Brain Disorders: Blood Brain Barrier Essay

There are many expecting mothers who suffer from serious mental illnesses like schizophrenia, bipolar disorder, or borderline personality disorder that requires they must take antipsychotic drugs to remain stable. There are different types of antipsychotics like typical and atypical. Typical antipsychotics are classified as the first generation of antipyschotics. The atypical antipsychotics, the second generation, are reported to be safer than the typical antipsychotics because they are the newer form of antipsychotic medication. Even though they are reported to be safer, they still have severe side effects on the individual consuming it, like tardive dyskinesia, which are uncontrollable movements of the mouth (McCauley et al., 2009). Some drugs can affect the fetus by transferring to the blood-brain barrier. The blood-brain barrier is a permeable barrier that allows some chemicals to pass through. It separates the circulating blood from the brain extracellular fluid in the central nervous system. The blood-brain barrier also transports molecules to the brain that are essential to function properly, like glucose and amino acids. Since capillary endothelial cells, which line the whole circulatory system, form the blood-brain barrier the medication could be transported to the fetus. From

Impaired cerebral blood flow disorders are extremely common and factors such as the lesion site, existing collateral’s, and the amount of tissue affected determines the actual neurological deficit that results. The impaired blood flow may have a number of causes. Things such as alterations in blood pressure, changes in the arterial walls, and occlusions of the arterial lumen are some of the more important causes.

Furthermore, the protective properties of APP are often correlated with its functions of synaptic formation and repair and iron transport and

Alzheimer’s. Parkinson’s. Brain Tumor. Hear any one of these triad of diseases and almost certainly, you diagnose yourself with an untimely death. And why should you not? A large percentage of the time, brain diseases are not curable, and treatment options remain very limited to none at all. However, thanks to a team at Sunnybrook Health Sciences Centre in Toronto, the possibility of a huge breakthrough in neurological treatment may be imminent. Under the leadership of Todd Mainprize, MD and Kullervo Hynynen, PhD, this team has astoundingly broken the blood-brain barrier(BBB).

The blood-brain barrier (BBB) is a multifunctional interface separating the bloodstream from the brain interior. This barrier is crucial for maintaining brain homeostasis and allowing proper neuronal function, as well as for protecting the CNS from potentially harmful agents in the blood. The onset of BBB properties takes place during embryonic development as a microenvironment of neural stem cells, pericytes, and neurons provide developmental cues for induction of tight junctions and regulation of molecular permeability in developing endothelial cells. In adults, blood-brain barrier maintenance is a result of composite interactions between brain endothelial cells and resident neural cell types including astrocytes, pericytes, and neurons.

The blood brain is the bodies own security system, a network of blood vessels that allows certain substances to enter while blocking others. The barrier protects against the passage of harmful foreign substances such as viruses, bacteria and toxins but can also dictates how life-saving drugs are formulated, as they must penetrate this barrier to be effective.

When it comes to the blood-brain barrier I think of it as a protective layer that only lets a small portion of substances past it because it wants to protect the brain as much as it can. The blood-brain barrier is semi permeable making it selective to what passes through. In the brain it has capillaries but they are not like the normal capillary that are pours due to spaces between the endothelial cells. The capillaries in the brain are surrounded by endothelial cells that are sealed by tight junctions and a thick basement membrane. The brain barrier then has cells called astrocytes that press firmly against the basement secreting chemicals that adjust the capillary permeability. The blood-brain barrier is there to protect the brain from pathogens

The BBB is not only a physical barrier, but also a physiological barrier separating the brain and the cerebrospinal fluid (CSF) from the blood circulating through the rest of the body (Braniste et al., 2014; Engelhardt & Sorokin, 2009). This barrier is a result of the presence of endothelial cells that line the microvascular structures in the brain as well as astrocytes, pericytes, neurons, and an extracellular matrix, all of which induce a physiology that separates the brain from blood (Braniste et al., 2014; Engelhardt & Sorokin, 2009; Persidsky, 2013). Due to the different components, the BBB

The age-old problem with the use of proteins to treat neurodegenerative diseases is that they are large, partially polar and often labile entities that, when injected, can aggregate, misfolded and tolerated other changes that render them biologically ineffective or worse. Moreover more problematic for CNS indications, they do not readily cross the blood–brain barrier and, when injected directly into the brain, do not spread significantly from the point of injection, thus reducing their exposure to the targeted tissue, which greatly decreases their therapeutic effect, finally, when protein delivery is mistargeted, significant side effects can occur (17-20). Gene therapy (gene transfer) refers to the use of a modified viral vector to introduce genetic information to site specific host cells to induce targeted, long-term,

theranostic approaches combining molecular imaging and in situ drug delivery. Targeting the cellular and molecular components that

Brain is highly metabolic and important organ of the body. Even though it weighs only 2% body weight, however, requires disproportionate amount (~20 %) of the total blood flow. Unprecedented fall in cerebral blood flow (CBF) would quickly lead to unconsciousness and, if sustained for longer period of time would result in brain damage and death. Therefore, CBF is tightly regulated in the brain, as it facilitates the delivery of essential substrates required for metabolism and removal of metabolic by products.

Neuroprotective activity of riluzole is already reported in the literature. At present, it is the only available successful drug for treating motor neuron disease like ALS. But its poor aqueous solubility, short half life with some side effects at higher concentration (as it is recommended twice or thrice a day for long time) restricted its use as a neuroprotective agent (Borderias-Clau, 2006; Cheah, 2010). In the present study, we have evaluated the neuroprotective activity of nanoriluzole (NR) for treating one of the most severe brain diseases at a quite low dose using nanocarrier. MCAO is one the best model for ischemic stroke as it mimic most of the feature of natural brain stroke (Longa, 1989; Heurteaux, 2006; Vaibhav, 2013). Ischemia was induced in rats through MCAO model for 1 hr followed by a reperfusion period of 24 hrs and NR was given intraperitonally after 1 hr of ischemia induction. Animals were evaluated for their behavior study and sacrificed to remove the brain for analysing various related parameters like infarct, biochemical, histopathology and immunohistochemical study.

     A few water soluble substances, like glucose, cross the brain blood barrier by active transport. Other substances like creatinine, vrea, and most ions, cross very slowly. Other substances and protions, including most antibiotic drugs, do not pass at all from the blood into brain tissue. Trauma, certain toxins, and inflammation, can all cause a breakdown of the Brain blood barrier.

The BBB evolved as an extremely tight barrier to protect the brain from potentially toxic compounds. Though it is an indispensable part of the Central Nervous System, its tightness makes delivering therapeutic drugs to the brain very difficult.

Due to the absence of Schwann cells in the central nervous system (CNS) and the formation of glial scar tissue (which when formed impedes the axon growth as well as myelination), the CNS is unable of self-regeneration or repair of the neurons that are damaged or lost owing to a disease without additional clinical therapy [3]. Ideal goal for PD investigation & therapy involves three major aspects. First, the need of a reliable biomarker for early, pre-symptomatic diagnosis [4]. Second, to improve the drug delivery to the brain across the blood-brain barrier [5]. Third, to facilitate & promote the functional regeneration of the damaged neurons [4]. This review focusses on the use of nanotechnology for the ‘third aspect’ of treatment of PD mentioned above. Also, it briefly summarizes the mechanism by which nanoparticles are used for efficient drug delivery across the BBB.