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Vitamin D deficiency (VDD) is widespread around the world and has been extensively documented to affect various health conditions, including the cognitive functioning of the brain. Serum 25-hydroxylated forms of vitamin D are traditionally used to determine vitamin D status. However, there is now evidence that cholecalciferol activation can occur and be controlled by locally expressed enzymes in the brain. This study aimed to investigate the effects of cholecalciferol supplementation on cognitive function in rats who underwent transient VDD in adulthood. Thirty-six adult Wistar rats were administered paricalcitol (seven doses of 32 ng injected every other day) along with a "vitamin D-free" diet to induce VDD, which was confirmed using a LC–MS/MS serum analysis of the cholecalciferol and 25-hydroxyvitamin D3 levels. Treatment was performed by including 1000 IU/kg and 10,000 IU/kg cholecalciferol in the diet. Cognitive performance was evaluated using the novel object recognition (NOR), Morris water maze (MWM), and radial arm maze (RAM) tests. An immunohistochemical analysis of the brain regions involved in learning and memory was performed by quantifying the neurons, astrocytes, and microglia labelled with anti-neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), and ionized calcium-binding adaptor molecule 1 (Iba-1) antibodies, respectively. The vitamin D deficient group showed the lowest performance in both the MWM and RAM tests. In contrast, the cholecalciferol-treated groups exhibited a faster learning curve. However, no difference was detected between the groups in the NOR test. On the other hand, differences in the cellular organization of the hippocampus and amygdala were observed between the groups. Cholecalciferol supplementation decreased the density of the Iba-1- and GFAP-labeled cells in the hilus and cornu Ammonis 3 (CA3) regions of the hippocampus and in the amygdala. These results support vitamin D's substantial role in learning and memory. They also highlight that subtle changes of cognitive function induced by transient VDD could be reversed by cholecalciferol supplementation. Further studies are needed to better understand VDD and cholecalciferol's effects on the brain structure and function. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of paricalcitol on bone metabolism and transforming growth factor-β（ TGF-β）/bone morphogenetic protein-7（ BMP-7）/Smad signaling pathway in rats with renal osteodystrophy（ ROD）. Methods: Total 90 rat were randomly divided into 6 groups: control group， model group， paricalcitol low-dose（ 0.2 μg/kg） group， paricalcitol medium-dose group （0.4 μg/kg） group， paricalcitol high-dose（ 0.8 μg/kg） group， calcitriol（ 10 μg/kg） group， with 15 rats in each group. Rats in control group were fed with ordinary feed， and rats in other groups were fed with feed containing adenine to induce the establishment of ROD model. After grouping and drug treatment， the blood urea nitrogen （BUN） and blood creatinine （Scr） levels， blood calcium and blood phosphorus levels， femoral bone mineral density （BMD）， maximum load， elasticity modulus and yield load， serum inflammatory fac-tors IL-6 and IL-17 levels of each group were measured； and the expression of TGF-β/BMP-7/Smad pathway protein in bone tissue was detected with Western blot. Another 45 rats were randomly divided into 3 groups: paricalcitol （0.8 μg/kg） group， TGF-β inhibition （LY2157299， 150 mg/kg） group， paricalcitol （0.8 μg/kg）+TGF-β inhibition （LY2157299，150 mg/kg） group， with 15 rats in each group. ROD model was established with the same method. After drug treatment， the renal function indexes and femoral biomechanical indexes were measured. Results: Compared with control group， the blood calcium level， BMD， elastic modulus， maximum load， yield load， bone tissue TGF-β/BMP-7/Smad pathway proteins TGF-β and BMP-7 expressions， p-Smad3/Smad3 were significantly re-duced in the model group （P<0.05）， the BUN and Scr levels， blood phosphorus level， and serum IL-6 and IL-17 levels were signifi-cantly increased （P<0.05）. Compared with the model group， the blood calcium level， BMD， elastic modulus， maximum load， yield load， bone tissue TGF-β/BMP-7/Smad pathway protein TGF-β and BMP-7 expression， p-Smad3/Smad3 were significantly increased in the paricalcitol low， medium and high dose groups and calcitriol group （P<0.05）， the BUN and Scr levels， blood phosphorus level， and serum IL-6 and IL-17 levels were significantly reduced， and paricalcitol groups showed a dose-dependent relationship （P<0.05）， there was no significant difference in the indexes of rats in high-dose paricalcitol group and calcitriol group （P>0.05）. Compared with paricalcitol+TGF-β inhibition group， the renal function indexes BUN， SCR and blood phosphorus level in paricalcitol group were de-creased（ P<0.05）， while the blood calcium level， BMD， elastic modulus， maximum load and yield load were increased（ P<0.05）. In TGF-β inhibition group， the renal function indexes BUN， SCR and blood phosphorus levels were increased（ P<0.05）， while the blood calcium level， BMD， elastic modulus， maximum load and yield load were decreased （P<0.05）. Conclusion: Paricalcitol can activate the TGF-β/BMP-7/Smad signaling pathway， inhibit inflammation， improve renal function and abnormal bone metabolism in ROD rats， reduce blood phosphorus level， increase blood calcium level and bone density， repair bone biomechanics， and improve the symptoms of osteodystrophy. [ABSTRACT FROM AUTHOR]

