Alessio Tempestini

Aponecrosis: Morphological and biochemical exploration of a syncretic process of cell death sharing apoptosis and necrosis†

A rat fibroblastic cell line (rat‐1/myc‐ER™) was treated with different concentration of Antimycin A, a metabolic poison that affects mitochondrial respiratory chain complex III. The modes of cell death were analyzed by time‐lapse videomicroscopy, in situ end‐labeling (ISEL) technique, and ultrastructural analysis. Intracellular ATP levels were also measured in order to detect whether the energetic stores were determinant for the type of cell death. It was found that while apoptosis was the prevalent cell death in the fibroblasts treated with low doses, 100 or 200 μM Antimycin A, a new type of cell demise that shared dynamic, molecular, and morphological features with both apoptosis and necrosis represents the most common cell death when the cells were exposed to high doses, 300 or 400 μM, of the hypoxic stimulus. This new type of cell death has been chimerically termed aponecrosis. The inhibition of caspase 3, an enzyme critical for the apoptotic DNA degradation, caused a clear shift from aponecrosis to necrosis in the cell culture, suggesting that this new type of cell death could account for an incomplete execution of the apoptotic program and the following degeneration in necrosis. After being treated with higher doses, i.e., 1000 μM Antimycin A, almost all of the cells died by true necrosis. The analysis of the cellular energetic stores showed that the levels of ATP were a primary determinant in directing toward active cell death (apoptosis), aponecrosis, or necrosis. We conclude that chemically induced hypoxia produces different types of cell death depending on the intensity of the insult and on the ATP availability of the cell, and that the classic apoptosis and necrosis may represent only two extremes of a continuum of intermediate forms of cell demise. J. Cell. Physiol. 182:41–49, 2000.

Flow‐Mediated Vasodilation and Carotid Intima‐Media Thickness in Systemic Sclerosis

Abstract:  Increased evidence suggests an accelerated macrovascular disease in systemic sclerosis (SSc). Brachial artery flow‐mediated vasodilation (FMD) and carotid intima‐media thickness (IMT) are two indicators of subclinic cardiovascular disease and are frequently used as surrogate measures of subclinic atherosclerosis. The aim of this study was to evaluate macrovascular involvement in SSc. We studied 35 SSc patients (6 males and 29 females; 11 with diffuse and 24 with limited disease) and 20 healthy controls. Brachial artery FMD was assessed by method described by Celermajer in all patients and 13 control subjects. IMT was measured using high‐resolution B‐mode ultrasonography in patients and controls. Traditional risk factors for atherosclerosis (hypertension, dyslipidemia, and smoke) were also assessed. FMD was significantly impaired (3.41%± 4.56% versus 7.66%± 4.24%; P < 0.037) and IMT was significantly elevated compared with healthy controls (0.93 ± 0.29 mm versus 0.77 ± 0.13 mm; P < 0.005). FMD was not significantly different in SSc with increased IMT compared with those with normal IMT). No correlation was found between risk factors for atherosclerosis and the impairment of FMD or IMT in SSc patients. The impairment of endothelial function and structural changes of large vessels are evident in SSc, but do not seem associated with traditional risk factors for atherosclerosis. Prospective studies including also clinical outcomes are needed to assess the features and significance of macrovacular involvement in SSc.

Systemic amyloidosis: a challenge for the rheumatologist

Amyloidosis comprises a group of diseases characterized by the extracellular deposition of insoluble fibrillar proteins. This mechanism generates different clinical syndromes depending on the site and extent of organ involvement. Amyloidosis is classified into categories of systemic and localized disease. Systemic amyloidosis is further subdivided into a hereditary familial form (for example, ATTR amyloidosis), a reactive form (AA amyloidosis), dialysis-related (Aβ2M) amyloidosis and immunoglobulin light chain (AL) amyloidosis. Treatment can be symptomatic, directed at the affected organ, or can be directed at reducing the production of the abnormal proteins with different strategies. Despite advances in treatment, the prognosis is still poor and depends on the underlying disease as well as the type and degree of dysfunction in involved organs. Early diagnosis is essential because patients with advanced disease are generally unable to undergo intensive therapy. Patients with systemic amyloidosis often present to a rheumatologist not only because the disease can include musculoskeletal and articular symptoms but also because it can be associated with chronic rheumatic diseases. This Review discusses the clinical features of amyloidosis and its rheumatic manifestations. The various types of amyloidosis, as well their prognosis and treatment, are also presented.

