Inositol 1,4,5-trisphosphate receptor type 3 is involved in resistance to apoptosis and maintenance of human hepatocellular carcinoma

The expression of the inositol 1,4,5-trisphosphate receptor type 3 (ITRP3) in hepatocytes is a common event in the pathogenesis of hepatocellular carcinoma (HCC), regardless of the type of underlying liver disease. However, it is not known whether ITPR3 expression in hepatocytes is involved in tumor maintenance. The aim of the present study was to determine whether there is an association between ITPR3 expression and clinical and morphological parameters using HCC samples obtained from liver explants from patients (n=53) with different etiologies of underlying chronic liver disease (CLD). ITPR3 expression, mitosis and apoptosis were analyzed in human liver samples by immunohistochemistry. Clinical and event-free survival data were combined to assess the relationship between ITPR3 and liver cancer growth in patients. RNA sequencing analysis was performed to identify apoptotic genes altered by ITPR3 expression in a liver tumor cell line. ITPR3 was highly expressed in HCC tumor cells relative to adjacent CLD tissue and healthy livers. There was an inverse correlation between ITPR3 expression and mitotic and apoptotic indices in HCC, suggesting that ITPR3 contributed to the maintenance of HCC by promoting resistance to apoptosis. This was confirmed by the upregulation of CTSB, CHOP and GADD45, genes involved in the apoptotic pathway in HCC. The expression of ITPR3 in the liver may be a promising prognostic marker of HCC.

Alkaloid and acetogenin-rich fraction from Annona crassiflora fruit peel inhibits proliferation and migration of human liver cancer HepG2 cells

Plant species from Annonaceae are commonly used in traditional medicine to treat various cancer types. This study aimed to investigate the antiproliferative potential of an alkaloid and acetogenin-rich fraction from the fruit peel of Annona crassiflora in HepG2 cells. A liquid-liquid fractionation was carried out on the ethanol extract of A. crassiflora fruit peel in order to obtain an alkaloid and acetogenin-rich fraction (AF-Ac). Cytotoxicity, proliferation and migration were evaluated in the HepG2 cells, as well as the proliferating cell nuclear antigen (PCNA), vinculin and epidermal growth factor receptor (EGFR) expression. In addition, intracellular Ca2+ was determined using Fluo4-AM and fluorescence microscopy. First, 9 aporphine alkaloids and 4 acetogenins that had not yet been identified in the fruit peel of A. crassiflora were found in AF-Ac. The treatment with 50 μg/mL AF-Ac reduced HepG2 cell viability, proliferation and migration (p < 0.001), which is in accordance with the reduced expression of PCNA and EGFR levels (p < 0.05). Furthermore, AF-Ac increased intracellular Ca2+ in the HepG2 cells, mobilizing intracellular calcium stores, which might be involved in the anti-migration and anti-proliferation capacities of AF-Ac. Our results support the growth-inhibitory potential of AF-Ac on HepG2 cells and suggest that this effect is triggered, at least in part, by PCNA and EGFR modulation and mobilization of intracellular Ca2+. This study showed biological activities not yet described for A. crassiflora fruit peel, which provide new possibilities for further in vivo studies to assess the antitumoral potential of A. crassiflora, especially its fruit peel.

Inositol 1,4,5-trisphosphate receptor type 3 plays a protective role in hepatocytes during hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury is seen in a variety of clinical conditions, including hepatic thrombosis, systemic hypotension, and liver transplantation. Calcium (Ca²⁺) signaling mediates several pathophysiological processes in the liver, but it is not known whether and how intracellular Ca²⁺ channels are involved in the hepatocellular events secondary to ischemia-reperfusion. Using an animal model of hepatic ischemia-reperfusion injury, we observed a progressive increase in expression of the type 3 isoform of the inositol trisphosphate receptor (ITPR3), an intracellular Ca²⁺ channel that is not normally expressed in healthy hepatocytes. ITPR3 expression was upregulated, at least in part, by a combination of demethylation of the ITPR3 promoter region and the increased transcriptional activity of the nuclear factor of activated T-cells (NFAT). Additionally, expression of pro-inflammatory interleukins and necrotic surface area were less pronounced in livers of control animals compared to liver-specific ITPR3 KO mice subjected to hepatic damage. Corroborating these findings, ITPR3 expression and activation of NFAT were observed in hepatocytes of liver biopsies from patients who underwent liver ischemia caused by thrombosis after organ transplant. Together, these results are consistent with the idea that ITPR3 expression in hepatocytes plays a protective role during hepatic injury induced by ischemia-reperfusion.