Glomerulosclerosis and tubulointerstitial fibrosis (TIF) are closely involved in the development of diabetic nephropathy (DN). Moreover, the development of TIF is closely related to epithelial-to-mesenchymal transition (EMT). Tanshinone IIA (Tan) has various pharmacological effects, especially the anti-fibrotic effect. And it is mainly used in the clinical treatment of cardiovascular diseases. Currently, the protective effect of Tan on DN and its possible mechanism have not been clearly elucidated. Our previous studies illustrated that Tan could improve the EMT of HK-2 cells induced by high glucose by regulating the vitamin D receptor (VDR)/Wnt/β-catenin pathway. Here, we collected demographic information and laboratory results from the National Health and Nutrition Examination Survey (NHANES) database in order to investigate the relationship between VD and DN. Then, we established a DN model and treated DN rats with Tan and paricalcitol (Par) for 6 weeks. We subsequently compared the changes in general condition, renal function, pathological changes, and TIF-related protein expression levels of control rats, DN rats induced by STZ, DN rats with Tan at 5.4 mg/kg, DN rats with Tan at 10.8 mg/kg, and DN rats with Par at 0.054 µg/kg, to explore the effect and mechanism of Tan and Par on DN rats. The results showed that VD had a protective effect against DN in diabetic patients. And we found that Tan had a protective effect on renal fibrosis in DN rats, which was superior to Par in improving the symptoms of "three more and one less," reducing fasting blood glucose level, improving renal index, BUN/SCr, and UACR, reducing histopathological damage of kidney, and improving the expression of fibrosis-related proteins in kidney tissue by regulating VDR/Wnt/β-catenin pathway. Tan was superior to Par in ameliorating tubulointerstitial fibrosis by regulating VDR/Wnt/β-catenin pathway in rats with diabetic nephropathy. [ABSTRACT FROM AUTHOR]

Objective To explore the impact of paricalcitol (Pal) on the oxidative stress-induced tight junction damage of mouse hepatocytes and its mechanism. Methods A model of cholestatic liver injury was created by routine bile duct ligation. The mice were randomly divided into control group (control), model group (BDL) and treatment group (BDL+Pal). HE staining microscopy was used to observe the morphological changes of liver tissues. The human hepatoma cell line HepG2 was cultured and divided into blank group, model group (400 μmol/L H2O2) and treatment group (400 μmol/L H2O2+20 nmol/L Pal). Western blot was used to examine the level of tight junction protein 1 (ZO-1), occludin, phosphorylated p65 (p-p65), phosphorylated ERK (p-ERK) and phosphorylated myosin II regulated light chain (p-MLC) protein were checked in each group. Results Compared with the control group, the level of p-p65, p-ERK and p-MLC in the model group was significantly increased (P＜0.000 1 or P＜0.01 or P＜0.001). The protein expression of ZO-1 and occludin was significantly decreased (P＜0.01). HE staining microscopy showed an increased hepatocyte necrosis and inflammatory cell infiltration. In contrast, the above levels in the treatment group showed an opposite trend relative to the model group. Conclusions Pal is able to alleviate the damage of hepatocyte tight junctions by inhibiting oxidative stress in cholestatic mice and HepG2 cells. Its mechanism is potentially related to the inhibition of reactive oxygen species and NF-κB/p65 and ERK signaling pathways.

