Ashraf A. Sabe

The Effects of Splenic Artery Embolization on Nonoperative Management of Blunt Splenic Injury: A 16-year Experience

INTRODUCTION Nonoperative management (NOM) of blunt splenic injury has become the preferred treatment for hemodynamically stable patients. The application of splenic artery embolization (SAE) in NOM has been controversial. We hypothesized that incorporation of initial use of SAE into a practice protocol for patients at high risk for NOM failure (contrast extravasation or pseudoaneurysm on computed tomography, grade 3 injury with large hemoperitoneum, grade 4 injuries) would improve patient outcomes. METHODS A retrospective analysis of three continuums of practice was performed: group I (January 1991-June 1998), SAE not part of routine NOM; group II (July 1998-December 2001), introduction and discretionary use of SAE; and group III (January 2002-June 2007), standardized use of initial SAE for patients considered at high risk of nonoperative failure. The primary outcome measure was the success of NOM. Failure of NOM was defined as the need for abdominal operation. Secondary outcomes were mortality, length of stay, and splenic salvage. RESULTS Over 16 years, 815 patients with blunt splenic injury were treated at our level 1 trauma center. There were 222 patients in group I, 195 in group II, and 398 in group III. There was an increase in the use of SAE over time with a significant improvement in the utilization of NOM (61% in group I; 82% in group II; 88% in group III; p < 0.05). This was associated with an increase in successful NOM (77%, group I; 94%, group II; 97%, group III; p < 0.0001 group I vs. group II and III). Mortality, length of stay, and splenic salvage were similar in groups II and III but significantly improved when compared with group I. CONCLUSIONS The increased use of initial SAE in high-risk patients expanded the successful use of NOM but was not associated with other incremental improvements.

Activating transcription factor 3 induction in sympathetic neurons after axotomy: Response to decreased neurotrophin availability

Activating transcription factor 3 (ATF3) is induced in a high proportion of axotomized sensory and motor neurons after sciatic nerve transection. In the present study, we looked at the expression of this factor in the superior cervical ganglion (SCG) after axotomy and after other manipulations that induce certain aspects of the cell body response to axotomy. Sympathetic ganglia from intact rats and mice exhibit only a very occasional neuronal nucleus with activating transcription factor 3-like immunoreactivity (ATF3-IR); however, as early as 6 h and as late as 3 weeks postaxotomy, many of the neurons showed intense ATF3-IR. A second population of cells had smaller and generally less intensely stained nuclei, and at least some of these cells were satellite cells. Lesions distal to the SCG induced by administration of 6-hydroxydopamine or unilateral removal of the salivary glands produced increases in ATF3-IR similar to those seen after proximal axotomy, indicating that this response is not strictly dependent on the distance of the lesion from the cell body. Two proposed signals for triggering ATF3 expression were examined: reduction in nerve growth factor (NGF) availability and induction of the cytokine leukemia inhibitory factor (LIF). While administration of an antiserum raised against NGF to intact animals induced ATF3-IR, induction of ATF3-IR after axotomy was not reduced in LIF null mutant mice. Since axotomy, 6-hydroxydopamine, and sialectomy are known to decrease the concentration of NGF in the SCG, our data suggest that these decreases in NGF lead to increases in ATF3-IR. Furthermore, since the number of neurons in the SCG expressing ATF3-IR was greater after axotomy than after antiserum against NGF treatment, this raises the possibility that decreased NGF is not the only process regulating ATF3 expression after axotomy.

The pig as a valuable model for testing the effect of resveratrol to prevent cardiovascular disease

Resveratrol is a naturally occurring polyphenol found in the skin of red grapes, peanuts, and red wine that has been shown to modify many cardiovascular risk factors. Small animal models have been extensively used to investigate cardiovascular disease, but the results often fail to translate in clinical trials. Disease‐specific pig models are emerging as clinically useful tools that may offer insight into cardiovascular disease and the effect of drugs such as resveratrol on cardiovascular health. In this paper, we discuss the advantage of using clinically relevant pig models of diabetes, hypercholesterolemia, and myocardial ischemia to investigate the role of resveratrol in cardiovascular disease prevention.

