Platelet-inspired synthetic nanoparticles improve hemostasis and hemodynamics in a rabbit model of abdominal hemorrhage.

BACKGROUND: Early platelet transfusion is associated with reduced mortality in traumatic hemorrhage. However, platelet usage is severely limited because of the challenges of donor availability, platelet portability, and storage. Here, we report on a bioinspired synthetic platelet (SP) nanoconstruct that utilizes liposome surface-decoration with peptides that mimic injury site-specific platelet adhesion to von Willebrand Factor and collagen, and fibrinogen-mediated platelet aggregation. Synthetic platelet has previously shown promising hemostatic outcomes in vitro and in vivo. Here, we evaluated hemostasis and hemodynamic effects of SP in a rabbit model of abdominal hemorrhage. METHODS: Twenty-three adult male New Zealand white rabbits (2.5-3.5 kg) were treated with either buffer, control particles (CPs), or SP. Under general anesthesia with invasive monitoring, rabbits underwent laparotomy with combined splenic and hepatic injury. Hemodynamics were monitored for 30 minutes and blood loss was quantified. Blood counts, aggregometry, catecholamine and platelet factor 4 (PF4) assays were performed at multiple timepoints. Analysis used analysis of variance and post hoc Tukey testing with α = 0.05. RESULTS: Rabbits in the SP (n = 7) group had significantly lower weight-normalized blood loss compared with both buffer (n = 8) and CP (n = 8) animals (21.1 vs. 33.2 vs. 40.4 g/kg, p < 0.001). Synthetic platelet-treated animals had higher systolic blood pressure area under curve compared with buffer- and CP-treated animals (1567 vs. 1281 vs. 1109 mm Hg*min, p = 0.006), although post hoc differences were only significant for the SP/CP comparison ( p = 0.005). Platelet counts, catecholamine levels, PF4, and aggregometry were similar between groups. CONCLUSION: Synthetic platelet treatment significantly reduced blood loss and improved hemodynamics in a rabbit abdominal hemorrhage model. Synthetic platelet has potential as an intravenous hemostatic platelet surrogate with donor-independent availability and scalable manufacture.

Identifying barriers to shared decision-making about bariatric surgery in two large health systems.

OBJECTIVE: Prior research suggests shared decision-making (SDM) could improve patient and health care provider communication about bariatric surgery. The aim of this work was to identify and prioritize barriers to SDM around bariatric surgery to help guide implementation of SDM. METHODS: Two large US health care systems formed multidisciplinary teams to facilitate the implementation of SDM around bariatric surgery. The teams used a nominal group process approach involving (1) generation of multilevel barriers, (2) round-robin recording of barriers, (3) facilitated discussion, and (4) selection and ranking of barriers according to importance and feasibility to address. RESULTS: One health system identified 13 barriers and prioritized 5 as the most important and feasible to address. The second health system identified 14 barriers and prioritized 6. Both health systems commonly prioritized six barriers: lack of insurance coverage; lack of understanding of insurance coverage; lack of organizational prioritization of SDM; lack of knowledge about bariatric surgery; lack of interdepartmental clarity between primary and specialty care; and limited training on SDM conversations and tools. CONCLUSIONS: Health systems face numerous barriers to SDM around bariatric surgery, and these can be easily identified and prioritized by multistakeholder teams. Future research should seek to identify effective strategies to address these common barriers.

Reduction in Long-term Mortality After Sleeve Gastrectomy and Gastric Bypass Compared to Nonsurgical Patients With Severe Obesity.