AIM: We aimed to investigate the possible cardioprotective effects of paricalcitol (PR), its vitamin D receptor agonist, and vitamin D³3 (VIT-D3) on an experimental model of doxorubicin (DX) cardiotoxicity by 99mTc-PYP scintigraphy, electrocardiographic (ECG) and biochemical methods. METHOD: Forty-two male Wistar/Albino rats (250-300 g; aged 10-12 weeks) were randomly separated into six groups, namely into control (CN), doxorubicin (DX), paricalcitol (PR), vitamin D³ (VIT-D³), paricalcitol + doxorubicin (PR+DX), and vitamin D³ + doxorubicin (VIT-D³+DX) groups. Cardiotoxicity was induced by three doses of DX (18 mg/kg, i.p.) at 24-hour intervals on days 18, 19 and 20. PR (0.5 ug/ kg, i.p) and VIT-D³ (5,000 IU/kg, i.p) were injected for 20 days before and after the application of DX (18 mg/kg, i.p.). On day 21 of the experiment, biochemical parameters [tumor necrosis factor TNF-alpha (TNF-α); interleukin-6 (IL-6), nitric oxide (NO), and cardiac troponin T (cTnT)], as well as ECG and scintigraphic (99mTc-PYP) features were assessed. RESULTS: Compared to CN, DX significantly raised TNF-α, IL-6, and NO in heart tissue, cTnT in serum, 99mTc-PYP uptake in the myocardium, and ECG parameters, specifically QRS complex duration, QT interval duration, and ST-segment amplitude, while also reducing heart rate (p<0.001). Pretreatment with PR and VIT-D³ mitigated these abnormalities produced by DX in the heart (p<0.001). CONCLUSION: Results show that vitamin D receptor agonist paricalcitol and vitamin D protect against DX-induced cardiotoxicity through anti-inflammatory and antioxidant effects [ABSTRACT FROM AUTHOR]

Neointimal hyperplasia is the main cause of vascular graft failure in the medium term. Vitamin D receptor activation modulates the biology of vascular smooth muscle cells and has been reported to protect from neointimal hyperplasia following endothelial injury. However, the molecular mechanisms are poorly understood. We have now explored the impact of the selective vitamin D receptor activator, paricalcitol, on neointimal hyperplasia, following guidewire-induced endothelial cell injury in rats, and we have assessed the impact of paricalcitol or vehicle on the expression of key cell stress factors. Guidewire-induced endothelial cell injury caused neointimal hyperplasia and luminal stenosis and upregulated the expression of the growth factor growth/differentiation factor-15 (GDF-15), the cytokine receptor CD74, NFκB-inducing kinase (NIK, an upstream regulator of the proinflammatory transcription factor NFκB) and the chemokine monocyte chemoattractant protein-1 (MCP-1/CCL2). Immunohistochemistry confirmed the increased expression of the cellular proteins CD74 and NIK. Paricalcitol (administered in doses of 750 ng/kg of body weight, every other day) had a non-significant impact on neointimal hyperplasia and luminal stenosis. However, it significantly decreased GDF-15, CD74, NIK and MCP-1/CCL2 mRNA expression, which in paricalcitol-injured arteries remained within the levels found in control vehicle sham arteries. In conclusion, paricalcitol had a dramatic effect, suppressing the stress response to guidewire-induced endothelial cell injury, despite a limited impact on neointimal hyperplasia and luminal stenosis. This observation identifies novel molecular targets of paricalcitol in the vascular system, whose differential expression cannot be justified as a consequence of improved tissue injury. [ABSTRACT FROM AUTHOR]