Expression of the type 3 inositol 1, 4, 5-trisphosphate receptor according to the chronic liver disease etiology in hepatocellular carcinoma

e16604

Background: The expression of type 3 isoform of the inositol 1, 4, 5-trisphosphate receptor (ITPR-3), an intracellular calcium (Ca2+) channel reported in liver cancer cells, is important in the Ca2+ signalling. Thus, it may be involved in the many events of hepatocarcinogenesis. Here, we investigated the ITPR-3 expression in hepatocellular carcinoma (HCC) and its association with clinicopathological parameters and long-term outcomes, according to the etiology of underlying chronic liver disease (CLD). Methods: Clinical and laboratory data from patients (n = 53) who underwent orthotopic liver transplantation for HCC treatment in a Brazilian referral center were retrospectively collected. After pathological reviewing of their explanted liver samples, ITPR-3 expression in both tumor and underlying cirrhosis were assessed by immunohistochemistry, and quantified using density histograms in the ImageJ software. Event (tumor recurrence or death from any cause) occurrence and event-free survival (EFS) were analysed. Results: Hepatitis C virus (HCV) (n = 31), alcohol abuse (n = 16) and cryptogenic cirrhosis (n = 6) were the underlying CLD etiology, and the groups were, in general, well balanced regarding clinicopathological indices. Median EFS was 78.9 months (range, 63.6-94.1). The ITPR-3 expression profile was cytoplasmatic, predominantly perinuclear, and was stronger in tumor than in adjacent cirrhosis, considering all etiologies together (intensity 9.1% higher in tumors, p < 0.001) However, analyzing each etiologic group, the cryptogenic was the only one in which there was no difference between tumor and underlying CLD. Comparing the ITPR-3 expression only in tumors, there was no difference regarding the etiology of CLD. The tumor ITPR-3 higher intensity was correlated with higher serum aspartate alanine-transferases (ALT) levels (p = 0.018) and lower mitotic index ( < 5 per 10 high power fields) (p = 0.009). There was no association between receptor expression and event occurrence or EFS. Conclusions: The ITPR-3 was expressed in HCC, regardless of the underlying CLD etiology. Its correlation with mitotic index, a cell proliferation marker, was demonstrated, but there were no associations with clinical outcomes. Apart from cryptogenic cirrhosis, ITPR-3 expression was more intense in tumors than in underlying cirrhosis. These findings suggest that ITPR-3 could have a role in carcinogenesis. However, the prognostic and therapeutic implications need to be investigated.

Molecular Mechanism for Protection Against Liver Failure in Human Yellow Fever Infection

Yellow fever (YF) is a viral hemorrhagic fever that typically involves the liver. Brazil recently experienced its largest recorded YF outbreak, and the disease was fatal in more than a third of affected individuals, mostly because of acute liver failure. Affected individuals are generally treated only supportively, but during the recent Brazilian outbreak, selected patients were treated with liver transplant. We took advantage of this clinical experience to better characterize the clinical and pathological features of YF-induced liver failure and to examine the mechanism of hepatocellular injury in YF, to identify targets that would be amenable to therapeutic intervention in preventing progression to liver failure and death. Patients with YF liver failure rapidly developed massive transaminase elevations, with jaundice, coagulopathy, thrombocytopenia, and usually hepatic encephalopathy, along with pathological findings that included microvesicular steatosis and lytic necrosis. Hepatocytes began to express the type 3 isoform of the inositol trisphosphate receptor (ITPR3), an intracellular calcium (Ca2+) channel that is not normally expressed in hepatocytes. Experiments in an animal model, isolated hepatocytes, and liver-derived cell lines showed that this new expression of ITPR3 was associated with increased nuclear Ca2+ signaling and hepatocyte proliferation, and reduced steatosis and cell death induced by the YF virus. Conclusion: Yellow fever often induces liver failure characterized by massive hepatocellular damage plus steatosis. New expression of ITPR3 also occurs in YF-infected hepatocytes, which may represent an endogenous protective mechanism that could suggest approaches to treat affected individuals before they progress to liver failure, thereby decreasing the mortality of this disease in a way that does not rely on the costly and limited resource of liver transplantation.

