Diabetes mellitus is associated with shortened activated partial thromboplastin time and increased fibrinogen values

Mechanisms of endothelial activation, hypercoagulation and thrombosis in COVID-19: a link with diabetes mellitus

Early since the onset of the COVID-19 pandemic, the medical and scientific community were aware of extra respiratory actions of SARS-CoV-2 infection. Endothelitis, hypercoagulation, and hypofibrinolysis were identified in COVID-19 patients as subsequent responses of endothelial dysfunction. Activation of the endothelial barrier may increase the severity of the disease and contribute to long-COVID syndrome and post-COVID sequelae. Besides, it may cause alterations in primary, secondary, and tertiary hemostasis. Importantly, these responses have been highly decisive in the evolution of infected patients also diagnosed with diabetes mellitus (DM), who showed previous endothelial dysfunction. In this review, we provide an overview of the potential triggers of endothelial activation related to COVID-19 and COVID-19 under diabetic milieu. Several mechanisms are induced by both the viral particle itself and by the subsequent immune-defensive response (i.e., NF-κB/NLRP3 inflammasome pathway, vasoactive peptides, cytokine storm, NETosis, activation of the complement system). Alterations in coagulation mediators such as factor VIII, fibrin, tissue factor, the von Willebrand factor: ADAMST-13 ratio, and the kallikrein-kinin or plasminogen-plasmin systems have been reported. Moreover, an imbalance of thrombotic and thrombolytic (tPA, PAI-I, fibrinogen) factors favors hypercoagulation and hypofibrinolysis. In the context of DM, these mechanisms can be exacerbated leading to higher loss of hemostasis. However, a series of therapeutic strategies targeting the activated endothelium such as specific antibodies or inhibitors against thrombin, key cytokines, factor X, complement system, the kallikrein-kinin system or NETosis, might represent new opportunities to address this hypercoagulable state present in COVID-19 and DM. Antidiabetics may also ameliorate endothelial dysfunction, inflammation, and platelet aggregation. By improving the microvascular pathology in COVID-19 and post-COVID subjects, the associated comorbidities and the risk of mortality could be reduced.

A lone spike in blood glucose can enhance the thrombo-inflammatory response in cortical venules

How transient hyperglycemia contributes to cerebro-vascular disease has been a challenge to study under controlled physiological conditions. We use amplified, ultrashort laser-pulses to physically disrupt brain-venule endothelium at targeted locations. This vessel disruption is performed in conjunction with transient hyperglycemia from a single injection of metabolically active D-glucose into healthy mice. The observed real-time responses to laser-induced disruption include rapid serum extravasation, platelet aggregation, and neutrophil recruitment. Thrombo-inflammation is pharmacologically ameliorated by a platelet inhibitor, by a scavenger of reactive oxygen species, and by a nitric oxide donor. As a control, vessel thrombo-inflammation is significantly reduced in mice injected with metabolically inert L-glucose. Venules in mice with diabetes show a similar response to laser-induced disruption and damage is reduced by restoration of normo-glycemia. Our approach provides a controlled method to probe synergies between transient metabolic and physical vascular perturbations and can reveal new aspects of brain pathophysiology.

Midlife Hemostasis Measures, 20-Year Cognitive Decline, and Incident Dementia

BACKGROUND AND OBJECTIVES

Blood concentrations of hemostatic factors affect thrombosis and bleeding diathesis and may contribute to cognitive impairment through modifiable vascular pathologies. Whether hemostasis, assessed in middle age, is associated with late-life cognitive impairment remains largely unknown in a community-dwelling population.

METHODS

Using data from 14,128 participants with cognitive function measurements in 1990-1992 from the Atherosclerosis Risk in Communities study, we assessed the associations of hemostasis measures with 20-year changes in cognitive performance and incident dementia. Activated partial thromboplastin time (aPTT) and level of fibrinogen, von Willebrand factor (VWF), factor VIII, factor VII, factor XI, d-dimer, and soluble thrombomodulin were measured in 1987-1989 or 1993-1995. Hemostasis measures were categorized into quintiles, with the lowest quintile indicating low coagulability. Cognitive performance was characterized using a combined z-score from 3 tests (that is, delayed word recall test [DWRT], digit symbol substitution [DSST], and word fluency test [WFT]), assessed in 1990-1992, 1996-1998, and 2011-2013. Dementia was determined either from in-person evaluations or using dementia surveillance through 2017. Mixed-effects models and Cox proportional hazards models were used to assess cognitive trajectories and risk of dementia, respectively.

RESULTS

Among 12,765 participants with hemostasis measures in 1987-1989, who were aged 47-70 years at the first cognitive assessment, we observed significant trends of shorter aPTT (p for trend <0.001; difference in 20-year cognitive decline for fifth vs first quintile [Q5 vs Q1]: -0.104 [95% CI -0.160 to -0.048]) and higher levels of factor VII (p < 0.002; Q5 vs Q1: -0.085 [-0.142, -0.028]) and factor VIII (p = 0.033; Q4 vs Q1: -0.055 [-0.111, -0.000]) with greater 20-year cognitive declines. The associations with the decline in DSST were stronger than those with the decline in WFT or DWRT. Consistently, shorter aPTT and higher factor VIII levels were associated with higher dementia risk with HRs for Q5 vs Q1 of 1.23 (95% CI 1.07 to 1.42) and 1.17 (1.01-1.36), respectively, and p for trend of 0.008 and 0.024, respectively.

DISCUSSION

Overall, our study found consistent trend associations of aPTT and factor VIII measured in midlife with cognitive decline and incident dementia over 20 years, likely driven by vascular pathologies.

The Role of Platelets in the Pathogenesis and Pathophysiology of Adenomyosis

Widely viewed as an enigmatic disease, adenomyosis is a common gynecological disease with bewildering pathogenesis and pathophysiology. One defining hallmark of adenomyotic lesions is cyclic bleeding as in eutopic endometrium, yet bleeding is a quintessential trademark of tissue injury, which is invariably followed by tissue repair. Consequently, adenomyotic lesions resemble wounds. Following each bleeding episode, adenomyotic lesions undergo tissue repair, and, as such, platelets are the first responder that heralds the subsequent tissue repair. This repeated tissue injury and repair (ReTIAR) would elicit several key molecular events crucial for lesional progression, eventually leading to lesional fibrosis. Platelets interact with adenomyotic cells and actively participate in these events, promoting the lesional progression and fibrogenesis. Lesional fibrosis may also be propagated into their neighboring endometrial-myometrial interface and then to eutopic endometrium, impairing endometrial repair and causing heavy menstrual bleeding. Moreover, lesional progression may result in hyperinnervation and an enlarged uterus. In this review, the role of platelets in the pathogenesis, progression, and pathophysiology is reviewed, along with the therapeutic implication. In addition, I shall demonstrate how the notion of ReTIAR provides a much needed framework to tether to and piece together many seemingly unrelated findings and how it helps to make useful predictions.

