The profibrinolytic effect of activated protein C in clots formed from plasma is TAFI-dependent

Thrombin-activatable fibrinolysis inhibitor (TAFI) is the precursor of an exopeptidase that is identical to plasma procarboxypeptidase B. Upon activation by thrombin, activated TAFI (TAFIa) attenuates fibrinolysis, presumably by catalyzing the removal of C-terminal lysines from partially degraded fibrin. Activated protein C (APC) proteolytically inactivates the essential cofactor in prothrombinase, factor Va, and limits both the formation of thrombin and subsequent activation of TAFI, thereby appearing profibrinolytic. TAFI is able to reconstitute an APC-dependent shortening of lysis time in a purified system; however, it remained to be determined the extent to which TAFI is involved in the profibrinolytic effect of APC in a plasma-based system. To aid in addressing this question, two monoclonal antibodies (MoAbTAFI#16 and #13) and a polyclonal antibody were produced against purified TAFI. MoAbTAFI#16 was shown to inhibit TAFI activation and thereby appears to stimulate fibrinolysis. Furthermore, an enzyme- linked immunosorbent assay was developed using MoAbTAFI#13 and the polyclonal antibody. Through its use, the plasma concentration of TAFI was determined to be 73 nmol/L. In addition, a turbidity assay was used to determine the effect of APC on tissue plasminogen activator-induced fibrinolysis of clots produced from normal human plasma (NHP), plasma immunodepleted of TAFI (TdP), and TdP reconstituted with purified TAFI. APC shortened lysis time of clots produced from NHP in a saturable and concentration-dependent manner. However, APC had no effect on lysis time of clots formed from either TdP or NHP in the presence of 80 nmol/L MoAbTAFI#16. The APC effect could be reconstituted in TdP by the addition of purified TAFI. The lysis time in TdP was increased from 50 to 180 minutes in a TAFI concentration-dependent manner. The EC50 was 15 nmol/L and saturation was approached at physiologically relevant concentrations (60 nmol/L). The profibrinolytic effect of APC was also compared with that of MoAbTAFI#16 and two competitive inhibitors, an inhibitor of the carboxypeptidase A and B family purified from potato tubers and 2-Guanidinoethylmercaptosuccinic acid (GEMSA). All were able to reduce lysis time of clots formed from normal human plasma by 90 minutes, yielding respective EC50 values of 5 nmol/L, 15 nmol/L, 50 nmol/L, and 90 mumol/L. Therefore, the majority of the profibrinolytic effect of APC, in an in vitro plasma system, is dependent on TAFI. Because TAFIa dramatically influences lysis time, inhibitors of TAFIa or TAFI activation may prove to be important adjuvants for thrombolytic therapy.     

External Validation of a Tool Predicting 7-Year Risk of Developing Cardiovascular Disease,Type 2 Diabetes or Chronic Kidney Disease

Background

Chronic cardiometabolic diseases, including cardiovascular disease (CVD), type 2 diabetes (T2D) and chronic kidney disease (CKD), share many modifiable risk factors and can be prevented using combined prevention programs. Valid risk prediction tools are needed to accurately identify individuals at risk.

Objective

We aimed to validate a previously developed non-invasive risk prediction tool for predicting the combined 7-year-risk for chronic cardiometabolic diseases.

Design

The previously developed tool is stratified for sex and contains the predictors age, BMI, waist circumference, use of antihypertensives, smoking, family history of myocardial infarction/stroke, and family history of diabetes. This tool was externally validated, evaluating model performance using area under the receiver operating characteristic curve (AUC)—assessing discrimination—and Hosmer–Lemeshow goodness-of-fit (HL) statistics—assessing calibration. The intercept was recalibrated to improve calibration performance.

Participants

The risk prediction tool was validated in 3544 participants from the Australian Diabetes, Obesity and Lifestyle Study (AusDiab).

Key Results

Discrimination was acceptable, with an AUC of 0.78 (95% CI 0.75–0.81) in men and 0.78 (95% CI 0.74–0.81) in women. Calibration was poor (HL statistic: p?<?0.001), but improved considerably after intercept recalibration. Examination of individual outcomes showed that in men, AUC was highest for CKD (0.85 [95% CI 0.78–0.91]) and lowest for T2D (0.69 [95% CI 0.65–0.74]). In women, AUC was highest for CVD (0.88 [95% CI 0.83–0.94)]) and lowest for T2D (0.71 [95% CI 0.66–0.75]).

