Contrast media (meglumine diatrizoate) aggravates renal inflammation, oxidative DNA damage and apoptosis in diabetic rats which is restored by sulforaphane through Nrf2/HO-1 reactivation.

Diabetes mellitus is an independent risk factor for renal impairment in patients exposed to contrast media. It doubles the risk and decreases survival rate of contrast induced nephropathy (CIN). Sulforaphane has antioxidant properties via Nrf2 activation. The interaction of diabetes and/or sulforaphane with contrast media on Nrf2 regulation is not yet understood. Herein, diabetes was induced by a single intra-peritoneal injection of streptozotocin. Animals were then divided into five groups; control non-diabetic group; diabetic group; diabetic/sulforaphane group; diabetic/CIN group; diabetic/CIN/sulforaphane group. Animals were assessed 24 h after CIN induction. Sulforaphane improved the impaired nephrotoxicity parameters, histopathological features, and oxidative stress markers induced by contrast media (meglumine diatrizoate) in diabetic rats. Immunofluorescence detection revealed increased Nrf2 expression in kidney sections after sulforaphane pretreatment. Moreover, gene expression of Nrf2 and HO-1 were up-regulated, while IL-6 and caspase3 were down-regulated in kidney tissues of animals pretreated with sulforaphane. In NRK-52E cells, sulforaphane pretreatment significantly ameliorated the cytotoxicity of meglumine diatrizoate. However, silencing Nrf2 using small interfering RNA (siRNA) abolished the cytoprotective effects of sulforaphane. Collectively, the results of this study suggest that Nrf2/HO-1 pathway has a protective role against CIN and support the clinical implication of Nrf2 activators, such as sulforaphane, in CIN particularly in diabetic patients.

Composite silica coated gold nanosphere and quantum dots nanoparticles for X-ray CT and fluorescence bimodal imaging.

In this study, silica coated Au nanospheres (Au@SiO2) were prepared by a reverse microemulsion method; subsequently, a layer of fluorescent quantum dots (QDs) were adsorbed onto it and then it was coated with silica again. After modifying with PVP, the composite silica coated gold nanosphere and quantum dots nanoparticle (Au@SiO2-QDs/SiO2-PVP) was obtained. This composite structure contained Au and QDs, and it could be used for contrast-enhanced X-ray CT imaging and fluorescence imaging. Characterization showed that the composite nanoparticle had good dispersity, a high fluorescence intensity and a good effect of X-ray absorption, and it was suitable for using as a bimodal imaging probe.

Preconditioning With Tauroursodeoxycholic Acid Protects Against Contrast-Induced HK-2 Cell Apoptosis by Inhibiting Endoplasmic Reticulum Stress.

To investigate whether tauroursodeoxycholic acid (TUDCA) could attenuate contrast media (CM)-induced renal tubular cell apoptosis by inhibiting endoplasmic reticulum stress (ERS), we exposed HK-2 cells to increasing doses of meglumine diatrizoate (20, 40, and 80 mg I/mL) for 2 to 16 hours, with/without TUDCA preconditioning for 24 hours. Cell viability test, Hoechst 33258 staining, and flow cytometry were used to detect meglumine diatrizoate-induced cell apoptosis, while real-time polymerase chain reaction and Western blot analysis were used to measure the expressions of ERS markers of glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), and the apoptosis-related marker of caspase 12. Cell apoptosis and messenger RNA (mRNA) expression of GRP78 (P = .005), ATF4 (P = .01), and caspase 12 (P = .001) were significantly higher in the CM 4 hours group than the control as well as the protein expressions. The TUDCA preconditioning reduced the mRNA expression of GRP78, ATF4, and caspase 12 in the CM 4 hours groups (P = .009, .019, and .003, respectively) as well as the protein expression. In conclusion, TUDCA could protect renal tubular cells from meglumine diatrizoate-induced apoptosis by inhibiting ERS.

Evaluation of the mutagenic effect of the iodinated contrast medium Urografina® 292 using the micronucleus test in mouse bone marrow cells.