OBJECTIVE: To separately compare the long-term risk of mortality among bariatric surgical patients undergoing either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) to large, matched, population-based cohorts of patients with severe obesity who did not undergo surgery. BACKGROUND: Bariatric surgery has been associated with reduced long-term mortality compared to usual care for severe obesity which is particularly relevant in the COVID-19 era. Most prior studies involved the RYGB operation and there is less long-term data on the SG. METHODS: In this retrospective, matched cohort study, patients with a body mass index ≥35 kg/m 2 who underwent bariatric surgery from January 2005 to September 2015 in three integrated health systems in the United States were matched to nonsurgical patients on site, age, sex, body mass index, diabetes status, insulin use, race/ethnicity, combined Charlson/Elixhauser comorbidity score, and prior health care utilization, with follow-up through September 2015. Each procedure (RYGB, SG) was compared to its own control group and the two surgical procedures were not directly compared to each other. Multivariable-adjusted Cox regression analysis investigated time to all-cause mortality (primary outcome) comparing each of the bariatric procedures to usual care. Secondary outcomes separately examined the incidence of cardiovascular-related death, cancer related-death, and diabetes related-death. RESULTS: Among 13,900 SG, 17,258 RYGB, and 87,965 nonsurgical patients, the 5-year follow-up rate was 70.9%, 72.0%, and 64.5%, respectively. RYGB and SG were each associated with a significantly lower risk of all-cause mortality compared to nonsurgical patients at 5-years of follow-up (RYGB: HR = 0.43; 95% CI: 0.35,0.54; SG: HR = 0.28; 95% CI: 0.13,0.57) Similarly, RYGB was associated with a significantly lower 5-year risk of cardiovascular-(HR = 0.27; 95% CI: 0.20, 0.37), cancer- (HR = 0.54; 95% CI: 0.39, 0.76), and diabetes-related mortality (HR = 0.23; 95% CI:0.15, 0.36). There was not enough follow-up time to assess 5-year cause-specific mortality in SG patients, but at 3-years follow-up, there was significantly lower risk of cardiovascular- (HR = 0.33; 95% CI:0.19, 0.58), cancer- (HR = 0.26; 95% CI:0.11, 0.59), and diabetes-related (HR = 0.15; 95% CI:0.04, 0.53) mortality for SG patients. CONCLUSION: This study confirms and extends prior findings of an association with better survival following bariatric surgery in RYGB patients compared to controls and separately demonstrates that the SG operation also appears to be associated with lower mortality compared to matched control patients with severe obesity that received usual care. These results help to inform the tradeoffs between long-term benefits and risks of bariatric surgery.

Characterization of the interaction of nanobubble ultrasound contrast agents with human blood components.

Nanoscale ultrasound contrast agents, or nanobubbles, are being explored in preclinical applications ranging from vascular and cardiac imaging to targeted drug delivery in cancer. These sub-micron particles are approximately 10x smaller than clinically available microbubbles. This allows them to effectively traverse compromised physiological barriers and circulate for extended periods of time. While various aspects of nanobubble behavior have been previously examined, their behavior in human whole blood has not yet been explored. Accordingly, herein we examined, for the first time, the short and long-term effects of blood components on nanobubble acoustic response. We observed differences in the kinetics of backscatter from nanobubble suspensions in whole blood compared to bubbles in phosphate buffered saline (PBS), plasma, or red blood cell solutions (RBCs). Specifically, after introducing nanobubbles to fresh human whole blood, signal enhancement, or the magnitude of nonlinear ultrasound signal, gradually increased by 22.8 ± 13.1% throughout our experiment, with peak intensity reached within 145 s. In contrast, nanobubbles in PBS had a stable signal with negligible change in intensity (-1.7 ± 3.2%) over 8 min. Under the same conditions, microbubbles made with the same lipid formulation showed a -56.8 ± 6.1% decrease in enhancement in whole blood. Subsequent confocal, fluorescent, and scanning electron microscopy analysis revealed attachment of the nanobubbles to the surface of RBCs, suggesting that direct interactions, or hitchhiking, of nanobubbles on RBCs in the presence of plasma may be a possible mechanism for the observed effects. This phenomenon could be key to extending nanobubble circulation time and has broad implications in drug delivery, where RBC interaction with nanoparticles could be exploited to improve delivery efficiency.

Glioma stem cells activate platelets by plasma-independent thrombin production to promote glioblastoma tumorigenesis.

Background: The interaction between platelets and cancer cells has been underexplored in solid tumor models that do not metastasize, for example, glioblastoma (GBM) where metastasis is rare. Histologically, it is known that glioma stem cells (GSCs) are found in perivascular and pseudsopalisading regions of GBM, which are also areas of platelet localization. High platelet counts have been associated with poor clinical outcomes in many cancers. While platelets are known to promote the progression of other tumors, mechanisms by which platelets influence GBM oncogenesis are unknown. Here, we aimed to understand how the bidirectional interaction between platelets and GSCs drives GBM oncogenesis. Methods: Male and female NSG mice were transplanted with GSC lines and treated with antiplatelet and anti-thrombin inhibitors. Immunofluorescence, qPCR, and Western blots were used to determine expression of coagulation mechanism in GBM tissue and subsequent GSC lines. Results: We show that GSCs activate platelets by endogenous production of all the factors of the intrinsic and extrinsic coagulation cascades in a plasma-independent manner. Therefore, GSCs produce thrombin resulting in platelet activation. We further demonstrate that the endogenous coagulation cascades of these cancer stem cells are tumorigenic: they activate platelets to promote stemness and proliferation in vitro and pharmacological inhibition delays tumor growth in vivo. Conclusions: Our findings uncover a specific preferential relationship between platelets and GSCs that drive GBM malignancies and identify a therapeutically targetable novel interaction.