Objective To explore the impact of paricalcitol（Pal) on the oxidative stress-induced tight junction damage of mouse hepatocytes and its mechanism. Methods A model of cholestatic liver injury was created by routine bile duct ligation. The mice were randomly divided into control group（control), model group（BDL) and treatment group（BDL+Pal) . HE staining microscopy was used to observe the morphological changes of liver tissues. The human hepatoma cell line HepG2 was cultured and divided into blank group, model group（400 μmol/L H2O2) and treatment group（400 μmol/L H2O2+20 nmol/L Pal) . Western blot was used to examine the level of tight junction protein 1（ZO-1), occludin, phosphorylated p65（p-p65), phosphorylated ERK（p-ERK) and phosphorylated myosin II regulated light chain（p-MLC) protein were checked in each group. Results Compared with the control group, the level of p-p65, p-ERK and p-MLC in the model group was significantly increased（P＜0.000 1 or P＜0.01 orP＜0.001) . The protein expression of ZO-1 and occludin was significantly decreased（P＜0.01) . HE staining microscopy showed an increased hepatocyte necrosis and inflammatory cell infiltration. In contrast, the above levels in the treatment group showed an opposite trend relative to the model group.Conclusions Pal is able to alleviate the damage of hepatocyte tight junctions by inhibiting oxidative stress in cholestatic mice and HepG2 cells. Its mechanism is potentially related to the inhibition of reactive oxygen species and NF-κB/p65 and ERK signaling pathways. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy (DN) is a specific kidney involvement in diabetes mellitus (DM), caused by hemodynamic and metabolic factors. In the kidneys takes place an important step in the metabolism of vitamin D — 1α-hydroxylation, which results in the formation of its biologically active form. Reduced number of functioning nephrons in DN leads to impaired vitamin D metabolism, contributing to the development of a number of complications. In this review, we have focused in detail on both normal vitamin D metabolism and the features of vitamin D metabolism in chronic kidney disease (CKD). DN is the most common cause of CKD and, as a consequence, of kidney transplantation and one of the leading causes of cardiovascular morbidity and mortality in patients with DM. Bone mineral disorders resulting from abnormal vitamin D metabolism are also independent factors of high mortality among patients with DM. The final part of our review briefly highlights current approaches to vitamin D therapy in CKD and, in particular, in DN. It is worth noting that, despite the increasing number of patients with DN, there is currently no unified view on the use of vitamin D as a therapeutic agent in this pathology.

Background: Previous studies investigating the effect of oral supplementation of paricalcitol on reactive protein levels in chronic kidney disease (CKD) patients reported inconsistent findings. In this systematic review and meta-analysis, we have analyzed and interpreted the results obtained from previous randomized clinical trials on the effect of paricalcitol on C-reactive protein in CKD patients in the literature. Methods: MEDLINE, SciVerse Scopus, and Clarivate Analytics Web of Science databases were searched until January 2023 and related articles were obtained through a careful screening process allowing extraction of required data from selected articles. The effect size was calculated using a random effect model and weighted mean differences (WMD) and 95% confidence intervals (CI). Heterogeneity among studies was evaluated using Cochran's Q test and I2. Results: Amongst the 182 articles obtained from the initial search, 4 studies (6 arms) were finally included in the meta-analysis. Pooled analysis shows that C-reactive protein levels significantly decrease after oral supplementation with paricalcitol (WMD: -2.55 mg/L, 95% CI (-4.99 to -0.11; P = 0.04). The studies used in this meta-analysis showed significant heterogeneity (I2 = 66.3% and P = 0.01). Conclusion: Oral paricalcitol supplementation in CKD patients can significantly reduce C-reactive protein levels, which may prevent CKD progression. [ABSTRACT FROM AUTHOR]

This study was designed to compare the beneficial effects of paricalcitol combined with or without cinacalcet on calcium and phosphorus metabolism in patients undergoing maintenance hemodialysis (MHD). A total of 140 patients who received MHD in our hospital from March 2021 to March 2022 were randomly divided into a control group (intravenous paricalcitol, n = 70) and a test group (intravenous paricalcitol combined with oral cinacalcet, n = 70). Clinical baseline data and relevant laboratory parameters before treatment were compared. Additionally, calcium, phosphorus, intact parathyroid hormone in serum were measured and compared between the 2 groups before treatment and 1, 2, 3, 4, 5, 6, 9, 10, and 12 months after treatment. As a result, comparison before treatment demonstrated no significant difference in baseline data such as age, sex, and most laboratory parameters between the 2 groups (P >.05), but there was a significant difference in mean corpuscular volume (P <.001). The serum phosphorus level decreased and calcium level increased significantly in the 2 groups after treatment, while the intact parathyroid hormone level showed no significant change within 12 months of treatment (P >.05). In addition, the combined treatment for 6‐12 months caused a much lower phosphorus level (P <.05) and higher calcium level (P <.05) than the treatment with paricalcitol alone, and the difference increased with the extension of treatment time. Collectively, paricalcitol combined with cinacalcet, which is more effective than paricalcitol alone, has a positive effect on calcium and phosphorus metabolism in patients receiving MHD. [ABSTRACT FROM AUTHOR]

