fakiha siddiqui
Loyola University Chicago, Pathology, Graduate Student
The prevalence of thrombosis in lymphoma patients is reportedly high and ranges from 3-10%. Vascular malfunction and inflammatory processes further contribute to the thrombotic activation process in these patients. Andexanet alfa (AA) is... more
The prevalence of thrombosis in lymphoma patients is reportedly high and ranges from 3-10%. Vascular malfunction and inflammatory processes further contribute to the thrombotic activation process in these patients. Andexanet alfa (AA) is an antidote for factor Xa inhibitors and its usage has been reported with thrombotic complications. This study was designed to compare the effect of AA on the thrombin generation (TG) potential. Blood samples from 78 patients with confirmed diagnosis of non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL) and Chronic lymphocytic leukemia (CLL) were collected from the University of Belgrade Clinic, Serbia. Normal human plasma (NHP) was used for referencing purposes. Individual samples were supplemented with AA at 100 ug/ml. TG studies were carried out using a commercially available fluorogenic substrate method. TG parameters such as peak thrombin (PT), lag time (LT) and area under the curve (AUC) were compiled. Cumulatively, lymphoma patients showed an ...
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Low molecular weight heparins (LMWH) represent depolymerized heparin prepared by various methods that exhibit differential, biochemical and pharmacological profiles. Enoxaparin is prepared by benzylation followed by alkaline... more
Low molecular weight heparins (LMWH) represent depolymerized heparin prepared by various methods that exhibit differential, biochemical and pharmacological profiles. Enoxaparin is prepared by benzylation followed by alkaline depolymerization of porcine heparin. Upon the expiration of its patent, several biosimilar versions of enoxaparin have become available. Heparinox (Sodic enoxaparine; Cristália Produtos Químicos Farmacêuticos LTDA, Sao Paulo, Brazil) is a new biosimilar form of enoxaparin. We assessed the molecular weight and the biochemical profile of Heparinox and compared its properties to the original branded enoxaparin (Lovenox; Sanofi, Paris, France). Clotting profiles compared included activated clotting time, activated partial thromboplastin time (aPTT), and thrombin time (TT). Anti-protease assays included anti-factor Xa and anti-factor IIa activities. Thrombin generation was measured using a calibrated automated thrombogram and thrombokinetic profile included peak thro...
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Introduction: Unfractionated heparin (UFH) is the first line anticoagulant for the management of medical indications. UFH complexes with antithrombin to produce strong inhibition of thrombin and factor Xa. The UFHs are standardized using... more
Introduction: Unfractionated heparin (UFH) is the first line anticoagulant for the management of medical indications. UFH complexes with antithrombin to produce strong inhibition of thrombin and factor Xa. The UFHs are standardized using USP compliant amidolytic anti-Xa and IIa methods in defined conditions. Clinically used UFH is solely sourced from porcine mucosal tissue. Because of the shortage of porcine tissue and the African Swine Fever, the supply chain of this anticoagulant is compromised. Thus, there is a need for resourcing of this anticoagulant. Bovine and ovine mucosal sources represent alternate material for production of UFH. Previous studies have shown that bovine and ovine UFH exhibit anticoagulant effects which can be standardized by using the USP method. Additionally, the standardized heparins from various sources can be blended and their potency can be adjusted to exhibit comparable effects as the single sourced UFH. The purpose of this study is to evaluate the ph...
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Introduction: Currently, there is a shortage of porcine heparin due to several factors such as limited availability of porcine mucosa, supply chain issues, and increased usage due to COVID-19. This has warranted the development of heparin... more
Introduction: Currently, there is a shortage of porcine heparin due to several factors such as limited availability of porcine mucosa, supply chain issues, and increased usage due to COVID-19. This has warranted the development of heparin from alternate sources such as bovine and ovine mucosa which is abundantly available for this purpose. On a mass basis, commercially available porcine heparins exhibit a similar potency (200 units/mg) to their ovine counterpart (190 units/mg) and a higher potency in contrast to their bovine counterpart (130-150 units/mg). Therefore, at gravimetric levels, the porcine heparins exhibit stronger biochemical and pharmacological effects in various laboratory assays in comparison to bovine heparin and similar effects in comparison to ovine heparins. Since heparin is standardized in biologic units and cross referenced against USP or EP Standard, it is hypothesized that potency equated porcine, ovine, and bovine heparin will exhibit similar biologic activi...
