Cardiac pathology in mucopolysaccharidosis I mice: Losartan modifies ERK1/2 activation during cardiac remodeling.

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder caused by mutations in the IDUA gene, that codifies the alpha-L-iduronidase enzyme, which deficiency leads to storage of glycosaminoglycans, with multiple clinical manifestations. One of the leading causes of death in MPS I patients are cardiac complications such as cardiac valve thickening, conduction abnormalities, myocardial dysfunction, and cardiac hypertrophy. The mechanism leading to cardiac dysfunction in MPS I is not entirely understood. In a previous study, we have demonstrated that losartan and propranolol improved the cardiac function in MPS I mice. Thus, we aimed to investigate whether the pathways influenced by these drugs may modulate the cardiac remodeling process in MPS I mice. According to our previous observation, losartan and propranolol restore the heart function, without altering valve thickness. MPS I mice presented reduced activation of AKT and ERK1/2, increased activity of cathepsins, but no alteration in metalloproteinase activity was observed. Animals treated with losartan showed a reduction in cathepsin activity and restored ERK1/2 activation. While both losartan and propranolol improved heart function, no mechanistic evidence was found for propranolol so far. Our results suggest that losartan or propranolol could be used to ameliorate the cardiac disease in MPS I and could be considered as adjuvant treatment candidates for therapy optimization.

Neonatal nonviral gene editing with the CRISPR/Cas9 system improves some cardiovascular, respiratory, and bone disease features of the mucopolysaccharidosis I phenotype in mice.

Mucopolysaccharidosis type I (MPS I) is caused by deficiency of alpha-L-iduronidase (IDUA), leading to multisystemic accumulation of glycosaminoglycans (GAG). Untreated MPS I patients may die in the first decades of life, mostly due to cardiovascular and respiratory complications. We previously reported that the treatment of newborn MPS I mice with intravenous administration of lipossomal CRISPR/Cas9 complexes carrying the murine Idua gene aiming at the ROSA26 locus resulted in long-lasting IDUA activity and GAG reduction in various tissues. Following this, the present study reports the effects of gene editing in cardiovascular, respiratory, bone, and neurologic functions in MPS I mice. Bone morphology, specifically the width of zygomatic and femoral bones, showed partial improvement. Although heart valves were still thickened, cardiac mass and aortic elastin breaks were reduced, with normalization of aortic diameter. Pulmonary resistance was normalized, suggesting improvement in respiratory function. In contrast, behavioral abnormalities and neuroinflammation still persisted, suggesting deterioration of the neurological functions. The set of results shows that gene editing performed in newborn animals improved some manifestations of the MPS I disorder in bone, respiratory, and cardiovascular systems. However, further studies will be imperative to find better delivery strategies to reach "hard-to-treat" tissues to ensure better systemic and neurological effects.

Copaiba Oil Attenuates Right Ventricular Remodeling by Decreasing Myocardial Apoptotic Signaling in Monocrotaline-Induced Rats.

There is an increase in oxidative stress and apoptosis signaling during the transition from hypertrophy to right ventricular (RV) failure caused by pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT). In this study, it was evaluated the action of copaiba oil on the modulation of proteins involved in RV apoptosis signaling in rats with PAH. Male Wistar rats (±170 g, n = 7/group) were divided into 4 groups: control, MCT, copaiba oil, and MCT + copaiba oil. PAH was induced by MCT (60 mg/kg intraperitoneally) and, 7 days later, treatment with copaiba oil (400 mg/kg by gavage) was given for 14 days. Echocardiographic and hemodynamic measurements were performed, and the RV was collected for morphometric evaluations, oxidative stress, apoptosis, and cell survival signaling, and eNOS protein expression. Copaiba oil reduced RV hypertrophy (24%), improved RV systolic function, and reduced RV end-diastolic pressure, increased total sulfhydryl levels and eNOS protein expression, reduced lipid and protein oxidation, and the expression of proteins involved in apoptosis signaling in the RV of MCT + copaiba oil as compared to MCT group. In conclusion, copaiba oil reduced oxidative stress, and apoptosis signaling in RV of rats with PAH, which may be associated with an improvement in cardiac function caused by this compound.

