Expression of vascular endothelial growth factor in human myocardial infarction

A case report of acute testicular pain secondary to segmental testicular infarction

BACKGROUND

Segmental testicular infarction is a rare condition that often occurs in the upper pole of the left testicle and usually presents with acute onset of scrotal pain. Contrast-enhanced ultrasound and MR are essential for diagnosing and differentiating segmental testicular infarction in clinical practice, and conservative treatment can only be adopted after a definitive diagnosis. In the present case, after conservative treatment, the infarct volume was reduced, the blood flow around the infarct was increased, and blood flow signals appeared in the infarct. We performed a correlation analysis to investigate the causes of these changes.

CASE PRESENTATION

A 33-year-old male, without any specific disease history, was admitted to the hospital with a 5-day history of left testicular pain, and the imaging showed focal necrosis of the left testicle with hemorrhage. He was diagnosed with segmental testicular infarction after differentiating and excluding it from malignant tumors. Conservative medical treatment was given, and the symptoms of testicular pain were relieved after treatment. After discharge, regular reexamination at follow-ups showed that the infarct's size was reduced, the blood flow around the infarct was increased, and blood flow signals appeared in the infarct.

CONCLUSION

Conservative treatment has become the standard treatment currently adopted after confirming the diagnosis of segmental testicular infarction through contrast-enhanced ultrasound and MR. The blood flow changes in and around the focus of testicular infarction can be related to various factors. At present, relevant conclusions of the underlying mechanisms were mainly deduced from infarction studies of other related organs such as the heart and brain; thus, the specific pathological mechanism needs further experimental verification.

Changes in gene expression patterns in postmortem human myocardial infarction

In murine models, the expression of inducible nitric oxide synthase (iNOS) in myocardial infarction (MI) has been reported to be the result of tissue injury and inflammation. In the present study, mRNA expression of iNOS, hypoxia-inducible factor-1α (HIF-1α), and vascular endothelial growth factor (VEGF) was investigated in postmortem human infarction hearts. Since HIF-1α is the inducible subunit of the transcription factor HIF-1, which regulates transcription of iNOS and VEGF, the interrelation between the three genes was observed, to examine the molecular processes during the emergence of MI. iNOS and VEGF mRNAs were found to be significantly upregulated in the affected regions of MI hearts in comparison to healthy controls. Upregulation of HIF-1α was also present but not significant. Correlation analysis of the three genes indicated a stronger and significant correlation between HIF-1α and iNOS mRNAs than between HIF-1α and VEGF. The results of the study revealed differences in the expression patterns of HIF-1 downstream targets. The stronger transcription of iNOS by HIF-1 in the affected regions of MI hearts may represent a pathological process, since no correlation of iNOS and HIF-1α mRNA was found in non-affected areas of MI hearts. Oxidative stress is considered to cause molecular changes in MI, leading to increased iNOS expression. Therefore, it may also represent a forensic marker for detection of early changes in heart tissue.

VEGF-A promotes angiogenesis after acute myocardial infarction through increasing ROS production and enhancing ER stress-mediated autophagy

Proangiogenesis is generally regarded as an effective approach for treating ischemic heart disease. Vascular endothelial growth factor (VEGF)-A is a strong and essential proangiogenic factor. Reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, and autophagy are implicated in the process of angiogenesis. This study is designed to clarify the regulatory mechanisms underlying VEGF-A, ROS, ER stress, autophagy, and angiogenesis in acute myocardial infarction (AMI). A mouse model of AMI was successfully established by occluding the left anterior descending coronary artery. Compared with the sham-operated mice, the microvessel density, VEGF-A content, ROS production, expression of vascular endothelial cadherin, positive expression of 78 kDa glucose-regulated protein/binding immunoglobulin protein (GRP78/Bip), and LC3 puncta in CD31-positive endothelial cells of the ischemic myocardium were overtly elevated. Moreover, VEGF-A exposure predominantly increased the expression of beclin-1, autophagy-related gene (ATG) 4, ATG5, inositol-requiring enzyme-1 (IRE-1), GRP78/Bip, and LC3-II/LC3-I as well as ROS production in the human umbilical vein endothelial cells (HUVECs) in a dose and time-dependent manner. Both beclin-1 small interfering RNA and 3-methyladenine treatment predominantly mitigated VEGF-A-induced tube formation and migration of HUVECs, but they failed to elicit any notable effect on VEGF-A-increased expression of GRP78/Bip. Tauroursodeoxycholic acid not only obviously abolished VEGF-A-induced increase of IRE-1, GRP78/Bip, beclin-1 expression, and LC3-II/LC3-I, but also negated VEGF-A-induced tube formation and migration of HUVECs. Furthermore, N-acetyl- l-cysteine markedly abrogated VEGF-A-increased ROS production, IRE-1, GRP78/Bip, beclin-1 expression, and LC3-II/LC3-I in the HUVECs. Taken together, our data demonstrated that increased spontaneous production of VEGF-A may induce angiogenesis after AMI through initiating ROS-ER stress-autophagy axis in the vascular endothelial cells.

Expression of vascular endothelial growth factor in cardiac repair: Signaling mechanisms mediating vascular protective effects

The present study was aimed to investigate the vascular endothelial growth factor expression pattern in acute myocardial infarction induced rats. Serum level of vascular endothelial growth factor and its mRNA expression in myocardium were determined. Protein expression of vascular endothelial growth factor and endothelial nitric oxide synthase were measured. Serum level of vascular endothelial growth factor was increased 105.3, 260, 378.2 and 271.3% following the onset of acute myocardial infarction at 3, 6, 9 and 12days respectively. The mRNA and protein expression of vascular endothelial growth factor was substantially increased following the onset of acute myocardial infarction. Protein expression of endothelial nitric oxide synthase was increased up to 1.02 fold. Taking all these data together, it is concluded that the vascular endothelial growth factor was increased in serum and tissue and attained peak at 9th day following the onset of acute myocardial infarction. Increased vascular endothelial growth factor level in serum and tissue could increase endothelial cell proliferation and angiogenesis, and endothelial nitric oxide synthase could inhibit apoptosis and protect cardiomyocytes. In conclusion, the increased vascular endothelial growth factor expression could play an essential role in cardiac repair following the onset of acute myocardial infarction.

