Table 1.

Major diseases and conditions associated with an increased intestinal permeability.

Disease/Condition	Paracellular Permeability	Transcellular Permeability	Uncategorized Permeability Changes
Inflammatory bowel disease	in vivo; altered expression and distribution of tight junction proteins [5]; ex vivo, increased passage of paracellular probes [6,7]	ex vivo; augmented mucosal passage of bacteria and horseradish peroxidase (HRP) [6,7,8]	in vivo; increased urinary secretion of probes [9]
Irritable bowel syndrome	altered expression of tight junction proteins [10]; ex vivo; increased passage of paracellular probes [1,2].	ex vivo; increased transepithelial passage of bacteria and HRP [11]	in vivo; increased urinary secretion of probes [12]
Celiac disease	in vivo: altered structure of tight junction proteins [13,14] ex vivo; increased passage of paracellular probes [15]; alteration in electrophysiological parameters [16]	ex vivo; augmented internalization of bacteria [17]; increased transcellular uptake of gliadin [18]	in vivo; increased urinary secretion of probes [15,19], increased levels of zonulin in blood [20]
Obesity	in vivo; altered expression of tight junction proteins [3]	ex vivo; increased lipid-induced transcellular permeability [3]	in vivo; increased levels of zonulin and lipopolysaccharide (LPS) in blood [3]
Diabetes type 2	-	-	in vivo; increased urinary secretion of probes [4]; increased levels of LPS [21] and zonulin [22] in blood
Alzheimer’s disease	-	-	in vivo: increased LPS [23] and zonulin levels in blood [24]
Parkinson disease	-	ex vivo: augmented uptake of bacteria [2]	in vivo: increased urinary secretion of probes [2]; increased blood zonulin levels [25]
Major depression disorder	-	-	in vivo: increased permeability markers in blood, I-FABP and zonulin [26]
Autism spectrum disorders	in vivo: altered expression of tight junction proteins [27]	-	in vivo: increased levels of zonulin [28,29]