Polymorphism in the Promoter Region of NFE2L2 Gene Is a Genetic Marker of Susceptibility to Cirrhosis Associated with Alcohol Abuse

Alcoholic liver disease (ALD) is a highly prevalent spectrum of pathologies caused by alcohol overconsumption. Morbidity and mortality related to ALD are increasing worldwide, thereby demanding strategies for early diagnosis and detection of ALD predisposition. A potential candidate as a marker for ALD susceptibility is the transcription factor nuclear factor erythroid-related factor 2 (Nrf2), codified by the nuclear factor erythroid 2-related factor 2 gene (NFE2L2). Nrf2 regulates expression of proteins that protect against oxidative stress and inflammation caused by alcohol overconsumption. Here, we assessed genetic variants of NFE2L2 for association with ALD. Specimens from patients diagnosed with cirrhosis caused by ALD were genotyped for three NFE2L2 single nucleotide polymorphisms (SNP) (SNPs: rs35652124, rs4893819, and rs6721961). Hematoxylin & eosin and immunohistochemistry were performed to determine the inflammatory score and Nrf2 expression, respectively. SNPs rs4893819 and rs6721961 were not specifically associated with ALD, but analysis of SNP rs35652124 suggested that this polymorphism predisposes to ALD. Furthermore, SNP rs35652124 was associated with a lower level of Nrf2 expression. Moreover, liver samples from ALD patients with this polymorphism displayed more severe inflammatory activity. Together, these findings provide evidence that the SNP rs35652124 variation in the Nrf2-encoding gene NFE2L2 is a potential genetic marker for susceptibility to ALD.

Cholesterol-enriched membrane microdomains are needed for insulin signaling and proliferation in hepatic cells

Hepatocyte proliferation during liver regeneration is a well-coordinated process regulated by the activation of several growth factor receptors, including the insulin receptor (IR). The IR can be localized in part to cholesterol-enriched membrane microdomains, but the role of such domains in insulin-mediated events in hepatocytes is not known. We investigated whether partitioning of IRs into cholesterol-enriched membrane rafts is important for the mitogenic effects of insulin in the hepatic cells. IR and lipid rafts were labeled in HepG2 cells and primary rat hepatocytes. Membrane cholesterol was depleted in vitro with metyl-β-cyclodextrin (MβCD) and in vivo with lovastatin. Insulin-induced calcium (Ca²⁺) signals studies were examined in HepG2 cells and in freshly isolated rat hepatocytes as well as in whole liver in vivo by intravital confocal imaging. Liver regeneration was studied by 70% partial hepatectomy (PH), and hepatocyte proliferation was assessed by PCNA staining. A subpopulation of IR was found in membrane microdomains enriched in cholesterol. Depletion of cholesterol from plasma membrane resulted in redistribution of the IR along the cells, which was associated with impaired insulin-induced nuclear Ca²⁺ signals, a signaling event that regulates hepatocyte proliferation. Cholesterol depletion also led to ERK1/2 hyper-phosphorylation. Lovastatin administration to rats decreased hepatic cholesterol content, disrupted lipid rafts and decreased insulin-induced Ca²⁺ signaling in hepatocytes, and delayed liver regeneration after PH. Therefore, membrane cholesterol content and lipid rafts integrity showed to be important for the proliferative effects of insulin in hepatic cells. NEW & NOTEWORTHY One of insulin's actions is to stimulate liver regeneration. Here we show that a subpopulation of insulin receptors is in a specialized cholesterol-enriched region of the cell membrane and this subfraction is important for insulin's proliferative effects.

