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-1β (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.

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.

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 ​= ​10 per group), with/without treatment with nf-AEA (obtained by electrospraying) at a weekly dose of 5 ​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.

Vitamin D-mitochondria cross-talk could modulate the signaling pathway involved in hypertension development: a translational integrative overview

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.

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.

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.

Implications of the transcription factor WT1 linked to the pathologic cardiac remodeling post-myocardial infarction

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.

The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation

Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

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.

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.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0250-6) contains supplementary material, which is available to authorized users.

Inactivation of urease by 1,4-benzoquinone: chemistry at the protein surface

The high activity of urease, a Ni(ii) enzyme, has several adverse effects on human health and agriculture, and its modulation needs the use of inhibitors.

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.

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.

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.

Abstract 450: Cardiac Electrophysiological Changes Linked to Vitamin D Receptors Deficiency in Obstructive Nephropathy

Background: Chronic kidney disease is highly prevalent and is associated with cardiovascular disease. Paricalcitol protects individuals from some of the renal and cardiovascular complications associated with kidney disease. However, its electrophysiological effect during myocardial ischemia-reperfusion is currently unknown.

Aims: Using an obstructive nephropathy (ON) model, we plan to investigate the potential, structural, and functional changes of the heart that are linked to vitamin D deficiency.

Methods: The ureters of adult rats (n = 10) were unilaterally obstructed. An inductor of the vitamin D receptor (VDR) was administered for 15 days (30ng/Kg/day, ip). We evaluated histological, molecular, and biochemical parameters, as well, cardiac electrophysiological activity with ischemia-reperfusion protocol.

Results: we found changes in the action potential duration (APD) at 90% (* P<0.05 vs. C, +P<0.05 vs. O). The analysis revealed arrhythmias, ventricular tachycardia (VT), and ventricular fibrillation (VF). Arrhythmias were quantified in the following ways: 0 − sinus rhythm, 1 – premature ventricular complex, 2 - salvos, 3 - no sustained VT, and 4 – sustained VT or VF (>30 seconds). * P<0.05 vs. C, +P<0.05 vs. O. Of interest was the finding that appears to prolong Pari ischemia DPA in both the controls and the obstructed animals. Also, a significant bradycardia was established in the ischemic phase of the animals obstructed with Pari, which reversed completely during reperfusion. In hearts from ON model animals, we found high AT 1 expression and marked low VDR expression; these changes were reversed by paricalcitol treatment.

Conclusions: The reduction of VDR expression in ON hearts could be related to increased arrhythmogenesis. The recovery induced by paricalcitol could protect against ventricular fibrillation by the lengthening of the action potential. Further studies will be necessary to elucidate these interesting kidney-heart interactions.

Caveolin-1-eNOS/Hsp70 interactions mediate rosuvastatin antifibrotic effects in neonatal obstructive nephropathy

Evidence suggesting that statins may contribute to renoprotection has been provided in experimental and clinical studies. Statins restore endothelial nitric oxide (NO) levels by mechanisms including up-regulation of endothelial NO synthase (eNOS) expression. Caveolin-1/eNOS interaction is essential preventing inadequate NO levels. Here, we evaluated whether caveolin-1 associated with eNOS/Hsp70 expression may be involved in the mechanism by which rosuvastatin exerts tubulointerstitial fibrosis protection in neonatal unilateral ureteral obstruction (UUO). Neonatal rats subjected to UUO within 2 days of birth and controls were treated daily with vehicle or rosuvastatin (10 mg/kg/day) by oral gavage for 14 days. After UUO, morphometric evaluation of interstitial fibrosis showed increased interstitial volume (Vv) associated with reduced NO availability, increased mRNA and protein caveolin-1 expression as well as downregulation eNOS and heat shock protein 70 (Hsp70) expression. Conversely, rosuvastatin treatment attenuated the fibrotic response linked to high NO availability, decreased mRNA and protein caveolin-1 expression, and marked upregulation of eNOS and Hsp70 expression at transcriptional and posttranscriptional levels. Moreover, protein-protein interactions determined by immunoprecipitation and by immunofluorescence co-localization have shown decreased caveolin-1/eNOS as well as increased Hsp70/eNOS interaction, after rosuvastatin treatment. A dose dependent effect of rosuvastatin on decreased caveolin-1 expression was shown in control cortex. In conclusion, our data suggest that statins contribute to the protection against tubulointerstitial fibrosis injury in neonatal early kidney obstruction by increased NO availability, involving interaction of up-regulated eNOS/Hsp70 and down-regulated caveolin-1.