Conclusions

Validation of our previously developed tool showed robust discriminative performance across populations. Model recalibration is recommended to account for different disease rates. Our risk prediction tool can be useful in large-scale prevention programs for identifying those in need of further risk profiling because of their increased risk for chronic cardiometabolic diseases.

     

Successful transplantation of HLA-matched and HLA-mismatched umbilical cord blood from unrelated donors: analysis of engraftment and acute graft-versus-host disease

To reduce the morbidity and mortality associated with unrelated donor bone marrow (BM) transplantation and potentially extend the pool of suitable donors, cryopreserved unrelated donor umbilical cord blood was considered as an alternate source of hematopoietic stem cells for transplantation. Patients with leukemia, BM failure syndrome, or inborn error of metabolism were eligible for a phase I clinical trial designed to estimate the risk of graft failure and severe acute graft-versus- host disease after transplantation of umbilical cord blood from unrelated donors. As of December 21, 1995, unrelated donor umbilical cord blood was used to reconstitute hematopoiesis in eighteen patients aged 0.1 to 21.3 years weighing 3.3 to 78.8 kg with acquired or congenital lympho-hematopoietic disorders or metabolic disease. Patients received either HLA-matched (n = 7) or HLA-1 to 3 antigen disparate (n = 11) grafts collected and evaluated by the New York Blood Center (New York, NY). The probability of engraftment after unrelated donor umbilical cord blood transplantation was 100% with no patient having late graft failure to date. The probability of grade III-IV acute graft-versus-host disease at 100 days was 11%. With a median follow-up of 6 months (range, 1.6 to 17 months); the probability of survival at 6 months is 65% in this high risk patient population. We conclude that cryopreserved umbilical cord blood from HLA-matched and mismatched unrelated donors is a sufficient source of transplantable hematopoietic stem cells with high probability of donor derived engraftment and low risk of refractory severe acute graft-versus-host disease. Limitations with regard to recipient size and degree of donor HLA disparity remain to be determined.     

Low risk of viral infection after administration of vapor-heated factor VIII concentrate. International Investigator Group

A multicenter prospective study was carried out to evaluate whether a vapor-heated factor VIII concentrate transmitted blood-borne viral infections over a surveillance period of 15 months. Thirty-five patients with hemophilia and von Willebrand disease who had never received any blood components were treated. Twenty-eight were analyzed and found not to have non-A, non-B hepatitis. Sera from 20 of these 28 patients were also tested for the antibody to the hepatitis C virus. None had sero-converted during the follow-up period. None of the patients analyzed developed markers of the hepatitis B virus (n = 17) or the human immunodeficiency virus (n = 31). This vapor-heated factor VIII concentrate carries a low risk of transmitting hepatitis and human immunodeficiency virus infection.     

EEG-Informed fMRI Reveals a Disturbed Gamma-Band–Specific Network in Subjects at High Risk for Psychosis

Objectives. Abnormalities of oscillatory gamma activity are supposed to reflect a core pathophysiological mechanism underlying cognitive disturbances in schizophrenia. The auditory evoked gamma-band response (aeGBR) is known to be reduced across all stages of the disease. The present study aimed to elucidate alterations of an aeGBR-specific network mediated by gamma oscillations in the high-risk state of psychosis (HRP) by means of functional magnetic resonance imaging (fMRI) informed by electroencephalography (EEG). Methods. EEG and fMRI were simultaneously recorded from 27 HRP individuals and 26 healthy controls (HC) during performance of a cognitively demanding auditory reaction task. We used single trial coupling of the aeGBR with the corresponding blood oxygen level depending response (EEG-informed fMRI). Results. A gamma-band–specific network was significantly lower active in HRP subjects compared with HC (random effects analysis, P < .01, Bonferroni-corrected for multiple comparisons) accompanied by a worse task performance. This network involved the bilateral auditory cortices, the thalamus and frontal brain regions including the anterior cingulate cortex, as well as the bilateral dorsolateral prefrontal cortex. Conclusions. For the first time we report a reduced activation of an aeGBR-specific network in HRP subjects brought forward by EEG-informed fMRI. Because the HRP reflects the clinical risk for conversion to psychotic disorders including schizophrenia and the aeGBR has repeatedly been shown to be altered in patients with schizophrenia the results of our study point towards a potential applicability of aeGBR disturbances as a marker for the prediction of transition of HRP subjects to schizophrenia.Key words: prodromal state of schizophrenia, auditory evoked gamma-band response, simultaneous EEG-fMRI, anterior cingulate cortex, auditory cortex     