Exercise Doppler Echocardiography Identifies Preclinic Asymptomatic Pulmonary Hypertension in Systemic Sclerosis

Abstract:  In systemic sclerosis (SSc), the involvement of the interstitium or vascular system of the lung may lead to pulmonary arterial hypertension (PAH). PAH is often asymptomatic or oligosymptomatic in early SSc and, when it becomes symptomatic, pulmonary vascular system is already damaged. Exercise echocardiography (ex‐echo), measuring pulmonary artery pressure (PAP) during exercise and allowing to differentiate physiologic from altered PAP responses, may identify subclinical PAH. Our aims were (a) to evaluate by ex‐echo the change of PAP in patients with SSc without lung involvement; and (b) to correlate PAP during exercise (ex‐PAP) values to clinical and biohumoral parameters of PAH. Twenty‐seven patients with limited SSc (lSSc) without interstitial lung involvement were studied. Patients underwent rest and exercise two‐dimensional and Doppler echocardiography by supine cycloergometer. Systolic PAP was calculated using the maximum systolic velocity of the tricuspid regurgitant jet at rest and during exercise values of systolic PAP exceeding 40 mmHg at ex‐echo were considered as abnormal, and biohumoral markers potentially related to PAH were assessed. Eighteen of 27 SSc patients presented an ex‐PAP >40 mmHg, while in 9 of 27 patients ex‐PAP values remained <40 mmHg (48.8 ± 4.5 mmHg versus 36.2 ± 3.1 mmHg; P < 0.001). Other echocardiographic and ergometric parameters, clinical tests, and biohumoral markers were not different in the two groups. Ex‐PAP significantly correlated with D‐dimer (P= 0.0125; r2= 0.2029). Ex‐echo identifies a cluster of SSc patients with subclinical PAH that may develop PAH. This group should be followed up and may be considered for specific therapies to prevent disease evolution.

Melatonin is a safe and effective treatment for chronic pulmonary and extrapulmonary sarcoidosis

Abstract:   Chronic sarcoidosis (CS) is often unresponsive to usual treatments. Melatonin, an immunoregulatory drug, was employed in CS patients in whom usual treatments were ineffective or induced severe side effects. Melatonin was given for 2 yr (20 mg/day in the first year, 10 mg/day in the second year) to 18 CS patients. Pulmonary function tests, chest X rays, pulmonary computed tomography, Ga67 scintigraphy and angiotensin‐converting enzyme (ACE) were assayed at baseline and in the follow‐up. Normalization of ACE, improvement of pulmonary parameters and resolution of skin involvement were found in the patients given melatonin. After 24 months of melatonin therapy, hylar adenopathy completely resolved in eight patients and parenchymal lesions were markedly improved in all patients; in the five patients with reduced diffusion capacity of the lung for carbon monoxide, the values normalized after 6 months of therapy and remained stable until month 24. After 24 months, Ga67 pulmonary and extra‐pulmonary uptake was totally normalized in seven patients and, at month 12 months, ACE was normalized in six patients in which the values were high at the baseline. Skin lesions, present in three patients, completely disappeared at month 24 months. No side effects were experienced and no disease relapse was observed during melatonin treatment. Melatonin may be an effective and safe therapy for CS when other treatments fail or cause side effects.

Downregulation of bcl-2 expression in lymphoma cells by bcl-2 ARE-targeted modified, synthetic ribozyme

Synthetic ribozymes are catalytic RNA molecules designed to inhibit gene expression by cleaving specific mRNA sequences. We investigated the potential of synthetic ribozymes to inhibit bcl-2 expression in apoptosis defective bcl-2 overexpressing tumors. A chemically stabilized hammerhead ribozyme has been targeted to the A+U-rich regulative element of bcl-2 mRNA that is involved in bcl-2 gene switch-off during apoptosis. The design of the ribozyme was based on the results of probing accessibility of the RNA target in cellular extracts with antisense DNA. The ribozyme was lipotransfected to a bcl-2 overexpressing human lymphoma cell line (Raji). The cellular uptake of this ribozyme resulted in a marked reduction of both bcl-2 mRNA and BCL-2 protein levels and dramatically increased cellular death by apoptosis. Our results suggest a potential therapeutic application of such ribozyme for the treatment of bcl-2 overexpressing tumors.

Reduced circulating levels of angiotensin-(1–7) in systemic sclerosis: a new pathway in the dysregulation of endothelial-dependent vascular tone control

Objective: Systemic sclerosis (SSc) impairs endothelium-dependent vasodilatation. Among angiotensin I (Ang I)-derived compounds, vasoconstrictor angiotensin II (Ang II) and vasodilator angiotensin-(1–7) (Ang-(1–7)), cleaved from ACE and neutral endopeptidase (NEP) 24.11, respectively, play an important role in vascular tone regulation. Ang-(1–7) may act independently or by activating other vasodilating molecules, such as nitric oxide (NO) or prostaglandin I2 (PGI2). Our aim was to assess, in patients with SSc, circulating levels of Ang I, Ang II and Ang-(1–7), with their metabolising enzymes ACE and NEP, and levels of NO and PGI2, and to correlate them to the main characteristics of SSc. Methods: Levels of Ang I, Ang II, Ang-(1–7), NEP, ACE, NO and PGI2 were measured in 32 patients with SSc, who were also assessed for humoral and clinical characteristics, and 55 controls. Results: Plasma Ang I, Ang II and Ang-(1–7) levels were lower in patients with SSc than in controls (p<0.001in all cases). When Ang II and Ang-(1–7) levels were expressed as a function of the available Ang I, lower Ang-(1–7) levels in patients with SSc than in controls were confirmed (p<0.001), while no difference was found for Ang II levels. In patients with SSc, the Ang II/Ang-(1–7) ratio indicated a prevalence of Ang II over Ang-(1–7), while in controls Ang-(1–7) was prevalent (p<0.001). Levels of ACE, NEP, NO and PGI2 were lower in patients with SSc than in controls (p<0.05 in all cases). Conclusion: In patients with SSc, prevalence of the vasoconstricting Ang II over the vasodilator Ang-(1–7) suggests a dysfunction of the angiotensin-derived cascade that may contribute to dysregulation of vascular tone.