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Introduction: Andexanet alfa (AA, Portola Pharmaceuticals, San Francisco, USA) is an approved reversal agent for the control of potential bleeding associated with apixaban and rivaroxaban. Beside the oral anti-Xa agents, parenteral forms... more
Introduction: Andexanet alfa (AA, Portola Pharmaceuticals, San Francisco, USA) is an approved reversal agent for the control of potential bleeding associated with apixaban and rivaroxaban. Beside the oral anti-Xa agents, parenteral forms of the inhibitors of factor Xa such as otamixaban (Sanofi Aventis, Paris, France) and DX9065a (Mitsubishi Pharmaceuticals, Tokyo, Japan) have also been developed. These agents represent synthetic organo-mimerics with comparable selectivity and inhibitory profile to the currently available oral anti-Xa agents. Parenteral anti-Xa agents are considered for clinical development. Andexanet alfa is a broad-spectrum neutralizing agent for anti-Xa drugs including heparin and heparino-mimerics. We hypothesized that andexanet alfa may also reverse the effects of such parenteral anti-Xa agents as otamixaban and DX9065a. This study is designed to compare the neutralization profile of andexanet alfa for apixaban and rivaroxaban with otamixaban and DX9065a in var...
Introduction: The multifactorial and complex pathophysiology of pulmonary embolism (PE) involves dysregulation of hemostatic system including fibrinolytic imbalance, endothelial compromise and generation of thrombotic mediators, along... more
Introduction: The multifactorial and complex pathophysiology of pulmonary embolism (PE) involves dysregulation of hemostatic system including fibrinolytic imbalance, endothelial compromise and generation of thrombotic mediators, along with cellular defects and hemodynamic derangement. It is estimated that 6000 cases of pulmonary embolism and DVT are reported yearly of which 1000 result in death. PE evolves from a pre-existing venous thrombus, obstructing pulmonary artery leading to pulmonary failure. The progression of clot formation results in increase in right ventricular pressure, systemic hypoperfusion, hypoxemia ischemia and eventually multi organ failure. Fibrinolytic dysregulation and generation of procoagulant mediators result in increased clot burden and lead to adverse outcomes. Profiling of the component of the fibrinolytic system for such mediators as the activators and inhibitors of fibrinolysis, vWF and cellular microparticles may provide additional insights into the p...
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Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN) are Severe Cutaneous Adverse Reactions (SCARS) characterized by fever and mucocutaneous lesions leading to necrosis and sloughing of the epidermis. Conjunctival lesions... more
Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN) are Severe Cutaneous Adverse Reactions (SCARS) characterized by fever and mucocutaneous lesions leading to necrosis and sloughing of the epidermis. Conjunctival lesions are reported in 85% of patients. The pathogenesis of SJS/TEN/SCARS is not completely understood. It is hypothesized that IL-13, IL-15 and Granulysin expressed in plasma and skin may play a role. We measured the circulating levels of these cytokines in the plasma using ELISA and their expression in the skin using immunofluorescence microscopy. A total of 12 SJS/TEN skin biopsy samples (8 SJS, 2 SJS/TEN overlap and 2 TEN) were analyzed. Biopsy samples from patients with Lichen Planus (an inflammatory condition of the skin and mucous membranes) served as controls. Studies were also performed in human corneal epithelial cells where expression of these cytokines were measured following a challenge with TNF-α (0, 1, 10 and 100 ng/ml). The intensity of immu...
