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The Fastest Way to Better Anticoagulants May Be a Land Snail
The fastest way to a new anticoagulation therapy that prevents blood clots without prolonging bleeding or healing time may be a land snail.
A recent preclinical study in ACS Central Science investigating bioactive molecules derived from the land snail Camaena cicatricosa identified a compound that significantly reduced clot formation without prolonging bleeding time and wound healing in rodent models, directly challenging the assumption that effective anticoagulant therapy must inherently disrupt physiologic repair processes.
“I was quite excited,” said Lisha Lin, PhD, lead author on the study and research assistant at the State Key Laboratory of Phytochemistry and Natural Medicines at the Kunming Institute of Botany, Chinese Academy of Sciences, in Kunming, China. “A novel polysaccharide was identified, and more importantly, it showed anticoagulant activity by inhibiting a novel target, with different action mechanism from heparins.”
What Led to the Land Snail?
The choice of C cicatricosa reflects a shift in thinking. The team screened a range of mollusk-derived biomolecules in search of safer anticoagulation strategies, ultimately isolating a novel galactosylated glycosaminoglycan (CCG) from this terrestrial species.
“We compared the anticoagulant activity of glycosaminoglycans from three snail species,” said Lin. They initially studied polysaccharides from C cicatricosa, Achatina fulica, and Helix lucorum — all sulfated glycosaminoglycans with similar structures. “However, we only found CCG from [C cicatricosa] showed anticoagulant activity but not other snail polysaccharides.”
This unexpected selectivity proved crucial. “The result indicated that the galactose branches and special sulfate substitution were important,” she explained, helping to explain why this particular species stood out among structurally similar compounds.
While CCG shares some similarities with heparin-like molecules, it notably lacks the specific pentasaccharide sequence required for antithrombin binding. Researchers hypothesized that this absence could reduce bleeding risk while maintaining antithrombotic activity.
Rather than broadly inhibiting coagulation, the compound selectively disrupts the intrinsic tenase complex, a pathway more closely associated with pathologic thrombosis than with physiologic hemostasis. This mechanism’s selectivity is central to the study’s findings and helps explain why normal wound healing remained intact in preclinical models.
The isolated compound demonstrated a rare combination in anticoagulant research: potent inhibition of pathologic thrombosis with no significant increase in bleeding time and intact wound healing across multiple experimental models. The compound did not act as a broad-spectrum anticoagulant, instead selectively targeting pathways more relevant to disease-associated clot formation.
The Hope of Lowering Bleeding Risk
For decades, anticoagulation therapy has been built on the assumption that inhibiting clot formation inevitably increases bleeding risk. For physicians treating patients with deep vein thrombosis or atrial fibrillation or those requiring postsurgical attention, the balancing act is constant. Prevent clot formation aggressively enough and the bleeding risk rises. Reduce intensity and thrombosis risk returns.
Current therapies, including heparin and direct oral anticoagulants (DOACs), function by broadly targeting the coagulation cascade. This lack of specialty is precisely what limits them. Even when carefully dosed, the treatments interfere with both pathologic clot formation and physiologic hemostasis.
Physicians managing patients on heparin and DOACs frequently encounter recurrent epistaxis, gastrointestinal bleeding ranging from occult to clinically significant, and urogenital bleeding. A degree of mild bleeding after surgery is often expected and usually resolves on its own. However, it’s crucial to evaluate in the context of ongoing anticoagulation to rule out early signs of clinically significant complications.
“There is definitely a lot of interest in the concept of ‘uncoupling’ thrombosis from hemostasis,” said Yazan Abou-Ismail, MD, hematologist and associate professor of medicine at the University of Utah Health in Salt Lake City, who was not involved in the research. “This concept highlights the differences in pathways essential for normal hemostasis at sites of vessel injury, in contrast with those needed for clot propagation and blood vessel lumen occlusion.”
Abou-Ismail noted that this approach has been explored with Factor XI (FXI) inhibitors currently in clinical trials. However, he raised an important mechanistic concern.