Effects of ovariectomy on antioxidant defence systems in the right ventricle of female rats with pulmonary arterial hypertension induced by monocrotaline.

The aim of this study was to evaluate the impact of ovariectomy on oxidative stress in the right ventricle (RV) of female rats with pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT). Rats were divided into 4 groups (n = 6 per group): sham (S), sham + MCT (SM), ovariectomized (O), and ovariectomized + MCT (OM). MCT (60 mg·kg-1 i.p.) was injected 1 week after ovariectomy or sham surgery. Three weeks later, echocardiographic analysis and RV catheterisation were performed. RV morphometric, biochemical, and protein expression analysis through Western blotting were done. MCT promoted a slight increase in pulmonary artery pressure, without differences between the SM and OM groups, but did not induce RV hypertrophy. RV hydrogen peroxide increased in the MCT groups, but SOD, CAT, and GPx activities were also enhanced. Non-classical antioxidant defenses diminished in ovariectomized groups, probably due to a decrease in the nuclear factor Nrf2. Hemoxygenase-1 and thioredoxin-1 protein expression was increased in the OM group compared with SM, being accompanied by an elevation in the estrogen receptor ß (ER-ß). Hemoxygenase-1 and thioredoxin-1 may be involved in the modulation of oxidative stress in the OM group, and this could be responsible for attenuation of PAH and RV remodeling.

Effect of Free and Nanoencapsulated Copaiba Oil on Monocrotaline-induced Pulmonary Arterial Hypertension.

Copaiba oil comes from an Amazonian tree and has been used as an alternative medicine in Brazil. However, it has not been investigated yet in the treatment of cardiovascular diseases. This study was designed to test whether copaiba oil or nanocapsules containing this oil could modulate monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). Male Wistar rats (170 ± 20 g) received oil or nanocapsules containing this oil (400 mg/kg) by gavage daily for 1 week. At the end of this period, a single injection of MCT (60 mg/kg i.p.) was administered and measurements were performed after 3 weeks. The animals were divided into 6 groups: control, copaiba oil, nanocapsules with copaiba oil, MCT, oil + MCT, and nanocapsules + MCT. Afterward, echocardiographic assessments were performed, and rats were killed to collect hearts for morphometry and oxidative stress. MCT promoted a significant increase in pulmonary vascular resistance, right ventricle (RV) hypertrophy, and RV oxidative stress. Both oil and copaiba nanocapsules significantly reduced RV hypertrophy and oxidative stress. Pulmonary vascular resistance was reduced by copaiba oil in natura but not by nanocapsules. In conclusion, copaiba oil seems to offer protection against MCT-induced PAH. Our preliminary results suggest that copaiba oil may be an important adjuvant treatment for PAH.

Aerobic Exercise Promotes a Decrease in Right Ventricle Apoptotic Proteins in Experimental Cor Pulmonale.

Pulmonary arterial hypertension is characterized by progressive increases in resistance and pressure in the pulmonary artery and Cor pulmonale. The effect of exercise on hydrogen peroxide-dependent signaling in the right ventricle (RV) of Cor pulmonale rats was analyzed. Rats were divided into sedentary control (SC), sedentary monocrotaline (SM), trained control (TC), and trained monocrotaline (TM) groups. Rats underwent exercise training (60% of VO2 max) for 5 weeks, with 3 weeks after monocrotaline injection (60 mg/kg intraperitoneally). Pulmonary resistance was enhanced in SM (2.0-fold) compared with SC. Pulmonary artery pressure was increased in SM (2.7-fold) and TM (2.6-fold) compared with their respective controls (SC and TC). RV hypertrophy indexes increased in SM compared with SC. Hydrogen peroxide was higher in SM (1.7-fold) than SC and was reduced by 47% in TM compared with SM. p-Akt was increased in TM (2.98-fold) compared with SM. The Bax/Bcl-2 ratio and caspase 3 were also increased (2.9-fold and 3.9-fold, respectively) in SM compared with SC. Caspase 3 was decreased in TM compared with SM (P < 0.05). Therefore, exercise training promoted a beneficial response by decreasing hydrogen peroxide concentrations, and consequently, apoptotic signaling in RV.

