Tag Archives: Aplastic anemia

Banking on Stem Cells


Advertisements in the media advise parents to “plan and protect your children’s future and their health status”. These are not commercials for insurance plans, but private stem cell banking facilities, where, for a steep price, your baby’s umbilical cord stem cells can be preserved for future use.
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Stem cells are in the news. Independent national and international laboratories are making claims and counterclaims about the “miracles” they have achieved with them. Paralysed people have been able to walk, rare degenerative nervous and muscular system diseases been reversed, and some cancers of the blood cells cured. People with terminal illnesses have also been offered hope…..click & see

Actress Lisa Ray underwent stem cell therapy for multiple myeloma, a cancer of the white blood cells...click & see

Stem cells may be embryonic, adult or derived from umbilical cords. Embryonic stem cells are obtained from the extra fertilised eggs at in vitro fertilisation (IVF) centres. The use of these cells is controversial, as, theoretically, they have the potential to become human beings. They are the “spare babies” belonging to a particular IVF couple. When supplied to a stem cell research facility, they are grown in a nutrient broth in a culture dish and used for research or treatment.

Adult stem cells are found in bone marrow. These are harvested from the bone marrow of living donors. It’s a surgical procedure done under anaesthesia with some post-operative discomfort. The cells are capable of eventually forming either various types of blood cells or stromal cells from which cartilage and fat tissues arise.

Haematologists treat a variety of hereditary blood disorders and some of the blood cancers with either autologous (the person’s own) stem cells or compatible donor cells from bone marrow transplants. This technology has been used for the last 30 years. Bone marrow transplants are life saving for people with certain blood cancers. They can also be used for serious blood disorders such as aplastic anaemia. They can also help boost the immune system if it is impaired because of an inherited genetic defect or destroyed by cancer.

Umbilical cords are a rich and non-controversial source of stem cells. Cord blood has a greater ability to generate new blood cells than does bone marrow. Also, smaller quantities of cord blood cells are needed for successful transplantation. These cords are normally discarded along with the placenta from labour wards all over the world.

At present, in India, patients who require stem cell treatment or a bone marrow transplant have to search for a relative who is an appropriate tissue match. Sometimes even close first-degree relatives like a parent or sibling are not compatible. India does not as yet have a centralised national bone marrow registry to match recipients and donors.

Some foresighted countries with efficient national health schemes like the United Kingdom and Brazil do have public cord blood banks. Blood is screened for infective agents, documented in a registry and stored. The chances of finding compatible stem cells are high because of the large volumes stored.

India has private cord blood banks which store blood only for the use of that particular child for a period of 21 years. It may be a cost effective option for parents who have a family history of certain genetic diseases, such as severe hereditary anaemias, immune disorders or certain cancers. Even then, the chance that the blood can be used for that particular child is only 1 in 2,000. In families with no such risk factors, there is only about a 1-in-20,000 chance of the child ever needing a stem cell transplantation. Also, even if the child does require a stem cell transplant, it is unlikely that his or her own cord blood would be the desired source of stem cells. The same chromosomal or genetic defect causing the leukaemia, any other cancer or metabolic disorder, is likely to be present in the child’s stem cell line. There is no proof that a transplant using the child’s own stem cells is effective or even safe, especially in cases of childhood cancers.

Indians have a very diverse genetic make-up. The large-scale collection and storage of cord blood in public banks will be very useful. It can be used for matched unrelated recipients who urgently need blood cell transplants.

Stem cells are probably the future of medicine and the human race. They are multifaceted and have the potential to develop into different cell types. They can theoretically keep dividing as long as the person is alive. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another specialised cell like a muscle cell, red blood cell, or brain cell. This means stem cells can be infused as a sort of emergency repair mechanism to replenish damaged tissues.

Perhaps disease, aging, cancer and even death can be controlled and conquered. And living healthily forever may become a reality.

