Metabolic Syndrome and Cardiac Remodeling Due to Mitochondrial Oxidative Stress Involving Gliflozins and Sirtuins.

PURPOSE OF REVIEW: To address the mechanistic pathways focusing on mitochondria dysfunction, oxidative stress, sirtuins imbalance, and other contributors in patient with metabolic syndrome and cardiovascular disease. Sodium glucose co-transporter type 2 (SGLT-2) inhibitors deeply influence these mechanisms. Recent randomized clinical trials have shown impressive results in improving cardiac function and reducing cardiovascular and renal events. These unexpected results generate the need to deepen our understanding of the molecular mechanisms able to generate these effects to help explain such significant clinical outcomes. RECENT FINDINGS: Cardiovascular disease is highly prevalent among individuals with metabolic syndrome and diabetes. Furthermore, mitochondrial dysfunction is a principal player in its development and persistence, including the consequent cardiac remodeling and events. Another central protagonist is the renin-angiotensin system; the high angiotensin II (Ang II) activity fuel oxidative stress and local inflammatory responses. Additionally, sirtuins decline plays a pivotal role in the process; they enhance oxidative stress by regulating adaptive responses to the cellular environment and interacting with Ang II in many circumstances, including cardiac and vascular remodeling, inflammation, and fibrosis. Fasting and lower mitochondrial energy generation are conditions that substantially reduce most of the mentioned cardiometabolic syndrome disarrangements. In addition, it increases sirtuins levels, and adenosine monophosphate-activated protein kinase (AMPK) signaling stimulates hypoxia-inducible factor-1ß (HIF-1 beta) and favors ketosis. All these effects favor autophagy and mitophagy, clean the cardiac cells with damaged organelles, and reduce oxidative stress and inflammatory response, giving cardiac tissue protection. In this sense, SGLT-2 inhibitors enhance the level of at least four sirtuins, some located in the mitochondria. Moreover, late evidence shows that SLGT-2 inhibitors mimic this protective process, improving mitochondria function, oxidative stress, and inflammation. Considering the previously described protection at the cardiovascular level is necessary to go deeper in the knowledge of the effects of SGLT-2 inhibitors on the mitochondria function. Various of the protective effects these drugs clearly had shown in the trials, and we briefly describe it could depend on sirtuins enhance activity, oxidative stress reduction, inflammatory process attenuation, less interstitial fibrosis, and a consequent better cardiac function. This information could encourage investigating new therapeutic strategies for metabolic syndrome, diabetes, heart and renal failure, and other diseases.

Genomic or Non-Genomic? A Question about the Pleiotropic Roles of Vitamin D in Inflammatory-Based Diseases.

Vitamin D (vit D) is widely known for its role in calcium metabolism and its importance for the bone system. However, various studies have revealed a myriad of extra-skeletal functions, including cell differentiation and proliferation, antibacterial, antioxidant, immunomodulatory, and anti-inflammatory properties in various cells and tissues. Vit D mediates its function via regulation of gene expression by binding to its receptor (VDR) which is expressed in almost all cells within the body. This review summarizes the pleiotropic effects of vit D, emphasizing its anti-inflammatory effect on different organ systems. It also provides a comprehensive overview of the genetic and epigenetic effects of vit D and VDR on the expression of genes pertaining to immunity and anti-inflammation. We speculate that in the context of inflammation, vit D and its receptor VDR might fulfill their roles as gene regulators through not only direct gene regulation but also through epigenetic mechanisms.

Consumption of oil macerated with garlic produces renovascular protective effects in adult apolipoprotein E-deficient mice.