Platelet-Inspired Intravenous Nanomedicine for Injury-Targeted Direct Delivery of Thrombin to Augment Hemostasis in Coagulopathies.

Severe hemorrhage associated with trauma, surgery, and congenital or drug-induced coagulopathies can be life-threatening and requires rapid hemostatic management via topical, intracavitary, or intravenous routes. For injuries that are not easily accessible externally, intravenous hemostatic approaches are needed. The clinical gold standard for this is transfusion of blood products, but due to donor dependence, specialized storage requirements, high risk of contamination, and short shelf life, blood product use faces significant challenges. Consequently, recent research efforts are being focused on designing biosynthetic intravenous hemostats, using intravenous nanoparticles and polymer systems. Here we report on the design and evaluation of thrombin-loaded injury-site-targeted lipid nanoparticles (t-TLNPs) that can specifically localize at an injury site via platelet-mimetic anchorage to the von Willebrand factor (vWF) and collagen and directly release thrombin via diffusion and phospholipase-triggered particle destabilization, which can locally augment fibrin generation from fibrinogen for hemostatic action. We evaluated t-TLNPs in vitro in human blood and plasma, where hemostatic defects were created by platelet depletion and anticoagulation. Spectrophotometric studies of fibrin generation, rotational thromboelastometry (ROTEM)-based studies of clot viscoelasticity, and BioFlux-based real-time imaging of fibrin generation under simulated vascular flow conditions confirmed that t-TLNPs can restore fibrin in hemostatic dysfunction settings. Finally, the in vivo feasibility of t-TLNPs was tested by prophylactic administration in a tail-clip model and emergency administration in a liver-laceration model in mice with induced hemostatic defects. Treatment with t-TLNPs was able to significantly reduce bleeding in both models. Our studies demonstrate an intravenous nanomedicine approach for injury-site-targeted direct delivery of thrombin to augment hemostasis.

Beyond the thrombus: Platelet-inspired nanomedicine approaches in inflammation, immune response, and cancer.

The traditional role of platelets is in the formation of blood clots for physiologic (e.g., in hemostasis) or pathologic (e.g., in thrombosis) functions. The cellular and subcellular mechanisms and signaling in platelets involved in these functions have been extensively elucidated and new knowledge continues to emerge, resulting in various therapeutic developments in this area for the management of hemorrhagic or thrombotic events. Nanomedicine, a field involving design of nanoparticles with unique biointeractive surface modifications and payload encapsulation for disease-targeted drug delivery, has become an important component of such therapeutic development. Beyond their traditional role in blood clotting, platelets have been implicated to play crucial mechanistic roles in other diseases including inflammation, immune response, and cancer, via direct cellular interactions, as well as secretion of soluble factors that aid in the disease microenvironment. To date, the development of nanomedicine systems that leverage these broader roles of platelets has been limited. Additionally, another exciting area of research that has emerged in recent years is that of platelet-derived extracellular vesicles (PEVs) that can directly and indirectly influence physiological and pathological processes. This makes PEVs a unique paradigm for platelet-inspired therapeutic design. This review aims to provide mechanistic insight into the involvement of platelets and PEVs beyond hemostasis and thrombosis, and to discuss the current state of the art in the development of platelet-inspired therapeutic technologies in these areas, with an emphasis on future opportunities.

Evaluation of Intensive Telephonic Nutritional and Lifestyle Counseling to Enhance Outcomes of Bariatric Surgery.

