Injuries and disease can now be treated by regeneration of tissues and organs, which are undoubtedly path breaking approaches that are also increasingly referred to as tissue engineering or regenerative medicine.
Selective cell drug delivery to the cardiovascular system optimizes the therapeutic efficacy of the treatment as for example potential repair by cell grafting. Specific cell therapy approaches include efforts to restart cardiomyocyte proliferation or conversion of bone marrow stem cells into cardiomyocytes.
Substitutes for electronic pacemakers
Thousands of people have irregular heartbeats which need implanted devices like pacemakers to make the heart beat return to normal. Recent research suggests that defective heart rhythms in animals as for example pigs can be brought back to normal, using specialized proteins and gene delivery systems. This raises the possibility that in the future patients could use bioengineered cells and therefore may not have to depend upon the use of implanted devices like pacemakers.
The basis of this emerging technology is to make the cells of the heart muscle to produce bioengineered HCN channels as for example when heart muscle of pigs is impinged with a gene encoding a bioengineered cell-surface protein. These HCN ion channels regulate the flow of sodium and potassium ions in and out of cells and which are ultimately responsible for electrical impulses which in turn results in even paced heartbeat.
The right atrium, which is the upper right chamber of the heart, receives deoxygenated blood from the body and it is here that the SA node can be found. The sinoatrial node creates the cardiac rhythms responsible for pumping blood. When this node malfunctions it could cause irregular heart beat. When the heart muscles start producing bioengineered HCN channels it leads to reconstruction of SA nodes and therefore implanted pacemakers can be avoided.
New heart using biotechnology
Research in biotechnology in the domain of organ-building has reached a state that it's possible to use stem cells to make transplantable hearts using a technique called organ decellularization. This means that theoretically an immunologically similar heart can be regenerated from a patient's own stem cells, and therefore could be of use to millions of people with prospects of possible heart failure and those who are in need of transplantation.
Decellularization process involves washing away the remnants of heart cells (at present done in animal cadaver hearts) leaving back the scaffold of tubes that earlier constituted the organ's blood vessels. By injecting this scaffold with progenitor cells from newborn animal hearts, new organ tissues could be grown and the heart can start working normally within eight days.
In a variant form of this technology, the leading biotech company Cytori is currently clinically evaluating adipose-derived stem and regenerative cells to treat acute myocardial infarction and chronic myocardial ischemia .
Cardiac markers facilitate early diagnosis and prevention of cardiac diseases. For example, the release of troponin is specific indicator for myocardial damage. Similarly, a high Lactase dehydrogenase-1 and lactase dehydrogenase-2 means myocardial infarction. CK-MB or creatine kinase test is considered as the gold standard amongst all cardiac biomarkers and is specific in the absence of skeletal muscle damage. Other biomarkers lack diagnostic efficiency but make it up by being more cardiospecific. Similarly aspartate transaminase, myoglobin, ischemia modified albumin, pro-brain natriuretic peptide, glycogen phosphorylase isoenzyme BB, are all cardiac markers.
Now the question arises why are cardiac markers relied upon? That's because a conventional ECG has only sensitivity in the range 55-75% when it comes to diagnosing myocardial infarction and hence cardiac markers such as Creatine kinase-MB isoenzyme, troponins and myoglobin come into play.
Apart from the role of biotechnology in improving surgical procedures and medicines in cardiac care the abundance of genomic information from tissue-specific sequencing projects is also of interest. For example the subject of molecular cardiovascular medicine has originated from cardiovascular tissue oriented database of genomic information.
As a matter of fact, the abundance of expressed sequence tags (ESTs) from different cDNA libraries of the cardiovascular system helps in studying diseased cardiovascular tissue across different population segments.
Molecular imaging is considered to be clinically useful as it has increased diagnostic sensitivity and brings out the underlying biological basis of disease as compared to anatomy or physiology-based imaging. In cardiovascular field it could help in selecting a drug that suits a patient's genome, or for other purposes such as for example, a doctor can have insight into the possibility of whether a patient with severe atherosclerotic plaques would eventually get a stroke or infarction.
Now smaller molecules such as antibody fragments or carbohydrates derived from biochemical screens with better molecular specificity are used in cardiovascular molecular imaging studies as compared to earlier use of radioisotope-derivatized monoclonal antibodies.
Considering the progress of biotechnology in the domain of cardiac care, in the future, one can expect gene therapy to be commonplace not only because it would be affordable, but also because a patient can forego the rigors associated with implanted stents and bypass surgery.
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