Role of mitochondria in paricalcitol-mediated cytoprotection during obstructive nephropathy

Vitamin D slows the progression of chronic kidney disease. Furthermore, activators of vitamin D receptors (VDR) have suppressant effects on the renin-angiotensin system, as well as anti-inflammatory and antifibrotic actions. This study aimed to evaluate the cytoprotective effects of paricalcitol, a VDR activator, at the mitochondrial level using an obstructive nephropathy model [unilateral ureteral obstruction (UUO)]. Rats subjected to UUO and controls were treated daily with vehicle or paricalcitol. The control group underwent a sham surgery. The treatment was done for 15 days (30 ng/kg). The following were determined: biochemical parameters; fibrosis; apoptosis; mitochondrial morphology; VDR, AT(1) receptor, and NADPH oxidase 4 expression; and NADPH oxidase activity (in total and in mitochondrial fractions from the renal cortex). VDR activation prevented fibrosis (20 ± 5 vs. 60 ± 10%) and the number of TUNEL-positive apoptotic cells (10 ± 3 vs. 25 ± 4) in UUO. Biochemical, histological, and molecular studies suggest mitochondrial injury. Electron microscopy revealed in UUO electronically luminous material in the nucleus. Some mitochondria were increased in size and contained dilated crests and larger than normal spaces in their interiors. These changes were not present with paricalcitol treatment. Additionally, high AT(1)-receptor mRNA and NADPH activity was reverted in mitochondrial fractions from obstructed paricalcitol-treated animals (0.58 ± 0.06 vs. 0.95 ± 0.05 relative densitometry units and 9,000 ± 800 vs. 15,000 ± 1,000 relative fluorescence units·μg protein(-1)·min(-1), respectively). These changes were consistent with an improvement in VDR expression (0.75 ± 0.05 vs. 0.35 ± 0.04 relative densitometry units). These results suggest that paricalcitol confers a protective effect and reveal, as well, a possible AT(1) receptor-dependent protective effect that occurs at the mitochondrial level.

WT-1 mRNA expression is modulated by nitric oxide availability and Hsp70 interaction after neonatal unilateral ureteral obstruction

Wilms tumor gene 1 (wt-1), a key regulator of mesenchymal-epithelial transformation, is downregulated during congenital obstructive nephropathy, leading to apoptosis. There is a functional interaction between WT-1 and inducible nitric oxide synthase (iNOS). In this regard, we reported that after neonatal unilateral ureteral obstruction, rosuvastatin prevents apoptosis through an increase in nitric oxide bioavailability, which in turn is linked to higher Hsp70 expression. Hence, the goal of this study was to determine whether a nitric oxide/Hsp70 interaction is involved in changes in WT-1 mRNA expression after ureteral obstruction. Neonatal rats submitted to experimental ureteral obstruction were treated with either vehicle or rosuvastatin for 14 days. Decreased nitric oxide and iNOS/Hsp70 expression associated with WT-1 low expression was shown in obstructed kidneys. Apoptosis was induced and it was associated with an increased Bax/BcL2 ratio. Conversely, iNOS/Hsp70 upregulation and an increased WT-1 mRNA expression, without an apoptotic response, were observed in the cortex of obstructed kidneys of rosuvastatin-treated rats. Nitric oxide also modulated Hsp70 and WT-1 mRNA expression in MDCK cells. Finally, in vivo experiments with nitric oxide modulators support our hypothesis that WT-1 mRNA expression is associated with nitric oxide level. Results suggest that rosuvastatin may modulate WT-1 mRNA expression through renal nitric oxide bioavailability, preventing neonatal obstruction-induced apoptosis associated with Hsp70 interaction.