BACKGROUND: To determine the impact of an intensive perioperative nutritional and lifestyle support protocol on long-term outcomes of bariatric surgery. METHODS: A retrospective observational study was conducted of 955 patients who underwent gastric bypass surgery between 2005 and 2015. Patients were divided into two cohorts: (1) 2005 through August 2013: these 767 patients were required to participate in the intensive telephone-based nutritional support program from 8 weeks preoperative through 44 weeks postoperative; (2) after August 2013, the program was discontinued and 188 patients did not have intensive telephonic nutritional support. Inverse probability weighting was used to obtain weight loss estimates at 1 and 3 years postoperative. Time-to-event analyses were used to investigate hospitalization rates postoperative. Poisson models were used to investigate healthcare utilization. RESULTS: Patients who participated in the program exhibited 1.97% (95% CI 0.7, 3.3) greater %TWL at 1 year and 2.2% (95% CI -0.3, 4.1) greater %TWL at 3 years postoperative than patients who did not participate. Secondary analyses indicated participation in the program was associated with 44% shorter time to first hospitalization postoperative (p < 0.001). CONCLUSIONS: In this health system, intensive nutritional support was associated with greater weight loss at 1 and 3 years postoperative and higher hospitalization rates.

Cerebral Venous Thrombosis in Acute Lymphoblastic Leukemia with Severe COVID-19: a Case Report.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has brought an unprecedented upheaval in our health-care systems. Amongst the many challenges posed by the disease, increased risk of thromboembolism has presented a distinct new front for increased mortality and morbidity. While there are multiple documented evidences for the same, the exact mechanism, knowledge of groups at-risk, and mitigation strategies are evolving. We present a case of a young individual who was diagnosed with acute lymphoblastic leukemia (ALL), was started on appropriate chemotherapy, and subsequently developed severe COVID-19 pneumonia. He was treated for COVID-19 pneumonia and recovered from the illness. However, his recovery from COVID-19 was further complicated by cortical venous sinus thrombosis (CVT). Contrast enhanced magnetic resonance imaging (CEMRI) brain and magnetic resonance venography (MRV) revealed the diagnosis of CVT with hemorrhagic parenchymal changes. He was managed with therapeutic anticoagulation and cerebral decongestants and was subsequently shifted to oral anticoagulant therapy. While the case was managed at a tertiary care setting, it opened up the question of identifying the high-risk groups and to formulate guidelines for extended thromboprophylaxis in these patients.

A quality-improvement optimization pilot of BariFit, a mobile health intervention to promote physical activity after bariatric surgery.

Bariatric surgery is the most effective treatment for severe obesity (body mass index >40), helping individuals lose, on average, 25%-29% of their body weight over the first year. However, many patients begin to plateau and regain weight within 12-24 months, and 20% of patients begin to regain weight within 6 months postsurgery. As physical activity (PA) is an important predictor of weight loss and maintenance postsurgery, there is a need for scalable, effective lifestyle interventions to help bariatric patients increase PA in order to maximize their weight loss and maintenance. To assess feasibility of using mobile health (mHealth) tools to support PA postsurgery, we conducted a quality-improvement optimization pilot of BariFit, an mHealth intervention that combines commercial devices and custom text messages. Fifty-one bariatric patients enrolled in a 16-week optimization pilot of BariFit. To assess feasibility, pre-post changes in PA were assessed using activPAL. In addition, the pilot randomized, using a 2 × 2 factorial design, two adaptive approaches to daily step goals (variable and 60th percentile goals) and provision of rest days (yes/no), and microrandomized provision of SMS-delivered activity suggestions five times a day for each participant. Adherence to using study equipment was over 95% at 16 weeks. Participants increased PA by 1,866 steps from baseline to end-of-study (p < .007). Participants who received variable step goals averaged 1,141 more steps per day (p = .096) than those who received 60th percentile goals. Activity suggestions had no effect. mHealth interventions are feasible for supporting PA postbariatric surgery.

A polymer-based systemic hemostatic agent.

Uncontrolled noncompressible hemorrhage is a major cause of mortality following traumatic injuries in civilian and military populations. An injectable hemostat for point-of-care treatment of noncompressible hemorrhage represents an urgent medical need. Here, we describe an injectable hemostatic agent via polymer peptide interfusion (HAPPI), a hyaluronic acid conjugate with a collagen-binding peptide and a von Willebrand factor-binding peptide. HAPPI exhibited selective binding to activated platelets and promoted their accumulation at the wound site in vitro. In vivo studies in mouse tail vein laceration model demonstrated a reduction of >97% in both bleeding time and blood loss. A 284% improvement in the survival time was observed in the rat inferior vena cava traumatic model. Lyophilized HAPPI could be stably stored at room temperature for several months and reconstituted during therapeutic intervention. HAPPI provides a potentially clinically translatable intravenous hemostat.