Transient growth hormone therapy to rats with low protein-inflicted intrauterine growth restriction does not prevent elevated blood pressure in later life

Intrauterine growth restriction (IUGR) is a risk factor for the development of hypertension in later life. Insulin-like growth factor I and growth hormone (GH) have the potential to improve metabolic syndrome after IUGR in adult animals. The objective of the present study was to examine whether transient GH treatment of pups after weaning can prevent the development of arterial hypertension in adult rats. IUGR was induced in Wistar rats by isocaloric protein restriction in pregnant dams and litter size was reduced to six male neonates after birth. Recombinant human GH was applied by daily subcutaneous injections at a dose of 3 microg/g body weight between days 24 and 60 of life. Control animals received vehicle treatment (VEH) only. Birth weight was significantly lower in low protein (LP) animals than in normal protein (NP) animals (5.1 +/- 0.3 g vs. 5.9 +/- 0.7 g, p < 0.05). Until weaning at day 23, LP animals reached similar body length, but had reduced body weight compared to NP animals. Intraarterially measured mean arterial blood pressure at day 120 was elevated in LP-VEH compared to NP-VEH animals (113 +/- 6 mmHg vs. 101 +/- 6 mmHg, p < 0.01). However, transient GH-treatment did not prevent arterial hypertension in LP animals (112 +/- 5 mmHg). Our data suggest that GH treatment between days 24 and 60 of life does not or at least not permanently reprogram blood pressure elevation after IUGR.     

Who copes well? Obesity‐related coping and its associations with shame,guilt, and weight loss

The relationship among weight-related coping, guilt, and shame was investigated in a sample of 98 obese German individuals over a 6-month period. In terms of the objectives, the study explored the kind and frequency of typical coping situations in which obese individuals become aware of being obese. Furthermore, the study sought to determine the predictive utility of weight-related shame and guilt concerning coping responses, and to establish whether there is an association between coping responses and weight change. A longitudinal examination over a 6-month period was chosen with two measurement points. As typical distressing coping situations, individuals reported mostly negative evaluations through others/self, physical exercise situations, or environmental hazards (mainly shopping for clothes). Weight-related shame at baseline was a significant negative predictor for problem-focused engagement coping, whereas weight-related guilt was a significant positive predictor for problem-focused engagement strategies and dietary restraint at follow-up. Although Body Mass Index showed no substantial association with the coping measures, weight loss was accompanied by a substantial drop in problem-focused disengagement coping (wishful thinking, problem avoidance). Discussion of these findings focuses on the issue of possible effects of weight-related feelings of guilt and shame on coping behavior, the link between weight loss and disengaging coping strategies, and the possible use of the findings for cognitive-behavioral therapy for obesity.     

Hepatitis E virus seroprevalence,seroincidence and seroreversion in the German adult population

A steep rise in Hepatitis E diagnoses is currently being observed in Germany and other European countries. The objective of this study was (i) to assess whether this trend mirrors an increase in infection pressure or is caused by increased attention and testing and (ii) estimate individual and population‐based Hepatitis E Virus (HEV) seroconversion and seroreversion rates for Germany. We measured anti‐HEV IgG prevalence in 10 407 adults participating in two linked, population‐representative serosurveys (total n = 12 971) conducted in 1998 and 2010. In this period, we found a moderate but statistically significant decline of overall anti‐HEV IgG prevalence from 18.6% to 15.3%. At both time points, seroprevalence increased with age and peaked in persons born between 1935 and 1959 suggesting a past period of increased infection pressure. Paired samples of individuals participating in 1998 and 2010 (n = 2564) revealed respective seroconversion and seroreversion rates of 6.2% and 22.6% among seronegative and seropositive individuals during 12 years, or 5.2 and 2.9 per 1000 inhabitants per year. This corresponds to a total of 417 242 [95%CI: 344 363‐495 971] new seroconversions per year in the German population. While anti‐HEV seroprevalence has decreased in the last decade, infection pressure and seroincidence remains high in Germany. Continuously rising numbers of Hepatitis E diagnoses in Europe are likely due to an increased awareness of clinicians and indicate that still there is a gap between incident and diagnosed cases. Studies on the true burden of the disease, specific risk factors and sources of autochthonous infections as well as targeted prevention measures are urgently needed.