“This mechanism may not necessarily accomplish that goal of uncoupling thrombosis from hemostasis, although it might at narrow therapeutic windows,” Abou-Ismail said. “The tenase complex is a central component of coagulation whose deficiency underlies hemophilia A and B, diseases that cause significant bleeding in humans, and it is more essential to hemostasis than [FXI inhibitors]. Tenase inhibition seems like it may pose a higher bleeding risk in humans.”
He explained that FXI inhibitors have a strong mechanistic rationale because they target the feedback loop that amplifies clot propagation, which is less essential for hemostasis. “FXI inhibitors have clinical trial data demonstrating that FXI inhibition is in fact associated with less bleeding compared to current established anticoagulants,” he said. “However, CCG disrupts the FIXa/FVIIIa intrinsic tenase complex itself, which is considered essential for hemostasis.”
Surprises and Confirmations
The researchers were not anticipating such a clear separation between antithrombotic activity and bleeding risk. The preservation of normal wound healing was equally surprising, directly challenging the belief that interfering with clot formation inevitably disrupts tissue repair.
However, the path to these conclusions was not straightforward. “The structural definition of complex macromolecules like sulfated polysaccharides is a common challenge in the research field,” Lin said. “We spent a lot of time to analyze the structure of CCG.”
Even after identifying the candidate compound, the team had to rigorously confirm that its effects were truly anticoagulant in nature, rather than secondary to anti-inflammatory or vascular remodeling properties. Mechanistic studies were essential in demonstrating its targeted disruption of the intrinsic tenase complex, helping to explain how thrombosis could be reduced without broadly impairing coagulation.
Lin is excited but knows patience and skepticism are needed. “Our research is still at the basic stage, but based on the available data, we may provide a potential anticoagulant option with low bleeding risk,” she said. “In the discussion section of our paper, we also stated that ‘the data suggest a wide therapeutic window of CCG, which may offer therapeutic advantages for patients with bleeding contraindication, such as elderly patients and those with renal failure, as well as for safer long-term anticoagulation.’”
A New Direction for Heparin Alternatives?
Despite these concerns, Abou-Ismail acknowledged that the research has genuinely noteworthy aspects. “A future anticoagulant with a novel mechanism of action may be useful in patients who have experienced anticoagulant failure or breakthrough thrombosis from currently established anticoagulants,” he said. “Having another option might be useful when all other options have failed or are not feasible.”
However, he added a note of caution: “If a therapeutic window exists where partial tenase disruption has antithrombotic effect that does not impair hemostasis, then that would definitely be a promising future finding, but it is too early to arrive at that conclusion with this study.”
The search for safer heparin alternatives has been ongoing for decades, but most candidates still operate within the same fundamental paradigm of broad coagulation inhibition. This snail can’t move fast enough.
Abou-Ismail reported having no relevant conflicts. Disclosure information for study authors is available in the original study publication.
A version of this article first appeared on Medscape.com.
The fastest way to a new anticoagulation therapy that prevents blood clots without prolonging bleeding or healing time may be a land snail.
A recent preclinical study in ACS Central Science investigating bioactive molecules derived from the land snail Camaena cicatricosa identified a compound that significantly reduced clot formation without prolonging bleeding time and wound healing in rodent models, directly challenging the assumption that effective anticoagulant therapy must inherently disrupt physiologic repair processes.
“I was quite excited,” said Lisha Lin, PhD, lead author on the study and research assistant at the State Key Laboratory of Phytochemistry and Natural Medicines at the Kunming Institute of Botany, Chinese Academy of Sciences, in Kunming, China. “A novel polysaccharide was identified, and more importantly, it showed anticoagulant activity by inhibiting a novel target, with different action mechanism from heparins.”
What Led to the Land Snail?
The choice of C cicatricosa reflects a shift in thinking. The team screened a range of mollusk-derived biomolecules in search of safer anticoagulation strategies, ultimately isolating a novel galactosylated glycosaminoglycan (CCG) from this terrestrial species.
“We compared the anticoagulant activity of glycosaminoglycans from three snail species,” said Lin. They initially studied polysaccharides from C cicatricosa, Achatina fulica, and Helix lucorum — all sulfated glycosaminoglycans with similar structures. “However, we only found CCG from [C cicatricosa] showed anticoagulant activity but not other snail polysaccharides.”
