β-cell Jagged1 is sufficient but not necessary for islet Notch activity and insulin secretory defects in obese mice

OBJECTIVE

Notch signaling, re-activated in β cells from obese mice and causal to β cell dysfunction, is determined in part by transmembrane ligand availability in a neighboring cell. We hypothesized that β cell expression of Jagged1 determines the maladaptive Notch response and resultant insulin secretory defects in obese mice.

METHODS

We assessed expression of Notch pathway components in high-fat diet-fed (HFD) or leptin receptor-deficient (db/db) mice, and performed single-cell RNA sequencing (scRNA-Seq) in islets from patients with and without type 2 diabetes (T2D). We generated and performed glucose tolerance testing in inducible, β cell-specific Jagged1 gain-of- and loss-of-function mice. We also tested effects of monoclonal neutralizing antibodies to Jagged1 in glucose-stimulated insulin secretion (GSIS) assays in isolated islets.

RESULTS

Jag1 was the only Notch ligand that tracked with increased Notch activity in HFD-fed and db/db mice, as well as in metabolically-inflexible β cells enriched in patients with T2D. Neutralizing antibodies to block Jagged1 in islets isolated from HFD-fed and db/db mice potentiated GSIS ex vivo. To demonstrate if β cell Jagged1 is sufficient to cause glucose tolerance in vivo, we generated inducible β cell-specific Jag1 transgenic (β-Jag1TG) and loss-of-function (iβ-Jag1KO) mice. While forced Jagged1 impaired glucose intolerance due to reduced GSIS, loss of β cell Jagged1 did not protect against HFD-induced insulin secretory defects.

CONCLUSIONS

Jagged1 is increased in islets from obese mice and in patients with T2D, and neutralizing Jagged1 antibodies lead to improved GSIS, suggesting that inhibition of Jagged1-Notch signaling may have therapeutic benefit. However, genetic loss-of-function experiments suggest that β cells are not a likely source of the Jagged1 signal.

The Pancreatic Beta Cell: Editorial

Pancreatic beta cells play a critical role in maintaining glucose homeostasis by serving as the primary source of insulin [...]

Notch-mediated hepatocyte MCP-1 secretion causes liver fibrosis

Patients with nonalcoholic steatohepatitis (NASH) have increased expression of liver monocyte chemoattractant protein-1 (MCP-1), but its cellular source and contribution to various aspects of NASH pathophysiology remain debated. We demonstrated increased liver CCL2 (which encodes MCP-1) expression in patients with NASH, and commensurately, a 100-fold increase in hepatocyte Ccl2 expression in a mouse model of NASH, accompanied by increased liver monocyte-derived macrophage (MoMF) infiltrate and liver fibrosis. To test repercussions of increased hepatocyte-derived MCP-1, we generated hepatocyte-specific Ccl2-knockout mice, which showed reduced liver MoMF infiltrate as well as decreased liver fibrosis. Forced hepatocyte MCP-1 expression provoked the opposite phenotype in chow-fed wild-type mice. Consistent with increased hepatocyte Notch signaling in NASH, we observed a close correlation between markers of Notch activation and CCL2 expression in patients with NASH. We found that an evolutionarily conserved Notch/recombination signal binding protein for immunoglobulin kappa J region binding site in the Ccl2 promoter mediated transactivation of the Ccl2 promoter in NASH diet-fed mice. Increased liver MoMF infiltrate and liver fibrosis seen in opposite gain-of-function mice was ameliorated with concomitant hepatocyte Ccl2 knockout or CCR2 inhibitor treatment. Hepatocyte Notch activation prompts MCP-1-dependent increase in liver MoMF infiltration and fibrosis.

An Overfeeding-Induced Obesity Mouse Model Reveals Necessity for Sin3a in Postnatal Peak β-Cell Mass Acquisition

The increase of functional β-cell mass is paramount to maintaining glucose homeostasis in the setting of systemic insulin resistance and/or augmented metabolic load. Understanding compensatory mechanisms that allow β-cell mass adaptation may allow for the discovery of therapeutically actionable control nodes. In this study, we report the rapid and robust β-cell hyperplasic effect in a mouse model of overfeeding-induced obesity (OIO) based on direct gastric caloric infusion. By performing RNA sequencing in islets isolated from OIO mice, we identified Sin3a as a novel transcriptional regulator of β-cell mass adaptation. β-Cell-specific Sin3a knockout animals showed profound diabetes due to defective acquisition of postnatal β-cell mass. These findings reveal a novel regulatory pathway in β-cell proliferation and validate OIO as a model for discovery of other mechanistic determinants of β-cell adaptation.

