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Acute cerebral infarction (ACI) – a term that strikes fear into countless families each year. Better known as ischemic stroke, ACI strikes when a blood vessel supplying the brain becomes blocked, cutting off oxygen and nutrients to brain tissue. In China alone, the burden is staggering: millions of individuals face mortality or long‑term disability annually, with only a fraction achieving full functional recovery.

The challenge is two‑fold. First, the therapeutic time window for standard treatments like intravenous thrombolysis is extremely narrow – typically under 4.5 hours from symptom onset. Second, even when blood flow is restored, reperfusion injury can paradoxically worsen brain damage through inflammatory “storms" and vascular dysfunction. As a result, clinicians worldwide are actively seeking adjunctive therapies that can extend the reach of acute‑phase stroke care beyond what conventional medicine alone can offer.

This is where nature steps in. For over two millennia, traditional Chinese medicine has documented the use of leeches (Hirudo) and earthworms (Pheretima) – two seemingly humble invertebrates – as potent agents for breaking up blood stasis, dissolving obstructions in the microvasculature, and improving circulation. Modern science has now caught up, revealing the precise molecular mechanisms that make these ancient remedies so remarkably effective.

In this article, we examine the published clinical evidence for the combination leech‑earthworm extract liquid (ELHE) in treating acute cerebral infarction, explore its mode of action from a pharmacological standpoint, and – most importantly – show you how Minkang Biotechnology is uniquely positioned to bring these life‑saving bioactives from the laboratory to the patient bedside.

Before we dive into the solution, let us take a moment to understand the problem. Acute cerebral infarction accounts for roughly 70–80% of all strokes. It occurs when a thrombus (blood clot) or embolus lodges in an artery supplying the brain, causing downstream ischemia. Within minutes, the ischemic core begins to die. Surrounding it lies the “penumbra" – salvageable tissue that can be rescued if blood flow is restored quickly.

Current first‑line interventions include:

• Intravenous thrombolysis (e.g., alteplase, recombinant tissue plasminogen activator) – effective but subject to strict time constraints.

• Mechanical thrombectomy – highly effective for large‑vessel occlusions but requires specialized facilities and skilled operators.

• Antiplatelet agents (aspirin, clopidogrel) – widely used but less potent in dissolving existing clots.

Even when these interventions succeed, the post‑ischemic inflammatory response can wreak further havoc. Activated microglia release inflammatory cytokines such as tumor necrosis factor‑alpha (TNF‑α) and interleukin‑1β (IL‑1β), while excessive free radical production leads to oxidative damage to neuronal membranes. Endothelial dysfunction impairs the formation of new blood vessels, limiting long‑term recovery.

In short, an ideal therapy for ACI would do three things: (1) dissolve clots efficiently, (2) dampen excessive inflammation, and (3) promote vascular repair. Remarkably, leech–earthworm extract appears to achieve all three simultaneously.

Leeches (Hirudo nipponica). The medicinal leech is nature’s own anticoagulant factory. Its salivary glands produce hirudin – the most potent naturally occurring thrombin inhibitor known to science. Unlike heparin, which requires the cofactor antithrombin III, hirudin binds directly and irreversibly to thrombin, preventing fibrinogen from being converted into fibrin. This direct inhibition translates into a predictable anticoagulant effect with a lower risk of heparin‑induced complications.

Beyond hirudin, leech saliva contains a cocktail of other bioactive molecules: calin (a collagen‑binding inhibitor of platelet adhesion), destabilase (which cleaves isopeptide bonds in stabilized fibrin), and various anti‑inflammatory peptides. Collectively, these components exert a multifaceted attack on thrombus formation and propagation.

Earthworms (Pheretima). If leeches are the anticoagulant specialists, earthworms are the fibrinolysis experts. Lumbrokinase – a group of proteolytic enzymes derived from earthworms – has been shown to directly degrade fibrin clots and also to promote the conversion of plasminogen to plasmin via endogenous tPA activation. Importantly, lumbrokinase exhibits specificity for fibrin, meaning it preferentially targets pathological clots while leaving physiological hemostatic plugs intact – a safety advantage over non‑selective thrombolytics.

