A maternal diet rich in fish oil may improve cardiac Akt-related signaling in the offspring of diabetic mother rats.

OBJECTIVE: Newborns of diabetic mothers have abnormal circulatory organs, so in this study, we explore insulin signaling in the newborn rat heart. METHODS: Pregnant rats were divided into streptozotocin-induced diabetic groups (DM) and control groups (CM). Rats were fed lard (21% fat), fish oil (21% fat), or a control diet (7% fat). To examine changes in insulin signaling in the hearts of infants of diabetic mothers (IDM) in relation to diet, we isolated the hearts from the IDM and control infants and determined the phosphorylation levels of Akt308, Akt473, p38, c-jun-NH2-terminal protein kinase (JNK), and extracellular signal-regulated protein kinase (ERK), and the expression levels of phosphoinositide-dependent protein kainase1 (PDK1) and mammalian target of rapamycin (mTOR). RESULTS: The mean blood glucose levels in the DM group and their infants were significantly higher than those in the CM group (P < 0.05) and their infants (P < 0.05), but the mean blood glucose levels of all infants was normal on postnatal d 4. Phosphorylation levels of Akt (Thr 308) (P < 0.05) and Akt (Ser 473) and the expression levels of PDK1 and mTOR were lower in infants of diabetic mothers (IDM) than in control infants. The phosphorylation level of Akt (Ser 473) and the expression level of mTOR increased in IDM fed the fish oil diet compared with those fed the lard diet (P < 0.05). CONCLUSION: A maternal diet rich in fish oil improves cardiac Akt-related signaling in the offspring of diabetic rats.

Diminished muscle growth in the obese Zucker rat following overload is associated with hyperphosphorylation of AMPK and dsRNA-dependent protein kinase.

Previous data have suggested that insulin-resistant skeletal muscle may exhibit a diminished ability to undergo hypertrophy and that this result may be mediated, at least in part, from decrements in mammalian target of rapamycin (mTOR) signaling (Katta A, Kundla S, Kakarla SK, Wu M, Fannin J, Paturi S, Liu H, Addagarla HS, Blough ER. Am J Physiol Regul Integr Comp Physiol 299: R1666-R1675, 2010). Herein, we attempt to extend these observations by determining if this attenuation in muscle growth is associated with alterations in AMP-activated protein kinase (AMPK) signaling, an upstream mediator of mTOR, and changes in the activation of dsRNA-dependent protein kinase (PKR), which functions as an inhibitor of protein synthesis and potential mediator of protein degradation. Compared with that observed in lean Zucker (LZ) rats, the phosphorylation of AMPKα at Thr172 was higher after 3 wk of overload in the insulin-resistant obese Zucker (OZ) soleus (P < 0.05). This change in AMPKα phosphorylation was accompanied by increases in the amount of phosphorylated PKR (Thr446), elevations in the PKR-dependent phosphorylation of eukaryotic initiation factor (eIF)-2α (Ser51), augmented p38 MAP kinase (Thr180/Tyr182) phosphorylation, and increases in the amount of protein ubiquitination (P < 0.05). Taken together, these results suggest that the diminished hypertrophic response we observe in the OZ rat may be mediated, at least in part, by the hyperactivation of AMPK- and PKR-related signaling.

Chronic paracetamol treatment influences indices of reactive oxygen species accumulation in the aging Fischer 344 X Brown Norway rat aorta.

Previous reports have demonstrated that increased levels of reactive oxygen species (ROS) and alterations in cell signaling characterize aging in the Fischer 344 X Brown Norway (FBN) rat aorta. Other work has suggested that increases in ROS may be related to vascular wall thickening and the development of hypertension. Paracetamol (acetaminophen) is a potent antioxidant that has been found to diminish free radicals in ischemia-reperfusion studies. However, it remains unclear whether chronic paracetamol administration influences signaling or ROS accumulation in the aging aorta. FBN rats (27 months old; n=8) were subjected to 6 months of treatment with a therapeutic dose of paracetamol (30 mg/kg/day) and compared to age-matched untreated FBN rat controls (n=8). Compared to measurements in the aortae of 6-month old animals, tunica media thickness, tissue superoxide levels, and protein oxidation levels were 38 ± 7%, 92 ± 31%, and 7 ± 2% higher in the aortae of 33-month control animals (p ≤0.05). Chronic paracetamol treatment decreased tunica media thickness and the amount of oxidized protein by 13 ± 4% and 30 ± 1%, respectively (p ≤0.05). This finding of diminished aortic thickening was associated with increased phosphorylation (activation) of the mitogen activated protein kinases and diminished levels of the anti-apoptotic protein Bcl-2. Taken together, these data suggest that chronic paracetamol treatment may decrease the deleterious effects of aging in the FBN rat aorta.