Effect of intermittent hypoxia on the cardiac HIF-1/VEGF pathway in experimental type 1 diabetes mellitus

OBJECTIVE

High altitude and hypoxic preconditioning have cardioprotective effects by increasing coronary vascularity, reducing post-ischemic injury, and improving cardiac function. Our purpose was to examine if intermittent hypoxia treatment has any restoring effects related to the possible role of the HIF-1/VEGF pathway on diabetic cardiomyopathy.

METHODS

Wistar Albino male rats (n=34) were divided into four groups: control (C), intermittent hypoxia (IH), diabetes mellitus (DM), and diabetes mellitus plus intermittent hypoxia (DM+IH). Following a streptozotocin (STZ) injection (50 mg/kg, i.p.), blood glucose levels of 250 mg/dL and above were considered as DM. IH and DM+IH groups were exposed to hypoxia 6 h/day for 42 days at a pressure corresponding to 3000 m altitude. Twenty-four hours after the IH protocol, hearts were excised. Hematoxylin and eosin-stained apical parts of the left ventricles were evaluated. Hypoxia inducible factor-1 (HIF-1), vascular endothelial growth factor 164 (VEGF164), and VEGF188 polymerase chain reaction products were run in agarose gel electrophoresis. Band density analysis of UV camera images was performed using Image J. The data were compared by one-way ANOVA, repeated measures two-way ANOVA, and the Kruskal-Wallis test.

RESULTS

The percent weight change was lower in the DM group than in the controls (p=0.004). The tissue injury was the highest in the DM group and the least in the IH group. Diabetes decreased, whereas the IH treatment increased the vascularity. A decrease was observed in the VEGF188 mRNA levels in the DM+IH group compared with the C group, but there were no difference in HIF-1α and VEGF164 mRNA levels between the groups.

CONCLUSION

The IH treatment restored the diabetic effects on the heart by reducing tissue injury and increasing the capillarity without transcriptional changes in HIF-1/VEGF correspondingly.

Blockade of EMAP II protects cardiac function after chronic myocardial infarction by inducing angiogenesis

Promoting angiogenesis is a key therapeutic target for protection from chronic ischemic cardiac injury. Endothelial-Monocyte-Activating-Polypeptide-II (EMAP II) protein, a tumor-derived cytokine having anti-angiogenic properties in cancer, is markedly elevated following myocardial ischemia. We examined whether neutralization of EMAP II induces angiogenesis and has beneficial effects on myocardial function and structure after chronic myocardial infarction (MI). EMAP II antibody (EMAP II AB), vehicle, or non-specific IgG (IgG) was injected ip at 30 min and 3, 6, and 9 days after permanent coronary artery occlusion in mice. EMAP II AB, compared with vehicle or non-specific antibody, significantly, p<0.05, improved the survival rate after MI, reduced scar size and attenuated the development of heart failure, i.e., left ventricular ejection fraction was significantly higher in EMAP II AB group, fibrosis was reduced by 24%, and importantly, more myocytes were alive in EMAP II AB group in the infarct area. In support of an angiogenic mechanism, capillary density (193/HPF vs. 172/HPF), doubling of the number of proliferating endothelial cells, and angiogenesis related biomarkers were upregulated in mice receiving EMAP II AB treatment as compared to IgG. Furthermore, EMAP II AB prevented EMAP II protein inhibition of in vitro tube formation in HUVECs. We conclude that blockade of EMAP II induces angiogenesis and improves cardiac function following chronic MI, resulting in reduced myocardial fibrosis and scar formation and increased capillary density and preserved viable myocytes in the infarct area.

Stable phase post-MI patients have elevated VEGF levels correlated with inflammation markers, but not with atherosclerotic burden

BACKGROUND

The role of vascular endothelial growth factor (VEGF) in patients in the stable phase after myocardial infarction (MI) has not yet been explored. Therefore, we compared the values of VEGF in post-MI patients with those obtained in healthy controls. Furthermore, we investigated whether the values of VEGF correlate to either inflammation markers or the atherosclerotic burden.

METHODS

41 male patients (on average 44 years old) in the stable phase after MI (on average 20.5 months after MI) were recruited, while 25 healthy age-matched males served as controls. Plasma levels of VEGF and several markers of inflammation were measured by standard procedures. The atherosclerotic burden was determined by the angiographic severity of coronary atherosclerosis, endothelial dysfunction (measured by ultrasound measurement of the flow mediated dilation of the brachial artery), the intima-media thickness of the common carotid artery and the ankle-brachial pressure index.

RESULTS

VEGF values were significantly elevated in post-MI patients compared to the controls (53.8 ± 42.7 pg/ml vs. 36.3 ± 8.9 pg/ml, p = 0.014). The elevated VEGF values significantly correlated to the (increased) values of the inflammatory molecules interleukin 6 and 8 (r = 0.37, p = 0.017; and r = 0.45, p = 0.003; respectively). In contrast, no correlation was found between VEGF and the parameters of the atherosclerotic burden, although FMD and IMT were significantly impaired in patients.

CONCLUSIONS

We found that plasma levels of VEGF are increased in the stable phase after MI and correlate with inflammation cytokines, but not with the atherosclerotic burden. Thus, this suggests that increased levels of VEGF are a part of ongoing inflammatory activity. Since VEGF in these patients stimulates neovascularization of inflamed plaques and induces their destabilization, the VEGF level can have an important negative prognostic value. Clearly, further studies are needed to clarify the role of VEGF as a prognostic marker.

Diabetic cardiomyopathy: understanding the molecular and cellular basis to progress in diagnosis and treatment

Diabetes mellitus is an important and prevalent risk factor for congestive heart failure. Diabetic cardiomyopathy has been defined as ventricular dysfunction that occurs in diabetic patients independent of a recognized cause such as coronary artery disease or hypertension. The disease course consists of a hidden subclinical period, during which cellular structural insults and abnormalities lead initially to diastolic dysfunction, later to systolic dysfunction, and eventually to heart failure. Left ventricular hypertrophy, metabolic abnormalities, extracellular matrix changes, small vessel disease, cardiac autonomic neuropathy, insulin resistance, oxidative stress, and apoptosis are the most important contributors to diabetic cardiomyopathy onset and progression. Hyperglycemia is a major etiological factor in the development of diabetic cardiomyopathy. It increases the levels of free fatty acids and growth factors and causes abnormalities in substrate supply and utilization, calcium homeostasis, and lipid metabolism. Furthermore, it promotes excessive production and release of reactive oxygen species, which induces oxidative stress leading to abnormal gene expression, faulty signal transduction, and cardiomyocytes apoptosis. Stimulation of connective tissue growth factor, fibrosis, and the formation of advanced glycation end-products increase the stiffness of the diabetic hearts. Despite all the current information on diabetic cardiomyopathy, translational research is still scarce due to limited human myocardial tissue and most of our knowledge is extrapolated from animals. This paper aims to elucidate some of the molecular and cellular pathophysiologic mechanisms, structural changes, and therapeutic strategies that may help struggle against diabetic cardiomyopathy.