Hemoglobin-based Oxygen Carriers: Current State-of-the-art and Novel Molecules.

In blood, the primary role of red blood cells (RBCs) is to transport oxygen via highly regulated mechanisms involving hemoglobin (Hb). Hb is a tetrameric porphyrin protein comprising of two α- and two ß-polypeptide chains, each containing an iron-containing heme group capable of binding one oxygen molecule. In military as well as civilian traumatic exsanguinating hemorrhage, rapid loss of RBCs can lead to suboptimal tissue oxygenation and subsequent morbidity and mortality. In such cases, transfusion of whole blood or RBCs can significantly improve survival. However, blood products including RBCs present issues of limited availability and portability, need for type matching, pathogenic contamination risks, and short shelf-life, causing substantial logistical barriers to their prehospital use in austere battlefield and remote civilian conditions. While robust research is being directed to resolve these issues, parallel research efforts have emerged toward bioengineering of semisynthetic and synthetic surrogates of RBCs, using various cross-linked, polymeric, and encapsulated forms of Hb. These Hb-based oxygen carriers (HBOCs) can potentially provide therapeutic oxygenation when blood or RBCs are not available. Several of these HBOCs have undergone rigorous preclinical and clinical evaluation, but have not yet received clinical approval in the USA for human use. While these designs are being optimized for clinical translations, several new HBOC designs and molecules have been reported in recent years, with unique properties. The current article will provide a comprehensive review of such HBOC designs, including current state-of-the-art and novel molecules in development, along with a critical discussion of successes and challenges in this field.

Trauma-targeted delivery of tranexamic acid improves hemostasis and survival in rat liver hemorrhage model.

BACKGROUND: Trauma-associated hemorrhage and coagulopathy remain leading causes of mortality. Such coagulopathy often leads to a hyperfibrinolytic phenotype where hemostatic clots become unstable because of upregulated tissue plasminogen activator (tPA) activity. Tranexamic acid (TXA), a synthetic inhibitor of tPA, has emerged as a promising drug to mitigate fibrinolysis. TXA is US Food and Drug Administration-approved for treating heavy menstrual and postpartum bleeding, and has shown promise in trauma treatment. However, emerging reports also implicate TXA for off-target systemic coagulopathy, thromboembolic complications, and neuropathy. OBJECTIVE: We hypothesized that targeted delivery of TXA to traumatic injury site can enable its clot-stabilizing action site-selectively, to improve hemostasis and survival while avoiding off-target effects. To test this, we used liposomes as a model delivery vehicle, decorated their surface with a fibrinogen-mimetic peptide for anchorage to active platelets within trauma-associated clots, and encapsulated TXA within them. METHODS: The TXA-loaded trauma-targeted nanovesicles (T-tNVs) were evaluated in vitro in rat blood, and then in vivo in a liver trauma model in rats. TXA-loaded control (untargeted) nanovesicles (TNVs), free TXA, or saline were studied as comparison groups. RESULTS: Our studies show that in vitro, the T-tNVs could resist lysis in tPA-spiked rat blood. In vivo, T-tNVs maintained systemic safety, significantly reduced blood loss and improved survival in the rat liver hemorrhage model. Postmortem evaluation of excised tissue from euthanized rats confirmed systemic safety and trauma-targeted activity of the T-tNVs. CONCLUSION: Overall, the studies establish the potential of targeted TXA delivery for safe injury site-selective enhancement and stabilization of hemostatic clots to improve survival in trauma.

Intravenous administration of synthetic platelets (SynthoPlate) in a mouse liver injury model of uncontrolled hemorrhage improves hemostasis.