Atorvastatin administered before myocardial infarction in rats improves contractility irrespective of metabolic changes.

Statins have a beneficial effect after myocardial infarction, but the relationship between glucose transporters and their use before the event has not yet been studied. We assessed the effects of atorvastatin treatment pre- and post-myocardial infarction on cardiovascular function and glucose transporter 4 (GLUT4) in the heart. Wistar-Kyoto rats were treated with 20 mg/kg atorvastatin or vehicle for 14 days before coronary artery occlusion surgery (myocardial infarction) or sham surgery. Echocardiographic evaluations were carried out 48 h after myocardial infarction (protocol A) and after 7 days (protocol B), when atorvastatin was also administered. Plasma inflammatory markers and GLUT4 in the heart were also evaluated. Animals were divided into the following groups: sham-operated and vehicle (C), myocardial infarction and vehicle (I), sham-operated and atorvastatin (CAt) and myocardial infarction and atorvastatin (IAt). After 48 h, myocardial infarction induced higher left ventricular fractional shortening in IAt versus I (~ 60%, P = 0.036), and the ejection fraction was lower (protocol A ~ 37%; protocol B ~ 30%). Myocardial infarction was associated with a rise in plasma membrane GLUT4 after 48 h (~ 40%, P < 0.001), and a reduction in GLUT4 after 7 days (I 25%; IAt 49%, P < 0.001). Atorvastatin treatment for 48 h after the infarction did not change GLUT4 expression, and after 7 days it had an additional negative effect on GLUT4 content (~ 39%, P = 0.030). In conclusion, atorvastatin treatment pre- and post-myocardial infarction improved myocardial contractility after 48 h, but not after 7 days, and was not associated with an increase in GLUT4 expression.

Characterization of heart disease in mucopolysaccharidosis type II mice.

Mucopolysaccharidosis type II (MPSII) is a progressive lysosomal storage disease caused by mutations in the IDS gene, that leads to iduronate 2-sulfatase (IDS) enzyme deficiency. The enzyme catalyzes the first step of degradation of two glycosaminoglycans (GAGs), heparan sulfate (HS) and dermatan sulfate (DS). The consequences of MPSII are progressively harmful and can lead to death by cardiac failure. The aim of this study was to characterize the cardiovascular disease in MPSII mice. Thus, we evaluated the cardiovascular function of MPSII male mice at 6, 8, and 10 months of age, through functional, histological, and biochemical analyzes. Echocardiographic analyses showed a progressive loss in cardiac function, observed through parameters such as reduction in ejection fraction (46% in control versus 28% in MPS II at 10 months, P < .01) and fractional area change (31% versus 23%, P < .05). Similar results were found in parameters of vascular competence, obtained by echo Doppler. Both aortic dilatation and an increase in pulmonary resistance were observed at all time points in MPSII mice. The histological analyses showed an increase in the thickness of the heart valves (2-fold thicker than control values at 10 months). Biochemical analyzes confirmed GAG storage in these tissues, with a massive elevation of DS in the myocardium. Furthermore, an important increase in the activity of proteases such as cathepsin S and B (up to 5-fold control values) was found and could be related to the progressive loss of cardiac function observed in MPSII mice. In this work, we demonstrated that loss of cardiac function in MPSII mice started at 6 months of age, although its global cardiac capacity was still preserved at this time. Disease progressed at later time points leading to heart failure. The MPSII mice at later times reproduce many of the cardiovascular events found in patients with Hunter's disease.