MafA Regulation in β-Cells: From Transcriptional to Post-Translational Mechanisms

β-cells are insulin-producing cells in the pancreas that maintain euglycemic conditions. Pancreatic β-cell maturity and function are regulated by a variety of transcription factors that enable the adequate expression of the cellular machinery involved in nutrient sensing and commensurate insulin secretion. One of the key factors in this regulation is MAF bZIP transcription factor A (MafA). MafA expression is decreased in type 2 diabetes, contributing to β-cell dysfunction and disease progression. The molecular biology underlying MafA is complex, with numerous transcriptional and post-translational regulatory nodes. Understanding these complexities may uncover potential therapeutic targets to ameliorate β-cell dysfunction. This article will summarize the role of MafA in normal β-cell function and disease, with a special focus on known transcriptional and post-translational regulators of MafA expression.

Notch-mediated Ephrin signaling disrupts islet architecture and β cell function

Altered islet architecture is associated with β cell dysfunction and type 2 diabetes (T2D) progression, but molecular effectors of islet spatial organization remain mostly unknown. Although Notch signaling is known to regulate pancreatic development, we observed “reactivated” β cell Notch activity in obese mouse models. To test the repercussions and reversibility of Notch effects, we generated doxycycline-dependent, β cell–specific Notch gain-of-function mice. As predicted, we found that Notch activation in postnatal β cells impaired glucose-stimulated insulin secretion and glucose intolerance, but we observed a surprising remnant glucose intolerance after doxycycline withdrawal and cessation of Notch activity, associated with a marked disruption of normal islet architecture. Transcriptomic screening of Notch-active islets revealed increased Ephrin signaling. Commensurately, exposure to Ephrin ligands increased β cell repulsion and impaired murine and human pseudoislet formation. Consistent with our mouse data, Notch and Ephrin signaling were increased in metabolically inflexible β cells in patients with T2D. These studies suggest that β cell Notch/Ephrin signaling can permanently alter islet architecture during a morphogenetic window in early life.

Stem Cell-Derived β Cells: A Versatile Research Platform to Interrogate the Genetic Basis of β Cell Dysfunction

Pancreatic β cell dysfunction is a central component of diabetes progression. During the last decades, the genetic basis of several monogenic forms of diabetes has been recognized. Genome-wide association studies (GWAS) have also facilitated the identification of common genetic variants associated with an increased risk of diabetes. These studies highlight the importance of impaired β cell function in all forms of diabetes. However, how most of these risk variants confer disease risk, remains unanswered. Understanding the specific contribution of genetic variants and the precise role of their molecular effectors is the next step toward developing treatments that target β cell dysfunction in the era of personalized medicine. Protocols that allow derivation of β cells from pluripotent stem cells, represent a powerful research tool that allows modeling of human development and versatile experimental designs that can be used to shed some light on diabetes pathophysiology. This article reviews different models to study the genetic basis of β cell dysfunction, focusing on the recent advances made possible by stem cell applications in the field of diabetes research.

Angiotensin converting enzyme 2 is a novel target of the γ-secretase complex

Angiotensin converting enzyme 2 (ACE2) is a key regulator of the renin-angiotensin system, but also the functional receptor of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Based on structural similarity with other γ-secretase (γS) targets, we hypothesized that ACE2 may be affected by γS proteolytic activity. We found that after ectodomain shedding, ACE2 is targeted for intramembrane proteolysis by γS, releasing a soluble ACE2 C-terminal fragment. Consistently, chemical or genetic inhibition of γS results in the accumulation of a membrane-bound fragment of ectodomain-deficient ACE2. Although chemical inhibition of γS does not alter SARS-CoV-2 cell entry, these data point to a novel pathway for cellular ACE2 trafficking.