Liver protection and hemostatic effects of medicinal plant Arnebia euchroma (Royle) I.M.Johnst extract in a rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Arnebia euchroma (Royle) I.M.Johnst. (AE) is a Chinese medicinal herb that is traditionally used to treat various circulatory diseases. It exhibits certain effects, such as the promotion of blood circulation and cooling, rash clearance, and detoxification.

AIM OF THE STUDY

This study was designed to explore the hepatoprotective and hemostatic effects of the ethyl acetate extract of AE in rats with carbon tetrachloride (CCl4)-induced liver injury.

MATERIALS AND METHODS

Wistar rats were treated via oral gavage with different doses of the ethyl acetate extract of AE (3.5, 7, or 14 g kg^-1·day^-1) for 14 consecutive days, following which hemostatic and liver function tests were conducted. For the hemostatic tests, the platelet count, blood platelet aggregation, blood platelet adhesion to fibrinogen, platelet factor 4 (PF-4) secretion from blood platelets, prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen levels were measured at the end of the treatment period. For the liver function tests, 0.25 mL/200 g (1.25 mL kg^-1·day^-1) of olive oil was injected into the abdominal cavity of the control rats, whereas 15% CCl₄ plus olive oil (prescription: 7.5 mL CCl₄ + 42.5 olive oil) was injected into that of the treated rats at 1 h after extract administration on day 6, 13, and 20. Additionally, food and water were withheld from all the animals. On the following day, the rats were anesthetized and their albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), gamma-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH), reactive oxygen species (ROS), methane dicarboxylic aldehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels were measured. Glutathione S-transferase (GST), glutathione reductase (GR), and glutathione peroxidase (GPx) levels among the groups were determined using a one-way analysis of variance.

RESULTS

The platelet count and blood platelet aggregation, blood platelet adhesion to fibrinogen and PF-4 secretion levels were significantly increased in the (3.5 g kg^-1 day^-1) AE group as compared to those in the control group (all p < 0.001; for the 7 and 14 g kg^-1 day^-1 AE groups, all p > 0.05, respectively). Although the PT and aPTT were not affected by the AE extract (all p > 0.05), the TT was reduced and the FIB levels were significantly increased in all AE groups (p < 0.05). Liver function tests showed that CCl₄ caused significant liver damage, thereby decreasing the albumin, SOD, CAT, GSH, GST, GR, and GPx levels, while increasing the AST, ALT, ALP, SGOT, SGPT, GGT, LDH, ROS, and MDA levels (all p < 0.001). By contrast, treatment with the different doses of AE extract reversed the CCl₄ effects on all these parameters. Compared with the levels in the CCl₄ group, the GSH and GR levels in the three AE groups (3.5, 7, and 14 g kg^-1·day^-1) were significantly higher (p < 0.05, p < 0.01, and p < 0.001, respectively), whereas the differences in the other parameters for these three groups were all at the significance levels of p < 0.05, p < 0.05, and p < 0.01, respectively.

CONCLUSIONS

AE extracts administered orally exhibited hepatoprotective activity by affecting platelet production and blood coagulation and ameliorating liver function-damaging modifications. Specifically, a dosage of 3.5 g kg^-1·day^-1 resulted in the most optimal effects.

Diabetes mellitus and diabetic nephropathy: a review of the literature on hemostatic changes in coagulation and thrombosis

Vascular complications lead to morbidity and mortality in patients with diabetes. Diabetic nephropathy (DN) is one of the main life-threatening problems for these patients, as it is the main cause of end-stage renal disease. This study aimed to measure the clinical effects of diabetes in patients with diabetes and in patients with diabetic nephropathy. Improved hypoglycemic control in patients with diabetes could impressively reduce platelet hyperreactivity, and oxidative stress alters the levels of many coagulation and thrombosis factors, resulting in an abnormal hemostasis and impaired levels of numerous serum markers. Most studies have revealed that coagulation factor levels are high in patients with diabetes and nephrodiabetes. Serum inflammatory factors, and coagulation and endothelial functions are good predictors of diabetic nephropathy. This literature review was conducted with access to scholarly databases and Google Scholar through Qassim University, and it analyzes studies from early 2010 until November 2020. Many studies have inferred that diabetes severely affects hemostasis and increases the risk of cardiovascular disease.

Association of Inflammatory Markers/Cytokines with Cardiovascular Risk Manifestation in Patients with Endometriosis

This study is aimed at determining the association of inflammatory markers and proinflammatory cytokines with cardiovascular risk manifestation in women with endometriosis as compared to healthy controls. A total of 181 females of reproductive age with the absence of other inflammatory or autoimmune disorders and a lack of hormonal therapy for at least 6 months voluntarily participated in this investigation. Patients were 81 females, laparoscopically diagnosed with endometriosis, while the control group comprised 80 healthy females without any pelvic pathology. All subjects were 20-40 years of age. Exclusion criteria were diabetes, obesity, hypertension, metabolic diseases, cardiovascular, and renal disorders. C-reactive protein, fibrinogen, homocysteine, interleukin-17, and interleukin-33 were analyzed using commercially available ELISA kits. For statistical interpretation, the unpaired Student “t” test was used. All inflammatory markers and cytokines demonstrated elevated levels (P < 0.001) in endometriosis patients as compared to healthy controls. The results of the study revealed that the patients with endometriosis demonstrate a hypercoagulable status due to inflammation, which initiates atherosclerosis and associated complications. Hence, endometriosis can cause a risk of cardiovascular disorders in these patients.

Hemostatic state of children with type 1 diabetes

PURPOSE

Hyperglycemia is one of the factors responsible for the molecular alterations that modify hemostasis. The aim of this study was to determine the levels of circulating molecules that have a prothrombotic impact on the child and adolescent population with type 1 diabetes mellitus.