Oxidative stress and chronic inflammatory conditions contribute as key determinants in the development of vascular and renal diseases. Organosulfur compounds (OSCs) of oil macerated with garlic (OMG) are promising phytochemicals which could protect us from hyper-inflammation and oxidative stress-induced organ damage. The present work evaluated the effect of OMG intake in apolipoprotein E-knockout (ApoE-KO) mice. Adult female ApoE-KO mice were randomly divided into three groups and fed with control chow, oil-supplemented diet and OMG-supplemented diet. After 8 weeks, the animals were euthanized and blood, aorta, kidneys, liver and abdominal adipose tissues were obtained for further analysis. Biochemical parameters were measured in plasma, lipid peroxidation as malondialdehyde (MDA) levels was determined in the adipose tissue, oil red O was used to stain atherosclerotic lesions, and histological and ultrastructural analyses of the kidneys were performed. Renal expression levels of Tumor Necrosis Factor α (TNF-α), Interleukin-6 (IL-6) and Wilms' Tumor Protein (WT-1) were determined by western blotting and the co-immunoprecipitation assay (p53/WT-1). Also, transmission electron microscopy for studying the expression of mitofusin 2 (Mfn-2) was used to assess mitochondrial damage. The results showed that long-term moderate intake of OMG improved serum triglyceride levels, diminished the atheroma plaque area, and reduced lipid peroxidation. Furthermore, we found a decrease in oxidative and inflammatory markers, less apoptosis and reduced WT-1 expression in the kidneys. Also, OMG increased p53/WT-1 protein interactions and reduced mitochondrial damage. Our findings suggest that OMG intake would produce anti-atherosclerotic, antifibrotic, anti-inflammatory and antiapoptotic effects in adult ApoE-KO mice, conferring significant renovascular protective actions in a mechanism mediated, at least in part, by WT-1.

Cannabinoids as Potential Molecules for Addiction Disorders.

BACKGROUND: Addictions are a group of chronic and recurrent diseases of the brain characterized by a pathological search for reward or relief through the use of a substance or other action. This situation implies an inability to control behavior, difficulty in permanent abstinence, a compelling desire to consume, decreased recognition of significant problems caused by behavior and interpersonal relationships, and a dysfunctional emotional response. The result is a decrease in the quality of life of the affected person, generating problems in their work, academic activities, social relationships, or family or partner relationships. Unfortunately, there are not enough pharmacotherapeutic solutions to treat addictions due to the complexity of their physiopathology and signaling pathways. Therefore, it is an imperative search for new pharmacological alternatives which may be used for this purpose. PURPOSE OF REVIEW: This review summarizes the main recent findings of the potential therapeutic effects of different cannabinoids on treating several addictions, including alcohol, opioids, methamphetamine, cocaine, and nicotine use disorders. Highlights Standpoints: It has been demonstrated that many phyto, synthetic, and endogenous cannabinoids may act as therapeutic molecules in this psychiatric pathology through their action on multiple cannabinoid receptors. To highlight, cannabinoid receptors, types 1 and 2 (CB1 and CB2) have a crucial role in modulating the anti-addictive properties of these compounds.

Anti-inflammatory, antioxidant, antihypertensive, and antiarrhythmic effect of indole-3-carbinol, a phytochemical derived from cruciferous vegetables.

BACKGROUND: Cardiovascular inflammation and oxidative stress are determining factors in high blood pressure and arrhythmias. Indole-3-carbinol is a cruciferous-derived phytochemical with potential anti-inflammatory and antioxidant effects. However, its implications on the modulation of cardiovascular inflammatory-oxidative markers are unknown. OBJECTIVES: To establish the effects of indole-3-carbinol on the oxidative-inflammatory-proarrhythmic conditions associated with hypertension. MATERIALS: Histological, biochemical, molecular, and functional aspects were evaluated in 1) Culture of mouse BV-2 glial cells subjected to oxidative-inflammatory damage by lipopolysaccharides (100 ng/mL) in the presence or absence of 40 µM indole-3-carbinol (n = 5); 2) Male spontaneously hypertensive rats (SHR) and Wistar Kyoto rats receiving indole-3-carbinol (2000 ppm/day, orally) during the first 8 weeks of life (n = 15); 3) Isolated rat hearts were submitted to 10 min regional ischemia and 10 min reperfusion. RESULTS: 1) lipopolysaccharides induced oxidative stress and increased inflammatory markers; indole-3-carbinol reversed both conditions (interleukin 6, tumor necrosis factor α, the activity of nicotinamide adenine dinucleotide phosphate oxidase, nitric oxide, inducible nitric oxide synthase, heat shock protein 70, all p < 0.01 vs lipopolysaccharides). 2) SHR rats showed histological, structural, and functional changes with increasing systolic blood pressure (154 ± 8 mmHg vs. 122 ± 7 mmHg in Wistar Kyoto rats, p < 0.01); Inflammatory-oxidative markers also increased, and nitric oxide and heat shock protein 70 decreased. Conversely, indole-3-carbinol reduced oxidative-inflammatory markers and systolic blood pressure (133 ± 8 mmHg, p < 0.01 vs. SHR). 3) indole-3-carbinol reduced reperfusion arrhythmias from 8/10 in SHR to 0/10 (p = 0.0007 by Fisher's exact test). CONCLUSIONS: Indole-3-carbinol reduces the inflammatory-oxidative-proarrhythmic process of hypertension. The nitric oxide and heat shock protein 70 are relevant mechanisms of indole-3-carbinol protective actions. Further studies with this pleiotropic phytochemical as a promising cardioprotective are guaranteed.