Iron-induced cardiac damage: role of apoptosis and deferasirox intervention.

Excess cardiac iron levels are associated with cardiac damage and can result in increased morbidity and mortality. Here, we hypothesize that elevations in tissue iron can activate caspase-dependent signaling, which leads to increased cardiac apoptosis and fibrosis, and that these alterations can be attenuated by iron chelation. Using an iron-overloaded gerbil model, we show that increased cardiac iron is associated with reduced activation of Akt (Ser473 and Thr308), diminished phosphorylation of the proapoptotic regulator Bad (Ser136), and an increased Bax/Bcl-2 ratio. These iron-overload-induced alterations in Akt/Bad phosphorylation and Bax/Bcl-2 ratio were coupled with increased activation of the downstream caspase-9 (40/38- and 17-kDa fragments) and apoptosis executioner caspase-3 (19- and 17-kDa fragments), which were accompanied by evidence of elevated cytoskeletal α-fodrin cleavage (150- and 120-kDa fragments), discontinuity of myocardial membrane dystrophin immunoreactivity, increases in the number of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells (nucleic DNA fragmentation), and cardiac fibrosis. We demonstrate that the administration of deferasirox, a tridentate iron chelator, is associated with diminished tissue iron deposition, attenuated activation of caspases, reduced α-fodrin cleavage, improved membrane integrity, decreased TUNEL reactivity, and attenuated cardiac fibrosis. These results suggest that the activation of caspase-dependent signaling may play a role in the development of iron-induced cardiac apoptosis and fibrosis, and deferasirox, via a reduction in cardiac tissue iron levels, may be useful for decreasing the extent of iron-induced cardiac damage.

Impaired overload-induced hypertrophy is associated with diminished mTOR signaling in insulin-resistant skeletal muscle of the obese Zucker rat.

Recent data have suggested that insulin resistance may be associated with a diminished ability of skeletal muscle to undergo hypertrophy (Paturi S, Gutta AK, Kakarla SK, Katta A, Arnold EC, Wu M, Rice KM, Blough ER. J Appl Physiol 108: 7-13, 2010). Here we examine the effects of insulin resistance using the obese Zucker (OZ) rat with increased muscle loading on the regulation of the mammalian target of rapamycin (mTOR) and its downstream signaling intermediates 70-kDa ribosomal protein S6 kinase (p70S6k), ribosomal protein S6 (rpS6), eukaryotic elongation factor 2 (eEF2), and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1). Compared with that observed in lean Zucker (LZ) rats, the degree of soleus muscle hypertrophy as assessed by changes in muscle wet weight (LZ: 35% vs. OZ: 16%) was significantly less in the OZ rats after 3 wk of muscle overload (P < 0.05). This diminished growth in the OZ rats was accompanied by significant impairments in the ability of the soleus to undergo phosphorylation of mTOR (Ser(2448)), p70S6k (Thr(389)), rpS6 (Ser(235/236)), and protein kinase B (Akt) (Ser(473) and Thr(308)) (P < 0.05). Taken together, these data suggest that impaired overload-induced hypertrophy in insulin-resistant skeletal muscle may be related to decreases in the ability of the muscle to undergo mTOR-related signaling.

Chronic acetaminophen attenuates age-associated increases in cardiac ROS and apoptosis in the Fischer Brown Norway rat.

There is a growing need for pharmacological agents to manage cardiovascular disease in the rapidly growing elderly population. Here, we determine if acetaminophen is efficacious in decreasing age-related increases in cardiac reactive oxygen species (ROS) and apoptosis in aging Fischer 344 X Brown Norway rats. Compared to 6-month control animals, indices of oxidative (superoxide anion [O2( *-)] and 4-hydroxy-2-nonenal [4-HNE]) and nitrosative (protein nitrotyrosylation) stress were markedly increased in 33-month-old rat hearts. 33-month animals that had been treated with acetaminophen (30 mg/kg/day p.o. for 6 months) exhibited diminished age-related increases in cardiac ROS levels and TUNEL positive nuclei and these changes were accompanied by improvements in the Bax/Bcl2 ratio, diminished evidence of caspase-3 activation and increased phosphorylation of protein kinase B, ERK1/2, p70S6K and GSK-3beta. Taken together these results suggests that acetaminophen may attenuate the age-associated increases in the cardiomyocyte apoptosis, possibly via diminishing age associated elevation in ROS production.