Contrast media (CM) are frequently used in diagnostic radiology and in radiotherapy as a diagnostic tool and in treatment planning. Previous studies have demonstrated that these compounds induce chromosomal aberrations. This study evaluates the mutagenic effects induced by the contrast medium Urografina® 292 (meglumine amidotrizoate and sodium-ionic dimmer) in bone marrow cells (BMC) of mice in vivo. Micronuclei assay was performed in BMC of CF-1 mice injected with CM 1.5 and 3.0 mL/kg intravenous doses and 1.0, 2.0, 3.0 mL/kg intraperitoneal doses. The animals were beheaded 24 h after treatment by cervical dislocation, and femur BMC from each animal were used in the micronucleus test. The group treated with the highest intravenous injection of Urografina® 292 (3.0 mL/kg) presented an increase in the frequency of micronucleated polychromatic erythrocytes (MNPCEs) in relation at the control group (P<0.05). The results obtained after intraperitoneal administration of CM showed that all doses (1.0 mL/kg, 2.0 mL/kg and 3.0 mL/kg) increased the frequency of MNPCEs, being significantly different from the negative control (P< 0.01). The present results suggest that iodinated contrast media Urografina® 292 may cause a significant increase of cytogenetic damage in bone marrow cells of mice.

Aged rats are susceptible to nephrotoxicity induced by iodinated contrast media.

OBJECTIVE: The objective of this study is to evaluate the effect and mechanism of aging on iodinated-contrast-media-induced nephropathy in male rats. METHODS: Twenty-four healthy male rats were initially divided into 12-month-old and 24-month-old age groups (adult and older age groups, respectively; n = 12/group); subsequently, each age group was randomly divided into saline control (NS) and contrast media (CM) groups (n = 6/group). CM (76% diatrizoate, 10 mL/kg b.w.) was given through the caudal vein. Urinary creatinine (Ucr) and serum creatinine (Scr) were detected by an automatic biochemical analyzer. The activities of renal malondialdehyde (MDA), superoxide dismutase (SOD), angiotensin-converting enzyme (ACE), angiotensin II (Ang II), and reduced form of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) were determined by spectrophotometric assays with commercially available kits according to the manufacturers' protocols. Renal histological changes were observed by hematoxylin and eosin staining and scored semiquantitatively. RESULTS: In diatrizoate-injected aged rats, Scr, the activities of ACE, Ang II, MDA, and NADPH oxidase in renal tissues were significantly increased (p < 0.01). The histologic scores were higher in the aged animals with CM treatment than those of control or adult rats (p < 0.01). There was an increasing trend but no significant statistical difference in renal ACE, Ang II, MDA, and NADPH oxidase or histologic scores in adult CM-injected rats compared with control animals (p > 0.05). CONCLUSIONS: Older age is an aggravating factor of iodinated-contrast-media-induced nephropathy in male rats. Oxidative stress and the renin-angiotensin system (RAS) may play an important role in nephrotoxicity induced by iodinated contrast media, especially in aged male rats.

Involvement of caspase-12-dependent apoptotic pathway in ionic radiocontrast urografin-induced renal tubular cell injury.

Contrast medium (CM) induces a direct toxic effect on renal tubular cells. This toxic effect subjects in the disorder of CM-induced nephropathy. Our previous work has demonstrated that CM shows to activate the endoplasmic reticulum (ER)-related adaptive unfolding protein response (UPR) activators. Glucose-regulated protein 78 (GRP78)/eukaryotic initiation factor 2α (eIF2α)-related pathways play a protective role during the urografin (an ionic CM)-induced renal tubular injury. However, the involvement of ER stress-related apoptotic signals in the urografin-induced renal tubular cell injury remains unclear. Here, we examined by the in vivo and in vitro experiments to explore whether ER stress-regulated pro-apoptotic activators participate in urografin-induced renal injury. Urografin induced renal tubular dilation, tubular cells detachment, and necrosis in the kidneys of rats. The tubular apoptosis, ER stress-related pro-apoptotic transcriptional factors, and kidney injury marker-1 (kim-1) were also conspicuously up-regulated in urografin-treated rats. Furthermore, treatment of normal rat kidney (NRK)-52E tubular cells with urografin augmented the expressions of activating transcription factor-6 (ATF-6), C/EBP homologous protein (CHOP), Bax, caspase-12, JNK, and inositol-requiring enzyme (IRE) 1 signals. Urografin-induced renal tubular cell apoptosis was not reversed by the inhibitors of ATF-6, JNK signals or CHOP siRNA transfection, but it could be partially reversed by the inhibitor of caspase-12. Taken together, the present results and our previous findings suggest that exposure of CM/urografin activates the ER stress-regulated survival- and apoptosis-related signaling pathways in renal tubular cells. Caspase-12-dependent apoptotic pathway may be partially involved in the urografin-induced nephropathy.

The role of endoplasmic reticulum stress-related unfolded protein response in the radiocontrast medium-induced renal tubular cell injury.