eNOS/Hsp70 interaction on rosuvastatin cytoprotective effect in neonatal obstructive nephropathy

There is growing evidence that statins may exert renoprotective effects beyond cholesterol reduction. The cholesterol-independent or "pleiotropic" effects of statins include the upregulation of endothelial nitric oxide synthase (eNOS). Here we determined whether eNOS associated with Hsp70 expression is involved in rosuvastatin resistance to obstruction-induced oxidative stress and cell death. Neonatal rats subjected to unilateral ureteral obstruction (UUO) within two days of birth and controls were treated daily with vehicle or rosuvastatin (10 mg/kg/day) for 14 days. Decreased endogenous nitric oxide (NO) and lower mRNA and protein eNOS expression associated with downregulation of heat shock factor 1 (Hsf1) mRNA and Hsp70 protein levels were observed in the obstructed kidney cortex. Increased nicotinamide adenine dinucleotide phosphate (NADHP) oxidase activity and apoptosis induction, regulated by mitochondrial signal pathway through an increased pro-apoptotic Bax/BcL(2) ratio and caspase 3 activity, were demonstrated. Conversely, in cortex membrane fractions from rosuvastatin-treated UUO rats, marked upregulation of eNOS expression at transcriptional and posttranscriptional levels linked to increased Hsf1 mRNA expression and enhanced mRNA and protein Hsp70 expression, were observed. Consequently, there was an absence of apoptotic response and transiently decreased NADPH oxidase activity. In addition, interaction between eNOS and Hsp70 was determined by communoprecipitation in cortex membrane fractions, showing an increased ratio of both proteins, after rosuvastatin treatment in obstructed kidney. In summary, our data demonstrate that the effect of rosuvastatin on eNOS interacting with Hsp70, results in the capacity of both to prevent mitochondrial apoptotic pathway and oxidative stress in neonatal early kidney obstruction.

Predictive indexes of nocturnal desaturation in COPD patients not treated with long term oxygen therapy

Nocturnal oxygen desaturation during the sleep is very frequent in patients affected by chronic obstructive pulmonary disease (COPD). Hypoventilation, rather than sleeping apnea, is commonly considered as the most relevant factor in the onset of nocturnal oxygen desaturation. On this topic, the Authors have carried on a study on the nocturnal hypoxemia in 70 hospitalized COPD patients with a mean FEV1% of 40 +/- 21 and a mean PaO2 of 67.7 +/- 6.1. Anthropometric features (sex, age, body mass index) and functional respiratory parameters (FEV1, FEV1/VC, PaO2, PaCO2, SaO2, pH) were considered. Moreover all the patients were monitorized with transcutaneous pulse oxymetry, while breathing environmental air, in nighttime. Mean oxyhemoglobinic nocturnal saturation (SaO2 noct.%), minimum registered value of nocturnal SaO2 (min SaO2 noct.%) and the minutes of nighttime SaO2 < or = 90% and < or = 85% (tSaO2 < or = 90% e < or = 85%) were considered. Fiftyfour patients (77.15%) were nocturnal desaturating (NOD), whereas 16 (22.85%) were not desaturating (nNOD). A statistically significant difference was found between the two groups as to the values of FEV1 (p < 0.05), PaCO2, pH, SaO2 noct.%, minimum SaO2 noct.% and tSaO2 < or = 90% and < or = 85% (p < 0.0001). A statistically significant correlation was found between tSaO2 < 90% and BMI (r = 0.44), PaCO2 (r = 0.48) and pH (r = -0.44), as well as between tSaO2 < 85% and PaCO2 (r = 0.57) and pH (r= -0.50), between SaO2 noct.% and BMI (r = -0.45), PaCO2 (r = -0,50), FEV1 (r = 0.44) and pH (r = 0.46) and finally between minimum SaO2 noct.% and PaCO2 (r = -0.47) was found. Eighty percent of the NOD patients had PaO2 < 75 mm Hg and PaCO2 > 44 mm Hg. All the patients with PaCO2 > 50 mm Hg were NOD. In conclusion, all COPD subjects with FEV1 < 49% and daytime PaO2 > 60 mm Hg, particularly when associated to elevated PaCO2 values and high BMI, should undergo a nocturnal pulse oxymetry in order to identify possible nocturnal desaturations. In these patients reduced FEV1, high BMI and/or elevated PaCO2 appear to be predictive indexes of nocturnal desaturation. A PaCO2 > 50 mm Hg is highly indicative for a nocturnal oxygen desaturation.