Central nervous system, peripheral and hemodynamic effects of nanoformulated anandamide in hypertension.

PURPOSE: Hypertensive lesions induce alterations at hemodynamic, peripheral, and central levels. Anandamide (N-arachidonoylethanolamine; AEA) protects neurons from inflammatory damage, but its free administration may cause central adverse effects. AEA controlled release by nanoformulations could reduce/eliminate its side effects. The present study aimed to evaluate the effects of nanoformulated AEA (nf-AEA) on systolic blood pressure (SBP), behavior, and central/peripheral inflammatory, oxidative, and apoptotic state in spontaneously hypertensive rats (SHR). MATERIALS/METHODS: Male rats were used, both Wistar Kyoto (WKY) and SHR (n â€‹= â€‹10 per group), with/without treatment with nf-AEA (obtained by electrospraying) at a weekly dose of 5 â€‹mg/kg IP for 4 weeks. SBP was measured and behavioral tests were performed. Inflammatory/oxidative markers were quantified at the central (brain cortex) and peripheral (serum) level. RESULTS: SHR showed hyperactivity, low anxiety, and high concentrations of central/peripheral inflammatory/oxidative markers, also higher apoptosis of brain cortical cells compared to WKY. As opposed to this group, treatment with nf-AEA in SHR significantly reduced SBP, peripheral/central inflammatory/oxidative makers, and central apoptosis. Nf-AEA also increased neuroprotective mechanisms mediated by intracellular heat shock protein 70 (Hsp70), which were attenuated in untreated SHR. Additionally, nf-AEA reversed the abnormal behaviors observed in SHR without producing central adverse effects. CONCLUSIONS: Our results suggest protective properties of nf-AEA, both peripherally and centrally, through a signaling pathway that would involve the type I angiotensin II receptor, Wilms tumor transcription factor 1, Hsp70, and iNOS. Considering non-nf-AEA limitations, this nanoformulation could contribute to the development of new antihypertensive and behavioral disorder treatments associated with neuroinflammation.

La interacción vitamina D-mitocondria podría modular el camino de señalización involucrado en el desarrollo de la hipertensión: una visión integrativa translacional / Vitamin D-mitochondria cross-talk could modulate the signaling pathway involved in hypertension development: a translational integrative overview

El déficit de vitamina D es una pandemia a nivel mundial y trae como consecuencia osteoporosis, hipertensión arterial (HTA) y otras enfermedades cardiovasculares. A nivel celular produce mayor carga oxidativa, marcadores inflamatorios y daño mitocondrial. Existe cada vez más evidencia sobre el protagonismo de la vitamina D en la regulación del sistema renina-angiotensina-aldosterona (RAAS), con posibles implicancias cardiovasculares así como para el sistema inmunológico. Valores de vitamina D inferiores a 25 ng/mL se relacionan con un aumento de tono vascular mediado por la contracción del músculo liso, ya sea a través de efectos directos sobre las células vasculares del músculo liso, sobrerregulación del RAAS, y/o a través de la modulación del metabolismo del calcio con hiperparatiroidismo secundario; lo cual predispone en los pacientes a desarrollar hipertrofia del ventrículo izquierdo y de la pared vascular originando HTA. En este trabajo se realizó una revisión de los principales mecanismos involucrados en el desarrollo de la HTA asociados al déficit de vitamina D. Entre ellos se destaca el vínculo que se establece entre los niveles de fosfato inorgánico extramitocondrial, sus principales hormonas reguladoras -como la vitamina D-, el aparato cardiovascular, las especies reactivas del oxígeno y el metabolismo mitocondrial. El papel del receptor de vitamina D a nivel mitocondrial y la regulación de la cadena respiratoria influirían en el remodelamiento arterial, ya que su activación reduciría el daño oxidativo y preservaría la vida celular. No obstante, existen aspectos aún no comprendidos sobre la intrincada red de señalización que resultan simples en ensayos experimentales, pero complejos en los estudios clínicos. En este sentido, la concreción de nuevos estudios como el VITAL podría clarificar, y así apoyar o refutar, los posibles beneficios de la vitamina D en la enfermedad cardiovascular hipertensiva