Source
:The Telegraph (Kolkata, India)

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Clean Living ‘Slows Cell Ageing’

Taking more exercise and eating the right foods may help increase levels of an enzyme vital for guarding against age-related cell damage, work suggests.
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Among 24 men asked to adopt healthy lifestyle changes for a US study in The Lancet Oncology, levels of telomerase increased by 29% on average.

Telomerase repairs and lengthens telomeres, which cap and protect the ends of chromosomes housing DNA.

As people age, telomeres shorten and cells become more susceptible to dying.

It is the damage and death of cells that causes ageing and disease in people.

Several factors such as smoking, obesity and a sedentary lifestyle are associated with shorter-than-average telomeres.

Professor Dean Ornish, from the Preventive Medicine Research Institute in California, and his team wanted to find out if improvements in diet and lifestyle might have the opposite effect.

They asked 30 men, all with low-risk prostate cancers, to take part in a three-month trial of comprehensive lifestyle changes.

These consisted of a diet high in fruit and vegetables, supplements of vitamins and fish oils, an exercise regimen and classes in stress management, relaxation techniques and breathing exercises.

Telomerase activity was measured at the beginning of the trial and again at the end.

Among the 24 men who had sufficient data for analysis, blood levels of telomerase increased by 29% on average.

Increases in telomerase activity were linked with decreases in “bad” LDL cholesterol and decreases in one measure of stress – intrusive thoughts.

The researchers say it is too early to tell if the boost in telomerase levels will translate to a change in telomere length.

But there is evidence to suggest that telomere shortness and low telomerase activity might be important risk factors for cancer and cardiovascular disease.

“This might be a powerful motivator for many people to beneficially change their diet and lifestyle,” they told The Lancet Oncology.

Professor Tim Spector, from King’s College London, who has been researching ageing and telomeres, said: “This work builds on what we already know.

“Lifestyle can affect your telomeres. It would be interesting to find out whether it is diet, stress or both that is important.”

“This might be a powerful motivator for many people to beneficially change their diet and lifestyle ”

The study authors

Source: BBC NEWS:15th. Sept. ’08

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Cytopenia

DEFINITION:

Cytopenia is a reduction in the number of blood cells. It takes a number of forms:
*Low red blood cell count: anemia.
*Low white blood cell count: leukopenia or neutropenia (because neutrophils make up at least half of all white cells, they are almost always low in leukopenia).
*Low platelet count: thrombocytopenia.
*Low granulocyte count: granulocytopenia
*Low red blood cell, white blood cell, and platelet counts: pancytopenia..

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Blood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell.

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Cancer patients may frequently develop cytopenia, a disorder in which the production of one or more blood cell types ceases or is greatly reduced. Cancer and chemotherapy used to treat cancer, and sometimes radiation therapy, may sometimes cause cytopenia.

TYPES:
A deficiency of red blood cells which  is called anemia; a deficiency of white blood cells, or leukocytes, leukopenia or neutropenia (neutrophils make up over half of all white blood cells); and deficiency of platelets is called  thrombocytopenia.

Pancytopenia is the deficiency of all three blood cell types and is characteristic of aplastic anemia, a potentially life-threatening disorder that requires a stem cell transplant.

Blood Cells
The blood consists of three different  types of cells: red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. Erythrocytes contain hemoglobin, the protein that carries oxygen from the lungs to all cells in the body. Proper cell function depends on an adequate oxygen supply. When cells are oxygen deprived, organ function can be seriously impaired.

Leukocytes (white blood cells) protect the body against viral, bacterial, and parasitic infection and detect and remove damaged, dying, or dead tissues. Someone with a deficiency of white blood cells is extremely vulnerable to infection.

The term “leukocyte” refers to all six types of white blood cells; each plays a unique role in the immune system:

1. Basophils circulate in the blood and initiate the inflammatory response.
2.Eosinophils kill infecting parasites and produce allergic reactions.
3.Lymphocytes produce antibodies and regulate immune responses.
4. Mast cells are fixed in tissues and initiate the inflammatory response.
5. Monocytes capture infecting organisms for identification, ingest infecting organisms, and remove damaged or dying cells and cell debris. When monocytes become fixed in tissue, they are called macrophages.
6.Neutrophils identify and kill infecting organisms, and remove dead tissue.