Essential role of glucokinase in the protection of pancreatic β cells to the glucose energetic status

Energy sensing is indispensable to balance anabolic and catabolic processes for the maintenance of cell viability. Pancreatic β cells are especially relevant because of their involvement in the coordination of insulin secretion when glucose concentration arises in the local milieu. In this work, we uncover the increased susceptibility of pancreatic β cells to cell death in response to different energy stressors. Upon glucose decline, from 25 to 5 mM, caused by stimulation with either 2-deoxyglucose or metformin, only pancreatic β cells showed an increase in cell death. Very interestingly, when we transfected either mouse insulinoma cell or human embryo kidney cells with a phospho-mutant form of B cell lymphoma 2 associated agonist of cell death at serine 155 (BAD S155D), an increase in the pro-survival factor B cell lymphoma 2 was detected in pancreatic β cells and not in human embryonic kidney cells in the presence of the energetic stressors. This data suggests that the protective capacity of this mutant form is only present in cells that present glucokinase. In contrast, upon hyperactivation of mechanistic target of rapamycin complex 1 signaling by knocking-down tuberous sclerosis complex protein, we observed increased susceptibility to cell death in response to energy stress in both pancreatic and non-pancreatic β cells. Therefore, mechanistic target of rapamycin complex 1 signaling presents a dual effect on cell viability. On the one hand, a chronic inhibition of mechanistic target of rapamycin complex 1 activity in response to the energy status is deleterious for pancreatic β cells, being attenuated by the overexpression of B cell lymphoma 2 associated agonist of cell death S155D. On the other hand, mechanistic target of rapamycin complex 1 hyperactivity provokes a susceptibility to energetic stress-induced cell death. Taken together, these results may open potential implications for the use of glucokinase activators or mechanistic target of rapamycin complex 1 modulators for the maintenance of pancreatic β cells for longer periods of time avoiding its loss in different pathologies such as type 2 diabetes mellitus.

Evidence for a Non-leptin System that Defends against Weight Gain in Overfeeding

Weight is defended so that increases or decreases in body mass elicit responses that favor restoration of one's previous weight. While much is known about the signals that respond to weight loss and the central role that leptin plays, the lack of experimental systems studying the overfed state has meant little is known about pathways defending against weight gain. We developed a system to study this physiology and found that overfed mice defend against increased weight gain with graded anorexia but, unlike weight loss, this response is independent of circulating leptin concentration. In overfed mice that are unresponsive to orexigenic stimuli, adipose tissue is transcriptionally and immunologically distinct from fat of ad libitum-fed obese animals. These findings provide evidence that overfeeding-induced obesity alters adipose tissue and central responses in ways that are distinct from ad libitum obesity and activates a non-leptin system to defend against weight gain.

TSC2 N-terminal lysine acetylation status affects to its stability modulating mTORC1 signaling and autophagy

There is a growing evidence of the role of protein acetylation in different processes controlling metabolism. Sirtuins (histone deacetylases nicotinamide adenine dinucleotide-dependent) activate autophagy playing a protective role in cell homeostasis. This study analyzes tuberous sclerosis complex (TSC2) lysine acetylation, in the regulation of mTORC1 signaling activation, autophagy and cell proliferation. Nicotinamide 5mM (a concentration commonly used to inhibit SIRT1), increased TSC2 acetylation in its N-terminal domain, and concomitantly with an augment in its ubiquitination protein status, leading to mTORC1 activation and cell proliferation. In contrast, resveratrol (RESV), an activator of sirtuins deacetylation activity, avoided TSC2 acetylation, inhibiting mTORC1 signaling and promoting autophagy. Moreover, TSC2 in its deacetylated state was prevented from ubiquitination. Using MEF Sirt1 +/+ and Sirt1 -/- cells or a SIRT1 inhibitor (EX527) in MIN6 cells, TSC2 was hyperacetylated and neither NAM nor RESV were capable to modulate mTORC1 signaling. Then, silencing Tsc2 in MIN6 or in MEF Tsc2-/- cells, the effects of SIRT1 modulation by NAM or RESV on mTORC1 signaling were abolished. We also observed that two TSC2 lysine mutants in its N-terminal domain, derived from TSC patients, differentially modulate mTORC1 signaling. TSC2 K599M variant presented a lower mTORC1 activity. However, with K106Q mutant, there was an activation of mTORC1 signaling at the basal state as well as in response to NAM. This study provides, for the first time, a relationship between TSC2 lysine acetylation status and its stability, representing a novel mechanism for regulating mTORC1 pathway.