Resveratrol regulates autophagy signaling in chronically ischemic myocardium

OBJECTIVE Autophagy is a cellular process by which damaged components are removed. Although autophagy can result in cell death, when optimally regulated, it might be cardioprotective. Resveratrol is a naturally occurring polyphenol also believed to be cardioprotective. Using a clinically relevant swine model of metabolic syndrome, we investigated the effects of resveratrol on autophagy in the chronically ischemic myocardium. METHODS Yorkshire swine were fed a regular diet (n = 7), a high cholesterol diet (n = 7), or a high cholesterol diet with supplemental resveratrol (n = 6). After 4 weeks, an ameroid constrictor was surgically placed on the left circumflex artery to induce chronic myocardial ischemia. The diets were continued another 7 weeks, and then the ischemic and nonischemic myocardium were harvested for protein analysis. RESULTS In the ischemic myocardium, a high cholesterol diet partly attenuated the autophagy, as determined by an increase in phosphorylated mammalian target of rapamycin (p-mTOR) and a decrease in p70 S6 kinase (P70S6K), lysosome-associated membrane protein (LAMP)-2, and autophagy-related gene 12-5 conjugate (ATG 12-5; P < .05). The addition of resveratrol blunted many of these changes, because the p-mTOR, P70S6K, and LAMP-2 levels were not significantly altered from those of the pigs fed a regular diet. Other autophagy markers were increased with a high cholesterol diet, including light chain 3A-II and beclin 1 (P < .05). In the nonischemic myocardium, beclin 1 was decreased in the high cholesterol-fed pigs (P < .05); otherwise no significant changes in protein expression were noted among the 3 groups. CONCLUSIONS In the chronically ischemic myocardium, resveratrol partly reversed the effects of a high cholesterol diet on autophagy. This might be a mechanism by which resveratrol exerts its cardioprotective effects.

Calpain inhibition decreases myocardial apoptosis in a swine model of chronic myocardial ischemia

INTRODUCTION Calpain is a family of cysteine proteases that has an important role in the initiation, regulation, and execution of cell death. Our recent studies using a hypercholesterolemic swine model demonstrated that in the setting of the metabolic syndrome, calpain inhibition (CI) improved collateral-dependent perfusion and increased expression of proteins implicated in angiogenesis and vasodilation. In this study, we hypothesized that CI (by MLD28170) would decrease myocardial apoptosis in the same model. METHODS Yorkshire swine, all fed a high-cholesterol diet for 4 weeks underwent placement of an ameroid constrictor on the left circumflex coronary artery. Three weeks later, animals received either no drug, termed the high-cholesterol control group (HCC; n = 8); low-dose CI (0.12 mg/kg; LCI, n = 9); or high-dose CI (0.25 mg/kg; HCI, n = 8). The high-cholesterol diet and the CI were continued for 5 weeks, after which the pig was humanely killed and the left ventricular myocardium was harvested and analyzed via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, oxyblot analysis, and Western blots. Data were analyzed using the Kruskal-Wallis test. RESULTS The percentage of apoptotic cells to total cells in ischemic myocardial territory was decreased in the LCI and HCI groups compared with the HCC group as shown by TUNEL staining (P = .018). There was a decrease in proapoptotic proteins, including cleaved caspase 3, caspase 9, cleaved caspase 9, Bax, BAD, p-BAD, and Erk 1/2 (P ≤ .049 each), but no decrease in caspase 3 (P = .737). There was also an increase in antiapoptotic proteins, including BCL-2 and p-BCL2 (P ≤ .025 each). In the ischemic myocardium, several proangiogenic proteins were increased in the LCI and HCI groups compared with the HCC group, including p-AKT, p-eNOS, and eNOS (P ≤ .006 each) but there was no increase in AKT (P = .311). CI decreased tissue oxidative stress in both the LCI and HCI groups compared to the HCC group as shown by oxyblot analysis (P = .021). CONCLUSION In the setting of hypercholesterolemia, CI decreases apoptosis and the expression of proteins in proapoptotic signaling pathways. CI also increased expression of proteins implicated in anti apoptotic pathways and improves oxidative stress in ischemic myocardial tissue.

Metformin mitigates apoptosis in ischemic myocardium.