BACKGROUND: Clinical resuscitative treatment of traumatic hemorrhage involves transfusion of RBC, platelets and plasma in controlled ratios. However, use of such blood components, especially platelets, present many challenges including availability, portability, contamination risks, and short shelf-life, which limit the use of platelet transfusions outside of large trauma centers such as remote civilian hospitals and austere prehospital settings. This has prompted significant research in platelet substitutes that may resolve the above issues while providing platelet-mimetic hemostatic action. In this framework, we have developed a synthetic platelet surrogate, SynthoPlate, by integrative decoration of platelet function mimetic peptides on a biocompatible lipid nanovesicle platform. We have previously demonstrated hemostatic capability of SynthoPlate in correcting tail-bleeding time in thrombocytopenic mice. Building on this, we hypothesized that SynthoPlate transfusion would decrease bleeding in a murine model of acute hemorrhagic shock. METHODS: A validated model of uncontrolled intraperitoneal hemorrhage, via liver laceration was used to induce hemorrhagic shock in mice. SynthoPlate, control (unmodified) particles, and normal saline were administered as pretreatment and recue infusions to mice undergoing liver laceration and evaluated for hemostatic benefit by determining differences in blood loss and monitoring real-time hemodynamic data. RESULTS: Pretreatment SynthoPlate transfusion resulted in significant reduction of blood loss following hemorrhage, compared with control particles or normal saline treatment (0.86 ± 0.16 g control particles [CP] vs. 0.84 ± 0.13 g normal saline [NS] vs. 0.68 ± 0.09 g SynthoPlate, p < 0.005). SynthoPlate transfused mice demonstrated improved hemodynamics taking significantly longer to develop post-injury hypotension (168.3 ± 106.6 seconds CP vs. 137 ± 58 seconds NS vs. 546.7 ± 329.8 seconds SynthoPlate, p < 0.05). SynthoPlate infusion following liver laceration, that is, rescue transfusion, also resulted in a significant decrease in blood loss (0.89 ± 0.17 g CP vs. 0.92 ± 0.19 g NS vs. 0.69 ± 0.18 g SynthoPlate, p < 0.05). CONCLUSION: Transfusion of SynthoPlate particles reduces blood loss in a murine model of liver injury, and SynthoPlates may represent a viable transfusion product for the mitigation of blood loss in acute, severe hemorrhagic shock.

Factor XII and uPAR upregulate neutrophil functions to influence wound healing.

Coagulation factor XII (FXII) deficiency is associated with decreased neutrophil migration, but the mechanisms remain uncharacterized. Here, we examine how FXII contributes to the inflammatory response. In 2 models of sterile inflammation, FXII-deficient mice (F12-/-) had fewer neutrophils recruited than WT mice. We discovered that neutrophils produced a pool of FXII that is functionally distinct from hepatic-derived FXII and contributes to neutrophil trafficking at sites of inflammation. FXII signals in neutrophils through urokinase plasminogen activator receptor-mediated (uPAR-mediated) Akt2 phosphorylation at S474 (pAktS474). Downstream of pAkt2S474, FXII stimulation of neutrophils upregulated surface expression of αMß2 integrin, increased intracellular calcium, and promoted extracellular DNA release. The sum of these activities contributed to neutrophil cell adhesion, migration, and release of neutrophil extracellular traps in a process called NETosis. Decreased neutrophil signaling in F12-/- mice resulted in less inflammation and faster wound healing. Targeting hepatic F12 with siRNA did not affect neutrophil migration, whereas WT BM transplanted into F12-/- hosts was sufficient to correct the neutrophil migration defect in F12-/- mice and restore wound inflammation. Importantly, these activities were a zymogen FXII function and independent of FXIIa and contact activation, highlighting that FXII has a sophisticated role in vivo that has not been previously appreciated.

Biomaterials and Advanced Technologies for Hemostatic Management of Bleeding.

Bleeding complications arising from trauma, surgery, and as congenital, disease-associated, or drug-induced blood disorders can cause significant morbidities and mortalities in civilian and military populations. Therefore, stoppage of bleeding (hemostasis) is of paramount clinical significance in prophylactic, surgical, and emergency scenarios. For externally accessible injuries, a variety of natural and synthetic biomaterials have undergone robust research, leading to hemostatic technologies including glues, bandages, tamponades, tourniquets, dressings, and procoagulant powders. In contrast, treatment of internal noncompressible hemorrhage still heavily depends on transfusion of whole blood or blood's hemostatic components (platelets, fibrinogen, and coagulation factors). Transfusion of platelets poses significant challenges of limited availability, high cost, contamination risks, short shelf-life, low portability, performance variability, and immunological side effects, while use of fibrinogen or coagulation factors provides only partial mechanisms for hemostasis. With such considerations, significant interdisciplinary research endeavors have been focused on developing materials and technologies that can be manufactured conveniently, sterilized to minimize contamination and enhance shelf-life, and administered intravenously to mimic, leverage, and amplify physiological hemostatic mechanisms. Here, a comprehensive review regarding the various topical, intracavitary, and intravenous hemostatic technologies in terms of materials, mechanisms, and state-of-art is provided, and challenges and opportunities to help advancement of the field are discussed.