Insulin-like growth factor 1 and 2 (IGF1, IGF2) expression in human microglia: differential regulation by inflammatory mediators

Table 1 IGF1 expression in human brain

Pathology	Case number	Microglia	Multinucleated giant cells	Microglial nodules	Inflammatory cells^a	Vessels and meninges^b	Other^c
HIV encephalitis ^d	Case 23	+	+	+	±	+	ependyma
	Case 1	+	+	−	+	+	ependyma
	Case 3	±	+	−	+	+	−
	Case 20	+	+	+	+	+	ependyma, neurons
	Case 22	+	+	+	+	+	−
	Case 9	+	+	+	±	+	−
No encephalitis ^e	Case 11 (HIV+)	+	NA ^f	NA ^f	NA ^f	+	−
	Case 12 (HIV+)	+	NA ^f	NA ^f	NA ^f	+	−
	Case 21(HIV+)	+	NA ^f	NA ^f	+	+	astrocytes
	Case 18 (HIV−)	+	NA ^f	NA ^f	NA ^f	+	neurons

^aInflammatory cells were mononuclear cells (lymphocytes, monocytes and macrophages) present in the brain parenchyma or in perivascular spaces; ^bIGF1 immunoreactivity was regularly associated with vessels in both brain parenchyma and meninges. Staining was present in smooth muscle cells, as well as in some endothelial cells. Some meningeal arachnoid cells and macrophages were also occasionally IGF1 positive; ^cOther parenchymal IGF1positive cells included ependymal cells, occasional astrocytes or rarely even neurons; ^dHIV encephalitis sections had characteristic pathology on H&E consisting of MGCs, microglial nodules, activated microglia and macrophages, and mononuclear inflammatory cell infiltration; ^eControl brain sections had no significant pathology on H&E;
^fNA (not applicable, since no inflammatory cells were present).

ISSN: 1742-2094