title: Impact of diabetes in blood-testis and blood-brain barriers: resemblances and differences.
abstract: Blood-tissue barriers prevent an uncontrolled exchange of large molecules between adjacent but metabolically separated compartments. There are several known barriers and two of the most important and tightest blood-tissue barriers are the blood-testis barrier (BTB) and the blood-brain barrier (BBB). Under normal conditions these barriers, formed by tight junctions between adjacent cells, control the entry of substances and metabolites. However, hyperglycemia and other diabetes-related complications, such as hypertension, impair the function of these biological barriers with dramatic consequences. Although both, BBB and BTB, are responsible for the maintenance of different biological processes, they have some remarkable similarities not always explored when looking at metabolic-related diseases such as diabetes. These barriers possess their own glucose sensing machinery, suffer a tied hormonal control and have specific mechanisms to counteract hyper- and hypoglycemia. In BBB and BTB the insulin signaling is also distinct from other tissues and organs thus evidencing their importance in protecting against or exacerbating the effects of diabetes on glucose metabolism. The control of glucose and lactate levels in brain and testis highlights the role of these barriers in protecting against peripheral glucose and lactate fluctuations that occur in the diabetic individual. We review the role of BBB and BTB in the control of glucose and metabolic dysfunction caused by diabetes in the brain and seminiferous epithelium. Gaining a better understanding of the molecular mechanisms through which glucose metabolism disrupts BBB and BTB function may highlight new opportunities for the treatment of diabetic complications in brain and male reproductive function.
authors.affiliation: CICS-UBI –Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal. alvesmarc@gmail.com
authors.forename: Marco G
authors.initials: MG
authors.lastname: Alves
authors.forename: Pedro F
authors.initials: PF
authors.lastname: Oliveira
authors.forename: Silvia
authors.initials: S
authors.lastname: Socorro
authors.forename: Paula I
authors.initials: PI
authors.lastname: Moreira
mesh_terms: D000818:Animals; D001692:Biological Transport; D001812:Blood-Brain Barrier / Q000503:physiopathology*; D001814:Blood-Testis Barrier / Q000503:physiopathology*; D048909:Diabetes Complications / Q000097:blood / Q000503:physiopathology*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000503:physiopathology*; D051272:Glucose Transporter Type 1 / Q000097:blood; D051274:Glucose Transporter Type 3 / Q000097:blood; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology*; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000503:physiopathology*; D051381:Rats; D012670:Seminiferous Epithelium / Q000473:pathology; D019108:Tight Junctions
chemical_list: D051272:Glucose Transporter Type 1; D051274:Glucose Transporter Type 3