Vitamin D deficiency is a worldwide pandemic and results in osteoporosis, hypertension, and other cardiovascular diseases. At the cellular level, it produces significant oxidative stress, inflammatory markers, and mitochondrial damage. There is increasing evidence about the role of vitamin D in the regulation of the renin-angiotensin-aldosterone system (RAAS). Moreover, there is evidence of involvement in cardiovascular complications, as well as in the immune system disorders. Vitamin D values below 25 ng/mL are related to an increase in vascular tone mediated by smooth muscle contraction. Furthermore, it can produce direct effects on vascular smooth muscle cells, RAAS over-regulation, modulation of calcium metabolism, and secondary hyperparathyroidism. All this predisposes patients to develop hypertrophy of the left ventricle and vascular wall, causing hypertension. In this work, a review is presented of the main mechanisms involved in the development of hypertension due to vitamin D deficiency. Among them are the link established between the levels of extra-mitochondrial inorganic phosphate, its main regulatory hormones -such as vitamin D-, the cardiovascular system, reactive oxygen species, and mitochondrial metabolism. The role of the mitochondrial vitamin D receptor and the regulation of the respiratory chain could influence arterial remodelling since its activation would reduce oxidative damage and preserve cell life. However, there are aspects not yet understood about the intricate signalling network that appeared simple in experimental trials, but complex in clinical studies. In this way, the completion of new studies as VITAL, could clarify, and thus support or refute the possible benefits of vitamin D in hypertensive cardiovascular disease

Vitamin D-mitochondria cross-talk could modulate the signaling pathway involved in hypertension development: a translational integrative overview. / La interacción vitamina D-mitocondria podría modular el camino de señalización involucrado en el desarrollo de la hipertensión: una visión integrativa translacional.

Vitamin D deficiency is a worldwide pandemic and results in osteoporosis, hypertension, and other cardiovascular diseases. At the cellular level, it produces significant oxidative stress, inflammatory markers, and mitochondrial damage. There is increasing evidence about the role of vitamin D in the regulation of the renin-angiotensin-aldosterone system (RAAS). Moreover, there is evidence of involvement in cardiovascular complications, as well as in the immune system disorders. Vitamin D values below 25ng/mL are related to an increase in vascular tone mediated by smooth muscle contraction. Furthermore, it can produce direct effects on vascular smooth muscle cells, RAAS over-regulation, modulation of calcium metabolism, and secondary hyperparathyroidism. All this predisposes patients to develop hypertrophy of the left ventricle and vascular wall, causing hypertension. In this work, a review is presented of the main mechanisms involved in the development of hypertension due to vitamin D deficiency. Among them are the link established between the levels of extra-mitochondrial inorganic phosphate, its main regulatory hormones -such as vitamin D-, the cardiovascular system, reactive oxygen species, and mitochondrial metabolism. The role of the mitochondrial vitamin D receptor and the regulation of the respiratory chain could influence arterial remodelling since its activation would reduce oxidative damage and preserve cell life. However, there are aspects not yet understood about the intricate signalling network that appeared simple in experimental trials, but complex in clinical studies. In this way, the completion of new studies as VITAL, could clarify, and thus support or refute the possible benefits of vitamin D in hypertensive cardiovascular disease.

Alterations on a key nephrogenic/cardiogenic gene expression linked to hypertension development / Alteraciones en la expresión de un gen clave en el desarrollo renal y cardíaco vinculada con el desarrollo de la hipertensión arterial

The elevation of blood pressure produces specific organic lesions, including kidney and cardiac damage. On the other hand, cardiovascular disease usually leads to the development of hypertension. Thus, hypertension could be both a cause and a consequence of cardiovascular disease. Previous studies linked the lack of nitric oxide to cardiovascular abnormalities, including hypertension, arteriosclerosis, myocardial infarction, cardiac hypertrophy, diastolic heart failure, and reduced endothelium-derived hyperpolarizing factor responses, with shorter survival. The lack of this gas also leads to renal/cardiac abnormalities.It is widely known that nephrogenic deficiency is a risk factor for kidney disease. Besides, recent evidence suggests that alterations in WT-1, a key nephrogenic factor, could contribute to the development of hypertension. Moreover, some genes involved in the development of hypertension depend on WT-1.This knowledge makes it essential to investigate and understand the mechanisms regulating the expression of these genes during renal/cardiac development, and hypertension. As a consequence, the most in-depth knowledge of the complex aetiopathogenic mechanism responsible for the hypertensive disease will allow us to propose novel therapeutic tools