Background: As the impacts of diabetes-induced reproductive damage are now evident in young people, we are now in urgent need to devise new ways to protect and enhance the reproductive health of diabetic people. The present study aimed to evaluate the protective effects of enalapril (an ACE inhibitor) and paricalcitol (a vitamin D analog), individually or in combination, on streptozotocin (STZ)-diabetes-induced testicular dysfunction in rats and to identify the possible mechanisms for this protection. Material and methods: This study was carried out on 50 male Sprague-Dawley rats; 10 normal rats were allocated as a non-diabetic control group. A total of 40 rats developed diabetes after receiving a single dose of STZ; then, the diabetic rats were divided into four groups of equivalent numbers assigned as diabetic control, enalapril-treated, paricalcitol-treated, and combined enalapril-and-paricalcitol-treated groups. The effects of mono and combined therapy with paricalcitol and enalapril on testicular functions, sperm activity, glycemic state oxidative stress, and inflammatory parameters, as well as histopathological examinations, were assessed in comparison with the normal and diabetic control rats. Results: As a result of diabetes induction, epididymal sperm count, sperm motility, serum levels of testosterone, follicle-stimulating hormone (FSH) as well as luteinizing hormone (LH), and the antioxidant enzyme activities, were significantly decreased, while abnormal sperm (%), insulin resistance, nitric oxide (NO), malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were significantly increased, along with severe distortion of the testicular structure. Interestingly, treatment with paricalcitol and enalapril, either alone or in combination, significantly improved the sperm parameters, increased antioxidant enzyme activities in addition to serum levels of testosterone, FSH, and LH, reduced insulin resistance, IL-6, and TNF-α levels, and finally ameliorated the diabetes-induced testicular oxidative stress and histopathological damage, with somewhat superior effect for paricalcitol monotherapy and combined therapy with both drugs compared to monotherapy with enalapril alone. Conclusions: Monotherapy with paricalcitol and its combination therapy with enalapril has a somewhat superior effect in improving diabetes-induced testicular dysfunction (most probably as a result of their hypoglycemic, antioxidant, anti-inflammatory, and anti-apoptotic properties) compared with monotherapy with enalapril alone in male rats, recommending a synergistic impact of both drugs. [ABSTRACT FROM AUTHOR]

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Background: As the impacts of diabetes-induced reproductive damage are now evident in young people, we are now in urgent need to devise new ways to protect and enhance the reproductive health of diabetic people. The present study aimed to evaluate the protective effects of enalapril (an ACE inhibitor) and paricalcitol (a vitamin D analog), individually or in combination, on streptozotocin (STZ)-diabetes-induced testicular dysfunction in rats and to identify the possible mechanisms for this protection. Material and methods: This study was carried out on 50 male Sprague-Dawley rats; 10 normal rats were allocated as a non-diabetic control group. A total of 40 rats developed diabetes after receiving a single dose of STZ; then, the diabetic rats were divided into four groups of equivalent numbers assigned as diabetic control, enalapril-treated, paricalcitol-treated, and combined enalapril-and-paricalcitol-treated groups. The effects of mono and combined therapy with paricalcitol and enalapril on testicular functions, sperm activity, glycemic state oxidative stress, and inflammatory parameters, as well as histopathological examinations, were assessed in comparison with the normal and diabetic control rats. Results: As a result of diabetes induction, epididymal sperm count, sperm motility, serum levels of testosterone, follicle-stimulating hormone (FSH) as well as luteinizing hormone (LH), and the antioxidant enzyme activities, were significantly decreased, while abnormal sperm (%), insulin resistance, nitric oxide (NO), malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were significantly increased, along with severe distortion of the testicular structure. Interestingly, treatment with paricalcitol and enalapril, either alone or in combination, significantly improved the sperm parameters, increased antioxidant enzyme activities in addition to serum levels of testosterone, FSH, and LH, reduced insulin resistance, IL-6, and TNF-α levels, and finally ameliorated the diabetes-induced testicular oxidative stress and histopathological damage, with somewhat superior effect for paricalcitol monotherapy and combined therapy with both drugs compared to monotherapy with enalapril alone. Conclusions: Monotherapy with paricalcitol and its combination therapy with enalapril has a somewhat superior effect in improving diabetes-induced testicular dysfunction (most probably as a result of their hypoglycemic, antioxidant, anti-inflammatory, and anti-apoptotic properties) compared with monotherapy with enalapril alone in male rats, recommending a synergistic impact of both drugs.