Contrast medium (CM) induces a direct toxic effect on renal tubular cells. This toxic effect may have a role in the pathophysiology of CM-induced nephropathy. CM has been shown to affect the endoplasmic reticulum (ER)-related capacity. Unfolded protein response (UPR) is known as a prosurvival response to reduce the accumulation of unfolded proteins and restore normal ER function. However, the role of ER stress-related UPR in the CM-induced renal cell injury still remains unclear. In this study, we examined whether UPR participates in urografin (an ionic CM)-induced renal tubular cells apoptosis. Treatment with urografin in normal rat renal tubular cell line (NRK52E) markedly increased cell apoptosis and decreased cell viability with a dose- and time-dependent manner. The cell necrosis was not increased in urografin-treated cells. Urografin also enhance the induction of ER stress-related markers in NRK52E cells, including glucose-regulated protein (GRP)78 and GRP94 expressions, procaspase-12 cleavage, phosphorylation of PERK (PKR [double-stranded RNA-activated protein kinase]-like ER kinase), and eukaryotic initiation factor 2alpha (eIF2alpha). Salubrinal, a selective inhibitor of eIF2alpha dephosphorylation, effectively decreased urografin-induced cell apoptosis. Furthermore, transfection of GRP78-small interfering RNA in NRK52E cells significantly enhanced urografin-induced cell apoptosis. These results suggest that GRP78/eIF2alpha-related signals play a protective role during UPR, and the activation of ER stress-related UPR may play an important regulative role in urografin-induced renal tubular injury.

[Protective effect of amlodipine on the cytotoxicity induced by contrast media in human kidney cells].

OBJECTIVE: To explore the protective effect of amlodipine on the cytotoxicity induced by contrast media (meglumine diatrizoate) in human kidney cells (HKC). METHODS: An HKC line was used. The experiment was divided into 4 groups: a model group (diatrizoate 111g/L), a prevention group (diatrizoate 111g/L+amlodipine 10(-5)mol/L), an amlodipine control group (amlodipine 10(-5)mol/L), and a culture medium control group (simple none blood serum DMEM-F12 medium). Cytotoxicity induced by meglumine diatrizoate was analysed by methyl thiazolyl tetrazolium (MTT) test, lactate dehydrogenase (LDH) assay, Hochest33258 fluorescence stained cytospins, and flow cytometric DNA analysis. The protein expression of Bax was determined by Western blot, and caspase-3 activity was examined by fluorometric method. RESULTS: In the prevention group, the cell viability increased significantly (P<0.05), LDH levels decreased (P<0.05), and the apoptosis was lower than that of the model group (P<0.05) .Bax protein expression and caspase 3 activity decreased (P<0.05). CONCLUSION: Amlodipine can inhibit the HKC apoptosis and protect the renal tubule cell from injury induced by meglumine diatrizoate.

Aspectos físico-químicos de los contrastes radiológicos iodados y sus posibles reacciones secundarias / Physical and chemical aspects of the iodine radiological contrasts and its possible secondary reactions

El objetivo del presente trabajo es exponer un grupo de compuestos iodados con tres y seis átomos de iodo en su molécula que son derivados del ácido benzoico y son utilizados en Radiología como medios de contraste de gran interés clínico. Se estudian sus constantes físico-químicas y las ventajas que presentan los contrastes no iónicos sobre los iónicos. Se describen también los posibles efectos colaterales indeseables en un pequeño pero importante número de pacientes que pueden producirse por su inyección intravascular (AU)

Comparison of hepatic damage from direct injections of iodinated contrast agents and carbon dioxide.

PURPOSE: This study guides the choice of contrast agent for localization of portal veins during transjugular intrahepatic portosystemic shunt (TIPS) placement or use in percutaneous transhepatic cholangiography (PTC) by providing gross anatomic and histologic comparison of effects from parenchymal injections of iodinated contrast agents and carbon dioxide. MATERIALS AND METHODS: Eighteen New Zealand White rabbits received direct injections of 2-5 mL of either the nonionic contrast agent iohexol 300 mgI or the ionic contrast agent diatrizoate meglumine 60% into one lobe of the liver and the same volume of CO2 into the other lobe. The rabbits were killed at 2-7 days for gross and histologic evaluation of the livers. RESULTS: At the time of injection, the diatrizoate and iohexol sites showed persistent dark discoloration, whereas CO2 sites showed minimal visible changes. On gross examination at death, all diatrizoate sites showed severe scarring and also commonly showed areas of necrosis. CO2 and iohexol sites showed only minimal discoloration and needle-puncture scars (P < .0001). The histologic grade for diatrizoate sites was significantly more severe than paired CO2 sites (P < .016). Iohexol sites showed mild histologic changes similar to paired CO2 sites (P = .375). CONCLUSION: Iohexol and CO2 produce less severe hepatic damage and are preferred to meglumine diatrizoate for hepatic injection.