This unexpected selectivity proved crucial. “The result indicated that the galactose branches and special sulfate substitution were important,” she explained, helping to explain why this particular species stood out among structurally similar compounds.
While CCG shares some similarities with heparin-like molecules, it notably lacks the specific pentasaccharide sequence required for antithrombin binding. Researchers hypothesized that this absence could reduce bleeding risk while maintaining antithrombotic activity.
Rather than broadly inhibiting coagulation, the compound selectively disrupts the intrinsic tenase complex, a pathway more closely associated with pathologic thrombosis than with physiologic hemostasis. This mechanism’s selectivity is central to the study’s findings and helps explain why normal wound healing remained intact in preclinical models.
The isolated compound demonstrated a rare combination in anticoagulant research: potent inhibition of pathologic thrombosis with no significant increase in bleeding time and intact wound healing across multiple experimental models. The compound did not act as a broad-spectrum anticoagulant, instead selectively targeting pathways more relevant to disease-associated clot formation.
The Hope of Lowering Bleeding Risk
For decades, anticoagulation therapy has been built on the assumption that inhibiting clot formation inevitably increases bleeding risk. For physicians treating patients with deep vein thrombosis or atrial fibrillation or those requiring postsurgical attention, the balancing act is constant. Prevent clot formation aggressively enough and the bleeding risk rises. Reduce intensity and thrombosis risk returns.
Current therapies, including heparin and direct oral anticoagulants (DOACs), function by broadly targeting the coagulation cascade. This lack of specialty is precisely what limits them. Even when carefully dosed, the treatments interfere with both pathologic clot formation and physiologic hemostasis.
Physicians managing patients on heparin and DOACs frequently encounter recurrent epistaxis, gastrointestinal bleeding ranging from occult to clinically significant, and urogenital bleeding. A degree of mild bleeding after surgery is often expected and usually resolves on its own. However, it’s crucial to evaluate in the context of ongoing anticoagulation to rule out early signs of clinically significant complications.
“There is definitely a lot of interest in the concept of ‘uncoupling’ thrombosis from hemostasis,” said Yazan Abou-Ismail, MD, hematologist and associate professor of medicine at the University of Utah Health in Salt Lake City, who was not involved in the research. “This concept highlights the differences in pathways essential for normal hemostasis at sites of vessel injury, in contrast with those needed for clot propagation and blood vessel lumen occlusion.”
Abou-Ismail noted that this approach has been explored with Factor XI (FXI) inhibitors currently in clinical trials. However, he raised an important mechanistic concern.
“This mechanism may not necessarily accomplish that goal of uncoupling thrombosis from hemostasis, although it might at narrow therapeutic windows,” Abou-Ismail said. “The tenase complex is a central component of coagulation whose deficiency underlies hemophilia A and B, diseases that cause significant bleeding in humans, and it is more essential to hemostasis than [FXI inhibitors]. Tenase inhibition seems like it may pose a higher bleeding risk in humans.”
He explained that FXI inhibitors have a strong mechanistic rationale because they target the feedback loop that amplifies clot propagation, which is less essential for hemostasis. “FXI inhibitors have clinical trial data demonstrating that FXI inhibition is in fact associated with less bleeding compared to current established anticoagulants,” he said. “However, CCG disrupts the FIXa/FVIIIa intrinsic tenase complex itself, which is considered essential for hemostasis.”
Surprises and Confirmations
The researchers were not anticipating such a clear separation between antithrombotic activity and bleeding risk. The preservation of normal wound healing was equally surprising, directly challenging the belief that interfering with clot formation inevitably disrupts tissue repair.
However, the path to these conclusions was not straightforward. “The structural definition of complex macromolecules like sulfated polysaccharides is a common challenge in the research field,” Lin said. “We spent a lot of time to analyze the structure of CCG.”
Even after identifying the candidate compound, the team had to rigorously confirm that its effects were truly anticoagulant in nature, rather than secondary to anti-inflammatory or vascular remodeling properties. Mechanistic studies were essential in demonstrating its targeted disruption of the intrinsic tenase complex, helping to explain how thrombosis could be reduced without broadly impairing coagulation.