Vitamin D deficiency (VDD) is widespread around the world and has been extensively documented to affect various health conditions, including the cognitive functioning of the brain. Serum 25-hydroxylated forms of vitamin D are traditionally used to determine vitamin D status. However, there is now evidence that cholecalciferol activation can occur and be controlled by locally expressed enzymes in the brain. This study aimed to investigate the effects of cholecalciferol supplementation on cognitive function in rats who underwent transient VDD in adulthood. Thirty-six adult Wistar rats were administered paricalcitol (seven doses of 32 ng injected every other day) along with a “vitamin D-free” diet to induce VDD, which was confirmed using a LC–MS/MS serum analysis of the cholecalciferol and 25-hydroxyvitamin D3 levels. Treatment was performed by including 1000 IU/kg and 10,000 IU/kg cholecalciferol in the diet. Cognitive performance was evaluated using the novel object recognition (NOR), Morris water maze (MWM), and radial arm maze (RAM) tests. An immunohistochemical analysis of the brain regions involved in learning and memory was performed by quantifying the neurons, astrocytes, and microglia labelled with anti-neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), and ionized calcium-binding adaptor molecule 1 (Iba-1) antibodies, respectively. The vitamin D deficient group showed the lowest performance in both the MWM and RAM tests. In contrast, the cholecalciferol-treated groups exhibited a faster learning curve. However, no difference was detected between the groups in the NOR test. On the other hand, differences in the cellular organization of the hippocampus and amygdala were observed between the groups. Cholecalciferol supplementation decreased the density of the Iba-1- and GFAP-labeled cells in the hilus and cornu Ammonis 3 (CA3) regions of the hippocampus and in the amygdala. These results support vitamin D’s substantial role in learning and memory. They also highlight that subtle changes of cognitive function induced by transient VDD could be reversed by cholecalciferol supplementation. Further studies are needed to better understand VDD and cholecalciferol’s effects on the brain structure and function.

In the present study, the possible protective effects of paricalcitol (P) were investigated in testicular damage because of 1800 MHz radiofrequency radiation (RFR) exposure. Male Sprague Dawley rats 8–10 weeks old (n = 28) were randomly divided into four groups as control (C) (n = 7), RFR (n = 7, 1800 MHz RFR 1 h/day for 30 days), P (n = 7, 0.2 μg/kg paricalcitol, 3 times a week for 30 days), and RFR + P (n = 7, 1800 MHz RFR 1 h/day for 30 days +0.2 μg/kg paricalcitol, 3 times a week for 30 days). Testicular tissue was evaluated with histological and biochemical methods. No statistically significant differences were detected between the groups in seminiferous tubule diameters and germinal epithelial thicknesses. While ultrastructural changes were observed in the seminiferous tubule and Leydig cells in the RFR group, these changes were decreased in the RFR + P group. It was found that the Johnsen Score, Ki67, and p63 immunoreactivity scores (IRS), superoxide dismutase (SOD), and catalase (CAT) activities in the RFR + P group were statistically increased as compared to the RFR group and the malondialdehyde (MDA) levels were decreased statistically and significantly. These results show that paricalcitol administration may have an ameliorative effect on testicular damage occurring because of 1800 MHz RFR exposure. • RFR can damage testicular tissue. • RFR-induced testis damage may be associated with subfertility and/or infertility. • Paricalcitol decreased lipid peroxidation and increased antioxidant enzyme levels in tissue with RFR exposure. • Paricalcitol has a protective role in testicular tissue against the damaging effect of RFR. [ABSTRACT FROM AUTHOR]

