correlation	−	Serum	Wallenius et al., 2011 (69)
sTNFR1,2	CS	Healthy Swedish men	M	58	100	ELISA	Western blot	Correlation	None	Serum	Wallenius et al., 2011 (69)
TNF-α	CC	66 NT or 92 HT patients	111 M; 47 F	49	66	ELISA	ELISA validated by Western blot	Correlation	None	Plasma	Solini et al., 2012 (51)

¹CC, case-control; CKD, chronic kidney disease; CS, cross-sectional; F, female; HT, hypertensive; M, male; MHD, maintenance hemodialysis; NIGT, normal or impaired glucose tolerance; NM, not mentioned; NT, normotensive; RBP, retinol binding protein; RBP4, retinol binding protein 4; ref, reference; sTNFR1,2, soluble TNF-α receptors 1 and 2; T2D, type 2 diabetes; +, positive; −, negative.

²Values are ranges, means ± SDs, or medians.