A new insight of mechanisms, diagnosis and treatment of diabetic cardiomyopathy

Diabetes mellitus is one of the most common chronic diseases across the world. Cardiovascular complication is the major morbidity and mortality among the diabetic patients. Diabetic cardiomyopathy, a new entity independent of coronary artery disease or hypertension, has been increasingly recognized by clinicians and epidemiologists. Cardiac dysfunction is the major characteristic of diabetic cardiomyopathy. For a better understanding of diabetic cardiomyopathy and necessary treatment strategy, several pathological mechanisms such as impaired calcium handling and increased oxidative stress, have been proposed through clinical and experimental observations. In this review, we will discuss the development of cardiac dysfunction, the mechanisms underlying diabetic cardiomyopathy, diagnostic methods, and treatment options.

Diabetic cardiomyopathy

Individuals with diabetes are at a significantly greater risk of developing cardioymyopathy and heart failure despite adjusting for concomitant risks such as coronary artery disease or hypertension. This has led to the increased recognition of a distinct disease process termed as "diabetic cardiomyopathy." In this article, we perform an extensive review of the pathogenesis and treatment of this disease. From a clinical perspective, physicians should be aware of this entity, and early screening should be considered because physical evidence of early diabetic cardiomyopathy could be difficult to detect. Early detection of the disease should prompt intensification of glycemic control, concomitant risk factors, use of pharmacologic agents such as β-blockers and renin-angiotensin-aldosterone system antagosists. From a research perspective, more studies on myocardial tissue from diabetic patients are needed. Clinical trials to evaluate the development of diabetic cardiomyopathy and fibrosis in early stages of the disease, as well as clinical trials of pharmacologic intervention in patients specifically with diabetic cardiomyopathy, need to be conducted.

Acute segmental testicular infarction at contrast-enhanced ultrasound: early features and changes during follow-up

OBJECTIVE

The purpose of this retrospective study was to assess whether contrast-enhanced ultrasound is useful for characterization of acute segmental testicular infarction.

MATERIALS AND METHODS

Twenty men with acute scrotal pain and suspected segmental testicular infarction underwent contrast-enhanced ultrasound. Three patients underwent orchiectomy. For the other patients, the final diagnosis was based on the absence of tumor markers and a change in the size or shape of the tumor during follow-up. Forty-nine color Doppler ultrasound studies (16 within 24 hours of the onset of pain; 14, 2-17 days after pain onset; 19 after 1 month or more), and 38 contrast-enhanced ultrasound studies (13 within 24 hours after pain onset; nine, 2-17 days; 16 after 1 month or more) were performed.

RESULTS

Fourteen of 16 lesions examined within 24 hours were oval, and two were wedge shaped. Eight lesions were isoechoic to the testis, six were hypoechoic, and two had mixed echogenicity. Twelve lesions were avascular and four were hypovascular at color Doppler examination. Contrast-enhanced ultrasound showed avascular parenchymal lobules in all cases and without perilesional rim enhancement in 12 of 13 studies. Two to 17 days after the symptoms appeared, contrast-enhanced ultrasound showed avascular lobules in all cases and perilesional rim enhancement in eight examinations. After 1 month or more, contrast-enhanced ultrasound depicted intralesional vascular spots in 12 of 14 infarcts. Perilesional enhancement was absent.

CONCLUSION

Recognition of lobular morphologic characteristics and the presence of perilesional rim enhancement at contrast-enhanced ultrasound can increase confidence in the diagnosis of segmental testicular infarction compared with reliance on gray-scale and color Doppler findings. Changes in lesion features during follow-up confirm the differential diagnosis from other testicular lesions and allow conservative management.

Diabetic cardiomyopathy

Diabetic cardiomyopathy is a distinct primary disease process, independent of coronary artery disease, which leads to heart failure in diabetic patients. Epidemiological and clinical trial data have confirmed the greater incidence and prevalence of heart failure in diabetes. Novel echocardiographic and MR (magnetic resonance) techniques have enabled a more accurate means of phenotyping diabetic cardiomyopathy. Experimental models of diabetes have provided a range of novel molecular targets for this condition, but none have been substantiated in humans. Similarly, although ultrastructural pathology of the microvessels and cardiomyocytes is well described in animal models, studies in humans are small and limited to light microscopy. With regard to treatment, recent data with thiazoledinediones has generated much controversy in terms of the cardiac safety of both these and other drugs currently in use and under development. Clinical trials are urgently required to establish the efficacy of currently available agents for heart failure, as well as novel therapies in patients specifically with diabetic cardiomyopathy.

Diabetic cardiomyopathy--a distinct disease?

Diabetic individuals have a significantly increased likelihood of developing cardiovascular disease. Whilst part of this association is explained by the presence of concomitant risk factors, large epidemiological studies have consistently reported diabetes as a strong risk factor for the development of heart failure after adjusting for such covariates. This has resulted in the notion that there is a distinct cardiomyopathy specific to diabetes, termed 'diabetic cardiomyopathy'. The natural history is characterized by a latent subclinical period, during which there is evidence of diastolic dysfunction and left ventricular hypertrophy, before overt clinical deterioration and systolic failure ensue. These clinical findings have been supported by a growing body of experimental data which support the notion that diabetes inflicts a direct insult to the myocardium, with cellular, structural and functional changes manifest as the diabetic myocardial phenotype. Several of these mechanisms appear to work in unison, forming complicated reciprocal pathways of disease. Reactive oxygen species and alterations in intracellular calcium homeostasis appear to play significant roles in many of these mechanisms. Determining the hierarchy of this cascade of disease will allow identification of the pathological trigger most responsible for disease. Translational research in this field is currently hindered by a lack of clinical studies and intervention trials specifically in patients with diabetic cardiomyopathy. Future clinical and experimental studies of accurate models of diabetic cardiomyopathy should help to define the true aetiology and lead to the development of specific pharmacotherapies for this condition, ultimately reducing the increased cardiovascular morbidity and mortality in diabetic patients.