Inositol 1, 4, 5-trisphosphate-dependent nuclear calcium signals regulate angiogenesis and cell motility in triple negative breast cancer

Increases in nuclear calcium concentration generate specific biological outcomes that differ from those resulting from increased cytoplasmic calcium. Nuclear calcium effects on tumor cell proliferation are widely appreciated; nevertheless, its involvement in other steps of tumor progression is not well understood. Therefore, we evaluated whether nuclear calcium is essential in other additional stages of tumor progression, including key steps associated with the formation of the primary tumor or with the metastatic cascade. We found that nuclear calcium buffering impaired 4T1 triple negative breast cancer growth not just by decreasing tumor cell proliferation, but also by enhancing tumor necrosis. Moreover, nuclear calcium regulates tumor angiogenesis through a mechanism that involves the upregulation of the anti-angiogenic C-X-C motif chemokine 10 (CXCL10-IP10). In addition, nuclear calcium buffering regulates breast tumor cell motility, culminating in less cell invasion, likely due to enhanced vinculin expression, a focal adhesion structural protein. Together, our results show that nuclear calcium is essential for triple breast cancer angiogenesis and cell migration and can be considered as a promising strategic target for triple negative breast cancer therapy.

Report of eight cases of fatal and severe Mediterranean spotted fever in Portugal

Mediterranean spotted fever (MSF), endemically present, is associated with a low mortality and morbidity in Portugal. Etiological agents are Malish and Israeli tick typhus strains of Rickettsia conorii. In the last few years severe forms of MSF have emerged, with patients presenting atypical symptoms, major neurological manifestations, and multiorgan involvement, who have required intensive care facilities. Advanced age, underlying chronic disease, and delay of appropriate treatment are bad prognostic factors. In the acute phase of diagnosis, serological studies are delayed, inconclusive, and often unhelpful. A definitive diagnosis can only be made using isolation or molecular biology which can establish and clearly identify agents. Using evidence-based case reports, clinical and laboratory data were evaluated from patients with severe or fatal MSF observed in Garcia da Orta Hospital-Almada. Of the eight reference cases, four died, three in an acute fulminant stage. Of the survivors, four presented atypical involvement: ocular inoculation, massive gastric hemorrhage, acute respiratory disease (ARDS), and necrotizing vasculitis. Diagnosis by isolation of the agent was made in two cases, by immunohistochemistry in three, and by the indirect fluorescent antibody test (IFA) in three others. Israeli tick typhus and Malish R. conorii strains were isolated once each in fatal cases. In early stages, diagnosis continues to be clinical and patients should start appropriate therapy without delay if clinical suspicion of rickettsiosis arises to prevent poor outcome. Patients ranged in age from 39 to 71 years (mean 60), APACHE II ranged from 15 to 38 points and TISS 28 was between 24 and 46 points. In reported cases severity of disease was not obviously related to the usual comorbidities. Accelerated clinical course may not suggest classical MSF. Another relevant factor was prior prescription of an inappropriate antibiotic that contributed to misleading clinical features. The reported complications and atypical manifestations illustrate well the diversity of this disease.

[Idiopathic hypercalciuria: presentation of 471 cases]

OBJECTIVE: To analyze the clinical history and evolution of children and adolescents with IH, emphasizing some of their peculiar features. METHODS: We followed 471 patients with IH at an outpatient clinic. Patients were submitted to the following protocol: abdominal X-ray, kidney and urinary tract ultrasonography; urinary ionogram, blood gas and biochemical analyses; 24-hour urine for measurement of calcium and other electrolytes and creatinine; urinalysis, urine culture and phase-contrast microscopy; second morning urine collected after fasting for measurement of calcium and creatinine. RESULTS: At the time of diagnosis, 6% of the patients were infants, 15% pre-school children, 55% school children, and 24% adolescents; 56% of them were boys. Clinical and laboratory findings were: 47% had hematuria and abdominal pain, 31% had isolated hematuria, 14% isolated abdominal pain, and 8% had urinary tract infection, nocturnal enuresis, suprapubic pain or urethralgia, or the frequency/urgency syndrome with urinary incontinence. Hypercalciuria was associated with urolithiasis in 56% of patients. There was association with hyperuricosuria in 18.5% of the cases, and hypocitraturia in 8.5% of the cases. Evolution was poor for 33% of the patients, with recurrence of nephrolithiasis, persistence of hematuria, and abdominal pain. CONCLUSIONS: IH must be diagnosed and treated with criteria in order to reduce consequences such as hematuria, abdominal pain, urinary stone formation and possible bone involvement. Signs and symptoms such as urgency and urinary incontinence, suprapubic pain and nocturnal enuresis may result from renal hyperexcretion of calcium.