METHODS

There were 35 patients with type 1 diabetes mellitus (11.0±2.5 years of age and a median 3.7±2.0 years of the disease) with no vascular complications and 20 healthy controls with similar age, sex, and body mass index included in the study. The evaluated parameters were fibrinogen, plasminogen activator inhibitor-1 (PAI1), von Willebrand factor antigen, and standard coagulation tests (platelet count, prothrombin time, and activated partial thromboplastin time). Glycemic control was evaluated by hemoglobin A1c and fasting blood glucose tests, and the presence of retinopathy and nephropathy was ruled out. The data obtained were analyzed by IBM SPSS Statistics ver. 20.0 and expressed as mean±standard deviation. The Pearson correlation coefficient was applied to investigate correlations between variables.

RESULTS

Diabetic patients showed significantly higher levels of fibrinogen (308±66 mg/dL vs. 246±18 mg/dL, P=0.0001), PAI-1 (41.6±12 ng/mL vs. 11.7±1.0 ng/mL, P=0.0001), and von Willebrand factor antigen (284%±55% vs. 121%±19%, P=0.0001). However, standard coagulation tests did not show differences between the 2 groups. PAI-1 was correlated with glycemia, hemoglobin A1c, fibrinogen, and von Willebrand factor antigen.

CONCLUSION

Elevated levels of fibrinogen, PAI-1, and von Willebrand factor antigen were found in the pediatric and adolescent population with type 1 diabetes mellitus, which suggests a prothrombotic state.

Valproic acid influences the expression of genes implicated with hyperglycaemia-induced complement and coagulation pathways

Because the liver plays a major role in metabolic homeostasis and secretion of clotting factors and inflammatory innate immune proteins, there is interest in understanding the mechanisms of hepatic cell activation under hyperglycaemia and whether this can be attenuated pharmacologically. We have previously shown that hyperglycaemia stimulates major changes in chromatin organization and metabolism in hepatocytes, and that the histone deacetylase inhibitor valproic acid (VPA) is able to reverse some of these metabolic changes. In this study, we have used RNA-sequencing (RNA-seq) to investigate how VPA influences gene expression in hepatocytes. Interesting, we observed that VPA attenuates hyperglycaemia-induced activation of complement and coagulation cascade genes. We also observe that many of the gene activation events coincide with changes to histone acetylation at the promoter of these genes indicating that epigenetic regulation is involved in VPA action.

Fibrinogen Glycation and Presence of Glucose Impair Fibrin Polymerization-An In Vitro Study of Isolated Fibrinogen and Plasma from Patients with Diabetes Mellitus

Background: Fibrin formation and structure may be affected by a plethora of factors, including both genetic and posttranslational modifications, such as glycation, nitration or acetylation. Methods: The present study examines the effect of fibrinogen glycation on fibrin polymerization, measured in fibrinogen concentration-standardized plasma of subjects with type 2 diabetes mellitus (T2DM) and in a solution of human fibrinogen exposed to 30 mM glucose for four days. Results: The fibrin polymerization velocity (V_max) observed in the T2DM plasma (median 0.0056; IQR 0.0049‒0.0061 AU/s) was significantly lower than in non-diabetic plasma (median 0.0063; IQR 0.0058‒0.0071 AU/s) (p < 0.05). Furthermore, significantly lower V_max was observed for glucose-treated fibrinogen (V_max 0.046; IQR 0.022‒0.085 AU/s) compared to control protein incubated with a pure vehicle (V_max 0.053; IQR 0.034‒0.097 AU/s) (p < 0.05). The same tendency was observed in the fibrinogen samples supplemented with 6 mM glucose just before measurements. It is assumed that glucose may affect the ability of fibrinogen to form a stable clot in T2DM subjects, and that this impairment is likely to influence the outcomes of some diagnostic assays. As the example, the impaired clotting ability of glycated fibrinogen may considerably influence the results of the standard Clauss method, routinely used to determine fibrinogen concentration in plasma. The stoichiometric analysis demonstrated that spontaneous glycation at both the sites with high and low glycation potential clearly dominated in T2DM individuals in all fibrinogen chains.

Study of Prothrombotic Changes in Metabolic Syndrome

The metabolic syndrome is a complex disorder of various metabolic risk factors in a single individual having central obesity and commonly associated with diabetes and cardiovascular diseases. The aim of our study was to study the relationship between coagulation abnormalities and metabolic syndrome. We performed a prospective cross-sectional study in a tertiary care hospital. A total of fifty cases of metabolic syndrome and fifty age & sex matched controls were selected. These two groups were investigated for Prothrombin Time (PT), Activated Partial Thromboplastin Time (APTT), Fibrinogen levels, Plasminogen Activator Inhibitor 1(PAI1) levels and Factor VIII levels. In cases with metabolic syndrome, significantly increased levels of Fibrinogen, Factor VIII and Plasminogen Activator Inhibitor1 (PAI1) were observed. PT & APTT were shorter in cases with metabolic syndrome. The coagulation parameters studied, correlated significantly with the components of metabolic syndrome. Metabolic syndrome is a hypercoagulable state and further studies are required for further evaluation of the consequences of this hypercoagulable state. There is a need for clinical trials evaluating prophylactic anticoagulation for prevention of venous thrombosis in patients with metabolic syndrome.

Is there a correlation between inflammatory markers and coagulation parameters in women with advanced ovarian endometriosis?

Background

Endometriosis is defined as a chronic inflammatory disease. Recent studies have shown that increased coagulation parameters including fibrinogen and platelets are associated with endometriosis. The objective of this study was to determine the levels of inflammatory markers and coagulation parameters and their correlations in women with endometriomas compared to those with benign ovarian cysts or normal pelvic anatomy.

Methods

Between June 2015 and June 2017, a total of 548 women who underwent laparoscopic/laparotomic surgery for ovarian endometriomas (OMA group, n = 226), non-endometriosis benign ovarian cysts (Cyst group, n = 210) and tubal reanastomosis (Control group, n = 112) were recruited in this study. Inflammatory markers including c-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and coagulation parameters including platelet count, thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time, and plasma fibrinogen as well as CA-125 were determined.

Results

Compared with Cyst group and Control group, TT and PT in OMA group were significantly shorter and plasma fibrinogen levels were significantly higher (P < 0.05). Moreover, the levels of plasma fibrinogen were positively correlated with CRP, NLR and PLR (P < 0.05). In addition, the confidence intervals for the area under the curve (AUC) for CA-125 × fibrinogen were significantly higher than those for CA-125 (0.904–0.952 vs. 0.899–0.949) in the diagnosis of endometrioma.

