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|Year : 2001 | Volume
| Issue : 5 | Page : 273-274
Leptin and obesity
|How to cite this article:|
. Leptin and obesity. Indian J Med Sci 2001;55:273-4
Obesity has become a major health problem all over the World and it affects mainly upper middle class and richer people in India. Obesity is associated with morbidity and increased mortality. It costs the individual and the nation in treatment. It is associated with diabetes mellitus type two, hypertension, cardiovascular diseases and probably cancer. The discovery of leptin and research into its role in the pathogenesis of obesity is of great importance. The present status of leptin in obesity is discussed here.
Body weight is dependent on balance between energy intake and energy expenditure. Obesity is a complex factor. It is positive prolonged energy balance. Daily energy expenditure including (a) resting energy expenditure, (b) energy required to metabolize food, (thermal effect of food) and (c) energy requirements for physical activity. Net excess either caused by greater intake or lesser expenditure results in weight gain. It is like bank balance increase or same income over less expenditure of money.
Obesity is multifactorial. It is not clear which factor is most important in its cause. Research indicates that leptin is most crucial in regulating body weight. Many -researches in humans and in animals indicate leptin is an important factor. Adiposite secretes primarily leptin, a circulating product of obesity gene. It is a cytokine hormone. It is a polypeptide. Human leptin and mouse leptin are homologues to 84%. The rate of leptin production, and Circulating leptin is directly related to fat mass. It is more in females in relation to body fat-a gender effect. Leptin is synthesized in placenta and it is a growth factor for fetus. Human leptin has a halflife of about 25 minutes. It is excreted by kidney. Leptin is the final product of gene. Adipose tissue produces a factor that regulates the body size, the full action spectra of leptin is not yet known. Evidence suggests hypothalamus is the crucial target for the satiety effect of leptin. The role of leptin in pathogenesis of obesity is complex. An increase in plasma leptin in obese subject suggests that obesity is a leptin resistant state. Leptin production is higher in subcutaneous than in visceral fat depot. Prolonged fasting reduces leptin levels. Exogenous glucocorticosteriods produces a sustained increase in leptin levels. Women have a higher level of leptin than men with same body weight and mass. Leptin levels vary with diurnal rhythm in both men and women. Leptin synthesis and release is a complex problem governed by neuroendocrine signals which direct towards adiposites.
Physiologic role of leptin is not yet understood. Leptin levels are consistently associated with body adiposity. This may suggest that leptin may signal the amount of body stores to the hypothalamus and provide important feed back to the brain that is necessary for the ,regulation of long terms energy balance. Also leptin has a key role in reproduction because maturation of the reproductive system can be regulated in normal animals. Leptin has been found to inhibit insulin mediated glucose uptake in skeletal muscle. Leptin is also concerned in growth hormone production. Leptin may have a role in regulation of immune system.
More than ninety percent of obesity is a leptin resistant than leptin deficient state. Exogenous leptin is'not at all ideal treatment of obesity. It may be mentioned that there are other hormones or other substances which have been known to be concerned in the cause of obesity like thyroid deficiency.
| ¤ Conclusion|| |
Leptin has revolutionised interest in obesity. It has certainly a role in causation of obesity either due to leptin deficiency or through resistance. It conveys message of energy status of the body to the hypothalamus. Leptin is a hormone provided primarily by adiposite. It provides information to the hypothalamus about the energy status of the body. The full spectrum of action of leptin is not yet understood. Recent studies have shown that leptin may have therapeutic effect it, lepton deficient or leptin resistant states.
| ¤ Cause|| |
- Leprosy is a chronic disease caused by a bacillus, Mycobacterium leprae.
- M. leprae multiplies very slowly and the incubation period of the disease is about five years. Symptoms can take as long as 20 years to appear.
- Leprosy is not highly infectious. It is transmitted via droplets, from the nose and mouth, during close and frequent contacts with untreated, infected persons.
| ¤ Symptoms|| |
- Leprosy mainly affects the skin and nerves.
- If untreated, there can be progressive and permanent damage to the skin, nerves, limbs and eyes.
- Paucibacillary (PB) leprosy results in one to five numb skin patches. Multibacillary (MB) leprosy results in more than five numb skin patches.
| ¤ History|| |
- Leprosy was recognized in the ancient civilizations of China, Egypt and India.
- The first known written mention of leprosy is dated 600 BC.
- Throughout history, the afflicted have often been ostracized by their communities and families.
| ¤ Treatment today|| |
- Leprosy is a curable disease and treatment provided in the early stages averts disability.
- With minimmal training, leprosy can be easily diagnosed on clinical signs alone.