Application of poly(amidoamine) dendrimers for use in bionanomotor systems.

The study and utilization of bionanomotors represents a rapid and progressing field of nanobiotechnology. Here, we demonstrate that poly(amidoamine) (PAMAM) dendrimers are capable of supporting heavy meromyosin dependent actin motility of similar quality to that observed using nitrocellulose, and that microcontact printing of PAMAM dendrimers can be exploited to produce tracks of active myosin motors leading to the restricted motion of actin filaments across a patterned surface. These data suggest that the use of dendrimer surfaces will increase the applicability of using protein biomolecular motors for nanotechnological applications.

Deferasirox decreases age-associated iron accumulation in the aging F344XBN rat heart and liver.

It is thought that aging in rats and humans is associated with increases in iron accumulation and cell apoptosis. Here, we examine the relationship between cardiac iron levels and apoptosis in aged F344XBN rats that had been treated with an oral iron chelator (Deferasirox; 100 mg/kg body weight) on alternate days for 6 months. Compared to adult animals (6 month), cardiac iron (+72%), liver iron (+87%), ferritin light chain (+59%), divalent metal transporter-1 (+56%) and the number of TdT-mediated dUTP nick end labeling (TUNEL) positive cells (4.3 fold increase) were higher in 33-month-old animals (P < 0.05). Deferasirox treatment decreased cardiac iron levels by 37% (P < 0.05), and this was associated with decreases in the number of TUNEL-positive cells. Age-associated increases in cell death were coupled with increases in Bax to Bcl-2 ratio, and the amount of Bad, full-length caspase-3, and cleaved caspase-3. Deferasirox treatment decreased the Bax to Bcl-2 ratio by 17% (P < 0.05) and the amount of Bad, full-length caspase-3, cleaved caspase-3 (19 kDa), and cleaved caspase-3 (17 kDa) by 41, 16, 22, and 37%, respectively (P < 0.05). Taken together, these data suggest that deferasirox may be effective in diminishing age-associated iron accumulation and cardiac apoptosis in the F344XBN rat model.

Effects of aging and gender on muscle mass and regulation of Akt-mTOR-p70s6k related signaling in the F344BN rat model.

Sarcopenia is the loss of muscle mass and strength which occurs with aging. Whether the molecular basis of sarcopenia differs with muscle type and across sex is not well understood. Here we examine how aging affects the regulation of protein kinase B (Akt), the mammalian target of rapamycin (mTOR), AMP activated kinase (AMPK), p70 ribosomal S6 kinase (p70s6k), S6 ribosomal protein (rps6) and calcineurin (CaN) in the slow soleus and fast extensor digitorum longus (EDL) muscles of 6- (adult), 30- (aged), and 36-month (very aged) male and 6- (adult), 26- (aged), and 30-month (very aged) female Fischer 344xBrown Norway (F344BN) rats. In male animals, soleus and EDL muscle to body weight ratios decreased steadily with age while in the females, losses remained unchanged after 26 months. These age-related changes in the degree of muscle atrophy across sex were associated with differences in the regulation of Akt, mTOR, and p70s6k in the slow-twitch soleus and the regulation of AMPK, 4EBP1, p70s6k and rpS6 in the fast-twitch EDL. Irrespective of muscle type, aging in both the genders was associated with increased calcineurin expression. Taken together, these data suggest that indices of protein synthesis and muscle adaptation are regulated differently with aging in different muscle types and sex.

Fluprostenol-induced MAPK signaling is independent of aging in Fischer 344/NNiaHSd x Brown Norway/BiNia rat aorta.