Role of hemolysis in potassium release by iodinated contrast medium.

It has been demonstrated that an iodinated contrast medium (CM) causes release of potassium into blood vessel lumina, resulting in an increase in serum potassium. The purpose of the present study was to assess whether this potassium release is due to hemolysis. Fresh human blood was mixed in vitro with CM at a ratio of 10:2. Potassium release rates were determined, and serum haptoglobin and free hemoglobin were measured after 30 min of exposure to CM. To compare the potassium release curve between CM exposure and true hemolysis induced by distilled water, fresh human blood was also mixed with distilled water. The level of serum haptoglobin decreased due to hemodilution. Changes in haptoglobin were not correlated with potassium release rates. The serum free hemoglobin level did not increase significantly, and there was no correlation between changes in the free hemoglobin level and the rate of potassium release. Hemolysis caused by water occurred instantaneously, whereas potassium release caused by CM was a slow response, which was linearly correlated with exposure time. Potassium release from blood cannot be explained by hemolysis.

Effects of radiocontrast, mannitol, and endothelin on blood pressure and renal damage in the aging male spontaneously hypertensive rat.

RATIONALE AND OBJECTIVES: The purpose of this research was to study the effects of the radiocontrast medium (CM) Hypaque-76 (diatrizoate meglumine sodium), equiosmolar mannitol, and endothelin on blood pressure and renal damage in a aging male spontaneously hypertensive rat, a small animal model for CM-induced renal damage. The importance of the pressor effect and the high osmolality of CM in producing renal damage was investigated by first reducing the blood pressure with pentobarbital anesthesia, which suppresses sympathetic nervous system activity, then testing the effects of CM, saline, mannitol, and the potent vasoconstrictor endothelin alone and in combination with CM. METHODS: Systolic blood pressure was measured in 14-month-old male rats (1) when awake, (2) after pentobarbital anesthesia, (3) after the administration of saline, CM, mannitol, endothelin, or CM plus endothelin, (4) after awakening the same day, and (5) the following day while awake. Renal damage was quantified by evaluating histopathologically the left kidney removed the day after administration of test substances. RESULTS: The pentobarbital-lowered blood pressure remained depressed after saline and mannitol but rose dramatically after CM, endothelin, and CM plus endothelin. Renal damage, compared with the saline controls, occurred with CM, mannitol, endothelin, and endothelin plus CM. The order of increasing severity was mannitol = CM < endothelin < endothelin plus CM. CONCLUSIONS: The effect of CM on systolic blood pressure is not related to its osmolality. High osmolality, however, appears to be a factor in CM-induced renal damage. Ischemia and direct nephrotoxicity are factors contributing to the renal-damaging effects of CM, mannitol, and endothelin.

The role of endothelin in radiocontrast nephropathy.

In the present study we investigated the role of endothelin and AT II in radiocontrast nephropathy induced in rats with reduced renal mass (70-75%). Thirty-five male Wistar albino rats weighing between 280 and 400 g were anaesthetized with ketamine (130 mg/kg b.w.) and right total, left 50% nephrectomy were performed. After this operation, the rats were kept under observation for six to eight weeks and then they were randomly separated into three groups. Group I rats were infused with 8.9 ml/kg (or 2.9 g of iodine/kg body weight) Na diatrizoate (Urovision, 1,500 mosm/kg). Group II rats were infused with 0.9% NaCl in an equal volume with the radiocontrast material. Group III rats were given 4.5% NaCl that had the same volume and osmolality as the radiocontrast material. Two hours after the drug infusions, blood and accumulated urine samples were collected from all the rats and tested for endothelin, AT II, BUN, creatinine, uric acid, electrolytes, calcium and phosphorus. We found that the plasma endothelin levels in Group I (77.64 +/- 29.62 pg/ml) were significantly higher than in Group II (20.52 +/- 5.83 pg/ml) and Group III (15.04 +/- 5.15 pg/ml) (t = 8.34 and t = 9.14, respectively, p < 0.001). Therefore elevation in circulating endothelin might have been an additional factor leading to the radiocontrast-induced nephrotoxicity.

[Endothelin-1 in the mechanisms of the nephrotoxic action of x-ray contrast media]. / Endotelin-1 v mekhanizmakh nefrotoksicheskogo deistviia rentgenokontrastnykh sredstv.