In addition, recent 2025 research from Tianjin has revealed that earthworm extract (EWE) exerts a powerful immunomodulatory effect in cerebral ischemia models. It suppresses the neurotoxic M1‑type microglial polarization (which secretes pro‑inflammatory cytokines) while promoting the healing M2‑type polarization (which secretes anti‑inflammatory IL‑10). Simultaneously, EWE activates the Ang1/Tie2 angiogenic pathway, stimulating the formation of new blood vessels in ischemic brain tissue.

Why combine them? The leech–earthworm combination is not arbitrary. Traditional Chinese medicine has long paired these two “insect‑derived" remedies to achieve complementary effects: leeches excel at breaking up established blood stasis, while earthworms open the collaterals and promote circulation. Modern pharmacology confirms the synergy: leech‑derived hirudin provides potent anti‑thrombotic coverage, while earthworm‑derived lumbrokinase actively clears existing fibrin deposits. Together, they form a dual‑mechanism attack on cerebral thrombosis.

A pivotal clinical study investigated exactly this synergy. The trial enrolled 78 patients with acute cerebral infarction, randomly divided into two groups:

• Control group (n = 38): standard medical therapy alone.

• Treatment group (n = 40): standard therapy plus intravenous leech–earthworm extract liquid (ELHE, 20 mL diluted in 250 mL of normal saline, once daily for 14 consecutive days).

What did the researchers find? The results were striking.

Neurological improvement. After just 14 days of treatment, the ELHE group showed a dramatic reduction in neurological deficit scores – from 9.4 ± 4.0 at baseline to 3.3 ± 1.2 post‑treatment. The difference was not only statistically significant (P < 0.05) but also clinically meaningful. Even more encouragingly, the Barthel Index – a validated measure of daily living independence – soared from 25.9 ± 4.6 to 67.4 ± 2.8, indicating that patients in the ELHE group were able to resume far more of their normal activities compared to controls.

Laboratory confirmation of mechanisms. The coagulation profile told the rest of the story. The ELHE group demonstrated a significant prolongation of both APTT (from 28.2 ± 3.8 seconds to 42.0 ± 5.2 seconds) and PT (from 12.2 ± 3.5 seconds to 19.5 ± 2.1 seconds) – clear evidence of enhanced anticoagulation. Meanwhile, markers of fibrinolysis improved dramatically:

• tPA levels (tissue plasminogen activator) rose from 10.1 ± 1.2 μg/L to 15.3 ± 2.1 μg/L.

• PAI‑1 levels (plasminogen activator inhibitor‑1, the body’s natural “brake" on fibrinolysis) declined.

These changes confirm that ELHE tilts the delicate balance of the clotting system toward active clot dissolution, not merely passive prevention.

Platelet function also improved. Thromboxane B₂ (TXB₂, a marker of platelet activation) dropped from 228.4 ± 48.9 ng/L to 152.7 ± 44.4 ng/L, while 6‑keto‑PGF1α (a stable metabolite of the vasoprotective prostacyclin PGI₂) increased. This shift in the TXB₂/PGI₂ ratio suggests that ELHE not only inhibits platelet aggregation but also actively supports vascular endothelial health.

Bottom line from the trial: leech–earthworm extract is safe, well‑tolerated, and significantly improves both neurological outcomes and independent daily functioning in patients with acute cerebral infarction. These findings have earned ELHE a place in clinical practice as an adjunctive therapy, particularly for patients ineligible for or poorly responsive to conventional thrombolytics.

Given the complexity of stroke pathophysiology, the most effective therapies are rarely “magic bullets" that hit a single target. Leeches and earthworms, in keeping with the holistic philosophy of traditional remedies, offer a multi‑targeted approach that contemporary drug designers are only beginning to emulate.