Intraperitoneal implant of recombinant encapsulated cells overexpressing alpha-L-iduronidase partially corrects visceral pathology in mucopolysaccharidosis type I mice.

BACKGROUND AIMS: Mucopolysaccharidosis type I (MPS I) is characterized by deficiency of the enzyme alpha-L-iduronidase (IDUA) and storage of glycosaminoglycans (GAG) in several tissues. Current available treatments present limitations, thus the search for new therapies. Encapsulation of recombinant cells within polymeric structures combines gene and cell therapy and is a promising approach for treating MPS I. METHODS: We produced alginate microcapsules containing baby hamster kidney (BHK) cells overexpressing IDUA and implanted these capsules in the peritoneum of MPS I mice. RESULTS: An increase in serum and tissue IDUA activity was observed at early time-points, as well as a reduction in GAG storage; however, correction in the long term was only partially achieved, with a drop in the IDUA activity being observed a few weeks after the implant. Analysis of the capsules obtained from the peritoneum revealed inflammation and a pericapsular fibrotic process, which could be responsible for the reduction in IDUA levels observed in the long term. In addition, treated mice developed antibodies against the enzyme. CONCLUSIONS: The results suggest that the encapsulation process is effective in the short term but improvements must be achieved in order to reduce the immune response and reach a stable correction.

Time course of hydrogen peroxide-thioredoxin balance and its influence on the intracellular signalling in myocardial infarction.

We investigated the myocardial thioredoxin-1 and hydrogen peroxide concentrations and their association with some prosurvival and pro-apoptotic proteins, during the transition from myocardial infarction (MI) to heart failure in rats. Male Wistar rats were divided into the following six groups: three sham-operated groups and three MI groups, each at at 2, 7 and 28 days postsurgery. Cardiac function was analysed by echocardiography; the concentration of H(2)O(2) and the ratio of reduced to oxidized glutathione were measured spectrophotometrically, while the myocardial immunocontent of thioredoxin-1, angiotensin II, angiotensin II type 1 and type 2 receptors, p-JNK/JNK, p-ERK/ERK, p-Akt/Akt, p-mTOR/mTOR and p-GSK3ß/GSK3ß was evaluated by Western blot. Our results show that thioredoxin-1 appears to make an important contribution to the reduced H(2)O(2) concentration. It was associated with lower JNK expression in the early period post-MI (2 days). However, thioredoxin-1 decreased, while renin-angiotensin system markers and levels of H(2)O(2) increased, over 28 days post-MI, in parallel with some signalling proteins involved in maladaptative cardiac remodelling and ventricular dysfunction. These findings provide insight into the time course profile of endogenous antioxidant adaptation to ischaemic injury, which may be useful for the design of therapeutical strategies targeting oxidative stress post-MI.

Early loss of cardiac function in acute myocardial infarction is associated with redox imbalance.

BACKGROUND: The loss of viable myocardium subsequent to myocardial infarction (MI) impairs cardiac function, and oxidative stress is considered to be critical in this process. OBJECTIVES: To assess cardiac function and correlate it with oxidative stress and antioxidant levels in cardiac tissue at 48 h post-MI. METHODS: Adult male Wistar rats (n=6 per group) with a mean (± SD) weight of 229±24 g were randomly assigned to either an infarcted group or a control group. MI was induced by occlusion of the left coronary artery. Cardiac function was evaluated by measuring left ventricular (LV) ejection fraction, LV fractional shortening, cardiac output, myocardial performance index and the peak early diastolic velocity/peak atrial velocity ratio using echocardiography. The myocardial oxidative stress profile was assessed by measuring the reduced glutathione/oxidized glutathione ratio, H2O2 levels, peroxiredoxin-6 protein levels and activity levels of superoxide dismutase, catalase and glutathione peroxidase. Lipid peroxidation was quantified using chemiluminescence, and protein oxidation was determined by measuring protein carbonyl levels. RESULTS: LV ejection fraction and LV fractional shortening were lower in the infarcted group compared with the sham group, whereas the peak early diastolic velocity/peak atrial velocity ratio and myocardial performance index were significantly increased, indicating systolic dysfunction. Lipid peroxidation, protein carbonyls and superoxide dismutase and catalase activity levels did not differ between the groups. Peroxyredoxin-6 levels were increased in the infarcted group, while H2O2 levels were reduced. The reduced glutathione/oxidized glutathione ratio and the glutathione peroxidase activity were reduced in the infarcted group compared with control. DISCUSSION AND CONCLUSION: These data suggest that MI-induced cardiac dysfunction and impaired redox balance may be associated with the activation of counter-regulatory responses to maintain reduced H2O2 concentrations and, thereby, prevent further oxidative damage at this early time point.