The factors that regulate vascular mechanotransduction and how this process may be altered with aging are poorly understood and have not been widely studied. Recent data suggest that increased tissue loading can result in the release of prostaglandin F2 alpha (PGF2alpha) and other reports indicate that aging diminishes the ability of the aged aorta to activate mitogen activated protein kinase (MAPK) signaling in response to increased loading. Using ex vivo incubations, here we investigate whether aging affects the ability of the aorta to induce phosphorylation of extracellular signal-regulated kinase 1/2 (ERK(1/2)-MAPK), p38-MAPK, and Jun N-terminal kinase (JNK-MAPK) activation following stimulation with a PGF2alpha analog, fluprostenol. Compared to aortas from 6-mo animals, the amounts of ERK(1/2)- and p38-MAPK remained unchanged with aging, while the level of JNK-MAPK protein increased by 135% and 100% at 30- and 36-mo, respectively. Aging increased the basal phosphorylation of ERK(1/2) (115% and 47%) and JNK (29% and 69%) (p <0.05) in 30- and 36-mo aortas, while p38 phosphorylation levels remained unaltered. Compared to age-matched controls, fluprostenol induced phosphorylation of ERK(1/2) (310%, 286%, and 554%), p38-MAPK (unchanged, 48%, and 148%), and JNK (78%, 88%, and 95%) in 6-, 30- and 36-mo aortas, respectively. These findings suggest that aging does not affect the ability of the rat aorta to activate ERK(1/2)-, p38-MAPK, and JNK-MAPK phosphorylation in response to PGF2alpha stimulation.

Shear stress activates Akt during vascular smooth muscle cell reorientation.

Vascular intervention procedures can lead to endothelial damage and expose the underlying VSMCs (vascular smooth muscle cells) to shear stress. Although shear stress has been implicated in the proliferation and migration of VSMCs, the molecular mechanism(s) underlying these events are not well understood. In the present study, we examined the effect of shear stress on VSMC reorientation and the activation of Akt (also called protein kinase B) pathway signalling. Cells were subjected to a shear of 9.8 dynes/cm2 (1 dyne=10-5 N) for 0 min, 5 min, 15 min, 30 min, 1 h, 4 h and 24 h. Shear stress caused the VSMCs to realign at an angle that was approximately 45 degrees relative to the shear force vector after 24 h. Immunoblotting demonstrated that the phosphorylations of Akt and Akt-related signalling proteins [mTOR (mammalian target of rapamycin), PTEN (phosphatase and tensin homologue deleted on chromosome 10) and p70S6k (p70 S6-kinase)] were increased after shear stimulation. These results indicate that the activation of the Akt pathway signalling is closely correlated with shear-induced VSMC reorientation.

Possible molecular mechanisms underlying age-related cardiomyocyte apoptosis in the F344XBN rat heart.

Despite advances in treatment, age-related cardiac dysfunction still remains a leading cause of cardiovascular death. Recent data have suggested that increases in cardiomyocyte apoptosis may be involved in the pathological remodeling of heart. Here, we examine the effects of aging on cardiomyocyte apoptosis in 6-, 30-, and 36-month-old Fischer344 x Brown Norway F1 hybrid rats (F344XBN). Compared with 6-month hearts, aged hearts exhibited increased TdT-mediated dUTP nick end labeling-positive nuclei, caspase-3 activation, caspase-dependent cleavage of alpha-fodrin and diminished phosphorylation of protein kinase B/Akt (Thr 308). These age-dependent increases in cardiomyocyte apoptosis were associated with alterations in the composition of the cardiac dystrophin glycoprotein complex and elevated cytoplasmic IgG and albumin immunoreactivity. Immunohistochemical analysis confirmed these data and demonstrated qualitative differences in localization of dystrophin-glycoprotein complex (DGC) molecules with aging. Taken together, these data suggest that aging-related increases in cardiac apoptotic activity model may be due, at least in part, to age-associated changes in DGC structure.

Impaired overload-induced hypertrophy in obese Zucker rat slow-twitch skeletal muscle.