Imaging of VEGF receptor in a rat myocardial infarction model using PET

Myocardial infarction (MI) leads to left ventricular (LV) remodeling, which leads to the activation of growth factors such as vascular endothelial growth factor (VEGF). However, the kinetics of a growth factor's receptor expression, such as VEGF, in the living subject has not yet been described. We have developed a PET tracer (64Cu-DOTA-VEGF121 [DOTA is 1,4,7,10-tetraazadodecane-N,N',N'',N'''-tetraacetic acid]) to image VEGF receptor (VEGFR) expression after MI in the living subject.

METHODS

In Sprague-Dawley rats, MI was induced by ligation of the left coronary artery and confirmed by ultrasound (n = 8). To image and study the kinetics of VEGFRs, 64Cu-DOTA-VEGF121 PET scans were performed before MI induction (baseline) and on days 3, 10, 17, and 24 after MI. Sham-operated animals served as controls (n = 3).

RESULTS

Myocardial origin of the 64Cu-DOTA-VEGF121 signal was confirmed by CT coregistration and autoradiography. VEGFR specificity of the 64Cu-DOTA-VEGF121 probe was confirmed by in vivo use of a 64Cu-DOTA-VEGFmutant. Baseline myocardial uptake of 64Cu-DOTA-VEGF121 was minimal (0.30 +/- 0.07 %ID/g [percentage injected dose per gram of tissue]); it increased significantly after MI (day 3, 0.97 +/- 0.05 %ID/g; P < 0.05 vs. baseline) and remained elevated for 2 wk (up to day 17 after MI), after which time it returned to baseline levels.

CONCLUSION

We demonstrate the feasibility of imaging VEGFRs in the myocardium. In summary, we imaged and described the kinetics of 64Cu-DOTA-VEGF121 uptake in a rat model of MI. Studies such as the one presented here will likely play a major role when studying pathophysiology and assessing therapies in different animal models of disease and, potentially, in patients.

A relationship between vascular endothelial growth factor, angiogenesis, and cardiac repair after muscle stem cell transplantation into ischemic hearts

OBJECTIVES

We investigated whether vascular endothelial growth factor (VEGF) was associated with the angiogenic and therapeutic effects induced after transplantation of skeletal muscle-derived stem cells (MDSCs) into a myocardial infarction (MI).

BACKGROUND

Because very few MDSCs were found to differentiate into new blood vessels when injected into the heart, the mechanism underlying the occurrence of angiogenesis after MDSC transplantation is currently unknown. In the present study, we used a gain- or loss-of-VEGF function approach with skeletal MDSCs engineered to express VEGF or soluble Flt1, a VEGF-specific antagonist, to identify the involvement of VEGF in MDSC transplantation-induced neoangiogenesis.

METHODS

Vascular endothelial growth factor- and soluble Flt1-engineered MDSCs were injected into an acute MI. Angiogenesis and cardiac function were evaluated by immunohistochemistry and echocardiography.

RESULTS

Both control and VEGF-overexpressing MDSCs induced angiogenesis, prevented adverse cardiac remodeling, and improved function compared with saline-injected hearts. However, these therapeutic effects were diminished in hearts transplanted with MDSCs expressing soluble Flt1 despite successful cell engraftment. In vitro experiments demonstrated that MDSCs increased secretion of VEGF in response to hypoxia and cyclic stretch (likely conditions in ischemic hearts), suggesting that transplanted MDSCs release VEGF in vivo.

CONCLUSIONS

Our findings suggest that VEGF is essential for the induction of angiogenesis and functional improvements observed after MDSC transplantation for infarct repair.

Endothelin antagonism normalizes VEGF signaling and cardiac function in STZ-induced diabetic rat hearts

Abnormal alterations in cardiac expression of vascular endothelial growth factor (VEGF) as well as its receptors and impairment in the development of coronary collaterals have recently been reported in diabetic subjects. However, the presence of pharmacological intervention on these defects in diabetes remains unsettled. Here, we studied the effect of endothelin (ET) receptor blockade on cardiac VEGF signaling pathways and cardiac function in Sprague-Dawley rats 5 wk after induction of type I diabetes with streptozotocin (65 mg/kg ip) in comparison with age-matched control rats. After streptozotocin (1 wk), some diabetic rats were treated with the ET receptor antagonist SB-209670 (1 mg/day) for 4 wk. VEGF, its receptors, and its angiogenic signaling molecules [phosphorylated Akt and endothelial nitric-oxide synthase (eNOS)] were analyzed by Western blot, ELISA, real-time PCR, and immunohistochemistry, and cardiac function was evaluated by echocardiography. Coronary capillary morphology was assessed by lectin and enzymatic double staining. We found significant decreases in cardiac expression of VEGF, its receptors, phosphorylation of Akt and eNOS, and coronary capillary density in diabetic rats compared with controls. Treatment of diabetic rats with SB-209670 reversed these alterations to the control levels and ameliorated impairment of cardiac function. From a molecular point of view, the present study is the first to indicate the potential usefulness of an ET receptor antagonist in the treatment of cardiac dysfunction in type I diabetes.

Clearance of apoptotic and necrotic cells and its immunological consequences

The ultimate and most favorable fate of almost all dying cells is engulfment by neighboring or specialized cells. Efficient clearance of cells undergoing apoptotic death is crucial for normal tissue homeostasis and for the modulation of immune responses. Engulfment of apoptotic cells is finely regulated by a highly redundant system of receptors and bridging molecules on phagocytic cells that detect molecules specific for dying cells. Recognition of necrotic cells by phagocytes is less well understood than recognition of apoptotic cells, but an increasing number of recent studies, which are discussed here, are highlighting its importance. New observations indicate that the interaction of macrophages with dying cells initiates internalization of the apoptotic or necrotic targets, and that internalization can be preceded by "zipper"-like and macropinocytotic mechanisms, respectively. We emphasize that clearance of dying cells is an important fundamental process serving multiple functions in the regulation of normal tissue turnover and homeostasis, and is not just simple anti- or pro-inflammatory responses. Here we review recent findings on genetic pathways participating in apoptotic cell clearance, mechanisms of internalization, and molecules involved in engulfment of apoptotic versus necrotic cells, as well as their immunological consequences and relationships to disease pathogenesis.