Association of the time course of pulmonary arterial hypertension with changes in oxidative stress in the left ventricle.

1. This study investigates the time course of pulmonary arterial hypertension (PAH) due to monocrotaline (MCT) and its association with cardiac function and oxidative stress markers in the left ventricle (LV). 2. Male Wistar rats were divided into six groups: 7 days, 21 days, and 31 days for both control and MCT groups. Following echocardiographic analysis, the heart was removed. The LV was separated and homogenized to analyze oxidized-to-total glutathione ratio and thioredoxin reductase (TrxR) activity as well as hydrogen peroxide (H(2) O(2) ) and ascorbic acid levels. 3. There was significant (P < 0.01) cardiac and right ventricle (RV) hypertrophy and pulmonary congestion in the MCT 21 day and 31 day groups. Echocardiography showed a change in the flow wave of the pulmonary artery at 21 days after MCT treatment. There was an increase in the LV ejection time (P < 0.05) at 31 days after MCT. The LV H(2)O(2) concentration was increased (P < 0.05) in the MCT 21 day and MCT 31 day groups compared with controls. There was a reduction (P < 0.05) in the LV ascorbic acid concentration and an increase (P < 0.05) in TrxR activity in the MCT 31 day rats. 4. Our findings showed RV changes due to pulmonary hypertension at 21 days after MCT injection. There was a correlation between the degree of dysfunction and the morphometry of the heart chambers, along with impairment of the antioxidant/pro-oxidant balance in the LV 31 days after the beginning of the protocol. This study suggests that LV changes follow RV dysfunction subsequent to pulmonary hypertension.

Effects of Copaiba Oil in Peripheral Markers of Oxidative Stress in a Model of Cor Pulmonale in Rats. / Efeitos do Óleo de Copaíba em Marcadores Periféricos de Estresse Oxidativo em um Modelo de Cor Pulmonale em Ratos.

BACKGROUND: To date, copaiba oil's systemic effects have never documented in Cor pulmonale induced by monocrotaline. OBJECTIVES: To investigate copaiba oil's effects in peripheral markers of oxidative stress in rats with Cor pulmonale. METHODS: Male Wistar rats (170±20g, n=7/group) were divided into four groups: control (CO), monocrotaline (MCT), copaiba oil (O), and monocrotaline+copaiba oil (MCT-O). MCT (60 mg/kg i.p.) was administered, and after one week, treatment with copaiba oil (400 mg/kg/day-gavage-14 days) was begun. Echocardiography was performed and, later, trunk blood collection was performed for oxidative stress evaluations. Statistical analysis: two-way ANOVA with Student-Newman-Keuls post-hoc test. P values<0.05 were considered significant. RESULTS: Copaiba oil reduced pulmonary vascular resistance and right ventricle (RV) hypertrophy (Fulton index (mg/mg): MCT-O=0.39±0.03; MCT=0.49±0.01), and improved RV systolic function (RV shortening fraction, %) in the MCT-O group (17.8±8.2) as compared to the MCT group (9.4±3.1; p<0.05). Moreover, in the MCT-O group, reactive oxygen species and carbonyl levels were reduced, and antioxidant parameters were increased in the peripheral blood (p<0.05). Conclusions: Our results suggest that copaiba oil has an interesting systemic antioxidant effect, which is reflected in the improvements in function and RV morphometry in this Cor pulmonale model. Cor pulmonale attenuation promoted by copaiba oil coincided with a reduction in systemic oxidative stress.