Conclusions

These results indicate that women with endometriomas demonstrate a hypercoagulable status due to the inflammatory nature of endometriosis. The combined determination for CA-125 and fibrinogen demonstrate a higher area under the curve than the single detection of CA-125 in those with endometriomas compared to these with benign ovarian cysts.

Trial registration

This study was approved by the Human Ethics Committee of the Women’s Hospital, School of Medicine, Zhejiang University (No.20170174) and all women provided written informed consent.

Relationship between hemoglobin A1c and serum troponin in patients with diabetes and cardiovascular events

OBJECTIVES

Diabetes mellitus is a group of metabolic disorders associated with high risk for cardiovascular disease. Although troponins are primarily clinically used for the diagnosis of acute coronary syndrome, they are also used in risk assessment in patients with acute coronary syndrome as well as in a number of other conditions. The aim of this review was to investigate the relationship between hemoglobin A1c and serum troponin in patients with diabetes and cardiovascular events.

METHODS

Hemoglobin A1c has been chosen as the best clinical indicator of glucose control and risk of micro and macrovascular complications. We investigated cardiac troponins as a group of markers of muscle injury which includes troponin T, troponin I and troponin C. Troponin T and I are specific for myocardial injury, compared to C which is specific for skeletal muscle.

RESULTS

In this review, we showed that there was a causal relation between hemoglobin A1c levels and serum troponin concentrations. Hemoglobin A1c has shown to be a positive predictive factor of incidence, mortality and morbidity of conditions such as acute coronary syndrome, arrhythmias, stroke, pulmonary embolism and other conditions that causes troponin elevation by its release in circulation.

CONCLUSIONS

Chronic hyperglycemia decreases glomerular filtration and consequently decreases troponin elimination and also by affecting the heart microcirculation it leads to microvascular damage and consequently to ischemia which contribute to troponin concentration elevation. Furthermore, correlation between hemoglobin A1c and troponin concentration manifests in their prognostic value for mortality.

Prothrombin time, activated partial thromboplastin time and platelet counts of type II diabetes mellitus: a comparative study

Background

The incidence of cardiovascular disease due to thrombosis is 2-4 folds greater in diabetic patients. Prothrombin time, activated partial thromboplastin time and platelet count are hematological indices that give an insight into the coagulation status. Hence, this study aims to assess the coagulation status of type II diabetic patients.

Methods

A comparative cross-sectional study was conducted at Bahir Dar Felege Hiwot referral hospital, Northwest Ethiopia. A total of 40 treated type II diabetic, 40 untreated diabetics and 40 non-diabetic subjects were included. After taking informed consent, structured questionnaire was used to collect socio-demographic data. Following interview, 4 ml of blood was collected to determine PT, aPTT and platelet count of the three groups. The data were entered into SPSS version 20 and analyzed. One-way ANOVA was used to compare means of PT, aPTT and platelet count among the groups. A P value less than 0.05 was considered as statistically significant.

Results

The mean aPTT of non-diabetic, treated and untreated type II diabetic patient was 32.8 ± 4.12 s, 34.4 ± 5.3 s, and 25.42 ± 8.46 s, respectively. The proportion of untreated diabetic patients with normal PT, aPTT and platelet counts was 60.0%, 7.5 and 92.5%, respectively. There was a significant shortening of aPTT in untreated diabetic as compared to both treated and non-diabetic controls (P < 0.001).

Conclusions

Shortening of aPTT in untreated type II diabetic patients might be useful marker in patients with diabetes. Therefore, monitoring the aPTT in newly diagnosed diabetic patients is important.

Hemostatic Abnormality and Associated Factors in Diabetic Patients at Jimma University Specialized Hospital, Jimma, Southwest Ethiopia: A Comparative Cross-sectional Study

BACKGROUND

Diabetes mellitus is a group of heterogeneous disorders of multiple etiologies characterized by chronic hyperglycemia resulting from defects in insulin secretion and/or insulin action. Diabetes mellitus has been reported to disturb normal hemostasis by various mechanisms. However, data on hemostasis of diabetic patients in the study area are lacking. This study was aimed at determining hemostatic profile and associated factors of hemostatic abnormality in diabetic patients.

METHODS

A comparative cross-sectional study was conducted involving a total of 238 (119 diabetic and 119 apparently healthy) individuals who came to the chronic care clinic, Jimma University Specialized Hospital. Socio-demographic and clinical data were collected through a structured questionnaire. A blood sample of 10ml was collected in EDTA (4ml), citrate (3ml) and chemistry (3ml) tubes to do platelet count, coagulation tests, and glucose and lipid profile analysis, respectively. Descriptive statistics as well as the median (25th, 75th) percentile and Mann Whitney U test were used during data analysis.

RESULTS

The overall hemostatic abnormality in diabetes individuals was 58.8%. The median (25th, 75th percentile) prothrombin time for diabetic and non-diabetic subjects was (12.8, 15.6) vs. (12.8, 14.2), respectively, and the difference was not statistically significant (p>0.05). The median (25th, 75th percentile) activated partial thromboplastin time was significantly different between the two groups (p<0.0001); (24, 36.8) vs. (36, 39.6). The median (25th, 75th percentile) fibrinogen level was significantly different between the two groups (p<0.0001); (277, 462) vs. (243, 328). The median (25th, 75th percentile) platelet count was also significantly different between the two groups (p<0.0001); (146,248) vs. (190,319). All variables were not significantly associated with hemostatic abnormality in multivariate regression analysis.

CONCLUSION

An overall hemostatic abnormality in diabetic patients was found to be high. The APTT and platelet count were lower in diabetic patients whilst the fibrinogen level was higher. Routine coagulation tests should be part of tests among diabetic patients. Advanced coagulation tests should also be considered to identify specific markers so as to pinpoint the particular problem.

Association of coagulation profile with microvascular complications and glycemic control in type 2 diabetes mellitus - a study at a tertiary care center in Delhi

Introduction

Type 2 diabetes mellitus, characterized by insulin resistance, corresponds to approximately 90% of cases of diabetes worldwide. Hyperglycemia in diabetes contributes to hyperfibrinogenemia and activates the coagulation cascade thereby producing atherothrombotic events.

Objectives

This study was designed to evaluate the coagulation profile (activated partial thromboplastin time, prothrombin time and fibrinogen) in Type 2 diabetes and to analyze correlations between body mass index, fasting blood glucose, glycated hemoglobin and duration of diabetes with coagulation parameters.