Context. Different vitamin D analogs might have advantages over calcitriol. Objective. To evaluate the effects of paricalcitol vs. calcitriol based vitamin D receptor activators on calcium-phosphate metabolism and pulse wave velocity in hemodialysis patients. Design. Observational, cross-sectional and 1 year follow-up study. Subjects and Methods. 181 hemodialysis patients were enrolled in this study as divided in to 5 groups based on vitamin D therapy. Baseline and 12th month data on blood biochemistry, pulse wave velocity and cumulative dose of treatments were compared in each study group as well as in overall paricalcitol vs. calcitriol-based treatment groups. Results. From baseline to 12th month, significant improvement in pulse wave velocity and parathyroid hormone was shown in paricalcitol-based treatment group without a significant change in calcium, phosphate, alkaline phosphatase. A significant increase in pulse wave velocity, serum phosphate levels, calcium x phosphate product and serum alkaline phosphatase levels were noted in calcitriolbased treatment group with no significant change in serum calcium and parathyroid hormone levels. Conclusion. Our findings revealed superiority of paricalcitol than calcitriol based vitamin D receptor activator therapy in terms of serum phosphate levels, CaxP product, dose requirement for vitamin D and the control of pulse wave velocity. [ABSTRACT FROM AUTHOR]

Acute cardiomyopathy is a significant global health concern and one of the leading causes of death in developed countries. Prior studies have shown an association between acute cardiomyopathy and low vitamin D levels. Although paricalcitol, a vitamin D receptor (VDR) activator, has demonstrated clinical benefits in patients with advanced kidney disease, its effect on cardiac remodeling in cardiomyopathy is unknown. This study aimed to investigate the relative effects of paricalcitol on cardiomyopathy in rats. Wistar--Kyoto rats were administered vehicle (sham control group) or isoproterenol to induce cardiomyopathy. Rats administered isoproterenol were subsequently treated with paricalcitol (experimental group) or vehicle (isoproterenol group). Picrosirius red and immunofluorescence staining were used to analyze cardiac fibrosis and hypertrophy. Immunohistochemistry staining was used to confirm the molecular mechanisms involved in isoproterenol-induced cardiomyopathy in rats. Injection of paricalcitol could reduce collagen and transforming growth factor-beta 1 (TGF-β1) levels while activating fibroblast growth factor receptor 1 (FGFR1) and fibroblast growth factor-23 (FGF23) without the help of Klotho, thereby reducing myocardial hypertrophy and fibrosis. As a VDR activator, paricalcitol reduces isoproterenol-induced cardiac fibrosis and hypertrophy by reducing the expression of TGF-β1 and enhancing the expression of VDR, FGFR1, and FGF23. [ABSTRACT FROM AUTHOR]

Neointimal hyperplasia is the main cause of vascular graft failure in the medium term. Vitamin D receptor activation modulates the biology of vascular smooth muscle cells and has been reported to protect from neointimal hyperplasia following endothelial injury. However, the molecular mechanisms are poorly understood. We have now explored the impact of the selective vitamin D receptor activator, paricalcitol, on neointimal hyperplasia, following guidewire-induced endothelial cell injury in rats, and we have assessed the impact of paricalcitol or vehicle on the expression of key cell stress factors. Guidewire-induced endothelial cell injury caused neointimal hyperplasia and luminal stenosis and upregulated the expression of the growth factor growth/differentiation factor-15 (GDF-15), the cytokine receptor CD74, NFκB-inducing kinase (NIK, an upstream regulator of the proinflammatory transcription factor NFκB) and the chemokine monocyte chemoattractant protein-1 (MCP-1/CCL2). Immunohistochemistry confirmed the increased expression of the cellular proteins CD74 and NIK. Paricalcitol (administered in doses of 750 ng/kg of body weight, every other day) had a non-significant impact on neointimal hyperplasia and luminal stenosis. However, it significantly decreased GDF-15, CD74, NIK and MCP-1/CCL2 mRNA expression, which in paricalcitol-injured arteries remained within the levels found in control vehicle sham arteries. In conclusion, paricalcitol had a dramatic effect, suppressing the stress response to guidewire-induced endothelial cell injury, despite a limited impact on neointimal hyperplasia and luminal stenosis. This observation identifies novel molecular targets of paricalcitol in the vascular system, whose differential expression cannot be justified as a consequence of improved tissue injury.