FUNDAMENTO: Até o presente momento, os efeitos sistêmicos do óleo de copaíba jamais foram documentados no Cor pulmonale induzido por monocrotalina. OBJETIVOS: Investigar os efeitos do óleo de copaíba nos marcadores periféricos de stress oxidativo em ratos com Cor pulmonale. MÉTODOS: Ratos Wistar machos (170±20g, n=7/grupo) foram divididos em quatro grupos: controle (CO), monocrotalina (MCT), óleo de copaíba (O), e monocrotalina + óleo de copaíba (MCT-O). Foi administrada a MCT (60 mg/kg i.p.) e, depois de uma semana, foi iniciado o tratamento com óleo de copaíba (400 mg/kg/day-gavagem-14 dias). Foi realizado o ecocardiograma e, depois disso, foi coletado sangue do tronco para a realização de avaliações de stress oxidativo. Análise estatística: ANOVA de duas vias com teste Student-Newman-Keuls post hoc. P-valores <0,05 foram considerados significativos. RESULTADOS: O óleo de copaíba reduziu a resistência vascular pulmonar e a hipertrofia do ventrículo direito (VD) hipertrofia (Índice de Fulton (mg/mg)): MCT-O= 0,39±0,03; MCT= 0,49±0,01), e função sistólica melhorada (fração de encurtamento do VD, %) no grupo MCT-O (17,8±8,2) em comparação com o grupo de MCT (9,4±3,1; p<0,05). Além disso, no grupo MCT-O, espécies reativas do oxigênio e os níveis de carbonila foram reduzidos, e os parâmetros antioxidantes aumentaram no sangue periférico (p <0,05). CONCLUSÕES: Os resultados deste estudo sugerem que o óleo de copaíba tem um efeito antioxidante sistêmico interessante, que se reflete na melhoria da função e na morfometria do VD nesse modelo de Cor pulmonale . A atenuação do Cor pulmonale promovida pelo óleo de copaíba coincidiu com uma redução no stress oxidativo sistêmico.

Redox-sensitive prosurvival and proapoptotic protein expression in the myocardial remodeling post-infarction in rats.

In this study, we investigated the oxidative stress influence in some prosurvival and proapoptotic proteins after myocardial infarction (MI). Male Wistar rats were divided in two groups: Sham-operated (control) and MI. MI was induced by left coronary artery occlusion. 28-days after surgery, echocardiographic, morphometric, and hemodynamic parameters were evaluated. Redox status (reduced to oxidized glutathione ratio, GSH/GSSG) and hydrogen peroxide levels (H(2)O(2)) were measured in heart tissue. The p-ERK/ERK, p-Akt/Akt, p-mTOR/mTOR and p-GSK-3beta/GSK-3beta ratios, as well as apoptosis-inducing factor (AIF) myocardial protein expression were quantified by Western blot. MI group showed an increase in cardiac hypertrophy (23%) associated with a decrease in ejection fraction (38%) and increase in left ventricular end-diastolic pressure (82%) when compared to control, characterizing ventricular dysfunction. Redox status imbalance was seen in MI animals, as evidenced by the decrease in the GSH/GSSG ratio (30%) and increased levels of H(2)O(2) (45%). This group also showed an increase in the ERK phosphorylation and a reduction of Akt and mTOR phosphorylation when compared to control. Moreover, we showed a reduction in the GSK-3beta phosphorylation and an increase in AIF protein expression in MI group. Taken together, our results show increased H(2)O(2) levels and cellular redox imbalance associated to a higher p-ERK and AIF immunocontent, which would contribute to a maladaptive hypertrophy phenotype.