Methods

This study included 60 type 2 diabetics and 30 controls. Diabetic patients were grouped in two sets based on the presence or absence of microvascular complications. The demographic profile and clinical details were recorded. Fasting blood glucose, glycated hemoglobin, coagulation parameters such as prothrombin time, activated partial thromboplastin time and fibrinogen along with other biochemical parameters were investigated.

Results

There were statistically significant differences in the coagulation parameters between the two groups of diabetics (with and without complications). The present study also found significant correlations between age and the duration of diabetes with and without complications and coagulation parameters such as the activated partial thromboplastin time, which was found to be significantly lower, and fibrinogen, which was found to be significantly higher in subjects with complications compared to subjects without complications.

Conclusion

Clinical tests for prothrombin time, activated partial thromboplastin time and fibrinogen are relatively inexpensive and readily available. The present study shows that shortened prothrombin time, activated partial thromboplastin time and increased fibrinogen levels might be useful hemostatic markers in diabetic patients, especially in those at high-risk for thrombotic complications.

The effects of nattokinase supplementation on collagen–epinephrine closure time, prothrombin time and activated partial thromboplastin time in nondiabetic and hypercholesterolemic subjects

For 8 weeks, individuals who consumed nattokinase, considered one of the most active functional ingredients found in natto, showed improved hemostatic factors.

High risk of coagulopathy among Type-2 Diabetes Mellitus clients at a municipal hospital in Ghana

Background

Persistent hyperglycaemia in diabetes mellitus causes coagulopathies due to glycation of haemoglobin, prothrombin, fibrinogen and other proteins involved in the clotting mechanism. Shortened activated partial thromboplastin time (APTT) and prothrombin time (PT) reflect hypercoagulable state, which is associated with an increased thrombotic risk and adverse cardiovascular effects. This study assessed the coagulation profile of type 2 diabetes mellitus (T2DM) clients at a municipal hospital in Ghana.

Methods

A hospital-based case-control study was conducted from January to April 2015 at the Agona Swedru Municipal Hospital. Sixty (60) persons with T2DM and 40 without were recruited and screened using appropriate protocols. Blood samples were collected for coagulation and biochemical tests. Demographic and clinical information were collected using pre-tested questionnaire. Data was analyzed with GraphPad Prism version 5.

Results

APTT and PT were significantly shorter among patients with T2DM compared to those without (20.88 ± 5.19 v 31.23 ± 5.41, P=0.0001; and 11.03 ± 2.06sec v 14.46 ± 1.86, P=0.0001 respectively). INR was decreased among patients with T2DM compared to those without (0.83 ± 0.18 v 1.13 ± 0.17, P=0.0001). No significant difference was found in platelet count between T2DM and non-diabetics (179.85 ± 66.15×10³ /mm³ v 168.55 ± 35.77×10³ /mm³, P=0.326). Serum magnesium was lower among the T2DM patients compared to the non-diabetics, while serum ionized calcium was significantly higher among the T2DM patients (P<0.05).

Conclusion

Clients with T2DM may have a high coagulation risk evidenced by shortened APTT, PT and a high ionized calcium compared with controls.

Funding

Study was funded by Lord Ampomah and Solomon Panford.

Diabetes mellitus: A review of some of the prognostic markers of response to treatment and management

Background: The WHO defined ‘diabetes mellitus’ (DM) as a metabolic disorder characterised by chronic hyperglycaemia with disturbances of carbohydrate, fat and protein metabolism resulting from the defect in insulin secretion, or inaction, or both. When not identified early and controlled, acute and chronic life-threatening consequences may result. Identifying DM early for treatment and management, as well as clinically monitoring recovery and improvement during treatment, involves the assessments of biomarkers. The types, choice, sensitivity and descriptive information trends of these biomarkers are very important. Aim: Some prognostic biomarkers and parameters that this review identified include glycated haemoglobin, white blood cells, mean neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, total leukocytes and neutrophils, plasma low-density lipoprotein, high-density lipoprotein and very low-density lipoprotein, platelet, fibrinogen, D-dimer and C-reactive proteins. Results: These parameters display increases in DM, while red blood cell, haemoglobin concentration, activated partial thromboplastin time, prothrombin time and partial thromboplastin time are decreased. Conclusion: With sound knowledge of the variations of these markers and parameters, observed reversal during treatment and management of DM and its complications can be better monitored, and guided decisions can be made.

Coagulation factor V gene 1691G>A polymorphism as an indicator for risk and prognosis of lower extremity deep venous thrombosis in Chinese Han population

The purpose of this study was to explore the negative influence coagulation factor V (FV) 1691G>A polymorphism had on the risk and prognosis of lower extremity deep venous thrombosis (LDVT) in Chinese Han population.A total of 348 patients with LDVT (LDVT group) and 398 healthy individuals (control group) were selected to further this study. A polymerase chain reaction-restriction fragment length polymorphism method was used to analyze the FV gene 1691G>A polymorphism; coagulation and anticoagulation indexes of patients with LDVT were detected as a result. A 3-year follow-up and logistic regression analysis were conducted to determine the corresponding correlations between FV gene and LDVT.In comparison with the control group, the frequencies of GA and AA genotypes and A allele of 1691G>A polymorphism significantly increased in the LDVT group. Also, in comparison with patients with LDVT carrying GG genotype of FV gene 1691G>A polymorphism, the following activities reduced significantly: prothrombin time, activated partial thromboplastin time, fibrinogen, protein C, and protein S, while activated protein C resistance and lupus anticoagulant positive rate increased in patients carrying A allele (GA + AA). Logistic regression analysis indicated that FV gene 1691G>A polymorphism, total cholesterol, low-density lipoprotein cholesterol, and LDVT family histories were all closely related with LDVT and were subsequent independent risk factors for LDVT. Moreover, patients with LDVT carrying A allele (GA + AA) had both higher patency and recurrence rates than those carrying GG genotype.FV gene 1691G>A polymorphism may be associated with both the risk and prognosis of LDVT, potentially being a useful index for monitoring LDVT prognosis and risk.