Lin is excited but knows patience and skepticism are needed. “Our research is still at the basic stage, but based on the available data, we may provide a potential anticoagulant option with low bleeding risk,” she said. “In the discussion section of our paper, we also stated that ‘the data suggest a wide therapeutic window of CCG, which may offer therapeutic advantages for patients with bleeding contraindication, such as elderly patients and those with renal failure, as well as for safer long-term anticoagulation.’”
A New Direction for Heparin Alternatives?
Despite these concerns, Abou-Ismail acknowledged that the research has genuinely noteworthy aspects. “A future anticoagulant with a novel mechanism of action may be useful in patients who have experienced anticoagulant failure or breakthrough thrombosis from currently established anticoagulants,” he said. “Having another option might be useful when all other options have failed or are not feasible.”
However, he added a note of caution: “If a therapeutic window exists where partial tenase disruption has antithrombotic effect that does not impair hemostasis, then that would definitely be a promising future finding, but it is too early to arrive at that conclusion with this study.”
The search for safer heparin alternatives has been ongoing for decades, but most candidates still operate within the same fundamental paradigm of broad coagulation inhibition. This snail can’t move fast enough.
Abou-Ismail reported having no relevant conflicts. Disclosure information for study authors is available in the original study publication.
A version of this article first appeared on Medscape.com.
The fastest way to a new anticoagulation therapy that prevents blood clots without prolonging bleeding or healing time may be a land snail.
A recent preclinical study in ACS Central Science investigating bioactive molecules derived from the land snail Camaena cicatricosa identified a compound that significantly reduced clot formation without prolonging bleeding time and wound healing in rodent models, directly challenging the assumption that effective anticoagulant therapy must inherently disrupt physiologic repair processes.
“I was quite excited,” said Lisha Lin, PhD, lead author on the study and research assistant at the State Key Laboratory of Phytochemistry and Natural Medicines at the Kunming Institute of Botany, Chinese Academy of Sciences, in Kunming, China. “A novel polysaccharide was identified, and more importantly, it showed anticoagulant activity by inhibiting a novel target, with different action mechanism from heparins.”
What Led to the Land Snail?
The choice of C cicatricosa reflects a shift in thinking. The team screened a range of mollusk-derived biomolecules in search of safer anticoagulation strategies, ultimately isolating a novel galactosylated glycosaminoglycan (CCG) from this terrestrial species.
“We compared the anticoagulant activity of glycosaminoglycans from three snail species,” said Lin. They initially studied polysaccharides from C cicatricosa, Achatina fulica, and Helix lucorum — all sulfated glycosaminoglycans with similar structures. “However, we only found CCG from [C cicatricosa] showed anticoagulant activity but not other snail polysaccharides.”
This unexpected selectivity proved crucial. “The result indicated that the galactose branches and special sulfate substitution were important,” she explained, helping to explain why this particular species stood out among structurally similar compounds.
While CCG shares some similarities with heparin-like molecules, it notably lacks the specific pentasaccharide sequence required for antithrombin binding. Researchers hypothesized that this absence could reduce bleeding risk while maintaining antithrombotic activity.
Rather than broadly inhibiting coagulation, the compound selectively disrupts the intrinsic tenase complex, a pathway more closely associated with pathologic thrombosis than with physiologic hemostasis. This mechanism’s selectivity is central to the study’s findings and helps explain why normal wound healing remained intact in preclinical models.
The isolated compound demonstrated a rare combination in anticoagulant research: potent inhibition of pathologic thrombosis with no significant increase in bleeding time and intact wound healing across multiple experimental models. The compound did not act as a broad-spectrum anticoagulant, instead selectively targeting pathways more relevant to disease-associated clot formation.
The Hope of Lowering Bleeding Risk
For decades, anticoagulation therapy has been built on the assumption that inhibiting clot formation inevitably increases bleeding risk. For physicians treating patients with deep vein thrombosis or atrial fibrillation or those requiring postsurgical attention, the balancing act is constant. Prevent clot formation aggressively enough and the bleeding risk rises. Reduce intensity and thrombosis risk returns.