La hipertensión produce lesiones orgánicas específicas como daño renal/cardíaco, mientras que la enfermedad cardiovascular generalmente conduce a la hipertensión. Por ello, la hipertensión sería tanto una causa como una consecuencia de la enfermedad cardiovascular. Estudios previos refieren falta de óxido nítrico con anomalías cardiovasculares como hipertensión y reducción de las respuestas del factor hiperpolarizante derivado del endotelio. La falta de este gas también conduce a anomalías renales/cardíacas. Además, la deficiencia nefrogénicaes un factor de riesgo para la enfermedad renal. Así, alteraciones en WT-1, un factor nefrógeno clave, podrían contribuir al desarrollo de hipertensión. Finalmente, el conocimiento más profundo del complejo mecanismo etiopatogénico responsable de la enfermedad hipertensiva nos permitirá proponer nuevas herramientas terapéuticas

Synthesis, physicochemical characterisation and biological activity of anandamide/ɛ-polycaprolactone nanoparticles obtained by electrospraying.

Drug encapsulation in nanocarriers such as polymeric nanoparticles (Nps) may help to overcome the limitations associated with cannabinoids. In this study, the authors' work aimed to highlight the use of electrospraying techniques for the development of carrier Nps of anandamide (AEA), an endocannabinoid with attractive pharmacological effects but underestimated due to its unfavourable physicochemical and pharmacokinetic properties added to its undesirable effects at the level of the central nervous system. The authors characterised physicochemically and evaluated in vitro biological activity of anandamide/ɛ-polycaprolactone nanoparticles (Nps-AEA/PCL) obtained by electrospraying in epithelial cells of the human proximal tubule (HK2), to prove the utility of this method and to validate the biological effect of Nps-AEA/PCL. They obtained particles from 100 to 900 nm of diameter with a predominance of 200-400 nm. Their zeta potential was -20 ± 1.86 mV. They demonstrated the stable encapsulation of AEA in Nps-AEA/PCL, as well as its dose-dependent capacity to induce the expression of iNOS and NO levels and to decrease the Na+/K+ ATPase activity in HK2 cells. Obtaining Nps-AEA/PCL by electrospraying would represent a promising methodology for a novel AEA pharmaceutical formulation development with optimal physicochemical properties, physical stability and biological activity on HK2 cells.

Alterations on a key nephrogenic/cardiogenic gene expression linked to hypertension development.

The elevation of blood pressure produces specific organic lesions, including kidney and cardiac damage. On the other hand, cardiovascular disease usually leads to the development of hypertension. Thus, hypertension could be both a cause and a consequence of cardiovascular disease. Previous studies linked the lack of nitric oxide to cardiovascular abnormalities, including hypertension, arteriosclerosis, myocardial infarction, cardiac hypertrophy, diastolic heart failure, and reduced endothelium-derived hyperpolarizing factor responses, with shorter survival. The lack of this gas also leads to renal/cardiac abnormalities. It is widely known that nephrogenic deficiency is a risk factor for kidney disease. Besides, recent evidence suggests that alterations in WT-1, a key nephrogenic factor, could contribute to the development of hypertension. Moreover, some genes involved in the development of hypertension depend on WT-1. This knowledge makes it essential to investigate and understand the mechanisms regulating the expression of these genes during renal/cardiac development, and hypertension. As a consequence, the most in-depth knowledge of the complex aetiopathogenic mechanism responsible for the hypertensive disease will allow us to propose novel therapeutic tools.

Implicaciones del factor de transcripción WT1 asociado al remodelado cardiaco patológico postinfarto miocárdico / Implications of the transcription factor WT1 linked to the pathologic cardiac remodeling post-myocardial infarction

Nuevos avances en el tratamiento del infarto agudo de miocardio involucran inéditas vías de señalización y progenie celular. En este sentido, la regeneración es una herramienta novedosa que contribuiría al remodelado ventricular fisiológico postinfarto. Más específicamente, la reexpresión del factor de transcripción WT1 en la pared miocárdica por isquemia e infarto se relacionaría con la invasión de células con la capacidad de regeneración. Este mecanismo parece no resultar suficiente para restituir completamente las células musculares y vasos perdidos. De especial interés, la presencia de la proteína de respuesta a golpe de calor 70 (Hsp70) y su interacción con el receptor de vitamina D modularían positivamente la expresión de WT1. En este contexto, se propone que la activación de los receptores de vitamina D asociados a Hsp70 podría favorecer el remodelado cardiaco fisiológico y reducir la progresión a insuficiencia cardiaca