Clinical Significance of Hemostatic Parameters in the Prediction for Type 2 Diabetes Mellitus and Diabetic Nephropathy

It would be important to predict type 2 diabetes mellitus (T2DM) and diabetic nephropathy (DN). This study was aimed at evaluating the predicting significance of hemostatic parameters for T2DM and DN. Plasma coagulation and hematologic parameters before treatment were measured in 297 T2DM patients. The risk factors and their predicting power were evaluated. T2DM patients without complications exhibited significantly different activated partial thromboplastin time (aPTT), platelet (PLT), and D-dimer (D-D) levels compared with controls (P < 0.01). Fibrinogen (FIB), PLT, and D-D increased in DN patients compared with those without complications (P < 0.001). Both aPTT and PLT were the independent risk factors for T2DM (OR: 1.320 and 1.211, P < 0.01, resp.), and FIB and PLT were the independent risk factors for DN (OR: 1.611 and 1.194, P < 0.01, resp.). The area under ROC curve (AUC) of aPTT and PLT was 0.592 and 0.647, respectively, with low sensitivity in predicting T2DM. AUC of FIB was 0.874 with high sensitivity (85%) and specificity (76%) for DN, and that of PLT was 0.564, with sensitivity (60%) and specificity (89%) based on the cutoff values of 3.15 g/L and 245 × 10⁹/L, respectively. This study suggests that hemostatic parameters have a low predicting value for T2DM, whereas fibrinogen is a powerful predictor for DN.

Evolutionarily derived networks to inform disease pathways

Methods to identify genes or pathways associated with complex diseases are often inadequate to elucidate most risk because they make implicit and oversimplified assumptions about underlying models of disease etiology. These can lead to incomplete or inadequate conclusions. To address this, we previously developed human phenotype networks (HPN), linking phenotypes based on shared biology. However, such visualization alone is often uninterpretable, and requires additional filtering. Here, we expand the HPN to include another method, evolutionary triangulation (ET). ET utilizes the hypothesis that alleles affecting disease risk in multiple populations are distributed consistently with differences in disease prevalence and compares allele frequencies among populations and their relationship to phenotype prevalence. We hypothesized that combining these methods will increase our ability to detect genetic patterns of association in complex diseases. We combined HPN and ET to identify network patterns associated with type 2 diabetes mellitus (T2DM), a leading cause of death worldwide. Fasting glucose, a continuous trait, was used as a proxy for T2DM and differs significantly among continental populations. The combined method identified several diabetes-related traits and several phenotypes related to cardiovascular diseases, for which diabetes is a major risk factor. ET-HPN found more phenotypes related to our target and related phenotypes than the application of either method alone. Not only could we detect phenotype connections related to T2DM, but we also identified phenotypes that are distributed in parallel to it, e.g., amyotrophic lateral sclerosis. Our analyses showed that ET-filtered HPN provides information that neither technique can individually.

The use of dielectric blood coagulometry in the evaluation of coagulability in patients with peripheral arterial disease

Background

Platelets and coagulation proteins contribute to the development of peripheral arterial disease, especially atherosclerotic disease. Several experimental studies have proven a significant correlation between hypercoagulability and atherosclerosis. We used dielectric blood coagulometry, which was initially designed to evaluate the coagulable status, to examine the coagulability of peripheral arterial disease patients, and investigated the factors that were significantly correlated with the results.

Methods

We performed dielectric blood coagulometry in 49 peripheral arterial disease patients. In addition, we recorded the patients’ demographic information, including the presence of comorbidities, hemodynamic status, and laboratory findings. To investigate coagulability, we calculated the T_max value, which indicates the time from recalcification to maximum normalized permittivity.

Results

The T_max values of diabetes mellitus patients were significantly lower than those of non-diabetic patients (1 MHz, P = 0.010; 10 MHz, 0.011). Furthermore, the T_max value was statistically correlated with the activated partial thromboplastin time (1 MHz, ρ = 0.286, P = 0.048; 10 MHz, ρ = 0.301, P = 0.037).

Conclusions

Dielectric blood coagulometry detected the hypercoagulable status in diabetes mellitus patients, and reflected their level of coagulability, which was also evaluated by the activated partial thromboplastin time.

Plasma Kallikrein Inhibitors in Cardiovascular Disease: An Innovative Therapeutic Approach

Plasma prekallikrein is the liver-derived precursor of the trypsin-like serine protease plasma kallikrein, and circulates in plasma bound to high molecular weight kininogen. Plasma prekallikrein is activated to plasma kallikrein by activated factor XII or prolylcarboxypeptidase. Plasma kallikrein regulates the activity of multiple proteolytic cascades in the cardiovascular system such as the intrinsic pathway of coagulation, the kallikrein-kinin system, the fibrinolytic system, the renin-angiotensin system, and the complement pathways. As such, plasma kallikrein plays a central role in the pathogenesis of thrombosis, inflammation, and blood pressure regulation. Under physiological conditions, plasma kallikrein serves as a cardioprotective enzyme. However, its increased plasma concentration or hyperactivity perpetuates cardiovascular disease (CVD). In this article, we review the biochemistry and cell biology of plasma kallikrein and summarize data from preclinical and clinical studies that have established important functions of this serine protease in CVD states. Finally, we propose plasma kallikrein inhibitors as a novel class of drugs with potential therapeutic applications in the treatment of CVDs.

Novel Dielectric Coagulometer Identifies Hypercoagulability in Patients with a High CHADS2 Score without Atrial Fibrillation

Background

Recent reports showed that the CHADS₂ score predicted the risk of strokes in patients without atrial fibrillation (AF). Although the hypercoagulability may contribute to the thrombogenesis, it has not been fully investigated due to a lack of a sensitive evaluation modality. Recently a novel dielectric blood coagulometry (DBCM) was invented for evaluating the coagulability by measuring the temporal change in whole blood dielectric permittivity.

Objective

We evaluated the utility of the DBCM for identifying the coagulability.

Patients/Methods

For fundamental experiments, 133 citrated blood samples were drawn from subjects with or without heparin administration. A DBCM analysis was performed to find the adequate coagulation index, and to delineate its measurement range by adding recombinant human tissue factor (TF) or heparin. Then the coagulability was assessed by DBCM and conventional coagulation assays in 84 subjects without AF, who were divided into 3 groups by their CHADS₂ score. Another 17 patients who received warfarin were also assessed by DBCM to evaluate the effect of anticoagulants.

Results and Conclusions

We calculated the derivative of the dielectric permittivity change after recalcification, and extracted the end of acceleration time (EAT) as a novel index. The EAT showed a dose-dependent shortening with the addition of serial dilutions of TF (×10−² to ×10−⁴), and a dose-dependent prolongation with the addition of heparin (0.05 to 0.15 U/ml). The EAT was significantly shorter in the higher CHADS₂ score group (19.8 ± 4.8, 18.6 ± 3.1, and 16.3 ± 2.7 min in the CHADS₂ = 0, 1, and ≥2 groups, respectively, p = 0.0065 by ANOVA). Patients receiving warfarin had a significantly more prolonged EAT than those without warfarin (18.6±4.2 vs. 25.8±7.3 min, p <0.001). DBCM detected the whole blood coagulability with a high sensitivity. Subjects with higher CHADS₂ scores exhibited hypercoagulability without AF.