Pancreatic β-cell failure mediated by mTORC1 hyperactivity and autophagic impairment

Hyperactivation of the mammalian target of rapamycin complex 1 (mTORC1) in β-cells is usually found as a consequence of increased metabolic load. Although it plays an essential role in β-cell compensatory mechanisms, mTORC1 negatively regulates autophagy. Using a mouse model with β-cell-specific deletion of Tsc2 (βTsc2(-/-)) and, consequently, mTORC1 hyperactivation, we focused on the role that chronic mTORC1 hyperactivation might have on β-cell failure. mTORC1 hyperactivation drove an early increase in β-cell mass that later declined, triggering hyperglycemia. Apoptosis and endoplasmic reticulum stress markers were found in islets of older βTsc2(-/-) mice as well as accumulation of p62/SQSTM1 and an impaired autophagic response. Mitochondrial mass was increased in β-cells of βTsc2(-/-) mice, but mitophagy was also impaired under these circumstances. We provide evidence of β-cell autophagy impairment as a link between mTORC1 hyperactivation and mitochondrial dysfunction that probably contributes to β-cell failure.

Persistent organic pollutants (POPs) in sediments from fishing grounds in the NW Mediterranean: ecotoxicological implications for the benthic fish Solea sp

Sediment polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCls) and polybrominated diphenyl ethers (PBDEs) were measured during winter 2011 at seven sites on the Catalan coast (NW Mediterranean). Also at these sites, the benthic fish Solea solea and Solea senegalensis were fished for biomarker analysis. Chemical concentrations did not exceed the values considered safe by sediment quality guidelines (SQGs) for PAHs. However, levels of DDT (94.5 ng/g d.w.) and PCBs (15.1 ng/g d.w.) were significant in the Ebre Delta. Nonspecific immune parameters in S. solea showed a positive correlation between lysozyme activity in plasma and PAH content in sediment (r=0.982, p<0.01) and the opposite trend occurred with the complement test (ACH50) (r=-0.837; p<0.05). Cell counts (monocytes, lymphocytes and granulocytes) were elevated at most PAH-affected sites. A high concentration of bile FACs (fluorescent aromatic compounds) occurred at the northern station.

Role of the TSC1-TSC2 complex in the integration of insulin and glucose signaling involved in pancreatic beta-cell proliferation

Tuberous sclerosis complex proteins 1-2 (TSC1-TSC2) complex integrates both nutrient and hormonal signaling and is a critical negative regulator of mammalian target of rapamycin (mTOR) complex 1. The use of different beta-cell lines expressing or not the insulin receptor (IR(+/+) and IR(-/-)) or with a reconstituted expression of IR isoform A or B (Rec A and Rec B) revealed that both phosphatidylinositol 3-kinase/Akt/TSC/mTOR complex 1 and MAPK kinase/ERK pathways mediate insulin signaling in IR(+/+)-, IRA-, or IRB-expressing cells. However, glucose signaling was mediated by MAPK kinase/ERK and AMP-activated protein kinase pathways as assessed in IR(-/-) cells. The effect of insulin on Akt phosphorylation was completely inhibited by the use of the phosphatidylinositol 3-kinase inhibitor wortmannin in IR(+/+) and Rec B cells, a partial inhibitory effect being observed in Rec A cell line. The knockdown of TSC2 expression up-regulated the downstream basal phosphorylation of 70-kDa ribosomal protein S6 kinase (p70S6K) and mTOR. More importantly, upregulation of p70S6K signaling impaired insulin-stimulated phosphorylation of Akt Ser(473) and p70S6K in IR(+/+) and Rec B but not in Rec A cell lines. In fact, insulin receptor substrate-1 Ser(307) phosphorylation signal in Rec B was stronger than in Rec A cell line during insulin action. Rec A cells induced a higher proliferation rate compared with Rec B or IR(+/+) during serum stimulation. Thus, we propose that the regulation of TSC2 phosphorylation by insulin or glucose independently integrates beta-cell proliferation signaling, the relative expression of IRA or IRB isoforms in pancreatic beta cells playing a major role.

Combined cardiohepatic transplantation due to severe heterozygous familiar hypercholesteremia type II: first case in Argentina--a case report

Heterozygous familial hypercholesteremia type II is a recessive autonomic disease with a population incidence <or=1:500. It develops as a consequence of a mutation in the LDLR gene. Patients suffer extremely high LDL and VLDL cholesterol values, dying from coronary compromise at early ages. As cholesterol synthesis is an hepatic process, and as there is a lack of gene therapy, hepatic transplantation is the only therapeutic option in cases refractory to medical treatment. In this report, we have described the first case of combined cardiohepatic transplantation in Argentina, which was performed in a male patient with severe aortic stenosis and terminal ischemic cardiopathy secondary to severe familial hypercholesteremia type II.