[Idiopathic hypercalciuria: presentation of 471 cases]

OBJECTIVE: To analyze the clinical history and evolution of children and adolescents with IH, emphasizing some of their peculiar features. METHODS: We followed 471 patients with IH at an outpatient clinic. Patients were submitted to the following protocol: abdominal X-ray, kidney and urinary tract ultrasonography; urinary ionogram, blood gas and biochemical analyses; 24-hour urine for measurement of calcium and other electrolytes and creatinine; urinalysis, urine culture and phase-contrast microscopy; second morning urine collected after fasting for measurement of calcium and creatinine. RESULTS: At the time of diagnosis, 6% of the patients were infants, 15% pre-school children, 55% school children, and 24% adolescents; 56% of them were boys. Clinical and laboratory findings were: 47% had hematuria and abdominal pain, 31% had isolated hematuria, 14% isolated abdominal pain, and 8% had urinary tract infection, nocturnal enuresis, suprapubic pain or urethralgia, or the frequency/urgency syndrome with urinary incontinence. Hypercalciuria was associated with urolithiasis in 56% of patients. There was association with hyperuricosuria in 18.5% of the cases, and hypocitraturia in 8.5% of the cases. Evolution was poor for 33% of the patients, with recurrence of nephrolithiasis, persistence of hematuria, and abdominal pain. CONCLUSIONS: IH must be diagnosed and treated with criteria in order to reduce consequences such as hematuria, abdominal pain, urinary stone formation and possible bone involvement. Signs and symptoms such as urgency and urinary incontinence, suprapubic pain and nocturnal enuresis may result from renal hyperexcretion of calcium.

Mushroom poisoning with Amanita phalloides - a report of four cases

Amanita mushroom poisoning is a rare but serious occurrence. Physicians need to recognize the phalloides syndrome promptly and to institute effective treatment as soon as possible in order to avoid the often fatal complications. The authors report four cases of Amanita poisoning, two of which resulted in fulminant hepatic failure and required orthotopic liver transplantation. The clinical symptoms and signs, laboratory alterations, and therapeutic options available are discussed.

Effects of mercury on the arterial blood pressure of anesthetized rats

The available data suggests that hypotension caused by Hg2+ administration may be produced by a reduction of cardiac contractility or by cholinergic mechanisms. The hemodynamic effects of an intravenous injection of HgCl2 (5 mg/kg) were studied in anesthetized rats (N = 12) by monitoring left and right ventricular (LV and RV) systolic and diastolic pressures for 120 min. After HgCl2 administration the LV systolic pressure decreased only after 40 min (99 +/- 3.3 to 85 +/- 8.8 mmHg at 80 min). However, RV systolic pressure increased, initially slowly but faster after 30 min (25 +/- 1.8 to 42 +/- 1.6 mmHg at 80 min). Both right and left diastolic pressures increased after HgCl2 treatment, suggesting the development of diastolic ventricular dysfunction. Since HgCl2 could be increasing pulmonary vascular resistance, isolated lungs (N = 10) were perfused for 80 min with Krebs solution (continuous flow of 10 ml/min) containing or not 5 microM HgCl2. A continuous increase in pulmonary vascular resistance was observed, suggesting the direct effect of Hg2+ on the pulmonary vessels (12 +/- 0.4 to 29 +/- 3.2 mmHg at 30 min). To examine the interactions of Hg2+ and changes in cholinergic activity we analyzed the effects of acetylcholine (Ach) on mean arterial blood pressure (ABP) in anesthetized rats (N = 9) before and after Hg2+ treatment (5 mg/kg). Using the same amount and route used to study the hemodynamic effects we also examined the effects of Hg2+ administration on heart and plasma cholinesterase activity (N = 10). The in vivo hypotensive response to Ach (0.035 to 10.5 microg) was reduced after Hg2+ treatment. Cholinesterase activity (microM h-1 mg protein-1) increased in heart and plasma (32 and 65%, respectively) after Hg2+ treatment. In conclusion, the reduction in ABP produced by Hg2+ is not dependent on a putative increase in cholinergic activity. HgCl2 mainly affects cardiac function. The increased pulmonary vascular resistance and cardiac failure due to diastolic dysfunction of both ventricles are factors that might contribute to the reduction of cardiac output and the fall in arterial pressure.