Utility of plasma fibrinogen in the differential diagnosis of thyrotoxicosis

BACKGROUND

A study had reported that a low TSH level is associated with elevated plasma fibrinogen (FIB) levels. Our purpose was to investigate the role of FIB in the differential diagnosis of thyrotoxicosis.

METHODS

The data of 104 patients with primary thyrotoxicosis at the First Hospital of China Medical University from July 2010 to March 2011 were analyzed and divided into three groups: 45 cases of subacute thyroiditis, 50 cases of Graves' disease, and 9 cases of toxic multinodular goiter. The patients with subacute thyroiditis were followed up before and after the treatment. FIB levels of the three groups were compared.

RESULTS

There was no significant difference in serum TSH, FT3 and FT4 between the patients with three different causes of thyrotoxicosis (P > 0.05). The proportion of hyperfibrinogenemia in patients with subacute thyroiditis was 98%. The FIB levels of patients with subacute thyroiditis were significantly higher than those with Graves' disease and toxic multinodular goiter (P < 0.05). Levels of ESR show a similar tendency. The FIB levels returned to normal with the remission of subacute thyroiditis.

CONCLUSIONS

Elevated plasma fibrinogen is a common manifestation of the active phase of subacute thyroiditis. A FIB test can be used for the differential diagnosis of thyrotoxicosis. We can anticipate the outcome of subacute thyroiditis through the dynamic changes of FIB.

The effect of hyperglycaemia on haemostasis testing--a volunteer study

We investigated whether the contamination of samples with glucose subsequently tested for haemostasis affected the results, including prothrombin time, activated partial thromboplastin time and fibrinogen concentration. Venous blood was collected from 12 healthy subjects and divided into four aliquots, which were subjected to different degrees of contamination with standard glucose solution (0%, 5%, 10%, 20%). With increasing glucose contamination, prothrombin time increased from mean (SD) 11.0 (0.7) s to 11.2 (0.7) s, 11.5 (0.7) s and 12.2 (0.8) s, all p < 0.001. Activated partial thromboplastin time decreased from 32.3 (0.9) s to 30.9 (0.8) s, 30.8 (0.8) s, and 29.7 (0.7) s, all p < 0.001. Fibrinogen concentration decreased from 3.8 (0.7) g.l(-1) to 3.7 (0.6) g.l(-1), 3.6 (0.6) g.l(-1), and 3.4 (0.6) g.l(-1), all p < 0.001. Bias was clinically meaningful from 5% contamination for activated partial thromboplastin time, 10% contamination for prothrombin time and 20% contamination for fibrinogen concentration. We conclude that if glucose contamination of haemostasis samples is suspected or has occurred, the specimens should not be analysed.

Proteomic analysis in type 2 diabetes patients before and after a very low calorie diet reveals potential disease state and intervention specific biomarkers

Very low calorie diets (VLCD) with and without exercise programs lead to major metabolic improvements in obese type 2 diabetes patients. The mechanisms underlying these improvements have so far not been elucidated fully. To further investigate the mechanisms of a VLCD with or without exercise and to uncover possible biomarkers associated with these interventions, blood samples were collected from 27 obese type 2 diabetes patients before and after a 16-week VLCD (Modifast ∼450 kcal/day). Thirteen of these patients followed an exercise program in addition to the VCLD. Plasma was obtained from 27 lean and 27 obese controls as well. Proteomic analysis was performed using mass spectrometry (MS) and targeted multiple reaction monitoring (MRM) and a large scale isobaric tags for relative and absolute quantitation (iTRAQ) approach. After the 16-week VLCD, there was a significant decrease in body weight and HbA1c in all patients, without differences between the two intervention groups. Targeted MRM analysis revealed differences in several proteins, which could be divided in diabetes-associated (fibrinogen, transthyretin), obesity-associated (complement C3), and diet-associated markers (apolipoproteins, especially apolipoprotein A-IV). To further investigate the effects of exercise, large scale iTRAQ analysis was performed. However, no proteins were found showing an exercise effect. Thus, in this study, specific proteins were found to be differentially expressed in type 2 diabetes patients versus controls and before and after a VLCD. These proteins are potential disease state and intervention specific biomarkers.

Trial Registration

Controlled-Trials.com ISRCTN76920690

High coagulation factor levels and low protein C levels contribute to enhanced thrombin generation in patients with diabetes who do not have macrovascular complications

AIMS

A prothrombotic state characterized by activation of the coagulation system has been implicated in the pathogenesis of vascular complications in diabetes mellitus. Recently, a thrombin generation assay was introduced as a laboratory assessment of global hemostatic potential. We used this thrombin generation assay to investigate global hemostatic potential in patients with diabetes who did not have macrovascular complications.

METHODS

This study was a prospective case-control study comparing 89 patients with diabetes with 49 healthy controls. The thrombin generation assay was conducted with the calibrated automated thrombogram using tissue factor with or without the addition of thrombomodulin, giving values for lag time, endogenous thrombin potential, and peak thrombin.

RESULTS

Patients with diabetes showed hypercoagulability, as detected by the thrombin generation assay, compared with healthy controls. Correspondingly, high levels of coagulation factors (II, V, VII, VIII, and X) and low levels of anticoagulant (protein C) were major contributing factors in this hypercoagulability. Interestingly, a high blood glucose level was correlated with shortened clotting time, reflecting the association between hyperglycemia and hypercoagulability. Patients who were taking statins or angiotensin receptor blockers showed decreased endogenous thrombin potential ratio and increased protein C levels, suggesting relative hypocoagulability.

CONCLUSIONS

Patients with diabetes showed hypercoagulability, high levels of coagulation factors, and low levels of protein C. Further study is required to investigate how this hemostatic potential may be used to guide physicians toward more effective management of hemostatic complications.

A review on the role of L-carnitine in the management of tamoxifen side effects in treated women with breast cancer

L-carnitine is an antioxidant and is found to be a protective agent against many diseases including cancer. This review illustrates the possible role of L-carnitine as an add-on therapy to breast cancer patients maintained on tamoxifen. The objectives of carnitine treatment are diverse: improving tamoxifen-related side effects, offering better cancer prognosis by reducing the risk of developing cancer recurrence or metastasis, and modulating the growth factors which may be, in part, a prospective illustration to overcome tamoxifen resistance. So, it could be recommended to supplement L-carnitine to breast cancer patients starting tamoxifen treatment.

