Treating One Non-infectious Disease: Type 2 Diabetes

Treatment only makes sense once you can name the mechanism it targets. In Type 2 diabetes, body cells respond poorly to insulin, which is called insulin resistance. To hold blood glucose in range, the pancreatic beta cells work harder and release more insulin. For a while this compensation keeps glucose near normal, but over years the beta cells cannot keep up. That decline is beta-cell exhaustion, and blood glucose then stays high, a state called chronic hyperglycaemia.

Persistently high glucose slowly damages blood vessels and nerves. This is why unmanaged Type 2 diabetes leads to cardiovascular disease, kidney disease, eye damage and nerve damage over time. Management therefore has two jobs at once: bring glucose back toward its range, and lower the long-term risk of these complications.

Type 2 diabetes management targets insulin resistance and excess blood glucose so that blood vessels and nerves are protected from long-term damage. A useful plan links each action back to this mechanism.

Pause, copy the highlighted definition into your notes before moving on.

Cystic fibrosis was described in 1938 and the CFTR gene was identified in 1989, yet the first truly effective treatment, the CFTR modulator Trikafta, only reached Australian patients through the PBS in 2022. Knowing the exact molecular cause was necessary, but turning that knowledge into a working therapy still took more than three decades.

Metastatic melanoma shows the payoff when mechanism knowledge matures. Five-year survival was about 20% in 2011; after the checkpoint inhibitors ipilimumab and pembrolizumab were approved, survival reached about 55%, and Allison and Honjo received the 2018 Nobel Prize. These treatments worked because they targeted the molecular brake on immune cells, not the tumour directly.

Four levels of intervention

Every treatment intervenes at one of four levels. Root cause treatments correct the underlying defect, as CFTR modulators restore CFTR protein function. Mechanism treatments interrupt a key pathway, as insulin replaces the missing hormone in Type 1 diabetes. Progression treatments slow worsening, as statins slow atherosclerosis. Symptomatic treatments, such as analgesics for cancer pain, relieve suffering without changing the disease.

The most desirable treatments address the root cause, but they are the hardest to develop because they demand detailed molecular knowledge. Most current therapies for non-infectious disease manage mechanisms or slow progression, which is why management plans are long-term and combine several approaches at once.

Each part of a Type 2 diabetes plan targets a different point in the mechanism. Read what each one does before you sort them.

Two more parts of the plan do not lower glucose by themselves. Monitoring uses HbA1c together with blood-pressure, lipid and kidney checks to show whether the plan is working and to catch complications early. Escalation means adding another medicine or insulin when targets are not met or beta-cell function keeps declining.

Pharmacological treatments work by binding specific molecular targets: receptors, enzymes, ion channels or signalling proteins. A drug either restores a function that has been lost or inhibits a process that has become overactive. The more precisely a drug matches the disease-causing mechanism, the fewer off-target side effects it tends to produce.

Statins and cardiovascular disease

Statins such as atorvastatin inhibit HMG-CoA reductase, the rate-limiting enzyme in the liver's cholesterol synthesis pathway. With hepatic cholesterol production blocked, liver cells upregulate LDL receptors and pull more LDL from the blood, so less LDL is available to infiltrate arterial walls and atherosclerotic plaque formation slows. Statins do not reverse existing plaques; they slow the disease.

Metformin, insulin and the diabetes spectrum

Metformin, usually the first medicine prescribed for Type 2 diabetes, reduces the glucose released by the liver and improves how muscle and fat tissue respond to insulin, without forcing exhausted beta cells to work harder. In Type 1 diabetes the treatment is replacement instead: rapid-acting analogues such as lispro cover meals, long-acting analogues such as glargine provide background cover, and closed-loop pumps now adjust delivery automatically.

ACE inhibitors protect two organs at once

ACE inhibitors such as ramipril block angiotensin-converting enzyme, cutting production of angiotensin II, the vasoconstrictor of the RAAS pathway you met in Lesson 4. Lower angiotensin II means less vasoconstriction, lower blood pressure and reduced pressure inside glomerular capillaries, which is why these drugs also protect the kidneys of patients with diabetes.

Some drugs modify the disease course itself. In rheumatoid arthritis, conventional DMARDs such as methotrexate suppress the overactive immune response broadly and cost a few hundred dollars a year, while newer biologic drugs target single cytokines such as TNF with greater precision but at many times the price. Choosing between them means weighing efficacy, side effects, cost and access, not assuming the most expensive option is automatically best.

Conventional cytotoxic chemotherapy kills all rapidly dividing cells, cancerous and healthy alike. Hair follicles, bone marrow and gut epithelium all divide quickly, so patients experience hair loss, nausea and immunosuppression. The treatment works because cancer cells divide faster than most tissues, but the collateral damage sets the dose limit.

BRAF inhibitors: a cancer-specific target

About 50% of melanomas carry the BRAF V600E mutation, which produces a permanently active kinase that keeps signalling the cell to divide. BRAF inhibitors such as vemurafenib and dabrafenib bind the mutant protein specifically, so they kill BRAF-mutant cancer cells while sparing most normal cells. The trade-off is that only mutation carriers benefit, and resistance often develops.

Checkpoint inhibitors: releasing the immune brake

Many tumours evade immunity by displaying PD-L1, which binds the PD-1 receptor on cytotoxic T cells and switches them off. Checkpoint inhibitors such as pembrolizumab and nivolumab are antibodies that block this interaction, releasing the brake so T cells can kill cancer cells again. Because the immune system forms memory, responses can be durable. This is targeted release of one brake, not general immune boosting.

Angioplasty, stents and bypass grafting

Some disease is structural and no drug can reverse it. In coronary angioplasty, a balloon catheter is inflated inside a blocked artery to compress the plaque, and a metal mesh stent holds the lumen open; drug-eluting stents release anti-proliferative drugs that limit scar tissue re-narrowing. In severe multi-vessel disease, coronary artery bypass grafting routes a grafted vessel around the blockage entirely.

Remission of Type 2 diabetes through weight loss

Type 2 diabetes can enter remission, meaning blood glucose returns to the non-diabetic range without medication. Excess visceral fat releases inflammatory adipokines that disrupt insulin receptor signalling; losing roughly 10 to 15 kg reduces that fat, signalling normalises, insulin sensitivity returns and overworked beta cells recover. In the DiRECT trial, structured dietary weight management put 46% of patients into remission at twelve months, against 4% with standard care.

A large prevention trial found lifestyle change cut progression from prediabetes to Type 2 diabetes by 58%, while metformin achieved 31%, yet lifestyle is not always the first choice because it demands sustained behaviour change, time and resources. Exercise also acts directly: contracting muscle upregulates GLUT4 transporters and takes up glucose without insulin. Remission is not a cure, since the genetic predisposition remains and weight regain brings recurrence.

The syllabus also asks for possible future directions for research. For Type 2 diabetes these include better glucose-monitoring systems, drugs that protect beta cells, precision treatment matched to a person's risk profile, and earlier prevention. A strong evaluation does not just list them: it weighs effectiveness, safety, cost, access and quality of evidence.