Increased vascular endothelial growth factor expression but impaired vascular endothelial growth factor receptor signaling in the myocardium of type 2 diabetic patients with chronic coronary heart disease

OBJECTIVES

The aim of the present study was to evaluate the expression and the activity of vascular endothelial growth factor (VEGF) in the hearts of diabetic patients with chronic coronary heart disease (CHD).

BACKGROUND

Diabetes is characterized by a decreased collateral vessel formation in response to coronary ischemic events, although the role of VEGF in human diabetic macroangiopathy has not been fully investigated.

METHODS

Biopsies of left ventricular (LV) myocardium were obtained from 10 patients with type 2 diabetes and 10 non-diabetic patients with chronic CHD, all undergoing surgical coronary revascularization. Right ventricle myocardial samples taken from normal hearts were used as control specimens. Vascular endothelial growth factor and VEGF-receptors (flt-1 and flk-1) were evaluated by Western blot, reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time RT-PCR. Akt and endothelial nitric oxide synthase (eNOS) protein expression and their phosphorylated forms were also evaluated by Western blot.

RESULTS

Vascular endothelial growth factor, flt-1, and flk-1 messenger ribonucleic acid (mRNA) and protein expressions were increased in non-diabetic patients with CHD compared with control subjects. Remarkably, in diabetic patients, VEGF mRNA and protein levels were significantly higher, whereas flt-1, flk-1 mRNA, and protein were lower when compared with non-diabetic patients. Interestingly, phospho-flk-1 was reduced in diabetic patients compared with non-diabetic patients. As a consequence, Akt phosphorylation, eNOS protein and its phosphorylated form were significantly higher in the samples from non-diabetic patients compared with diabetic patients.

CONCLUSIONS

Chronic CHD in diabetic patients is characterized by an increased VEGF myocardial expression and a decreased expression of its receptors along with a down-regulation of its signal transduction. The latter could be partially responsible for the reduced neoangiogenesis in diabetic patients with ischemic cardiomyopathy.

Diabetic cardiomyopathy: mechanisms, diagnosis and treatment

Independent of the severity of coronary artery disease, diabetic patients have an increased risk of developing heart failure. This clinical entity has been considered to be a distinct disease process referred to as 'diabetic cardiomyopathy'. Experimental studies suggest that extensive metabolic perturbations may underlie both functional and structural alterations of the diabetic myocardium. Translational studies are, however, limited and only partly explain why diabetic patients are at increased risk of cardiomyopathy and heart failure. Although a range of diagnostic methods may help to characterize alterations in cardiac function in general, none are specific for the alterations in diabetes. Treatment paradigms are very much limited to interpretation and translation from the results of interventions in non-diabetic patients with heart failure. This suggests that there is an urgent need to conduct pathogenetic, diagnostic and therapeutic studies specifically in diabetic patients with cardiomyopathy to better understand the factors which initiate and progress diabetic cardiomyopathy and to develop more effective treatments.

Vascular endothelial cell growth factor and fibroblast growth factor 2 expression in patients with critical limb ischemia

BACKGROUND

For patients with critical limb ischemia (CLI), there is a great need for alternative treatment strategies. One option is therapeutic angiogenesis by administration of vascular growth factors. The lack of convincing clinical data supporting this strategy may be due to the ignorance of endogenous angiogenic processes in CLI. To evaluate the importance of vascular growth factors in the pathogenesis in CLI and provide information for clinical growth factor treatment trials, we determined the levels of vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF-2) in the ischemic legs of patients with this disease.

METHODS

Skin and muscle biopsies from the calf and groin were gathered from 25 patients with CLI. Control samples came from 10 orthopedic patients and from 5 patients who were undergoing coronary artery bypass. The concentration of VEGF and FGF-2 in the biopsies was measured by enzyme-linked immunoassay, and to localize growth factor production, biopsied sections were immunostained.

RESULTS

Patients with CLI had lower levels of VEGF in distal skin samples than in proximal ones (mean difference: 16.7 pg/mg total protein, 95% confidence interval: -1.0 to -32.3, P =.038), but these levels were similar to those in distal samples from control subjects (8.0, -4.6 to 20.5, P =.65). In muscle, VEGF concentrations were similar in calf and groin (5.4, -12.4 to 23.1, P =.55), but distal levels were higher than in distal samples from control subjects (23.7, 1.2 to 56.7, P =.028). Skin FGF levels tended to be higher in distal samples (45.3, 26.5 to 117.5, P =.090) and were higher than in skin from control subjects (106.2, -11.4 to 223.8, P =.050). Also in muscle, distal samples had higher levels of FGF-2 (35.6, -1.6 to 59.7, P =.006), but these levels were similar to what was found in control subjects (29.4., -16.3 to 81.2, P =.39). Growth factors were located in connective tissue between muscle fibers. In skin, the predominant FGF-2 staining was just below the epidermal layer, whereas VEGF appeared in the dermal layer.

CONCLUSIONS

The results indicate that there are elevated concentrations of FGF-2 in calf muscle, whereas VEGF concentrations do not appear to be higher in the ischemic part of the leg in patients with CLI. These findings suggest that VEGF supplementation may be a more appropriate strategy for therapeutic angiogenesis to the calf area for CLI than FGF-2.

Potential role for antiangiogenic proteins in the myocardial infarction repair process

OBJECTIVE

Although angiogenic proteins have been identified as positive modulators of myocardial revascularization following acute myocardial infarction, little if anything is known regarding the role that antiangiogenic proteins have in myocardial revascularization. We explored the temporospatial distribution of endothelial-monocyte activating polypeptide (EMAP) II to determine whether antiangiogenic proteins have a role in the repair of myocardial tissue following infarction.

METHODS

A rat model of myocardial infarction was utilized to examine EMAP II distribution (in situ hybridization) and protein expression (Western analysis) over a 6-week period.

RESULTS

At baseline, EMAP II protein and mRNA are minimally expressed with transcription products localizing predominately to the perivascular stroma region in the normal rat myocardium. Six hours following myocardial infarction, EMAP II changes its distribution from the perivascular stroma to an invading inflammatory cell population. This is associated with a 2-fold (P < 0.0009) increase in EMAP II protein and its transcription primarily localized to the infarct region. EMAP II protein expression remains elevated throughout the weeks following the infarction with transcription limited to the infarct region and a notable decrease in EMAP II transcription products noted in the viable vasculature surrounding the infarct zone. Six weeks following myocardial infarction, EMAP II protein is elevated above control, changes its location of transcription from the inflammatory cell population to that of the fibroblasts located in the relative avascular scar tissue, and has resumed its perivascular stromal distribution in the viable periinfarct tissue.