Small doses of canrenone block the effects of ouabain on the mechanical activity of the heart and vessels of the rat

Canrenone has been described as an antihypertensive drug that blocks endogenous ouabain effects in volume-dependent hypertensive models. Considering that some canrenone metabolites may be putative mutagenic factors, therapeutic dose reduction might be advantageous if the blockade of ouabain effects is maintained. In this study, the effects of low doses or concentrations of canrenone were investigated in rats by using isolated papillary muscles, Langendorff-perfused hearts, perfused rat-tail vascular bed, and anesthetized animals. Canrenone (0.5, 1, 2, and 5 mg/ml) produced a dose-dependent negative inotropic effect in papillary muscles contracting isometrically and blocked the positive inotropic effect produced by 660 microM ouabain. In Langendorff-perfused hearts beating spontaneously, a low concentration of canrenone (10 microg/ml) increased the isovolumic systolic pressure obtained at several diastolic pressures. Higher concentrations of canrenone (20, 30 microg/ml) brought the isovolumic pressure toward control values, and 100 microg/ml canrenone produced an isovolumic pressure reduction. In these preparations, 20 microg/ml canrenone reduced significantly the positive inotropic effects of 100 microM ouabain. Investigating the vascular smooth muscle reactivity to phenylephrine (PE; 0.5, 1, and 2 microg bolus injections) in the perfused rat-tail vascular bed, it was observed that canrenone blocked completely the enhancement of PE pressor effect produced by 1-h treatment with 100 microM ouabain. Similar results were obtained with the arterial blood pressure reactivity to PE in anesthetized rats. In these animals, canrenone (1 mg/kg) blocked the sensitizing effect of 18 microg/kg ouabain on PE reactivity. In conclusion, results presented here suggest that canrenone may block ouabain effects at very low concentrations. It blocked myocardial positive inotropic effects of ouabain on both papillary muscle and perfused hearts, and the sensitization of PE pressor effects. The results also suggest that canrenone at very small doses might be used to reduce arterial blood pressure in hypertensive conditions accompanied by increased ouabain plasma levels as the main therapeutic procedure or as an adjunct treatment to prevent ouabain sensitizing effects on pressor responses.

[Direct coronary angioplasty versus thrombolysis in the acute phase of myocardial infarction--inpatient outcome]

Both thrombolysis and percutaneous transluminal coronary angioplasty (PTCA) are effective methods for the treatment of acute myocardial infarction (AMI). In our centre we perform primary PTCA during the available schedule of the hemodynamics laboratory. In this article we compare the predischarge evolution of patients submitted to each therapeutic procedure. From January 1996 to June 1997, 298 patients were admitted with the diagnosis of AMI. Eighty-four patients (28%) were thrombolysed (TB group) and 30 patients (10%) underwent primary PTCA (PTCA group). There were no significant differences among the two groups concerning demographic characteristics: age (61 +/- 13--TB and 59 +/- 12 years--PTCA); sex (male 81%--TB; 83%--PTCA), risk factors and previous cardiac history. The mean time since the onset of symptoms until arrival at the hospital was 156 +/- 156 minutes for TB and 202 +/- 210 minutes for PTCA (p < 0.02). The delay since admission until the beginning of treatment was 100 +/- 88 minutes for TB and 119 +/- 142 minutes for PTCA. The primary success rate of PTCA was 94% and there were no complications during the procedure. During the hospital stay, 12 patients developed post-infarction angina in the TB group and two patients in the PTCA group; in 15 patients of the TB group a revascularization procedure was performed (surgery in 5 and PTCA in 10 patients); one patient suffered reinfarction in the TB group. Two patients of the TB group (2.4%) had intracranial hemorrhage; the in-hospital mortality was 9.5% in the TB group and 3.3% in the PTCA (p < 0.001). The mean in-hospital stay was 11 +/- 5.6 in the TB group and 7.8 +/- 2.5 days in the PTCA group (p = 0.055). In our experience, primary PTCA in AMI appeared to be a safe procedure with lower occurrence of coronary events and hemorrhagic complication, with an earlier hospital discharge when compared to thrombolysis.