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Definitive pharmacological therapies for COVID-19 have yet to be identified. Several hundred trials are ongoing globally in the hope of a solution. However, nearly all treatments rely on systemic delivery but COVID-19 damages the lungs... more
Definitive pharmacological therapies for COVID-19 have yet to be identified. Several hundred trials are ongoing globally in the hope of a solution. However, nearly all treatments rely on systemic delivery but COVID-19 damages the lungs preferentially. The use of a targeted delivery approach is reviewed where engineered products are able to reach damaged lung tissue directly, which includes catheter-based and aerosol-based approaches. In this review we have outlined various target directed approaches which include microbubbles, extracellular vesicles including exosomes, adenosine nanoparticles, novel bio-objects, direct aerosol targeted pulmonary delivery and catheter-based drug delivery with reference to their relative effectiveness for the specific lesions. Currently several trials are ongoing to determine the effectiveness of such delivery systems alone and in conjunction with systemic therapies. Such approaches may prove to be very effective in the controlled and localized COVID-...
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The complex pathophysiology of pulmonary embolism (PE) involves hemostatic activation, inflammatory processes, cellular dysfunction, and hemodynamic derangements. Due to the heterogeneity of this disease, risk stratification and diagnosis... more
The complex pathophysiology of pulmonary embolism (PE) involves hemostatic activation, inflammatory processes, cellular dysfunction, and hemodynamic derangements. Due to the heterogeneity of this disease, risk stratification and diagnosis remains challenging. Biochip-array technology provides an integrated high throughput method for analyzing blood plasma samples for the simultaneous measurement of multiple biomarkers for potential risk stratification. Using biochip-array method, this study aimed to quantify the inflammatory biomarkers such as interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and epidermal growth factor (EGF) in 109 clinically confirmed PE patients in comparison to the control group comprised of plasma samples collected from 48 healthy subjects. Cytokines IL-4, IL-6, IL-8, IL-10, IL-1β, and MCP-1 demonstrated ...
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Background One year after the declaration of the coronavirus disease 2019 (COVID-19) pandemic by the World Health Organization (WHO) and despite the implementation of mandatory physical barriers and social distancing, humanity remains... more
Background One year after the declaration of the coronavirus disease 2019 (COVID-19) pandemic by the World Health Organization (WHO) and despite the implementation of mandatory physical barriers and social distancing, humanity remains challenged by a long-lasting and devastating public health crisis. Management Non-pharmacological interventions (NPIs) are efficient mitigation strategies. The success of these NPIs is dependent on the approval and commitment of the population. The launch of a mass vaccination program in many countries in late December 2020 with mRNA vaccines, adenovirus-based vaccines, and inactivated virus vaccines has generated hope for the end of the pandemic. Current Issues The continuous appearance of new pathogenic viral strains and the ability of vaccines to prevent infection and transmission raise important concerns as we try to achieve community immunity against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and its variants. The need of a ...
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Introduction: Sulodexide represents a mixture of fast-moving heparin (FMH) and dermatan sulfate (DS) and has been used for the management of venous diseases such as DVT and related disorders. The purpose of this study is to compare... more
Introduction: Sulodexide represents a mixture of fast-moving heparin (FMH) and dermatan sulfate (DS) and has been used for the management of venous diseases such as DVT and related disorders. The purpose of this study is to compare sulodexide and its components with unfractionated heparin (UFH) to determine its suitability for the indications in which UFH is used. Materials and Method: Active pharmaceutical ingredients (API) versions of sulodexide, FMH and DS were obtained from Alfasigma. API versions of UFH were obtained from Medefil Inc. Normal human citrated plasma was obtained from blood bank of the Loyola University Medical Center. Each of the individual agents were supplemented in plasma at a graded concentration of 0.0-10 µg/mL. Clotting assays (PiCT, aPTT, PT and TT), anti-Xa and anti-IIa and thrombin generation studies were carried out. Results were compiled as mean ± SD of 3 individual determination. Result: In the clot based (PiCT, aPTT and TT), anti-Xa and IIa assays, bo...