CONCLUSIONS

Thus, the temporospatial distribution of this antiangiogenic protein suggests that negative vascular modulators may have a function in the revascularization process following acute myocardial infarction.

Concentrations of Hepatocyte Growth Factor, Basic Fibroblast Growth Factor, and Vascular Endothelial Growth Factor in Pericardial Fluid and Plasma

Some angiogenic factors, including hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF), have been reported to promote angiogenesis and improve myocardial perfusion in experimental models of ischemic heart disease. These factors are produced in various tissues, including myocardium. We measured the concentrations of HGF, bFGF, and VEGF by enzyme-linked immunosorbent assay in plasma and in pericardial fluid sampled during open heart surgery (12 patients with ischemic heart disease and 17 with nonischemic heart disease). HGF levels were significantly higher in plasma than in pericardial fluid (12.0 +/- 1.8 versus 0.26 +/- 0.04 ng/mL, P < 0.0001). On the other hand, bFGF levels were significantly higher in pericardial fluid than in plasma (243.5 +/- 50.9 versus 49.6 +/- 7.8 pg/mL, P = 0.009). VEGF levels were not significantly different between pericardial fluid and plasma (47.2 +/- 17.6 versus 24.5 +/- 3.6 pg/mL, P = 0.23). Concentrations of angiogenic factors in pericardial fluid and in plasma were not significantly different between patients with ischemic and nonischemic heart disease. These results suggest that the production, secretion, and kinetics of HGF, bFGF, and VEGF are different. These angiogenic factors may have different pathophysiologic roles.

Increased vascular endothelial growth factor mRNA expression in the heart of streptozotocin-induced diabetic rats

The aim of the present study was to evaluate vascular endothelial growth factor (VEGF), fms-like tyrosine kinase 1 (flt-1), and fetal liver kinase (flk-1) expression in the heart of experimental diabetic rats. Ten young adult male Wistar rats (5 streptozotocin [STZ]-induced diabetic rats, without insulin treatment, and 5 controls) were studied. Ninety days after the induction of diabetes, semiquantitative reverse transcription (RT)-polymerase chain reaction (PCR) coamplification of VEGF/glyceraldehyde 3-phosphate dehydrogenase (GAPDH) transcription was performed. RT-PCR was also performed for VEGF receptors flk-1 and flt-1. VEGF mRNA expression, at 234 bp, was detectable in the heart of the rats and was significantly higher in those with diabetes. Densitometric analysis of PCR products showed that VEGF mRNA levels were meanly 4.8-fold higher in STZ-induced diabetic rats than controls (VEGF/GAPDH densitometric ratio, 3.46 +/- 0.20 v 0.74 +/- 0.10, P <.001). No significant difference was found in flt-1 and flk-1 amplification products between STZ-induced diabetic rats and controls (flt-1/GAPDH densitometric ratio, 0.58 +/- 0.01 v 0.64 +/- 0.05, P>.1; flk-1/GAPDH densitometric ratio, 0.66 +/- 0.10 v 0.7 +/- 0.06, P >.2). The increase in VEGF mRNA expression observed in this experimental diabetic model is in contrast with the typical impairment in collateral vessels of diabetic hearts. This apparent discrepancy might be explained by a resistance of cardiac tissue to VEGF. The lack of mRNA flt-1 and flk-1 overexpression in diabetic hearts could be one of the mechanisms for this resistance.

Pulmonary expression of vascular endothelial growth factor in sepsis

CONTEXT

Vascular endothelial growth factor (VEGF), an angiogenic and chemotactic peptide, is abundantly expressed in normal lung tissue, especially in alveolar and bronchial epithelium, glandular cells of the bronchi, and activated alveolar macrophages.

OBJECTIVE

To investigate the role of VEGF in progressively impaired lung function as the major complication and cause of death in septic patients.

MATERIALS AND METHODS

We evaluated pulmonary VEGF expression in lung autopsy material from septic patients who had been cared for by intensive care medicine using enzyme-linked immunosorbent assay (ELISA), reverse transcriptase-polymerase chain reaction (RT-PCR), and immunohistochemical methods.

RESULTS

Compared with expression in nonseptic control individuals (n = 10), pulmonary VEGF expression as determined by ELISA was significantly (P <.001) decreased in septic patients (n = 8). As monitored by RT-PCR, mRNA for the 2 splice variants, VEGF(121) and VEGF(165), and for VEGFR-2/KDR were expressed in both groups, the yields being lower in the sepsis group. Samples from septic patients lacked or showed only sparse immunoreaction on bronchial and alveolar epithelium, whereas this reaction was strong in all control samples. However, alveolar macrophages were similarly immunopositive in both groups.

CONCLUSIONS

The precise underlying mechanisms for the distinctly different expression of pulmonary VEGF in septic patients and nonseptic control individuals are not clear at present. Particularly the role of VEGF in the development of sepsis-induced lung injury and acute respiratory distress syndrome in mechanically ventilated patients suffering from severe sepsis remains to be clarified.

Serum hepatocyte growth factor predicts ventricular remodeling following myocardial infarction

Hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) stimulate endothelial cell proliferation and induce angiogenesis, but the timing and significance of their release in patients with acute myocardial infarction (AMI) are unknown in relation to future left ventricular remodeling. Venous blood samples were obtained at admission and up to 3 weeks later in 40 patients with AMI and in 40 age- and sex-matched control subjects. Blood samples were also taken from the coronary sinus (CS) in 20 patients on day 7 following AMI. Left ventricular end-diastolic volume in the subacute (1 week) and chronic (3 months) phases was assessed by left ventriculography to identify the remodeling group (n=15), which was defined as an increase in left ventricular end-diastolic volume index > or =5 ml/m(2) relative to the baseline value. Serum HGF and VEGF concentrations were higher in newly admitted patients with AMI than in the controls (HGF, 0.33 +/-0.09 vs 0.24+/-0.08 ng/ml, p<0.01; VEGF, 92.2+/-43.1 vs 67.2+/-29.8 pg/ml, p<0.01), peaking on day 7 (HGF, 0.41+/-0.12; VEGF, 161.7+/-76.9), and gradually decreasing between days 14 and 21. The HGF concentration in the CS did not differ from the concentration in the periphery, but the VEGF concentration was significantly more abundant in the CS than in the peripheral sample on day 7 (p<0.05). The serum HGF concentration on day 7 was higher in the remodeling group than in the nonremodeling group (0.47 +/-0.13 vs 0.36+/-0.09 ng/ml, p<0.01), but there was no difference between the groups on admission, day 14 and day 21. The serum VEGF concentration did not differ between the remodeling and nonremodeling groups at any time. Thus, the serum HGF concentration on day 7 after AMI is mostly from noncardiac sources and predicts left ventricular remodeling.