BACKGROUND Epidemiologic data has shown that metformin confers a survival advantage in patients with cardiovascular disease. Although the underlying cardioprotective mechanism is unclear, it appears to be independent of metformins insulin-sensitizing effect. The purpose of this study was to evaluate the effect of metformin on the apoptosis pathway in the ischemic and nonischemic cardiac tissue in a swine model of metabolic syndrome. MATERIALS AND METHODS Ossabaw miniswine were fed either a regular diet (Ossabaw control, n = 8), a high-cholesterol diet (Ossabaw high cholesterol, n = 8), or a high-cholesterol diet supplemented with metformin (Ossabaw high-cholesterol metformin, n = 8). After 9 wk, all animals underwent placement of an ameroid constrictor to the left circumflex coronary artery to induce chronic ischemia. Seven weeks after ameroid placement, animals underwent cardiac harvest. RESULTS In the chronically ischemic myocardium, metformin significantly upregulates prosurvival proteins: extracellular signal-regulated kinases, nuclear factor κB, phosphorylated endothelial nitric oxide synthase, and P38. Metformin also significantly inhibits or downregulates proapoptosis proteins: FOXO3 and caspase 3. Metformin decreased the percent apoptotic cells in the ischemic and nonischemic myocardium. There was no difference in arteriolar density, capillary density, intramyocardial fibrosis, or collagen deposition in the ischemic or nonischemic myocardium. CONCLUSIONS Metformin selectively alters the apoptosis pathway by inhibiting FOXO3 and decreasing the active form of caspase 3, cleaved caspase 3. Metformin also upregulates mitogen-activated kinase proteins p38 and extracellular signal-regulated protein kinases 1 and 2, which are considered cardioprotective during ischemic preconditioning. Perhaps, the altered activation of the apoptosis pathway in ischemic myocardium is one mechanism by which metformin is cardioprotective.

Calpain inhibition improves collateral-dependent perfusion in a hypercholesterolemic swine model of chronic myocardial ischemia

PURPOSE Calpain overexpression is implicated in aberrant angiogenesis. We hypothesized that calpain inhibition (MDL28170) would improve collateral perfusion in a swine model with hypercholesterolemia and chronic myocardial ischemia. METHODS Yorkshire swine fed a high cholesterol diet for 4 weeks underwent surgical placement of an ameroid constrictor to their left circumflex coronary artery. Three weeks later, animals received no drug, high cholesterol control group (n = 8); low-dose calpain inhibition (0.12 mg/kg; n = 9); or high-dose calpain inhibition (0.25 mg/kg; n = 8). The heart was harvested after 5 weeks. RESULTS Myocardial perfusion in ischemic myocardium significantly improved with high-dose calpain inhibition at rest and with demand pacing (P = .016 and .011). Endothelium-dependent microvessel relaxation was significantly improved with low-dose calpain inhibition (P = .001). There was a significant increase in capillary density, with low-dose calpain inhibition and high-dose calpain inhibition (P = .01 and .01), and arteriolar density with low-dose calpain inhibition (P = .001). Calpain inhibition significantly increased several proangiogenic proteins, including vascular endothelial growth factor (P = .02), vascular endothelial growth factor receptor 1 (P = .003), vascular endothelial growth factor receptor 2 (P = .003), and talin, a microvascular structural protein (P = .0002). There was a slight increase in proteins implicated in endothelial-dependent (nitric oxide mediated) relaxation, including extracellular signal-regulated kinase, phosphorylated extracellular signal-regulated kinase, and inducible nitric oxide synthase with calpain inhibition. CONCLUSIONS In the setting of hypercholesterolemia, calpain inhibition improved perfusion, with a trend toward increased collateralization on angiography and increased capillary and arteriolar densities in ischemic myocardium. Calpain inhibition also improved endothelium-dependent microvessel relaxation and increased expression of proteins implicated in angiogenesis and vasodilatation.

Calpains and Coronary Vascular Disease.

Despite many advances in percutaneous and surgical interventions in the treatment of coronary artery disease (CAD), up to one-third of patients are still either not candidates or receive suboptimal revascularization. Calpains are a class of calcium-activated non-lysosomal cysteine proteases that serve as a proteolytic unit for cellular homeostasis. Uncontrolled activation of calpain has been found to be involved in the pathogenesis of myocardial reperfusion injury, cardiac hypertrophy, myocardial stunning and cardiac ischemia. Inhibition of calpains has been shown to significantly attenuate myocardial stunning and reduced infarct size after ischemia-reperfusion. Calpain inhibition therefore serves as a potential medical therapy for patients suffering from a number of diseases, including CAD.