New advances in the treatment of acute myocardial infarction involve novel signaling pathways and cellular progeny. In this sense, regeneration is a novel tool that would contribute to post-infarction physiological ventricular remodeling. More specifically, re-expression of the WT1 transcription factor in the myocardial wall by ischemia and infarction would be related to the invasion of cells with the capacity for regeneration. This mechanism seems not to be sufficient to restore muscle cells and lost vessels entirely. Of particular interest, the presence of the heat-shock response protein 70 (Hsp70) and its interaction with the vitamin D receptor would modulate the expression of WT1 positively. In this context, it is proposed that the activation of vitamin D receptors associated with Hsp70 could favor physiological cardiac remodeling and reduce the progression to heart failure

Implications of the transcription factor WT1 linked to the pathologic cardiac remodeling post-myocardial infarction. / Implicaciones del factor de transcripción WT1 asociado al remodelado cardiaco patológico postinfarto miocárdico.

New advances in the treatment of acute myocardial infarction involve novel signaling pathways and cellular progeny. In this sense, regeneration is a novel tool that would contribute to post-infarction physiological ventricular remodeling. More specifically, re-expression of the WT1 transcription factor in the myocardial wall by ischemia and infarction would be related to the invasion of cells with the capacity for regeneration. This mechanism seems not to be sufficient to restore muscle cells and lost vessels entirely. Of particular interest, the presence of the heat-shock response protein 70 (Hsp70) and its interaction with the vitamin D receptor would modulate the expression of WT1 positively. In this context, it is proposed that the activation of vitamin D receptors associated with Hsp70 could favor physiological cardiac remodeling and reduce the progression to heart failure.

Antiarrhythmic effect linked to melatonin cardiorenal protection involves AT1 reduction and Hsp70-VDR increase.

Lethal ventricular arrhythmias increase in patients with chronic kidney disease that suffer an acute coronary event. Chronic kidney disease induces myocardial remodeling, oxidative stress, and arrhythmogenesis. A manifestation of the relationship between kidney and heart is the concomitant reduction in vitamin D receptor (VDR) and the increase in angiotensin II receptor type 1 (AT1 ). Melatonin has renal and cardiac protective actions. One potential mechanism is the increase in the heat shock protein 70 (Hsp70)-an antioxidant factor. We aim to determine the mechanisms involved in melatonin (Mel) prevention of kidney damage and arrhythmogenic heart remodeling. Unilateral ureteral-obstruction (UUO) and sham-operated rats were treated with either melatonin (4 mg/kg/day) or vehicle for 15 days. Hearts and kidneys from obstructed rats showed a reduction in VDR and Hsp70. Associated with AT1 up-regulation in the kidneys and the heart of UUO rats also increased oxidative stress, fibrosis, apoptosis, mitochondrial edema, and dilated crests. Melatonin prevented these changes and ventricular fibrillation during reperfusion. The action potential lengthened and hyperpolarized in melatonin-treated rats throughout the experiment. We conclude that melatonin prevents renal damage and arrhythmogenic myocardial remodeling during unilateral ureteral obstruction due to a decrease in oxidative stress/fibrosis/apoptosis associated with AT1 reduction and Hsp70-VDR increase.

Heat shock protein 70/nitric oxide effect on stretched tubular epithelial cells linked to WT-1 cytoprotection during neonatal obstructive nephropathy.