[Amiodarone pulmonary toxicity]

The Authors discuss a case of amiodarone pulmonary toxicity, with simultaneous alveolar and interstitial infiltrates, in a female patient 75 years old, who took the drug for 6 months at a low dosage (200 mg/daily for 5 days a week). It is outlined that the diagnosis can be achieved only by exclusion of other aetiologies, since clinical and diagnostic features are not pathognomonic for such disease. The withdrawal of the drug and the administration of the steroid therapy determined a fast improvement of the clinical and radiological appearance.

Drug-resistance of Mycobacterium tuberculosis in time

Tuberculosis is heavily worldwide spreading in the last years. More and more signalations seem to indicate that the incidence of drug-resistant Mycobacteria is increasing in almost all industrialized countries. The authors have carried on a study on the percentage of drug-resistant strains of Mycobacterium Tuberculosis (MT) among isolates from patients affected by active pulmonary tuberculosis hospitalized through the years 1992-94. Out of 59 isolates of MT, 20.3% were drug-resistant: 25% of them to 2 drugs and 16.6% to 3 or more drugs. Resistance to single drug was so distributed: Streptomycin 11.8%, Isoniazid 6.7%, Rifampycin 3.4%, Ethambutol 6.7%, Ansamycin 3.4%, Pyrazinamide 5.0%, Ethionamide 1.7%. These results were confronted with analogous data on MT drug-resistance collected in the same hospital division in the years 1978-82 and 1985-87. The data analysis shows that actual incidence of drug resistant strains of MT is only slightly decreased but quite similar to that observed in 1978-82, except for Ethambutol, while there is a remarkable reduction vs. 1985-87; in that period, in fact, the highest incidence of drug resistance was recorded. The authors' conclusion is that only little differences were observed in the total amount of resistant strains of MT through 20 years; they also outline that resistance to Ansamycin, most recent out of all tested drugs, is quite similar to that observed for Rifampycin, that is chemically analogous.

Post-tuberculosis chronic empyema of the "forty years after"

The authors present 110 cases of patients hospitalized in the last 5 years, with long-term disabling sequelae of pulmonary tuberculosis. Twelve out of them (= 10.9%) suffered from post-tuberculous chronic empyema, with an average latency period of 44.83 years between the acute tuberculous illness and the clinical manifestation of the empyema. Nine of the patients had been treated with collapsotherapy, induced by artificial intrapleural pneumothorax, 1 with thoracoplasty, and 2 only with late and inadequate anti-mycobacterial chemotherapy. Eleven patients (91.6%) also had a cutaneous fistula (7 cases) and/or a bronchopleural fistula (4 cases). The authors show how the issue of tuberculous sequelae is a significant not only from the numerical standpoint, but also for the seriousness of the caused pathological conditions, often posing problems for differential diagnosis. Moreover, they stress how tuberculosis should never be neglected or considered last in the differential diagnosis of empyema and pyopneumothorax.