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COVID-19 has proven to be particularly challenging given the complex pathogenesis of SARS-CoV-2. Early data have demonstrated how the host response to this novel coronavirus leads to the proliferation of pro-inflammatory cytokines,... more
COVID-19 has proven to be particularly challenging given the complex pathogenesis of SARS-CoV-2. Early data have demonstrated how the host response to this novel coronavirus leads to the proliferation of pro-inflammatory cytokines, massive endothelial damage, and generalized vascular manifestations. While SARS-CoV-2 primarily targets the upper and lower respiratory tract, other organ systems are also affected. SARS-CoV-2 relies on 2 host cell receptors for successful attachment: angiotensin-converting enzyme 2 and transmembrane protease serine 2. Clinicopathologic reports have demonstrated associations between severe COVID-19 and viral coagulopathy, resulting in pulmonary embolism; venous, arterial, and microvascular thrombosis; lung endothelial injury; and associated thrombotic complications leading to acute respiratory distress syndrome. Viral coagulopathy is not novel given similar observations with SARS classic, including the consumption of platelets, generation of thrombin, and...
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Andexanet alfa is a recombinant factor Xa decoy protein, designed to reverse bleeding associated with oral anti-Xa agents. Andexanet alfa is also reported to neutralize the effects of heparin-related drugs. This study focused on the... more
Andexanet alfa is a recombinant factor Xa decoy protein, designed to reverse bleeding associated with oral anti-Xa agents. Andexanet alfa is also reported to neutralize the effects of heparin-related drugs. This study focused on the neutralization profiles of unfractionated heparin (UFH), enoxaparin, and, a chemically synthetic pentasaccharide, fondaparinux by andexanet alfa. Whole blood clotting studies were carried out using thromboelastography (TEG) and activated clotting time (ACT). The anticoagulant profile of UFH, enoxaparin, and fondaparinux was studied using the activated partial thromboplastin time (aPTT), thrombin time (TT), and amidolytic anti-Xa, and anti-IIa methods. Thrombin generation inhibition was studied using the calibrated automated thrombogram system. Reversal of each of these agents was studied by supplementing andexanet alfa at 100 µg/mL. In the TEG, andexanet alfa produced almost a complete reversal of the anticoagulant effects of UFH and enoxaparin; however,...
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The introduction of direct oral anticoagulant drugs has added a new dimension to the management of thrombotic and cardiovascular diseases. Although clinical useful, the use of these drugs has been associated with bleeding complications of... more
The introduction of direct oral anticoagulant drugs has added a new dimension to the management of thrombotic and cardiovascular diseases. Although clinical useful, the use of these drugs has been associated with bleeding complications of varying magnitude. Until recently, there was no antidote available for the control of bleeding associated with DOAC's. Such traditional approaches as the use of blood products and mechanical methods have been used to control bleeding in past. Molecular approaches have resulted in the development of specific antidotes for the oral anti-Xa and anti-IIa drugs. Andexanet alfa is a molecularly modified recombinant human factor Xa which is developed as an antidote for rivaroxaban and apixaban. Praxbind is an antibody which neutralizes dabigatran. Both agents have approved by the FDA and the European Medicine Agency, while these two agents are valuable in the management of bleeding with DOAC's, their use is associated with various adverse responses. Since both agents are proteins, antibody generation and interactions with endogenous proteins may also contribute to some of the observed adverse effects. The clinical data on their use is rather limited and additional studies are warranted to optimize their use. A global antidote, Ciraparantag, (PER977) is also developed for the neutralization of DOAC's. Both the activated and non-activated forms of prothrombin complexes are reportedly effective as an antidote for DOAC's. Additional studies are needed to develop guidelines for the safe use of antidotes to minimize the observed complications with the use of antidotes.
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Introduction: Currently, there is a shortage of porcine heparin due to limited availability of porcine mucosa and supply chain issues. Bovine heparin has been used for clinical purposes globally and is being considered for reintroduction... more
Introduction: Currently, there is a shortage of porcine heparin due to limited availability of porcine mucosa and supply chain issues. Bovine heparin has been used for clinical purposes globally and is being considered for reintroduction in the U.S. On a mass basis, commercially available porcine heparins exhibit a higher potency (180-220 units/mg) than their bovine counterpart (130-150 units/mg). Therefore, at gravimetric levels, the porcine heparins exhibit stronger biochemical and pharmacological effects in comparison to bovine heparin. Since heparin is standardized in biologic units relative to the USP or EP Standard, it is hypothesized that potency equated porcine and bovine heparin will exhibit similar biologic activities in laboratory assays. The purpose of this study was to compare the biologic properties of the porcine and bovine heparin at USP potency equated levels in standardized laboratory assays used for measuring and monitoring heparins. Materials and Methods: Active ...