Pathway 1: Anti‑inflammation. Ischemic stroke triggers a powerful inflammatory cascade. Microglial cells – the resident immune cells of the central nervous system – rapidly adopt a pro‑inflammatory M1 phenotype, releasing TNF‑α, IL‑1β, and monocyte chemoattractant protein‑1 (MCP‑1). These mediators amplify neuronal injury and recruit systemic leukocytes into the brain. Animal studies have shown that leech–earthworm extract suppresses the expression of NF‑κB – the master transcriptional regulator of inflammation – thereby reducing the production of these harmful cytokines. By dampening the “cytokine storm," ELHE limits secondary brain damage beyond the initial ischemic insult.

Pathway 2: Anti‑oxidation. Ischemia‑reperfusion generates copious quantities of reactive oxygen species (ROS), including superoxide anions, hydrogen peroxide, and hydroxyl radicals. These ROS attack lipid membranes (lipid peroxidation), proteins, and even DNA. Studies measuring malondialdehyde (MDA, a marker of lipid peroxidation) and superoxide dismutase (SOD, a key endogenous antioxidant enzyme) have demonstrated that leech–earthworm extract reduces oxidative stress and preserves cellular antioxidant capacity. This antioxidant effect is particularly important for salvaging the ischemic penumbra.

Pathway 3: Angiogenesis and vascular repair. Long‑term recovery from stroke depends on the brain’s ability to build new microvessels – a process known as angiogenesis. As highlighted by the 2025 Tianjin study, earthworm extract alone promotes microglial M2 polarization and activates the Ang1/Tie2 signaling pathway, which is essential for endothelial cell migration and tube formation. In animal models of middle cerebral artery occlusion/reperfusion (MCAO/R), EWE treatment reduced infarct volume by fully 40% and increased the number of CD206+ M2‑type microglia while enhancing the expression of angiogenic markers like ki67. These findings suggest that leech–earthworm extract supports not just acute clot resolution but also long‑term neural‑vascular repair.

Let us make this concrete with a short patient‑inspired illustration – not a specific medical record, but a representative composite based on clinical findings.

Mr. Zhang’s story. A 63‑year‑old retired factory worker with a history of hypertension and atrial fibrillation was brought to the emergency room with sudden right‑sided weakness and an inability to speak. He arrived 7 hours after symptom onset – beyond the window for intravenous alteplase. The treating physicians started standard secondary prevention (antiplatelet agents, statins, blood pressure control) and, given his ineligibility for thrombolysis, added intravenous ELHE on day two.

By day seven, Mr. Zhang’s neurological deficit score had fallen from an initial 11 to 5. By day 14, he was able to walk with a cane, feed himself, and speak in short phrases. His Barthel Index climbed from 18 at admission to 62 at discharge. One month later, he was navigating his home independently – a far cry from the grim prognosis that often accompanies late‑presenting acute stroke.

Why ELHE made the difference. For Mr. Zhang – and many others like him – ELHE provided the clot‑resolving and neuroprotective effects that conventional antiplatelet therapy alone could not achieve. The extract’s ability to promote fibrinolysis and dampen inflammation likely limited the expansion of the ischemic penumbra, turning what might have been a devastating disability into a manageable recovery.

No discussion of thrombolytic or anticoagulant therapy is complete without addressing the risk of bleeding. In the clinical trial of ELHE for ACI, no serious hemorrhagic events were reported. Patients in the treatment group did not experience an increased incidence of gastrointestinal bleeding, intracerebral hemorrhage, or other significant adverse effects compared to controls.

This favorable safety profile likely stems from the multi‑targeted yet controlled action of the extract: hirudin acts locally on already‑formed thrombi, while lumbrokinase exhibits a degree of fibrin‑specificity that spares normal hemostatic plugs. Nonetheless, as with any agent affecting coagulation, caution is warranted. ELHE should be used under proper medical supervision, with monitoring of bleeding parameters, particularly in patients with known coagulopathies, severe liver disease, or recent major surgery.

Science has established the what and the why of leech‑based stroke therapy. But none of this translates into clinical reality without the how – and that is where Minkang Biotechnology comes in.