An essential role of the NF-kappa B/Toll-like receptor pathway in induction of inflammatory and tissue-repair gene expression by necrotic cells

Tissue damage induced by infection or injury can result in necrosis, a mode of cell death characterized by induction of an inflammatory response. In contrast, cells dying by apoptosis do not induce inflammation. However, the reasons for underlying differences between these two modes of cell death in inducing inflammation are not known. Here we show that necrotic cells, but not apoptotic cells, activate NF-kappaB and induce expression of genes involved in inflammatory and tissue-repair responses, including neutrophil-specific chemokine genes KC and macrophage-inflammatory protein-2, in viable fibroblasts and macrophages. Intriguingly, NF-kappaB activation by necrotic cells was dependent on Toll-like receptor 2, a signaling pathway that induces inflammation in response to microbial agents. These results have identified a novel mechanism by which cell necrosis, but not apoptosis, can induce expression of genes involved in inflammation and tissue-repair responses. Furthermore, these results also demonstrate that the NF-kappaB/Toll-like receptor 2 pathway can be activated both by exogenous microbial agents and endogenous inflammatory stimuli.

Increased vascular endothelial growth factor expression in human hearts with microvascular fibrin

We have shown that microvascular changes that promote fibrin deposition in human cardiac allografts adversely affect clinical outcome. However, some allografts exhibit phenotypic changes in capillaries following the deposition of fibrin, which subsequently provide a significant survival advantage. The mechanism(s) involved in these capillary changes is(are) unknown. Similarly, although we have shown a significant temporal relationship between microvascular fibrin deposition and vascular endothelial growth factor (VEGF) immunoreactivity in cardiac allografts, the cellular source and relative changes in VEGF gene expression under these conditions are not known. Using immunocytochemical techniques, biopsies devoid of fibrin deposition lacked detectable VEGF immunoreactivity, whereas biopsies with fibrin deposition showed VEGF immunoreactivity in cardiocytes, interstitium, and some microvessels. By in situ hybridization, biopsies without microvascular fibrin deposition showed faint VEGF hybridization signals confined primarily to cardiocytes. In biopsies with fibrin deposition, strong VEGF hybridization signals were detected in cardiocytes, arteriolar smooth muscle cells were occasionally labeled, and endothelial cells were rarely labeled. By quantitative RT-PCR, biopsies with fibrin deposition (n=5) relatively expressed approximately three-fold more VEGF mRNA than biopsies without fibrin deposition (n=5 P=0.02). Serum VEGF titers also were greater (P=0.01) in recipients with fibrin deposition (372.9+/-66.7 pg/ml n=18) compared to recipients without fibrin deposition (172.1+/-25.0 pg/ml n=16). Collectively, these results support the hypothesis that increased myocyte-derived VEGF production following microvascular fibrin deposition in transplanted human hearts may act in a paracrine manner to promote activational and phenotypic changes in capillaries that provide a survival advantage for the allografts.

Sequential changes in localization of repair-related proteins (heat shock protein 70, ubiquitin and vascular endothelial growth factor) in the different stages of myocardial infarction

AIMS

The myocardium expresses vascular endothelial growth factor (VEGF), heat shock protein 70 (HSP70), and ubiquitin immediately after the onset of cardiac ischaemia. This study demonstrated the sequential changes in localization of these proteins, in addition to fibronectin and troponin T (TnT), in human hearts with myocardial infarction (MI).

METHODS AND RESULTS

Myocardial tissues from 40 autopsied MI cases were immunostained with the five antibodies against VEGF, HSP70, ubiquitin, fibronectin and TnT. Fibronectin was recognized only in the cardiomyocytes with infarction. Although TnT, HSP70, ubiquitin and VEGF were detected in the affected myocardium in the early stages, their expression in cardiomyocytes around infarcted foci were more intense. The cardiomyocytes with coagulative myocytolysis were positive for fibronectin, but negative or weakly positive for TnT, HSP70, ubiquitin and VEGF. In contrast, the cardiomyocytes with colliquative myocytolysis were strongly positive for TnT, HSP70, ubiquitin and VEGF, but negative for fibronectin.

CONCLUSIONS

Immunostaining using antibodies to fibronectin, TnT, HSP70, ubiquitin and VEGF is useful for the discrimination between infarcted myocytes and ischaemia-damaged myocytes in the human heart with MI at autopsy.

Role of vascular endothelial growth factor in diabetic vascular complications

BACKGROUND

Much of the morbidity and mortality associated with diabetes mellitus predominantly reflects its deleterious effects on microcirculation and macrocirculation. During the past few years, rapid advancement has been made in our understanding of the mechanisms and molecules involved in the pathogenesis of diabetic microvasculopathy. This is particularly true with regard to retinal vascular disease and the role of the angiogenesis- and vasopermeability-inducing molecule, vascular endothelial growth factor (VEGF).

METHODS

Biochemical studies in many relevant cell types have been performed. Effects of VEGF action and inhibition have been evaluated in animals. Interventions that block the biochemical pathways initiated by VEGF have been tested both in culture and in animals. Human clinical trials have begun.

RESULTS

VEGF induces vascular endothelial cell proliferation, migration and vasopermeability in many cells and tissues. In vivo, VEGF has been identified as a primary initiator of proliferative diabetic retinopathy, and as a potential mediator of nonproliferative retinopathy. In addition, VEGF has been implicated in the development of neuropathy and nephropathy in the patient with diabetes. In patients with diabetes and coronary artery or peripheral vascular disease, VEGF may induce development of cardiac and limb vascular collateralization, respectively. Many biochemical processes mediating these actions have now been elucidated.