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Introduction: Currently there are four commercially available oral anti-Xa agents namely apixaban, betrixaban, edoxaban and rivaroxaban available for indication specific clinical use. All agents used are at a fixed dosage and their use... more
Introduction: Currently there are four commercially available oral anti-Xa agents namely apixaban, betrixaban, edoxaban and rivaroxaban available for indication specific clinical use. All agents used are at a fixed dosage and their use may be associated with potential hemorrhagic complications. Although factor Xa inhibitory effect is considered to be a surrogate marker for the biologic action of these drugs we have demonstrated that factor Xa inhibitory profile of apixaban, betrixaban, edoxaban, and rivaroxaban does not fully reflect their biologic spectrum (https://doi.org/10.1177/1076029619847524). Furthermore the prothrombin time (PT) and activated partial thromboplatin time (aPTT) methods are of limited sensitivity and are dependant on several other enodogenous factors. Prothrombinase induced clotting time (PiCT), (Pentaharm, Basel, Switzerland) is a sensitive test for the global monitoring of anticoagulant drugs including heparins and parenteral oral anti-Xa and anti-IIa agents...
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Introduction: Andexanet Alpha (Coagulation factor Xa recombinant, inactivated Zh-zo; AA, Portola Pharmaceuticals) is a recombinant factor Xa decoy protein which is designed to reverse the effects of apixaban and rivaroxaban and is... more
Introduction: Andexanet Alpha (Coagulation factor Xa recombinant, inactivated Zh-zo; AA, Portola Pharmaceuticals) is a recombinant factor Xa decoy protein which is designed to reverse the effects of apixaban and rivaroxaban and is approved for the control of bleeding complications associated with their use. The molecular modification in this recombinant protein involves the substitution of serine active site by alanine and the removal of the gamma-carboxyglutamic acid (GLA) domain to restrict its assemblage into prothrombinase complex. Beside the reversal of the effects of anti-Xa agents AA is also reported to neutralize the biologic effects of heparin and related drugs. Assay dependent variations in the neutralization profile of various factor Xa inhibitors by andexanet has been recently reported https://doi.org/10.1177/1076029619847524. Since heparin and related drugs also mediate their biologic actions by inhibiting factor Xa via AT complexation, it is hypothesized that AA may al...
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Introduction: The prevalence of thrombosis in lymphoma patients is reportedly high and ranges from 3 - 10%, and further increased at advanced stages of the disease especially in hgNHL. Inflammation and other vascular factors contribute to... more
Introduction: The prevalence of thrombosis in lymphoma patients is reportedly high and ranges from 3 - 10%, and further increased at advanced stages of the disease especially in hgNHL. Inflammation and other vascular factors contribute to the pathogenesis of these thrombotic complications. Biomarkers of hemostatic activation, vascular dysfunction and inflammation are elevated in lymphoma. We have previously reported that thrombin generation biomarkers such as D-Dimer, thrombin anti-thrombin complex (TAT) and prothrombin fragment (F1.2) along with inflammatory biomarkers are increased in cancer patients. Interestingly, despite an increase in thrombin generation markers, thrombin generation potential in these patients is decreased. This study was designed to compare the thrombin generation potential and its relevance to the generation of various biomarkers of hemostatic activation process and inflammatory responses. Methods: Citrated blood samples from 90 patients with confirmed diagn...