Platelets are essential factors for blood clotting. Sudden blood loss triggers platelet activity at the site of the wound. Exposure to oxygen in the air causes platelets to break apart and combine with a substance called fibrinogen to form fibrin. Fibrin has a thread-like structure and forms a scab, or external clot, as it dries. Platelet deficiency causes one to bruise and bleed easily. Blood does not clot at an open wound, and there is greater risk for internal bleeding.

All blood cells have a lifespan: erythrocytes have a lifespan of about 120 days; leukocytes, 1 to 3 days; and platelets, approximately 10 days. The body continually replenishes the blood supply through a process called hematopoiesis.

Blood Cell Formation—Hematopoiesis, the formation and development of blood cells, occurs in bone marrow. Bone marrow is a nutrient-rich spongy tissue located mainly in the central portions of long flat bones (e.g., sternum, pelvic bones) in adults and all bones in infants.

All blood cells derive from blood-forming stem cells that reside in bone marrow. Stem cells replicate indefinitely and develop into mature, specialized cells. A hormone produced in the kidneys, erythropoietin, stimulates blood stem cells to produce all three types of blood cells.

CAUSES & RISK FACTORS:-

Chemotherapy and radiation therapy both reduce the number of blood-forming stem cells in cancer patients, but chemotherapeutic agents have a greater adverse effect because they suppress bone marrow function in several ways.The degree of damage is related to the particular drug(s) and the dose.

Chemotherapeutic agents can produce deficiencies in all blood cell types by

* damaging blood-forming stem cells,
* suppressing the kidneys? production of erythropoietin (hormone that stimulates blood cell production), and
* triggering red cell destruction (hemolysis) by inducing an immune response that causes the body to mistakenly identify erythrocytes as foreign bodies and destroy them.

Malignant tumors can cause anemia and other cytopenias when they directly invade bone marrow and suppress marrow function. Malignant cells also can migrate from tumors in other parts of the body to bone marrow. Tumors also can replace normal blood-forming stem cells with abnormal clones.

SIGN & SYMPTOMS:-

Anemia
A deficiency in erythrocytes reduces the amount of oxygen reaching all cells in the body, thus impairing all tissue and organ function. Severe fatigue is the most common symptom of anemia and is experienced by approximately 75% of chemotherapy patients. Patients find it more disabling than other treatment side effects, including nausea and depression.

Anemia also produces these symptoms:

* Confusion
* Dizziness
* Headache
* Lightheadedness
* Loss of concentration
* Pallor (pale skin, nail beds, gums, linings of eyelids)
* Rapid heart rate (tachycardia)
* Shortness of breath (dyspnea)

Neutropenia
Patients with a white blood cell deficiency experience frequent and/or severe bacterial, viral, and/or fungal infections; fever; and mouth and throat ulcers.

Complications—Bacteremia, the form of sepsis characterized by the presence of bacteria in the blood, can develop in immunocompromised patients who have neutropenia. Fever, rapid heart rate, and quick shallow breathing are signs of early sepsis, usually a reversible condition.

Untreated bacteremia can lead to severe sepsis, in which one or more organs become dysfunctional. Septic shock is severe sepsis with low blood pressure. The risk for death increases with the development of septic shock. Even aggressive treatment can fail to reverse the condition.

Thrombocytopenia
Platelet deficiency causes patients to bruise and bleed easily. Bleeding occurs most often in the mucous membranes lining the mouth, nose, colon, and vagina. Tiny reddish-purple skin lesions (petechiae), evidence of pinpoint hemorrhages, may appear on the skin or in the mouth.

Pancytopenia
Patients who are deficient in all blood cell types experience signs and symptoms associated with each, but bleeding from the nose and gums, and easy bruising usually appear first. Symptoms of anemia (e.g., fatigue, shortness of breath) are also common. Patients may look and feel well, otherwise, despite the seriousness of their condition.

