Pericyte degeneration leads to neurovascular uncoupling and limits oxygen supply to brain.

Pericytes are perivascular mural cells of brain capillaries. They are positioned centrally in the neurovascular unit between endothelial cells, astrocytes and neurons. This position allows them to regulate key neurovascular functions of the brain. The role of pericytes in the regulation of cerebral blood flow (CBF) and neurovascular coupling remains, however, under debate. Using loss-of-function pericyte-deficient mice, here we show that pericyte degeneration diminishes global and individual capillary CBF responses to neuronal stimuli, resulting in neurovascular uncoupling, reduced oxygen supply to the brain and metabolic stress. Neurovascular deficits lead over time to impaired neuronal excitability and neurodegenerative changes. Thus, pericyte degeneration as seen in neurological disorders such as Alzheimer's disease may contribute to neurovascular dysfunction and neurodegeneration associated with human disease.

Imaging Diagnosis of Herlyn-Werner-Wunderlich Syndrome- An Extremely Rare Urogenital Anomaly.

Herlyn-Werner-Wunderlich (HWW) syndrome is a very rare congenital anomaly of the urogenital tract resulting from maldevelopment of both Mullerian and Wolffian ducts. It is characterized by the triad of uterus didelphys, obstructed hemivagina and ipsilateral renal agenesis. It generally presents at puberty shortly following menarche with the symptom of acute pelvic pain. Management of these cases is surgical and consists mainly of vaginoplasty with excision of the vaginal septum in order to release the obstruction and prevent the long term complication of recurrent pyocolpos and infertility. We report here a case of Herlyn-Werner-Wunderlich syndrome in a 13-year-old adolescent girl, emphasizing the role of imaging in the accurate and prompt diagnosis of this rare developmental urogenital anomaly. Only a few hundred such cases have been reported in literature till date.

Central role for PICALM in amyloid-ß blood-brain barrier transcytosis and clearance.

PICALM is a highly validated genetic risk factor for Alzheimer's disease (AD). We found that reduced expression of PICALM in AD and murine brain endothelium correlated with amyloid-ß (Aß) pathology and cognitive impairment. Moreover, Picalm deficiency diminished Aß clearance across the murine blood-brain barrier (BBB) and accelerated Aß pathology in a manner that was reversible by endothelial PICALM re-expression. Using human brain endothelial monolayers, we found that PICALM regulated PICALM/clathrin-dependent internalization of Aß bound to the low density lipoprotein receptor related protein-1, a key Aß clearance receptor, and guided Aß trafficking to Rab5 and Rab11, leading to Aß endothelial transcytosis and clearance. PICALM levels and Aß clearance were reduced in AD-derived endothelial monolayers, which was reversible by adenoviral-mediated PICALM transfer. Inducible pluripotent stem cell-derived human endothelial cells carrying the rs3851179 protective allele exhibited higher PICALM levels and enhanced Aß clearance. Thus, PICALM regulates Aß BBB transcytosis and clearance, which has implications for Aß brain homeostasis and clearance therapy.