Association of activated partial thromboplastin time and fibrinogen level in patients with type II diabetes mellitus

Background

Patients with diabetes mellitus have a high risk of atherothrombotic events. Diabetes contributes for initiation and progression of microvascular and macrovascular complications. Shortened activated partial thromboplastin time (aPTT) values may reflect hypercoaguable state, which is associated with increased thrombotic risk and adverse cardiovascular events. Increased level of fibrinogen is common in type II diabetes. The present study was conducted to study the aPTT and fibrinogen levels in diabetics in a tertiary care Teaching Hospital of Nepal.

Methods

Observational study was performed at out-patients visiting Pathology Department at Tribhuvan University Teaching Hospital from August 5 to September 7, 2012. Research protocol was approved by Institutional Review Board at Tribhuvan University Institute of Medicine. Altogether 90 people who came to the hospital during study period and who met inclusion criteria were selected, out of which 72 were diabetics and 18 were normal controls. Diabetic cases were identified via verbal interview with patients themselves and review of laboratory findings and diagnosis performed by their physicians. Diabetics with a diabetic history of more than one year and stabilized with antidiabetic medicines such as insulin, metformin, glibenclamide, and gliclazide and diabetics with controlled diabetes as revealed by HbA_1c in the range 6.2-7% were taken for the study purpose. Data were analyzed with chi square test and Fischer’s exact test (when each cell frequency was less than 5) using Statistical Package for Social Sciences 17.

Results

Maximum (53; 73.6%) diabetics and all non-diabetics had aPTT in the range 26–40 seconds. Maximum (51; 70.8%) patients had fibrinogen beyond 351 whereas all non-diabetics had fibrinogen in the range 151–350. Mean aPTT values of the diabetic patients and non-diabetic persons were 29.88 ± 4.89 seconds and 32.44 ± 2.25 seconds respectively. Mean fibrinogen values of the diabetic patients and non-diabetic persons were 388.57 ± 60.90 mg/dL and 320.89 ± 10.20 mg/dL respectively. Test data identified in results were statistically significant for aPTT (p value 0.000) and fibrinogen (p value 0.000) between the diabetics and non-diabetics.

Conclusions

Diabetics have an increased level of fibrinogen and relatively shortened aPTT as compared to the non-diabetic patients.

Plasma kallikrein-kinin system and diabetic retinopathy

Diabetic retinopathy (DR) occurs, to some extent, in most people with at least 20 years' duration of diabetes mellitus. The progression of DR to its sight-threatening stages is usually associated with the worsening of underlying retinal vascular dysfunction and disease. The plasma kallikrein-kinin system (KKS) is activated during vascular injury, where it mediates important functions in innate inflammation, blood flow, and coagulation. Recent findings from human vitreous proteomics and experimental studies on diabetic animal models have implicated the KKS in contributing to DR. Vitreous fluid from people with advanced stages of DR contains increased levels of plasma KKS components, including plasma kallikrein (PK), coagulation factor XII, and high-molecular-weight kininogen. Both bradykinin B1 and B2 receptor isoforms (B1R and B2R, respectively) are expressed in human retina, and retinal B1R levels are increased in diabetic rodents. The activation of the intraocular KKS induces retinal vascular permeability, vasodilation, and retinal thickening, and these responses are exacerbated in diabetic rats. Preclinical studies have shown that the administration of PK inhibitors and B1R antagonists to diabetic rats ameliorates retinal vascular hyperpermeability and inflammation. These findings suggest that components of plasma KKS are potential therapeutic targets for diabetic macular edema.

Role of plasma kallikrein in diabetes and metabolism

Plasma kallikrein (PK) is a serine protease generated from plasma prekallikrein, an abundant circulating zymogen expressed by the Klkb1 gene. The physiological actions of PK have been primarily attributed to its production of bradykinin and activation of coagulation factor XII, which promotes inflammation and the intrinsic coagulation pathway. Recent genetic, molecular, and pharmacological studies of PK have provided further insight into its role in physiology and disease. Genetic analyses have revealed common Klkb1 variants that are association with blood metabolite levels, hypertension, and coagulation. Characterisation of animal models with Klkb1 deficiency and PK inhibition have demonstrated effects on inflammation, vascular function, blood pressure regulation, thrombosis, haemostasis, and metabolism. These reports have also identified a host of PK substrates and interactions, which suggest an expanded physiological role for this protease beyond the bradykinin system and coagulation. The review summarises the mechanisms that contribute to PK activation and its emerging role in diabetes and metabolism.

Estimating the contributions of rare and common genetic variations and clinical measures to a model trait: adiponectin

Common genetic variation frequently accounts for only a modest amount of interindividual variation in quantitative traits and complex disease susceptibility. Circulating adiponectin, an adipocytokine implicated in metabolic disease, is a model for assessing the contribution of genetic and clinical factors to quantitative trait variation. The adiponectin locus, ADIPOQ, is the primary source of genetically mediated variation in plasma adiponectin levels. This study sought to define the genetic architecture of ADIPOQ in the comprehensively phenotyped Hispanic (n = 1,151) and African American (n = 574) participants from the Insulin Resistance Atherosclerosis Family Study (IRASFS). Through resequencing and bioinformatic analysis, rare/low frequency (<5% MAF) and common variants (>5% MAF) in ADIPOQ were identified. Genetic variants and clinical variables were assessed for association with adiponectin levels and contribution to adiponectin variance in the Hispanic and African American cohorts. Clinical traits accounted for the greatest proportion of variance (POV) at 31% (P = 1.16 × 10-(47)) and 47% (P = 5.82 × 10-(20)), respectively. Rare/low frequency variants contributed more than common variants to variance in Hispanics: POV = 18% (P = 6.40 × 10-(15)) and POV = 5% (P = 0.19), respectively. In African Americans, rare/low frequency and common variants both contributed approximately equally to variance: POV = 6% (P = 5.44 × 10-(12)) and POV = 9% (P = 1.44 × 10-(10)), respectively. Importantly, single low frequency alleles in each ethnic group were as important as, or more important than, common variants in explaining variation in adiponectin. Cumulatively, these clinical and ethnicity-specific genetic contributors explained half or more of the variance in Hispanic and African Americans and provide new insight into the sources of variation for this important adipocytokine.