Phase II study of irinotecan (cpt-11) and cisplatin (cddp) regimen (IP) with concurrent thoracic radiotherapy (TRT) in limited-stage small cell lung cancer (LS-SCLC)

7084

Background: the combination of CPT-11 and CDDP (IP) is an active regimen for SCLC. (Noda et al NEJM ’02, Hanna et al ASCO 2005). We performed a multicenter phase II study to assess the efficacy and toxicity of IP regimen with concurrent TRT in previously untreated LS-SCLC pts. Methods: Eligible pts were required to have histologically confirmed SCLC, measurable disease, no prior therapy, ECOG PS of 0–2, adequate organ functions, and to give informed consent. Treatment consisted of: CDDP 60 mg/m2 D1, I 60mg/m2 IV D1, 8 Q 21D for 4 cycles, and concurrent TRT 2.0 Gy daily to a total of 60.0 Gy, beginning with the 2nd cycle. I was adjusted to 50 mg/m2 at 2nd and 3rd cycles (during TRT). Pts were restaged after 4 cycles. Pts without progression or undue toxicity received 2 additional cycles. PCI (2.0 Gy X 10) was offered to CR pts. The primary endpoints were response rate and OS. Results: Twenty-six pts were included and 25 pts were evaluable for response (median age 62; M/F, 22/4; PS 0/1/2, 9/17; T2–4N0,T2–4N+ 6/20pts). Among 126 cycles administered, the relative dose-intensities of I and CDDP were 80% and 92% respectively. Median number of cycles/pt was 5 (1–6), and 22 pts completed the IP + TRT program. Fifteen pts achieved a CR and 6 pts a PR, for an overall RR of 84%. Median TTP was 12 months. At a median follow-up of 14 months, 19 pts are alive, and estimated median survival is 17 months. Grade 3–4 (NCI-CTC 3.0) toxicity (per cycle) during concurrent therapy included: neutropenia (25%), anemia (3%), thrombocytopenia (3%), diarrhea (10%), vomiting (5%), esophagitis (10%). There were no treatment-related deaths. Two pts required hospitalization during the concurrent therapy due to g3 diarrhea (1 pt) and febrile neutropenia (1 pt). Conclusions: The concurrent regimen of IP + TRT is highly effective in pts with LS-SCLC. The associated toxicity profile is predictable and adequate. Further study is warranted.

No significant financial relationships to disclose.

Enantioselective synthesis of fluorinated alpha-amino acids and derivatives in combination with ring-closing metathesis: intramolecular pi-stacking interactions as a source of stereocontrol

[reaction: see text]. Hydride reduction of C=N bonds stereocontrolled by intramolecular pi-stacking interactions of 1-naphthylsulfinyl and N-aryl groups, nonoxidative Pummerer rearrangement, and ring-closing metathesis are efficiently combined in a highly stereoselective entry to enantiomerically pure cyclic and acyclic fluorinated beta-amino alcohols and alpha-amino acid derivatives, respectively.

[Study of the brachial plexus by magnetic resonance]

OBJECTIVE

Magnetic resonance (MR) is considered to be the best method available at present for diagnosis of lesions of the brachial plexus. In this study we analyze our experience in patients with pathology of the brachial plexus.

MATERIAL AND METHODS

Between August 1991 and March 1997 we did magnetic resonance studies on 42 patients with pathology of the brachial plexus. Our protocols included T1, T2 axial spin-echo sequences with 5 mm cuts and coronal echo of a T1-3D gradient with 2 mm cuts, together with a T1 coronal spin-echo, with cuts 2 mm in width.

RESULTS

The causes found were: traumatic 16 patients (38%), pathology of bone 2 (4.7%), 19 tumours (45.2%) with breast cancer being commonest, and no obvious aetiology in 5 (11.9%).

CONCLUSIONS

MR is the technique of choice for study of pathology of the brachial plexus of traumatic or tumour origin. In some patients, 11.9% in our series, no aetiology could be detected using MR.

[Comparison of 2 systems for continuous intraoperative monitoring of oxygen saturation in the jugular bulb]

OBJECTIVE

To compare accuracy, precision and stability of two jugular venous blood catheters for continuous monitoring of oxygen saturation during surgery, in a nonrandom, prospective sample.