CONCLUSIONS

VEGF appears to play a central role in mediating diabetic vasculopathy in many organs. Improved understanding of the molecular mechanisms underlying these processes has permitted development of novel therapeutic interventions, several of which are now in human clinical trials. These scientific advances and various implications for the future care of vasculopathy associated with diabetes will be discussed.

Expression of vascular endothelial growth factor in patients with acute myocardial infarction

OBJECTIVE

The purpose of this study was to investigate the clinical significance of vascular endothelial growth factor (VEGF) in acute myocardial infarction (AMI). We also examined the involvement of peripheral blood mononuclear cells (PBMCs), which are a possible source of VEGF in AMI.

BACKGROUND

VEGF is a potent endothelial cell-specific mitogen and could affect the outcome of AMI.

METHODS

Thirty patients with AMI were used for this study. Serum and PBMCs were isolated from peripheral blood on days 1, 7, 14 and 21 after the onset of AMI. PBMCs were cultured at a density of 5 x 10(6) cells/ml for 24 h. VEGF levels in serum and the culture media were measured by enzyme-linked immunosorbent assay using a specific anti-human VEGF antibody.

RESULTS

Serum VEGF levels elevated gradually after the onset of AMI and reached a peak on day 14. VEGF levels in the culture medium of PBMCs after incubation for 24 h (PBMC-VEGF) were maximally elevated 7 days after the onset. Maximum serum VEGF levels showed significant positive correlations with maximum creatine phosphokinase (CPK) levels (r = +0.70, p < 0.001), but maximum PBMC-VEGF levels did not correlate with maximum CPK levels. Patients showing improvement in left ventricular systolic function during the course of AMI showed significantly higher PBMC-VEGF levels than patients without improvement.

CONCLUSIONS

The extent of myocardial damage contributes to the elevation of serum VEGF levels in AMI. VEGF produced by PBMCs may play an important role in the improvement of left ventricular function by promoting angiogenesis and reendothelialization after AMI.

Elevated circulating levels of basic fibroblast growth factor and vascular endothelial growth factor in patients with acute myocardial infarction

Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have both shown strong angiogenetic effects in ischemic animal models and it has been reported that these growth factors were increased after acute myocardial ischemia. However, there have been few reports on the serum levels of bFGF and VEGF after acute myocardial infarction (AMI), in particular there has not been a comparative study of bFGF and VEGF in human subjects. The time course of circulating levels of bFGF and VEGF was examined in 36 patients with AMI who were within 24h of the onset of the AMI. The serum bFGF and VEGF levels of 50 age- and sex-matched healthy volunteers served as the baseline value. All the patients had undergone coronary angiography on the day of admission (Day 0), but prior to that the serum bFGF and VEGF levels were examined by enzyme-linked immunoassay. The serum bFGF and VEGF levels were also evaluated on Days 7, 14 and 28. Creatine kinase, myosin light chain I and troponin-T were measured subsequently and radionuclide examinations were performed during the early phase of AMI to determine the infarct size. The serum bFGF levels were significantly increased at Day 0 and were maintained until Days 7 and 14. Although serum VEGF levels at Day 0 were similar to the baseline values, they showed a remarkable increase by Days 7 and 14. A high serum level of bFGF was detected in the acute phase of AMI, and a later increase in VEGF was determined in the sub-acute phase, which suggest that these 2 growth factors play an important role at different time points of the reconstructing process of infarcted myocardial tissue.

Differential immunolocalization of VEGF in rat and human adult lung, and in experimental rat lung fibrosis: light, fluorescence, and electron microscopy

Vascular endothelial growth factor (VEGF) is a cytokine with main angiogenetic functions in embryonic development and tumor-formation. In the adult lung, reports of the localization of VEGF were controversial. A precise cell typing of VEGF-positive pulmonary cells is still lacking. Nothing is known about a potential role in pulmonary fibrosis. Immunohistochemistry (IH), double immunofluorescence microscopy (DIF), and immunoelectron microscopy (IEM) were used to study the differential distribution of VEGF in paraffin-embedded (IH, DIF) and in cryo-substituted, Lowicryl-embedded (IEM) specimens of normal rat and human lungs and fibrotic rat lungs. Fibrosis was induced by intratracheal bleomycin treatment. IH and DIF showed that VEGF was present in surfactant protein (SP) D-positive alveolar type II pneumocytes, bronchiolar Clara cells, smooth muscle (SM) cells, and alpha-SM actin-positive myofibroblasts of normal rat and human lungs. Fibrotic lesions in bleomycin-treated rat lungs were rich in VEGF-positive cells presenting with a heterogeneous phenotype (mainly SP-D-positive type II pneumocytes, alpha-SM actin-positive myofibroblasts). There were no signs of angiogenesis. Post-embedding immunogold labeling using protein A-gold and IgG-gold technique revealed a specific localization of VEGF to mitochondria, Clara cell secretory granules, and capillary interendothelial cell junctions. The predominant localization of VEGF to bronchiolar and alveolar epithelial and alpha-SM actin-positive cells, and the marked increase of VEGF-positive type II pneumocytes and myofibroblasts in fibrotic lung lesions, indicate that in adult lungs VEGF is involved in processes other than angiogenesis.

The necessary role of the autopsy in cardiovascular epidemiology

The autopsy rate in the United States today is remarkably low, with proportionally fewer autopsies for natural causes of death. Consequently, most cardiovascular epidemiology studies do not use autopsy data and rely on death certificates, medical records, questionnaires, and family interviews as sources of mortality information. These practices introduce a high degree of variability and uncertainty regarding cause of death. This review illustrates the necessity for increased use of autopsies in cardiovascular epidemiology by critically evaluating other measures of cardiovascular disease (CVD) incidence. We evaluated the literature regarding CVD as cause of death and conducted discussions with cardiologists, pathologists, and epidemiologists. No attempt was made for meta-analysis. This review shows the limited reliability of death certificates, medical records, and interviews as sources of mortality statistics. In addition, the autopsy's role in clearly indicating the presence of CVD is illustrated. The autopsy used in conjunction with medical records is the only reliable means for establishing cause of death from CVD. There is an urgent need to reassess the current dependence of statistical mortality data on death certificates and other inadequate sources of CVD incidence. Death certificates, in general, are inadequately monitored for quality control and appropriate administrative oversight. With an increase in the number of hospitals performing no autopsies to investigate cause of death, a uniform national autopsy database is needed.