The effect of insulin resistance (IR) on the adaptation of skeletal muscle loading is not well understood. Here we examine whether the soleus muscles of the lean Zucker (LZ) and insulin-resistant obese Zucker (OZ) rat exhibit differences in their ability to undergo muscle hypertrophy following 8 wk of mechanical overload. Four-week-old male LZ (n = 5) and OZ (n = 5) rats underwent unilateral surgical ablation of the gastrocnemius muscle while the contralateral hindlimb was used as an internal control. Mechanical overload increased soleus muscle wet weight (LZ 57% and OZ 33%, respectively; P < 0.05) and average type 1 fiber cross-sectional area (LZ 32% and OZ 5%, respectively; P < 0.05) in LZ and OZ rats, while the magnitude of these increases was greater in the LZ animals (P < 0.05). The reduced degree of muscle hypertrophy observed in the OZ animals was associated with decreases in the ability of the OZ soleus muscle to phosphorylate p70s6k(Thr 389) and mTOR, while phosphorylation of p70s6k(Thr 389) was increased in the LZ overloaded soleus by 83% (P < 0.05). The amount of Tuberin/TSC2 phosphorylation, an inhibitor of mTOR, was unchanged in the LZ soleus after overload while it was increased (68.3%, P < 0.05) in OZ animals. Conversely, AMPK phosphorylation was decreased in the LZ (-22.77%, P < 0.05) but increased (57%, P < 0.05) in the OZ soleus with overload. Taken together, these data suggest that IR or other related comorbidities may impair the ability of the soleus to activate mTOR signaling and undergo load-induced muscle hypertrophy.

Deferasirox removes cardiac iron and attenuates oxidative stress in the iron-overloaded gerbil.

Iron-induced cardiovascular disease is the leading cause of death in iron-overloaded patients. Deferasirox is a novel, once daily oral iron chelator that was recently approved for the treatment of transfusional iron overload. Here, we investigate whether deferasirox is capable of removing cardiac iron and improving iron-induced pathogenesis of the heart using the iron overload gerbil model. Animals were randomly divided into three groups: control, iron overload, and iron overload + deferasirox treatment. Iron-dextran was given 100 mg/kg per 5 days i.p for 10 weeks. Deferasirox treatment was taken post iron loading and was given at 100 mg/kg/day p.o for 1 or 3 months. Cardiac iron concentration was determined by inductively coupled plasma atomic emission spectroscopy. Compared with the untreated group, deferasirox treatment for 1 and 3 months decreased cardiac iron concentration 17.1% (P = 0.159) and 23.5% (P < 0.05), respectively. These treatment-associated reductions in cardiac iron were paralleled by decreases in tissue ferritin expression of 20% and 38% at 1 and 3 months, respectively (P < 0.05). Using oxyblot analysis and hydroethidine fluorescence, we showed that deferasirox significantly reduces cardiac protein oxidation and superoxide abundance by 36 and 47.1%, respectively (P < 0.05). Iron-induced increase in oxidative stress was also associated with increased phosphorylation of ERK-, p38-, and JNK-mitogen-activated protein kinase (MAPK). Interestingly, deferasirox treatment significantly diminished the phosphorylation of all three MAPK subfamilies. These results suggest that deferasirox may confer a cardioprotective effect against iron induced injury.

Aging-associated dysfunction of Akt/protein kinase B: S-nitrosylation and acetaminophen intervention.

BACKGROUND: Aged skeletal muscle is characterized by an increased incidence of metabolic and functional disorders, which if allowed to proceed unchecked can lead to increased morbidity and mortality. The mechanism(s) underlying the development of these disorders in aging skeletal muscle are not well understood. Protein kinase B (Akt/PKB) is an important regulator of cellular metabolism and survival, but it is unclear if aged muscle exhibits alterations in Akt function. Here we report a novel dysfunction of Akt in aging muscle, which may relate to S-nitrosylation and can be prevented by acetaminophen intervention. PRINCIPAL FINDINGS: Compared to 6- and 27-month rats, the phosphorylation of Akt (Ser473 and Thr308) was higher in soleus muscles of very aged rats (33-months). Paradoxically, these increases in Akt phosphorylation were associated with diminished mammalian target of rapamycin (mTOR) phosphorylation, along with decreased levels of insulin receptor beta (IR-beta), phosphoinositide 3-kinase (PI3K), phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and phosphorylation of phosphoinositide-dependent kinase-1 (PDK1) (Ser241). In vitro Akt kinase measurements and ex vivo muscle incubation experiments demonstrated age-related impairments of Akt kinase activity, which were associated with increases in Akt S-nitrosylation and inducible nitric oxide synthase (iNOS). Impairments in Akt function occurred parallel to increases in myocyte apoptosis and decreases in myocyte size and the expression of myosin and actin. These age-related disorders were attenuated by treating aged (27-month) animals with acetaminophen (30 mg/kg body weight/day) for 6-months. CONCLUSIONS: These data demonstrate that Akt dysfunction and increased S-nitrosylation of Akt may contribute to age-associated disorders in skeletal muscle and that acetaminophen may be efficacious for the treatment of age-related muscle dysfunction.

