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Researchers have found special brain immune cells that can protect against Alzheimer’s disease. These cells, called microglia, help reduce brain inflammation and slow the buildup of harmful proteins that damage memory.

What is Alzheimer disease?

Alzheimer’s disease is a progressive brain disorder that slowly destroys memory, thinking skills, and the ability to carry out daily tasks.

At its core, Alzheimer’s happens when brain cells (neurons) become damaged and eventually die. Over time, this loss spreads through the brain, shrinking it and disrupting how brain regions communicate with each other.

It involves a mix of factors:

• Abnormal protein buildup — sticky clumps of amyloid plaques and twisted strands of tau tangles interfere with neuron function.
• Inflammation and immune system changes — brain immune cells can overreact, causing further damage.
• Genetic and lifestyle influences — some people inherit genes that increase risk, while factors like age, poor heart health, and low physical or mental activity also play a role.

As the disease progresses, people experience:

• Memory loss (especially recent events)
• Confusion and trouble thinking clearly
• Difficulty communicating or recognizing loved ones
• Changes in mood, personality, and behaviour

Current Status:

• According to the World Health Organization (WHO), in 2021 roughly 57 million people worldwide were living with dementia (of which Alzheimer’s is the most common form).
• A National Institute of Health, study in India found that among adults aged 60 + years, dementia prevalence is about 4 %, equating to roughly 8.8 million people.
• Projections: If prevalence remains unchanged, the number of older Indians with dementia could rise to 9 million by 2036.
• It is estimated that about 70% of the Indian dementia burden is likely due to Alzheimer’s disease specifically. 

What is the scientific discovery about brain cells that may stop Alzheimer’s?

Microglia are immune cells in the brain. They can either protect the brain by cleaning up waste or cause harm if they become too active.

A research team from Mount Sinai and several international institutes discovered a unique group of microglia that seem to protect the brain from Alzheimer’s damage.

These helpful microglia:

• Have lower levels of a protein called PU.1
• Have higher levels of a receptor called CD28

Together, these changes allow microglia to calm brain inflammation, slow the buildup of plaques, and reduce toxic proteins linked to Alzheimer’s.

How it works?

Using both mice and human brain samples, scientists showed that lowering PU.1 makes microglia more protective.
If CD28 was removed, brain inflammation and plaque buildup got worse — showing CD28’s key role in keeping these cells active and protective.

What are the key concerns of this discovery?

Complexity of the Human Brain

• What works in mice or lab models may not behave the same way in human brains.
• Microglia are extremely diverse and context-dependent, so tweaking them safely in humans is difficult.

Targeting PU.1 and CD28 Safely

• These molecules control gene activity and immune function — not only in the brain but throughout the body.
• Changing PU.1 levels or CD28 signaling might have side effects such as immune suppression or inflammation in other tissues.

Understanding Long-Term Effects

• Boosting “protective microglia” may help initially, but it’s unclear if these effects last long-term or if the cells eventually become harmful under stress or ageing.

Drug Delivery to the Brain

• The blood–brain barrier blocks many drugs from entering the brain. Finding ways to safely deliver molecules that affect microglia is a huge technical obstacle.

Ethical and Regulatory Challenges

• Modifying immune function in the brain raises ethical questions about unintended consequences.
• Regulatory agencies (like FDA or CDSCO in India) will require extensive safety data before human trials. 

What are the measures world has adopted to stop Alzheimer disease?

• The World Health Organization (WHO) in 2017 adopted the “Global action plan on the public health response to dementia 2017‑2025”. This sets out seven strategic action areas:
• Making dementia a public health priority;
• Raising awareness;
• Reducing risk;
• improving diagnosis/treatment/care;
• Supporting carers;
• Building information systems;
• Promoting research and innovation.
• India’s legislation such as the Mental Healthcare Act, 2017 gives rights to persons with “mental illness”, which includes cognitive disorders/ dementia‑type conditions — guaranteeing access to care, protection of dignity, informed consent etc. 

• State of Karnataka has drafted a “dementia action plan” to declare dementia a public health priority, focus on screening, risk‑reduction, awareness and training of healthcare professionals.

Conclusion:

Alzheimer’s disease is a progressive brain disorder that gradually impairs memory, thinking, and daily functioning. Its prevalence is rising globally and in India, creating significant health, social, and economic challenges. Recent discoveries, like protective microglia, offer hope for new treatments, but translating them into safe, effective therapies faces scientific and practical hurdles. Government measures focus on awareness, early diagnosis, care, and research, but gaps remain. Combating Alzheimer’s requires combined efforts in research, healthcare, prevention, and support for patients and caregivers.

 Source: Science Daily