BACKGROUND: Mechanical stress is a key pathogenic driver of apoptosis in the tubular epithelium in obstructive nephropathy. Heat shock protein 70 (Hsp70) and Wilms' tumor (WT-1) have been proposed to represent linked downstream effectors of the cytoprotective properties of NO. In the present study, we sought to evaluate whether the cytoprotective effects of L-arginine in neonatal obstructive nephropathy may be associated with NO-dependent increases in WT-1 and Hsp70 expression. METHODS: Neonatal Wistar-Kyoto rats were submitted to complete unilateral ureteral obstruction (UUO) and treated thereafter with vehicle, L-NAME or L-arginine by daily gavage for 14 days to block or augment NO levels, respectively. Normal rat kidney epithelial cells by NRK-52E were exposed to mechanical stress in vitro in the presence or absence of L-NAME, L-arginine, sodium nitroprusside (SNP), L-arginine + SNP or L-arginine/L-NAME. Induction of apoptosis and the mRNA expression of WT-1 and Hsp70 genes were assessed. RESULTS: WT-1 and Hsp70 genes expression decreased in the presence of L-NAME and following UUO coincident with increased tubular apoptosis. L-arginine treatment increased NO levels, reduced apoptosis and restored expression levels of WT-1 and Hsp70 to control levels. L-arginine treatment in vitro reduced basal apoptotic rates and prevented apoptosis in response to mechanical strain, an effect enhanced by SNP co-incubation. L-NAME increased apoptosis and prevented the anti-apoptotic action of L-arginine. CONCLUSIONS: L-arginine treatment in experimental neonatal UUO reduces apoptosis coincident with restoration of WT-1 and Hsp70 expression levels and directly inhibits mechanical strain-induced apoptosis in an NO-dependent manner in vitro. This potentially implicates an NO-Hsp70-WT-1 axis in the cytoprotective effects of L-arginine.

Growing evidence suggests WT1 effects in the kidney development are modulated by Hsp70/NO interaction.

The study of kidney development at the cellular and molecular levels remains an active area of nephrology research. The functional integrity of the kidney depends on normal development as well as on physiological cell turnover. Apoptosis induction is essential for these mechanisms. A route to cell death revealed in the past decade shows that heat shock proteins (HSPs) and their cofactors are responsible for regulating the apoptotic pathway. Specifically, heat shock protein 70 (Hsp70), the most ubiquitous and highly conserved HSP, helps proteins adopt native conformation or regain function after misfolding. Hsp70 is an important cofactor for the function of Wilms' tumour 1 (WT1) and suggests a potential role for this chaperone during kidney differentiation. In addition, we have demonstrated that WT1 expression is modulated by nitric oxide (NO) availability and Hsp70 interaction after neonatal unilateral ureteral obstruction. NO has been identified as playing an important role in the developing kidney. These findings suggest that Hsp70 and NO may play a critical and fundamental role in the capacity to modulate both apoptotic pathway and oxidative stress during kidney development. Furthermore, the design of experimental protocols that assess renal epithelial functionality in this context, could contribute to the understanding of renal development and alterations.

Changes in renal WT-1 expression preceding hypertension development.

BACKGROUND: Hypertension is a public health problem with mostly unknown causes, and where strong hereditary genetic alterations have not been fully elucidated. However, the use of experimental models has provided valuable information. Recent evidences suggest that alterations in key nephrogenic factors, such as Wilms' tumor 1 transcription factor (WT-1), could contribute to the development of hypertension. The aim of this paper is to evaluate the expression of WT-1 and related genes in the nephrogenic process in connection with the development of hypertension as well as the corresponding anatomical and functional correlation. METHODS: Male spontaneously hypertensive and control rats were evaluated weekly from birth until week 8 of life. Their blood pressure was taken weekly using the tail-cuff blood pressure system. Weekly, 5 rats per group were sacrificed with a lethal injection of pentobarbital, and their kidneys were removed, decapsulated and weighed. The serum was collected for measuring biochemical parameters. The results were assessed using one-way analysis of variance for comparisons between groups. RESULTS: The relationship between renal weight/total body weights was established, without significantly different values. These data were compared with apoptosis, fibrosis, number and size of the glomeruli. The elevation of systolic blood pressure was significant since week 6. Biochemical values differed slightly. Histology showed a slight increase in deposits of collagen fibers since week 4. Additionally, in kidney cortices, the expression of WT-1, heat shock protein 70 (Hsp70) and vitamin D receptors (VDR) decreased since week 4. Finally, we demonstrated ultrastructural damage to mitochondria since week 4. CONCLUSIONS: Our results would suggest an unprecedented link, possibly a regulatory mechanism, between WT-1 on nephrogenic alteration processes and their relationship with hypertension. Moreover, and previous to the increase in blood pressure, we demonstrated low expressions of WT-1, VDR and Hsp70 in kidneys from neonatal SHRs. If so, this may suggest that deregulation in the expression of WT-1 and its impact on nephrogenesis induction could be crucial in understanding the development and maintenance of hypertension.

Mediators and mechanisms of heat shock protein 70 based cytoprotection in obstructive nephropathy.