Circadian phase difference of leptin in android versus gynoid obesity

A circadian rhythm in serum leptin, measured every 4 h for 24 h, characterizes normal-weight women (N = 14), and women with gynoid (N = 17) or android (N = 26) obesity, peaking around midnight (P < 0.05), but differing by about 3 h between android and gynoid women (P < 0.01). Obesity is associated with a higher MESOR (rhythm-adjusted mean; P < 0.001) and a smaller relative circadian amplitude (P < 0.05). Gynoid obesity is associated with a larger circadian amplitude of cortisol (P < 0.05), whereas android obesity is associated with a larger circadian amplitude and a higher MESOR of insulin (P < 0.05). Understanding putative mechanisms underlying different body fat distribution may lead to improved chronotherapeutic measures.

Therapeutic challenges for systemic sclerosis: facts and future targets.

Abstract:  Pulmonary arterial hypertension (PAH) is an important cause of death in systemic sclerosis (SSc), despite the improvement of therapies. An early diagnosis and the use of drugs interfering with the main pathogenic pathways of PAH is pivotal for the improvement of prognosis in primary PAH and PAH secondary to autoimmune rheumatic diseases, mainly SSc. Lately, new specific therapies have been developed targeting prostacyclin, endothelin, and nitric oxide pathways, the major pathogenic pathways leading to endothelial dysfunction in PAH. Epoprostenol improved life expectancy of patients with primary and secondary PAH, but its continuous intravenous administration requires experienced centers. More stable analogues of prostacyclin, administrated by intravenous (iloprost, treprostinil), subcutaneous, inhalatory (treprostinil, iloprost), and oral route (Beraprost) have shown efficacy in PAH. Bosentan, the first oral endothelin receptor antagonist (with affinity for endothelin A and B receptors) improves exercise function and survival in PAH, both primary and secondary to autoimmune rheumatic diseases. This is confirmed also for Sitaxsentan and Ambrisentan, selective A receptor antagonists. Because of its short half‐life and systemic side effects, short‐term NO inhalation is used only in short‐term management of PAH in critically ill adults. Inhibitors of NO degradation, such as sildenafil, a phosphodiesterase (PDE) type 5 inhibitor, improved functional and hemodynamic parameters without significant side effects. Vardenafil and taladafil, longer‐acting PDE inhibitors, also have vascular pulmonary selectivity. All these drugs may be used in combination, to maximize their clinical benefit not only in patients unresponsive to single drugs, but also potentially as initial therapy of PAH.

Impact of Targeting the Adenine- and Uracil-Rich Element of bcl-2 mRNA with Oligoribonucleotides on Apoptosis, Cell Cycle, and Neuronal Differentiation in SHSY-5Y Cells

We have identified previously a destabilizing adenine- and uracil-rich element (ARE) in the 3′-UTR of bcl-2 mRNA that interacted with ARE-binding proteins to down-regulate bcl-2 gene expression in response to apoptotic stimuli. We have also described three contiguous 2′-O-methyl oligoribonucleotides (ORNs) in both sense and antisense orientation with respect to the bcl-2 ARE that are able to regulate the bcl-2 mRNA half-life and Bcl-2 protein level in two different cell lines. Here we show that treatment of neuronal cell line (SHSY-5Y) with antisense ORNs targeting the bcl-2 ARE (bcl-2 ARE asORNs) prevents bcl-2 down-regulation in response to apoptotic stimuli with glucose/growth factor starvation (Locke medium) or oxygen deprivation and enhances the apoptotic threshold as evaluated by time-lapse videomicroscopy, fluorescence-activated cell sorting analysis, and caspase-3 activation. Additional effects of bcl-2 ARE asORNs included inhibition of cell cycle entry and a marked increase of cellular neurite number and length, a hallmark of neuronal differentiation resulting from bcl-2 up-regulation. The ability of bcl-2 ARE asORNs to enhance the apoptotic threshold and to induce neuronal differentiation implies their potential application as a novel informational tool to protect cells from ischemic damage and to prevent neuronal degeneration.