Anemia
People with anemia (reduced red cell production) are advised to rest and eat foods high in iron (meat, fish, poultry, lentils, legumes, iron-enriched grains and flours).

If immediate remedy is necessary, treatment may include medication that helps restore the red blood supply and a transfusion of packed red blood cells.

Epoetin alpha (Epogen®, Procrit®)is a synthetic erythropoietin (normally produced by the kidneys) that stimulates stem cells to produce red blood cells. Restoration of the red blood cell supply with medication is gradual.

Darbepoetin alfa (Aranesp®) also stimulates red blood cell production but requires fewer doses and less disruption of daily living.

In March 2007, the Food and Drug Administration (FDA) issued a warning about these medications in response to studies indicating that they may increase the risk for blood clots, strokes, and heart attacks in some patients (e.g., patients who have kidney disease).

Thrombocytopenia
People with an abnormally low platelet count should avoid bruising or breaking the skin, and should carefully brush their teeth. A persistently decreased platelet count may be treated with a transfusion of platelets.

Neutropenia
The patient with a low white blood cell count is advised to  do the following:

*Avoid contact with people who are ill,
*Monitor closely for signs of infection (e.g., fever), and
*Take antibiotics when appropriate.

Medication, a colony-stimulating factor (CSF), may be prescribed to speed the development of white blood cells and shorten the period of susceptibility to infection.

Growth Factors
Growth factors are synthetic versions of substances involved in stimulating red and white blood cell production. Physicians exercise caution when prescribing these medications for people with tumors that involve the bone marrow, because growth factors might stimulate malignant cell growth.

These medications include the following:

Epoetin alpha (Procrit®, Epogen®; stimulates red blood cell production)
G-CSF (granulocyte colony-stimulating factor; e.g., filgrastim [Neupogen®]; stimulates neutrophil production)
GM-CSF (granulocyte-macrophage colony-stimulating factor; stimulates production of several white blood cells, including macrophages)

Leukocytes and other cells that contain granules are also called granulocytes.

Side effects
Fever, fatigue, dizziness, diarrhea, nausea, vomiting, weakness, and paresthesia (prickling sensation) are side effects associated with epoetin alpha.

Bone pain, malaise, headache, flu-like symptoms, muscle ache, redness at the injection site, and skin rash may occur with GM-CSF.

G-CSF commonly produces bone pain.

MEDICATIONS:-

Medications used to treat bacterial infection and other illnesses also can contribute to immune system suppression.

Some of these are :

* Antacids: cimetidine (Tagamet®)
* Antibiotics: chloramphenical (Chloromycetin®), sulfonamide (Thiosulfil®, Gantanol®); cephalosporin (Cephalaxin®), vancomycin (Vancocin®)
* Anticonvulsants: phenytoin/hydantoin (Dilantin®), felbamate (Felbatol®), carbamazepine (Tegretol®)
* Antimalarials: chloroquine (Aralin®)
* Antivirals: ganciclovir (Vitrasert®), zidovudine (AZT®)
* Cardiac drugs: diltiazem (Cardizem®), nifedipine (Procardia®), verapamil (Calan®)
* Diabetes drugs: glipizide (Glucotrol®), glyburide (Micronase®)
* Hyperthyroid drug: propylthiouracil
* NSAIDs (nonsteroidal anti-inflammatory drugs): phenylbutazone (Butazolidine®), indomethacin (Indocin®, Indochron E-R®)—Due to potentially severe gastrointestinal and cardiovascular side effects, NSAIDs should only be used as instructed.
* Rheumatoid arthritis drugs: auranofin (Ridaura®), aurothioglucose (Solganal®), gold sodium thiomalate (Myochrisine®)

Bone Marrow and Stem Cell Transplantation:-
The treatment of choice for the pancytopenic patient with a matched bone marrow donor is stem cell transplantation. The goal of transplantation is to restore blood-forming stem cells to the marrow.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://www.oncologychannel.com/cytopenia/index.shtml
http://en.wikipedia.org/wiki/Cytopenia
http://www.cancer.umn.edu/cancerinfo/NCI/CDR378089.html

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