Chronic whole-body heat treatment relieves atherosclerotic lesions, cardiovascular and metabolic abnormalities, and enhances survival time restoring the anti-inflammatory and anti-senescent heat shock response in mice.

Unhealthy lifestyle persistently feeds forward inflammation in metabolic organs thus imposing senescence-associated secretory phenotype (SASP), as observed in obesity and type 2 diabetes. However, SASP blocks physiological resolution of inflammation by suppressing the anti-inflammatory and anti-senescent heat shock (HS) response, i.e., the gene program centered in heat shock factor-1 (HSF1)-dependent expression heat shock proteins (HSPs). As SASP-inducing factors are not removed, leading to the perpetuation of inflammation, we argued that SIRT1-HSF1-HSP axis might also be suppressed in atherosclerosis, which could be reversible by heat treatment (HT), the most powerful HS response trigger. LDLr-/- adult mice were fed on high-fat/high-cholesterol diet from the age of 90 days until the end of study (age of 270 days). After 120 days under atherosclerotic diet, the animals were submitted to either whole-body HT (n = 42; 40 °C) or sham (n = 59; 37 °C) treatment (15 min/session), under anesthesia, once a week, for 8 weeks, being echographically and metabolically monitored. Aortic expressions of SIRT1, HSF1, HSP27, HSP72 and HSP73 were progressively depressed in atherosclerotic animals, as compared to normal (LDLr+/+; n = 25) healthy counterparts, which was paralleled by increased expression of NF-κB-dependent VCAM1 adhesion molecule. Conversely, HT completely reversed suppression of the above HS response proteins, while markedly inhibiting both VCAM1 expression and NF-κB DNA-binding activity. Also, HT dramatically reduced plasma levels of TG, total cholesterol, LDL-cholesterol, oxidative stress, fasting glucose and insulin resistance while rising HDL-cholesterol levels. HT also decreased body weight gain, visceral fat, cellular infiltration and aortic fatty streaks, and heart ventricular congestive hypertrophy, thereby improving aortic blood flow and myocardial performance (Tei) indices. Remarkably, heat-treated mice stopped dying after the third HT session (= 8 human years), suggesting a curative effect. Therefore, evolution of atherosclerosis is associated with suppression of the anti-inflammatory and anti-senescent SIRT1-HSF1-HSP molecular axis, which is refreshed by chronic heat treatment.

In vivo genome editing of mucopolysaccharidosis I mice using the CRISPR/Cas9 system.

Mucopolysaccharidosis type I (MPS I) is a multisystemic disorder caused by the deficiency of alpha-L-iduronidase (IDUA) that leads to intracellular accumulation of glycosaminoglycans (GAG). In the present study we aimed to use cationic liposomes carrying the CRISPR/Cas9 plasmid and a donor vector for in vitro and in vivo MPS I gene editing, and compare to treatment with naked plasmids. The liposomal formulation was prepared by microfluidization. Complexes were obtained by the addition of DNA at +4/-1 charge ratio. The overall results showed complexes of about 110 nm, with positive zeta potential of +30 mV. The incubation of the complexes with fibroblasts from MPS I patients led to a significant increase in IDUA activity and reduction of lysosomal abnormalities. Hydrodynamic injection of the liposomal complex in newborn MPS I mice led to a significant increase in serum IDUA levels for up to six months. The biodistribution of complexes after hydrodynamic injection was markedly detected in the lungs and heart, corroborating the results of increased IDUA activity and decreased GAG storage especially in these tissues, while the group that received the naked plasmids presented increased enzyme activity especially in the liver. Furthermore, animals treated with the liposomal formulation presented improvement in cardiovascular parameters, one of the main causes of death observed in MPS I patients. We conclude that the IDUA production in multiple organs had a significant beneficial effect on the characteristics of MPS I disease, which may bring hope to gene therapy of Hurler patients.

Cathepsin B inhibition attenuates cardiovascular pathology in mucopolysaccharidosis I mice.