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Introduction: Sepsis associated coagulopathy (SAC) is commonly seen in patients which eventually leads to dysfunctional hemostasis and disseminated intravascular coagulation (DIC). Thrombin generation plays an important role in the... more
Introduction: Sepsis associated coagulopathy (SAC) is commonly seen in patients which eventually leads to dysfunctional hemostasis and disseminated intravascular coagulation (DIC). Thrombin generation plays an important role in the overall pathophysiology of this process. Previous studies have reported an increase in thrombin generation markers such as thrombin antithrombin complex (TAT) and prothrombin fragment (F1.2). (Hoppensteadt et al. Clin Appl Thromb Hemost. 2014 Mar;20(2):129-35). Sepsis eventually results in consumption coagulopathy in which some of the clotting factors are consumed. The purpose of this study is to determine the thrombin generation potential of baseline blood samples obtained from sepsis associated coagulopathy patients and demonstrate their relevance to thrombin generation markers. Materials and Methods: Baseline citrated blood samples were prospectively collected from 49 patients with sepsis and suspected DIC. DIC scores were determined according to the I...
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Introduction: Heparin prevents blood clots from forming in patients undergoing heart surgeries, dialysis, multiple other procedures, and for medical treatment of thrombosis such as associated with cancer. Currently, all heparin products... more
Introduction: Heparin prevents blood clots from forming in patients undergoing heart surgeries, dialysis, multiple other procedures, and for medical treatment of thrombosis such as associated with cancer. Currently, all heparin products in the U.S. are derived from the intestinal mucosa of pigs. Seventy-five percent of the crude porcine heparin used to make the active pharmaceutical ingredient (API) comes from outside the U.S., with a majority originating from China. Reintroduction of bovine heparin into the U.S. market would expand sources for this critical drug, thus addressing concerns about potential shortages and product adulteration. This study was undertaken to determine the bioequivalence of bovine and porcine heparins using assays relevant to the clinical setting. The assays used in this study were chosen because they overcome limitations of the conventional APTT for heparin monitoring. Selected TEG and ACT assays use whole blood which better simulates physiologic condition...
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Recombinant coagulation factor Xa (FXa), inactivated Zh-zo, also known as andexanet alfa (AA), is a modified version of human FXa that has been developed to neutralize FXa inhibitors. We studied the reversal effect of AA for these... more
Recombinant coagulation factor Xa (FXa), inactivated Zh-zo, also known as andexanet alfa (AA), is a modified version of human FXa that has been developed to neutralize FXa inhibitors. We studied the reversal effect of AA for these inhibitors in various anticoagulant and thrombin generation (TG) assays. Individual aliquots of normal human plasma containing 1 µg/mL of apixaban, betrixaban, edoxaban, and rivaroxaban, were supplemented with saline or AA at a concentration of 100 µg/mL. Clotting profiles include prothrombinase-induced clotting time, activated partial thromboplastin time, and prothrombin time. Factor Xa activity was measured using an amidolytic method. Thrombin generation was measured using a calibrated automated thrombogram. Differential neutralization of all 4 anticoagulants was noted in the activated clotting time and other clotting tests. The FXa activity reversal profile varied with an observed decrease in apixaban (22%), betrixaban (56%), edoxaban (28%), and rivarox...
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The currently available oral anti-Xa agents are claimed to produce their anticoagulant and antithrombotic effects solely by the inhibition of factor Xa. This study profiled various anti-Xa drugs in routinely used laboratory assays to... more
The currently available oral anti-Xa agents are claimed to produce their anticoagulant and antithrombotic effects solely by the inhibition of factor Xa. This study profiled various anti-Xa drugs in routinely used laboratory assays to demonstrate that their effects are not solely related to the anti-Xa activities. Apixaban, betrixaban, edoxaban, and rivaroxaban were obtained commercially. Native and citrated whole blood was used for the activated clotting time (ACT) and thromboelastography (TEG). Citrated plasma was used for monitoring the prothrombin time (PT), activated partial thromboplastin time (aPTT), Heptest, and prothrombinase-induced clotting time (PiCT) tests. An amidolytic method was used for the determination of anti-Xa effects. Thrombin-induced fibrinokinetics was monitored optically. Thrombin generation studies were carried out using the calibrated automated thrombogram. All of the anti-Xa agents produced concentration- and assay-dependent effects. In the ACT at 2.5 μg/...