Urinary heat shock protein 70 (Hsp70) is rapidly increased in patients with clinical acute kidney injury, indicating that it constitutes a component of the endogenous stress response to renal injury. Moreover, experimental models have demonstrated that Hsp70 activation is associated with the cytoprotective actions of several drugs following obstruction, including nitric oxide (NO) donors, geranylgeranylacetone, vitamin D, and rosuvastatin. Discrete and synergistic effects of the biological activities of Hsp70 may explain its cytoprotective role in obstructive nephropathy. Basic studies point to a combination of effects including inhibition of apoptosis and inflammation, repair of damaged proteins, prevention of unfolded protein aggregation, targeting of damaged protein for degradation, and cytoskeletal stabilization as primary effectors of Hsp70 action. This review summarizes our understanding of how the biological actions of Hsp70 may affect renal cytoprotection in the context of obstructive injury. The potential of Hsp70 to be of central importance to the mechanism of action of various drugs that modify the genesis of experimental obstructive nephropathy is considered.

Heart remodeling and ischemia-reperfusion arrhythmias linked to myocardial vitamin d receptors deficiency in obstructive nephropathy are reversed by paricalcitol.

Cardiovascular disease is often associated with chronic kidney disease and vice versa; myocardial vitamin D receptors (VDRs) are among the probable links between the 2 disorders. The vitamin D receptor activator paricalcitol protects against some renal and cardiovascular complications. However, the structural and electrophysiological effects of myocardial vitamin D receptor modification and its impact on the response to ischemia-reperfusion are currently unknown. This work attempted to determine whether obstructive nephropathy induced myocardial changes (in rats) linked to vitamin D receptor deficiency and to ventricular arrhythmias in Langendorff-perfused hearts. Unilateral ureteral-obstructed and Sham-operated rats were treated with either paricalcitol (30 ng/kg/d intraperitoneal) or vehicle for 15 days. In 5 hearts from each group, we found that obstructed rats showed a reduction in VDRs and an increase in angiotensin II type 1 receptor expression (messenger RNA and protein), suffered fibrosis (determined by Masson trichrome stain) and myofibril reduction with an increase in mitochondrial size, and had dilated crests (determined by electron microscopy). These changes were reversed by paricalcitol. In 8 additional hearts per group, we found that obstructed rats showed a higher incidence of ventricular fibrillation during reperfusion (after 10 minutes of regional ischemia) than did those treated with paricalcitol. The action potential duration was prolonged throughout the experiment in paricalcitol-treated rats. We conclude that the reduction in myocardial vitamin D receptor expression in obstructed rats might be related to myocardial remodeling associated with an increase in arrhythmogenesis and that paricalcitol protects against these changes by restoring myocardial vitamin D receptor levels and prolonging action potentials.

Vitamin D receptor-modulated Hsp70/AT1 expression may protect the kidneys of SHRs at the structural and functional levels.

Previous hypertension studies have shown that low levels of vitamin D are linked to elevated renin-angiotensin system. The heat shock protein 70 regulates signaling pathways for cellular oxidative stress responses. Hsp70 has been shown to protect against angiotensin II-induced hypertension and exert a cytoprotective effect. Here, we wanted to evaluate whether the vitamin D receptor (VDR) associated with Hsp70/AT1 expression may be involved in the mechanism by which paricalcitol provides renal protection in spontaneously hypertensive rats (SHRs). One-month-old female SHRs were treated for 4 months with vehicle, paricalcitol, enalapril, or a combination of both paricalcitol and enalapril. The following were determined: blood pressure; biochemical parameters; fibrosis; apoptosis; mitochondrial morphology; and VDR, AT1 receptor, and Hsp70 expression in the renal cortex. Blood pressure was markedly reduced by enalapril or the combination but not by paricalcitol alone. However, VDR activation, enalapril or combination, prevented fibrosis, the number of TUNEL-positive apoptotic cells, mitochondrial damage, and NADPH oxidase activity in SHRs. Additionally, high AT1 receptor expression, like low Hsp70 expression (immunohistochemical/immunofluorescence studies), was reversed in the renal cortices of paricalcitol- and/or enalapril-treated animals (SHRs), and these changes were most marked in the combination therapy group. Finally, all of the recovery parameters were consistent with an improvement in VDR expression. Data suggest that Hsp70/AT1 modulated by VDR is involved in the mechanism by which paricalcitol provides renal protection in SHRs. We propose that low AT1 expression through VDR induction could be a consequence of the heat shock response Hsp70-mediated cell protection.