The authors study mechanisms of nephrotoxic action of high-osmolar radiopaque substance (RPS) and the role of endothelin-1, hormonal endothelial factor, in these mechanisms in patients with different variants of chronic glomerulonephritis. Endothelin-1 is a potent endogenic vasoconstrictor participating in regulation of intrarenal hemodynamics and renal function the synthesis of which id related to Ca metabolism. Mechanisms of nephrotoxic action of RPS involve disturbances of Ca metabolism (hypercalcemia), high concentration of blood endothelin-1 which directly correlated with baseline creatinine in the serum and deterioration of renal function after RPS introduction. Ca ions antagonists (corinfar) contribute to prevention of changes in endothelin-1 synthesis relevant renal dysfunction induced by RPS.

Do iodinated contrast media increase serum potassium levels?

PURPOSE: To test the hypothesis that iodinated contrast media may induce an elevation in serum potassium level. MATERIALS AND METHODS: Protocol A: After intravenous infusion of contrast media into six rabbits, alterations of potassium ion concentrations were measured. Protocol B: Fresh rabbit blood was mixed in vitro with contrast media, and the fluctuations in potassium were monitored over a 30-minute period. Protocol C: Similar to protocol B, except that blood from humans with no reaction to contrast media was used. RESULTS: For protocol A, blood potassium levels increased above baseline levels. The elevations were statistically significant (P < .05). For protocol B, diatrizoate and ioxaglate caused a gradual increase in blood potassium levels, but iopamidol did not. In protocol C, all three contrast media caused statistically significant elevation in potassium levels. The release of potassium was statistically significant at 5 minutes (P < .05 for diatrizoate and ioxaglate, and P < .01 for iopamidol). The mean release rates (+/- standard deviation) by means of linear regression analysis were 0.0190 mmol/min +/- 0.0112 with diatrizoate, 0.0159 mmol/min +/- 0.0057 with iopamidol, and 0.0088 mmol/min +/- 0.0033 with ioxaglate. CONCLUSION: Iodinated contrast media increase blood potassium levels causing release of potassium into intravascular spaces. This potassium release may play some role in contrast medium-induced adverse reactions.

Histologic study of the effects of short and long-term therapy of iodide administration on the periodontium of albino rats.

Iodine is a natural mineral essential for good health and highly concentrated in thyroid tissue. It is used for diagnostic purposes as well as for therapeutic means. The present study was conducted to evaluate the effect of a single dose of iodine administration and multiple doses of the drug for a short and long term therapy on the periodontium. Sixty male albino rats were participated in the study. Twenty rats were used as a control group, the rest of the animals were divided into two experimental groups. The first group received single dose (diagnostic dose) of iodine. The second experimental group was divided into two subgroups. The first subgroup received multiple doses of iodine for a short period of 15 days, while the second subgroup received the same multiple doses for one month. Three rats of the control group and four of each experimental group were sacrificed at the end of the first, second, third and fourth weeks from the beginning of the study. Maxillary and mandibular specimens were dissected, stained with H. & E. and examined microscopically. The results of the study revealed that single diagnostic dose of iodine has no effect on the periodontium while multiple doses of the drug used for therapeutic purposes caused degeneration of periodontal tissues. The effect increased when the drug is used for a long period, the effect of the drug may be related to the direct effect of iodine concentrated in saliva on living cells or indirectly through the effect of xerostomia induced by the drug.

Contrast nephrotoxicity: predictive value of urinary enzyme markers in a rat model.

RATIONALE AND OBJECTIVES: We tested whether urinary enzymes are an accurate and useful marker of renal damage in a rat model of contrast media nephrotoxicity. METHODS: Thirty rats were pretreated with a combination of salt depletion, indomethacin, and contrast material. Alanine aminopeptidase (AAP), gamma-glutamyltranspeptidase (GGT), and N-acetyl-beta-D-glucosaminidase (NAG) were measured before and 24 hr after injection of contrast material. Enzyme concentrations were correlated with glomerular filtration rate (GFR) and histology. RESULTS: Decreasing GFR and histopathologic changes were found only in rats treated with all three variables. NAG levels increased from baseline for both diatrizoate meglumine- and ioversol-treated animals (from 83.9 +/- 48.6 to 145.5 +/- 55.4 and from 69.41 +/- 43.6 to 123.1 +/- 50.7, respectively; P < 0.05 from baseline for ioversol) and declined in other groups. GGT and AAP levels did not correlate well with structural and functional changes. CONCLUSIONS: In this model of contrast nephrotoxicity, NAG concentration appears to correlate with structural and functional changes associated with contrast media nephrotoxicity. However, the large range of baseline values makes this of dubious clinical use. AAP and GGT levels appear less helpful in detecting renal damage.