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder with multisystemic features, including heart enlargement, heart valve dysfunction, and aortic stiffness and dilatation. Previous studies have shown that MPS I mice overexpress cathepsin B (CtsB) in multiple tissues, including those from the cardiovascular system. Here, we hypothesized that inhibition of CtsB could ameliorate cardiac function parameters, as well as aorta and valve abnormalities found in MPS I. First, we found that total elastase activity in an MPS I aorta is elevated. Following that, we demonstrated that CtsB leaks from the lysosome in MPS I human fibroblasts, possibly acting as a degradative agent of extracellular matrix components from the aorta, cardiac muscle, and heart valves. We then used a CtsB inhibitor in vivo in the MPS I mouse model. After 4 months of treatment, partial inhibition of CtsB activity in treated mice reduced aortic dilatation, as well as heart valve thickening, and led to improvements in cardiac function parameters, although none of these were completely normalized. Based on these results, we conclude that lysosomal alterations in this disease promote leakage of CtsB to outside the organelle, where this protein can have multiple pathological roles. CtsB inhibition improved cardiovascular parameters in MPS I mice and can have a potential benefit in this disease.

Progressive heart disease in mucopolysaccharidosis type I mice may be mediated by increased cathepsin B activity.

Mucopolysaccharidosis type I (MPS I) is a lysosomal disorder characterized by a deficiency of alpha-L-iduronidase and storage of undegraded glycosaminoglycans (GAGs). Clinical findings of the disease include heart failure, and patients often need valve replacement. It has been shown that, later in life, MPS I mice develop those abnormalities, but to date, there have not been studies on the progression and pathogenesis of the disease. Therefore, in the present study, we evaluated heart function in normal and MPS I male mice from 2 to 8 months of age. Echocardiographic analysis showed left ventricular enlargement with progressive reduction in ejection fraction, fractional area change, and left ventricular fractional shortening in the MPS I hearts at 6 and 8 months of age and a reduction in acceleration time/ejection time ratio of the pulmonary artery starting at 6 months of age, which suggests pulmonary vascular resistance. Histological and biochemical analysis confirmed progressive GAG storage from 2 months of age and onwards in the myocardium and heart valves, which had also increased in thickness. Additionally, macrophages were present in the MPS I heart tissue. Collagen content was reduced in the MPS I mouse valves. Cathepsin B, an enzyme that is known to be able to degrade collagen and is involved in heart dilatation, displayed a marked elevation in activity in the MPS I mice and could be responsible for the heart dilatation and valves alterations observed. Our results suggest that the MPS I mice have progressive heart failure and valve disease, which may be caused by cathepsin B overexpression.

Deleterious effects of interruption followed by reintroduction of enzyme replacement therapy on a lysosomal storage disorder.

Temporary interruption of enzyme replacement therapy (ERT) in patients with different lysosomal storage disorders may happen for different reasons (adverse reactions, issues with reimbursement, logistic difficulties, and so forth), and the impact of the interruption is still uncertain. In the present work, we studied the effects of the interruption of intravenous ERT (Laronidase, Genzyme) followed by its reintroduction in mice with the prototypical lysosomal storage disorder mucopolysaccharidosis type I, comparing to mice receiving continuous treatment, untreated mucopolysaccharidosis type I mice, and normal mice. In the animals which treatment was temporarily interrupted, we observed clear benefits of treatment in several organs (liver, lung, heart, kidney, and testis) after reintroduction, but a worsening in the thickness of the aortic wall was detected. Furthermore, these mice had just partial improvements in behavioral tests, suggesting some deterioration in the brain function. Despite worsening is some disease aspects, urinary glycosaminoglycans levels did not increase during interruption, which indicates that this biomarker commonly used to monitor treatment in patients should not be used alone to assess treatment efficacy. The deterioration observed was not caused by the development of serum antienzyme antibodies. All together our results suggest that temporary ERT interruption leads to deterioration of function in some organs and should be avoided whenever possible.