Acetaminophen prevents aging-associated hyperglycemia in aged rats: effect of aging-associated hyperactivation of p38-MAPK and ERK1/2.

BACKGROUND: Aging-related hyperglycemia is associated with increased oxidative stress and diminished muscle glucose transporter-4 (Glut4) that may be regulated, at least in part, by the mitogen-activated protein kinases (MAPK). METHODS: To test the possibility that aging-related hyperglycemia can be prevented by pharmacological manipulation of MAPK hyperactivation, aged (27-month old) Fischer 344/NNiaHSD x Brown Norway/BiNia F1 (F344BN) rats were administered acetaminophen (30 mg/kg body weight/day) for 6 months in drinking water. RESULTS: Hepatic histopathology, serum aspartate aminotransferase and alanine aminotransferase analyses suggested that chronic acetaminophen did not cause hepatotoxicity. Compared with adult (6-month) and aged (27-month) rats, very aged rats (33-month) had higher levels of blood glucose, phosphorylation of soleus p38-MAPK and extracellular-regulated kinase 1/2 (ERK1/2), superoxide and oxidatively modified proteins (p<0.05), and these changes were associated with decreased soleus Glut4 protein abundance (p<0.05). Chronic acetaminophen treatment attenuated age-associated increase in blood glucose by 61.3% (p<0.05) and increased soleus Glut4 protein by 157.2% (p<0.05). These changes were accompanied by diminished superoxide levels, decrease in oxidatively modified proteins (-60.8%; p<0.05) and reduced p38-MAPK and ERK1/2 hyperactivation (-50.4% and -35.4%, respectively; p<0.05). CONCLUSIONS: These results suggest that acetaminophen may be useful for the treatment of age-associated hyperglycemia.

Diabetes alters vascular mechanotransduction: pressure-induced regulation of mitogen activated protein kinases in the rat inferior vena cava.

BACKGROUND: Diabetes mellitus is an important risk factor for increased vein graft failure after bypass surgery. However, the cellular and molecular mechanism(s) underlying vessel attrition in this population remain largely unexplored. Recent reports have suggested that the pathological remodeling of vein grafts may be mediated by mechanically-induced activation of the mitogen activated protein kinase (MAPK) signaling pathways and the MAPK-related induction of caspase-3 activity. On the basis of these findings, we hypothesized that diabetes may be associated with alterations in how veins "sense" and "respond" to altered mechanical loading. METHODS: Inferior venae cavae (IVC) from the non-diabetic lean (LNZ) and the diabetic obese (OSXZ) Zucker rats were isolated and incubated ex vivo under basal or pressurized conditions (120 mmHg). Protein expression, basal activation and the ability of increased pressure to activate MAPK pathways and apoptosis-related signaling was evaluated by immunoblot analysis. RESULTS: Immunoblot analyses revealed differential expression and activation of extracellular signal-regulated kinase (ERK1/2), p38 and c-Jun NH2-terminal kinase (JNK) MAPKs in the IVCs of diabetic rats as compared to non-diabetic rats. In particular, the expression and basal phosphorylation of p38beta- (52.3 +/- 11.8%; 45.8 +/- 18.2%), JNK 1- (21.5 +/- 9.3%; 19.4 +/- 11.6%) and JNK3-MAPK (16.8 +/- 3.3%; 29.5 +/- 17.6%) were significantly higher (P < 0.05) in the diabetic vena cava. An acute increase in IVC intraluminal pressure failed to increase the phosphorylation of ERK1-, JNK-2, or any of the p38-MAPKs in the diabetic obese Zucker rats. Also, IVC loading in the LNZ led to a 276.0 +/- 36.0% and 85.8 +/- 25.1% (P < 0.05) increase in the cleavage of caspase-3 and caspase-9, respectively, with no effect on these molecules in the OSXZ. No differences were found in the regulation of Bax and Bcl-2 between groups. However, basal expression levels of Akt, phospho-Akt, PTEN, phospho-PTEN and phospho-Bad were higher in the diabetic venae cavae (P < 0.05). CONCLUSION: These data suggest that diabetes is associated with significant alteration in the ability of the vena cava to activate MAPK- and apoptosis-related signaling. Whether these changes are associated with the increased vein graft attrition seen in the diabetic population will require further investigation.