Differential effects of atorvastatin on autophagy in ischemic and nonischemic myocardium in Ossabaw swine with metabolic syndrome

OBJECTIVES The perioperative administration of pleomorphic statin drugs has been implicated in improving outcomes after cardiac surgery. Adaptive autophagy is a highly conserved cellular process that allows for the elimination of dysfunctional cell components in response to stress and survival under starving conditions. We sought to investigate the effects of the statin drug atorvastatin on autophagy in ischemic and nonischemic myocardia using a clinically relevant porcine model of metabolic syndrome. METHODS Male Ossabaw swine were fed a regular diet (n = 8), a high-cholesterol diet (n = 8), or a high-cholesterol diet with supplemental atorvastatin (1.5 mg/kg/d) (n = 8). After 14 weeks, all animals underwent surgical placement of an ameroid constrictor to the circumflex coronary artery to induce chronic ischemia. Nonischemic and ischemic myocardia were harvested 6 months after initiation of the diet and processed for Western blotting. RESULTS In the nonischemic myocardium, Western blot results demonstrate that a high cholesterol diet resulted in a statistically significant decrease in autophagy as indicated by an increase in mammalian target of rapamycin and the accumulation of several essential autophagy markers, including Beclin-1, light chain 3B-I, and light chain 3B-II. Atorvastatin supplementation prevented these changes and resulted in an increase in autophagy as indicated by a decrease in autophagy flux marker P62. In the ischemic myocardium, atorvastatin had the opposite effect, with a decrease in autophagy flux as indicated by an increase in p62 and an accumulation of light chain 3B-I, light chain B-II, and lysosome-associated membrane protein 2. CONCLUSIONS Atorvastatin administration has differential effects on autophagy in ischemic and nonischemic myocardia. In the setting of metabolic syndrome, atorvastatin stimulates autophagy in nonischemic myocardium while partly inhibiting autophagy in ischemic myocardium. The differential regulation on autophagy may, in part, explain the cardioprotective effect of statins in both ischemic and nonischemic myocardia, and these findings may have implications in the setting of cardiac surgery.

Metabolic syndrome impairs notch signaling and promotes apoptosis in chronically ischemic myocardium

OBJECTIVE Impaired angiogenesis is a known consequence of metabolic syndrome (MetS); however, the mechanism is not fully understood. Recent studies have shown that the notch signaling pathway is an integral component of cardiac angiogenesis. We tested, in a clinically relevant swine model, the effects of MetS on notch and apoptosis signaling in chronically ischemic myocardium. METHODS Ossabaw swine were fed either a regular diet (control [CTL], n = 8) or a high-cholesterol diet (MetS, n = 8) to induce MetS. An ameroid constrictor was placed to induce chronic myocardial ischemia. Eleven weeks later, the wine underwent cardiac harvest of the ischemic myocardium. RESULTS Downregulation of pro-angiogenesis proteins notch2, notch4, jagged2, angiopoietin 1, and endothelial nitric oxide synthase were found in the MetS group compared with the CTL group. Also, upregulation of pro-apoptosis protein caspase 8 and downregulation of anti-angiogenesis protein phosphorylated forkhead box transcription factor 03 and pro-survival proteins phosphorylated P38 and heat shock protein 90 were present in the MetS group. Cell death was increased in the MetS group compared with the CTL group. Both CTL and MetS groups had a similar arteriolar count and capillary density, and notch3 and jagged1 were both similarly concentrated in the smooth muscle wall. CONCLUSIONS MetS in chronic myocardial ischemia significantly impairs notch signaling by downregulating notch receptors, ligands, and pro-angiogenesis proteins. MetS also increases apoptosis signaling, decreases survival signaling, and increases cell death in chronically ischemic myocardium. Although short-term angiogenesis appears unaffected in this model of early MetS, the molecular signals for angiogenesis are impaired, suggesting that inhibition of notch signaling might underlie the decreased angiogenesis in later stages of MetS.