- A World Health Organization (WHO) Study Group recommended multidrug therapy (MDT) in 1981. MDT consists of three drugs: dapsone, rifampicin and clofazimine. This drug combination kills the pathogen and cures the patients.
- MDT is safe, effective and easily administered under field conditions.
- Novartis and the Novartis Foundation for Sustainable Development have made MDT available free of charge to all leprosy patients in the world.
Through WHO, this MDT is provided to countries in sufficient supply to treat all people diagnosed with the disease.
| ¤ High effectiveness of multidrug therapy|| |
- PB patients treated with MDT are cured within six months.
- MB patients treated with MDT are cured within twelve months.
- Patients are no longer infectious to others after the first dose of MDT. In other words, transmission of leprosy is interrupted.
- There are virtually no relapses, i.e., recurrences of the disease after treatment is completed.
- No resistance of the bacillus to MDT has been detected.
- WHO estimates that early detection and treatment with MDT has prevented about 3-4 million people from being disabled. This suggests great cost-effectiveness of MDT as a health intervention, considering the economic and social loss averted.
| ¤ History of treatment|| |
- The first breakthrough occurred in the 1940s with the development of the drug dapsone, which arrested the disease. But the duration of the treatment of leprosy was many years, even a lifetime, making it difficult for patients to follow.
- In the 1960s, M. leprae started to develop resistance to dapsone, the world's only known anti-leprosy drug.
- Rifampicin and clofazimine, the other two components of MDT, were discovered in the early 1960s.
| ¤ The elimination of leprosy as a public health problem|| |
- The widespread use of MDT has reduced the disease burden dramatically.
- Over the past fifteen years, around 11 million leprosy patients have been cured. The prevalence rate of the disease has dropped by 85% and leprosy has been eliminated from 98 countries.
- Elimination of leprosy as a public health problem is defined as a prevalence rate on the global level of less than one case per 10 000 persons. Once this is achieved, transmission will dwindle and eventually stop. Future generations will not contract the disease.
| ¤ Figures on the current leprosy situation|| |
- As of January 2000, the leprosy prevalence rate at the global level was 1.25 cases per 10 000 people.
- Approximately 740 000 new cases of leprosy were detected during 1999. 750 000 cases were registered and were undergoing treatment at the beginning of 2000.
- It is estimated that about 2.5 million additional leprosy patients will be detected in the period 20002005.
- In 24 countries in Africa, Asia and Latin America leprosy is still considered a public health problem.
- According to the latest available information, special efforts will be needed to reach the leprosy elimination target in 10 countries: Brazil, Democratic Republic of the Congo, Guinea, India, Indonesia, Madagascar, Mozambique, Myanmar, Nepal and Tanzania. Taken all together, these 10 countries account for 90% of the prevalence of the disease in the world in early 2000.
- At the start of 2000, about 70% of the world's registered leprosy patients lived in India where they are being treated.
| ¤ Actions and resources required|| |
- Political commitment needs to be strengthened in countries where leprosy remains a public health problem.
- In order to reach all patients, treatment of leprosy needs to be integrated into general health services. This is a key to successful elimination of the disease. Strong leadership by ministries of health is absolutely necessary, especially in some of the major endemic countries.
- Partners in leprosy elimination need to further accelerate activities and ensure that human and financial resources are made available.
- US$ 100 million is needed for the period 2000-2005. Of that amount, US$ 54 million has been pledged as of the beginning of 2001, leaving a shortfall of US$ 46 million.
- The age-old stigma associated with the disease remains an obstacle to selfreporting and early treatment. The image of leprosy has to be changed at the global, national and local levels. A new environment, in which patients will not hesitate to come forward for diagnosis and treatment, must be created.
| ¤ The strategy for leprosy elimination|| |
The following actions are part of the ongoing leprosy elimination capaign:
- Ensuring accessible and uninterrupted MDT services available to all patients through flexible and patient-friendly drug delivery systems;
- Ensuring the sustainability of MDT services by building the ability of general health workers and community volunteers to treat leprosy;
- Encouraging selfreporting and early treatment by promoting community awareness and changing the image of leprosy;
- Monitoring the performance of MDT services, the quality of patient' care and the progress being made towards elimination by developing a simple leprosy information system.
To promote political commitment, leadership by ministries of health in endemic countries and partners' support for leprosy elimination, the Global Alliance for Elimination of Leprosy (GAEL) was created in November 1999. Core members of the Alliance are governments of leprosy endemic countries, the Nippon Foundation, the International Federation of AntiLeprosy Associations (ILEP), Novartis and WHO. The Alliance is co-operating closely with other nongovernment organizations, the Danish International Development Agency (DANIDA) and the World Bank.