Current therapies, including heparin and direct oral anticoagulants (DOACs), function by broadly targeting the coagulation cascade. This lack of specialty is precisely what limits them. Even when carefully dosed, the treatments interfere with both pathologic clot formation and physiologic hemostasis.
Physicians managing patients on heparin and DOACs frequently encounter recurrent epistaxis, gastrointestinal bleeding ranging from occult to clinically significant, and urogenital bleeding. A degree of mild bleeding after surgery is often expected and usually resolves on its own. However, it’s crucial to evaluate in the context of ongoing anticoagulation to rule out early signs of clinically significant complications.
“There is definitely a lot of interest in the concept of ‘uncoupling’ thrombosis from hemostasis,” said Yazan Abou-Ismail, MD, hematologist and associate professor of medicine at the University of Utah Health in Salt Lake City, who was not involved in the research. “This concept highlights the differences in pathways essential for normal hemostasis at sites of vessel injury, in contrast with those needed for clot propagation and blood vessel lumen occlusion.”
Abou-Ismail noted that this approach has been explored with Factor XI (FXI) inhibitors currently in clinical trials. However, he raised an important mechanistic concern.
“This mechanism may not necessarily accomplish that goal of uncoupling thrombosis from hemostasis, although it might at narrow therapeutic windows,” Abou-Ismail said. “The tenase complex is a central component of coagulation whose deficiency underlies hemophilia A and B, diseases that cause significant bleeding in humans, and it is more essential to hemostasis than [FXI inhibitors]. Tenase inhibition seems like it may pose a higher bleeding risk in humans.”
He explained that FXI inhibitors have a strong mechanistic rationale because they target the feedback loop that amplifies clot propagation, which is less essential for hemostasis. “FXI inhibitors have clinical trial data demonstrating that FXI inhibition is in fact associated with less bleeding compared to current established anticoagulants,” he said. “However, CCG disrupts the FIXa/FVIIIa intrinsic tenase complex itself, which is considered essential for hemostasis.”
Surprises and Confirmations
The researchers were not anticipating such a clear separation between antithrombotic activity and bleeding risk. The preservation of normal wound healing was equally surprising, directly challenging the belief that interfering with clot formation inevitably disrupts tissue repair.
However, the path to these conclusions was not straightforward. “The structural definition of complex macromolecules like sulfated polysaccharides is a common challenge in the research field,” Lin said. “We spent a lot of time to analyze the structure of CCG.”
Even after identifying the candidate compound, the team had to rigorously confirm that its effects were truly anticoagulant in nature, rather than secondary to anti-inflammatory or vascular remodeling properties. Mechanistic studies were essential in demonstrating its targeted disruption of the intrinsic tenase complex, helping to explain how thrombosis could be reduced without broadly impairing coagulation.
Lin is excited but knows patience and skepticism are needed. “Our research is still at the basic stage, but based on the available data, we may provide a potential anticoagulant option with low bleeding risk,” she said. “In the discussion section of our paper, we also stated that ‘the data suggest a wide therapeutic window of CCG, which may offer therapeutic advantages for patients with bleeding contraindication, such as elderly patients and those with renal failure, as well as for safer long-term anticoagulation.’”
A New Direction for Heparin Alternatives?
Despite these concerns, Abou-Ismail acknowledged that the research has genuinely noteworthy aspects. “A future anticoagulant with a novel mechanism of action may be useful in patients who have experienced anticoagulant failure or breakthrough thrombosis from currently established anticoagulants,” he said. “Having another option might be useful when all other options have failed or are not feasible.”
However, he added a note of caution: “If a therapeutic window exists where partial tenase disruption has antithrombotic effect that does not impair hemostasis, then that would definitely be a promising future finding, but it is too early to arrive at that conclusion with this study.”
The search for safer heparin alternatives has been ongoing for decades, but most candidates still operate within the same fundamental paradigm of broad coagulation inhibition. This snail can’t move fast enough.
Abou-Ismail reported having no relevant conflicts. Disclosure information for study authors is available in the original study publication.
A version of this article first appeared on Medscape.com.
The Fastest Way to Better Anticoagulants May Be a Land Snail
The Fastest Way to Better Anticoagulants May Be a Land Snail