PATIENTS AND METHODS

We studied 47 patients requiring continuous monitoring of SjvO2 during a variety of neurosurgical procedures. Swan-Ganz pediatric 5.5F catheters (Opticath P575-EH) were used in 27 patients; neonatal umbilical artery 4F catheters (Opticath U425C) were used in 20. Both catheters were equipped with a fiberoptic system for continuous monitoring of hemoglobin oxygen saturation. After checking correct placement, readings transmitted were compared with co-oximetry readings for a sample taken from the distal end of the catheter. We also compared time spent placing the catheters and stability of SjvO2 reading during surgery.

RESULTS

Insertion time (+/- SD) was 10.3 +/- 2.5 minutes for the 4F catheter and 15.9 +/- 5.5 minutes for the 5.5F model (p < 0.01). Although both systems tended to overestimate, the 5.5F catheters were more accurate: the mean differences were -6.8% for the 4F catheter and -1.2% for the 5.5F. These results made it necessary to calibrate the 4F catheters after placement and before use, a procedure not needed if the 5.5F catheters are used. Stability of SjvO2 readings during surgery was significantly greater (p < 0.01) for the 5.5F catheters, such that only 25.9% were considered clinically useful based on this parameter. However, 70% of the 5.5F catheters provided acceptable SjvO2 readings. Intracranial pressure during insertion and removal of the SjvO2 catheters was measured in only 5 patients; there were no changes greater than 1 mmHg.

CONCLUSIONS

Although the 5.5F pediatric catheters take longer to put into position, their greater accuracy, precision and stability makes them preferable to the 4F catheters for continuous monitoring of SjvO2. Long-term vascular effects must be studied further.

[Utilization of inhaled nitric oxide in a case of respiratory insufficiency following lung transplantation]

Pulmonary hypertension and transient graft dysfunction may complicate the immediate postoperative course of patients undergoing lung transplantation. We report the effect of inhaled nitric oxide (NO) in a patient with pulmonary edema and severe hypoxemia in the period following bilateral lung transplantation. NO was delivered through the inspiratory line and its mean concentration was monitored in the trachea. PaO2/FiO2 improved from 65 to 105 with an NO concentration of 1 ppm, but no further improvement was obtained by increasing the dose to 5 ppm. Pulmonary vascular resistance (PVR) decreased from a baseline value of 251 dynes-sec/cm5 to a low of 213 dynes-sec/cm5 with NO administration. A slight increase in PVR seems to have been the main factor limiting the therapeutic efficacy of inhaled NO in this case.

[Anesthesia in a patient with latex allergy]

Anaphylactic reactions triggered by latex-based products are increasingly frequent, particularly in the hospital environment. We describe a patient with a prior history of atopic allergy and documented allergy to latex who was scheduled for abdominal surgery. A great deal of anesthetic and surgical equipment contains latex and substitutes for such material must be used in order to prevent severe hypersensitivity reactions.

[Neuroepithelial tumors in the pediatric population]

We have studied the neuroepithelial tumors in childhood, about their epidemiological, clinical and histological aspects, the macroscopic tumoral structure and the findings obtained by magnetic resonance imaging. We stress the differential diagnosis features among the various tumoral types, based on bibliography and our own clinical experience.

[Primary ventricular fibrillation. Clinical features and prognostic significance]

The objective of this study was to evaluate the clinic conditions and the prognosis of patients with primary ventricular fibrillation (PVF) as complication of acute myocardial infarction. We retrospectively analyzed 1,120 patients admitted in Coronary Care Unit within 12 hours of onset of symptoms. PVF (not associated with significative heart failure or shock and occurred within 48 hours of onset of symptoms) occurred in 62 patients (5.53%). The frequency of PVF was highest in patients admitted in the first hours after infarction (p = 0.01) and the inferior localization (p = 0.001). Cigarette smoking was identified as strong independent risk factor for ventricular fibrillation (p = 0.009; relative risk 1.945). A statistically significant excess of pericarditis (p = 0.002), ventricular tachycardia (p = 0.004), atrioventricular block (second-third degree) (p = 0.001) and moderate degree of heart failure (p = 0.003), was found in patients with PVF. The occurrence of PVF was not associated to a significantly higher in hospital mortality rate than that observed in reference group (without ventricular fibrillation) (12.90 vs 14.36%). In the long-term survival at 5 years in patients with PVF, who are discharged alive, was 87.82% vs 80.58% in control group. We conclude: 1. Patients with PVF had more complications rate than among those without it. 2. PVF isn't a marker of increase in hospital death rate. 3. PVF by itself does not indicate an adverse long-term prognosis.