Unmatched scale and purity. Minkang Biotechnology is China’s leading vertically integrated producer of pharmaceutical‑grade Hirudo nipponica (Japanese medicinal leech). The company operates a state‑of‑the‑art facility encompassing over 14,000 m² of standardized purification workshops, with an annual output capacity exceeding 100 million medical grade leeches. This scale – the largest of its kind in China – ensures a consistent, high‑volume supply of leech‑derived bioactives for both domestic and international partners.

Whole‑lifecycle control. Unlike wild‑caught leeches or small‑scale farms, Minkang maintains closed‑cycle artificial breeding that covers the entire leech lifecycle – from egg cocoon to mature adult. This level of control eliminates variability in active ingredient content and ensures complete traceability, a critical requirement for pharmaceutical and clinical applications.

Innovation beyond tradition. The company holds over 20 domestic and international patents covering leech breeding, extraction methodologies, and product formulations. Production processes are certified under ISO9001, ISO45001, and ISO12001 standards, with full quarantine and origin documentation. This commitment to quality has not gone unnoticed – recent site visits by a provincial expert panel from Hubei’s “515" science‑technology initiative specifically highlighted Minkang’s achievements in medical leech aquaculture and extraction technology as benchmarks for the industry.

From ingredient to integrated medicine. While EMINK is perhaps best known as a premier supplier of live medicinal leeches for hirudotherapy and research, the company’s ambitions run deeper. Through strategic development of leech‑based extracts, freeze‑dried powders, and specialized formulations, Minkang is increasingly positioning itself as a partner for pharmaceutical companies and research institutions seeking standardized, reliable sources of leech‑derived thrombolytic and anticoagulant molecules.

A tradition reimagined. The Japanese medical leech has been documented in Chinese medical texts since 221 BCE. For millennia, healers understood its power through experience and observation. Today, we understand its power through clinical trials, molecular pharmacology, and rigorous quality control. Minkang Biotechnology stands at the intersection of these two worlds – respecting the wisdom of tradition while leveraging the tools of modern science to standardize, scale, and deliver.

The global stroke therapeutics market is evolving rapidly. As the aging population grows, so too does the demand for effective, accessible post‑stroke therapies that work beyond the four‑hour thrombolysis window. Leech‑derived and earthworm‑derived bioactives are poised to play an increasingly central role, particularly in markets where conventional thrombolytics remain unavailable or under‑utilized.

Ongoing research continues to uncover new applications. Recent network pharmacology analyses have pinpointed specific hirudin‑containing signaling pathways involved in ischemic protection. Preclinical studies are exploring the use of leech extracts in combination with existing neuroprotectants to further enhance functional outcomes. Meanwhile, advances in extraction and purification technology are making it possible to isolate individual bioactive components – rather than crude extracts – for targeted therapeutic development.

For Minkang Biotechnology, the path forward is clear: continue to lead the industry in quality, innovation, and scale; forge partnerships with pharmaceutical innovators worldwide; and expand the global reach of the Japanese medical leech – one of nature’s most elegant answers to the scourge of ischemic disease.

Acute cerebral infarction remains a formidable enemy. But humanity has faced formidable enemies before – and often, the answers sit quietly in the natural world, waiting to be rediscovered through the lens of modern science.

The clinical trial data summarized above leaves little room for doubt: leech–earthworm extract liquid exerts a potent, multi‑targeted therapeutic effect in acute ischemic stroke, improving neurological function, enhancing daily independence, and doing so with a safety profile that supports its use as an adjunctive therapy. From anticoagulation and fibrinolysis to anti‑inflammation, anti‑oxidation, and even vascular repair, the combined power of Hirudo and Pheretima offers a comprehensive approach that no single synthetic drug can yet match.

And for Minkang Biotechnology, the commitment is equally simple: to bring these ancient‑yet‑modern therapeutics from the pristine breeding ponds of Jingzhou to the world stage, reliably, safely, and at scale.

Disclaimer: This article is for informational and educational purposes only. It does not constitute medical advice. Leech‑based products and extracts should only be used under the supervision of qualified healthcare professionals. Individual patient outcomes may vary.