Background Renoprotective effects of vitamin D analogues have been shown in several experimental and clinical studies, the exact mechanism of the therapeutic effectiveness of these analogues in Nephrotic syndrome remains unclear, and these are relatively few studies on potential treatment roles for vitamin D analogues in nephrotic-range proteinuria. ?ndicate similar efficacy of the vitamin D analogues calcitriol and paricalcitol in time-limited amelioration of proteinuria in nephrotic syndrome, yet suggest the likelihood of mechanisms other than direct upregulation of nephrin and podocin in podocytes underlie the renoprotective effects of vitamin D analogues. Objective To investigate the effect of vitamin D (Vit D) analogues calcitriol and paricalcitol on urinary protein/creatinine ratio (UPCR) and renal podocin and nephrin expression in a rat model of puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS). Methods A total of 28 male Wistar Albino rats were separated into 4 groups (n=7 for each) including CON [control; intraperitoneal (IP) saline injection], PAN (NS + IP saline injection), PAN-C (NS + IP 0.4 µg/kg/day calcitriol injection), and PAN-P (NS + IP 240 ng/kg/day paricalcitol injection). Nephrotic syndrome was induced via intravenous (IV) administration of 10mg/100gr PAN. The UPCR as well as histopathological, immuno-histochemical, and real time PCR analyses of kidney tissue specimens were recorded and analyzed among the 4 groups. Results Median UPCR (Day 4) was significantly lower in both the PAN-C [1.45 (range 1.20-1.80)] and PAN-P [1.40 (range 1.10-1.80)] groups than in the PAN group [2.15 (range 2.00-2.40)] (P

Screening for Type 1 Diabetes (T1D, incidence 1:300) with T1D autoantibodies (T1Ab) at ages 2 and 6, while sensitive, lacks a preventive strategy. Cholecalciferol 2000 IU daily since birth reduced T1D by 80% at 1 year. T1D-associated T1Ab negativized within 0.6 years with oral calcitriol in 12 children. To further investigate secondary prevention of T1D with calcitriol and its less calcemic analog, paricalcitol, we initiated a prospective interventional non-randomized clinical trial, the PRECAL study (ISRCTN17354692). In total, 50 high-risk children were included: 44 were positive for T1Ab, and 6 had predisposing for T1D HLA genotypes. Nine T1Ab+ patients had variable impaired glucose tolerance (IGT), four had pre-T1D (3 T1Ab+, 1 HLA+), nine had T1Ab+ new-onset T1D not requiring insulin at diagnosis. T1Ab, thyroid/anti-transglutaminase Abs, glucose/calcium metabolism were determined prior and q3–6 months on calcitriol, 0.05 mcg/Kg/day, or paricalcitol 1–4 mcg × 1–3 times/day p.o. while on cholecalciferol repletion. Available data on 42 (7 dropouts, 1 follow-up < 3 months) patients included: all 26 without pre-T1D/T1D followed for 3.06 (0.5–10) years negativized T1Ab (15 +IAA, 3 IA2, 4 ICA, 2 +GAD, 1 +IAA/+GAD, 1 +ICA/+GAD) within 0.57 (0.32–1.3) years or did not develop to T1D (5 +HLA, follow-up 3 (1–4) years). From four pre-T1D cases, one negativized T1Ab (follow-up 1 year), one +HLA did not progress to T1D (follow-up 3.3 years) and two +T1Ab patients developed T1D in 6 months/3 years. Three out of nine T1D cases progressed immediately to overt disease, six underwent complete remission for 1 year (1 month–2 years). Five +T1Ab patients relapsed and negativized again after resuming therapy. Four (aged <3 years) negativized anti-TPO/TG, and two anti-transglutaminase-IgA. Eight presented mild hypercalciuria/hypercalcemia, resolving with dose titration/discontinuation. Secondary prevention of T1D with calcitriol and paricalcitol seems possible and reasonably safe, if started soon enough after seroconversion. [ABSTRACT FROM AUTHOR]

Currently, the incidence and prevalence of chronic kidney disease (CKD) are increasing annually worldwide, and clinical data show that CKD patients commonly experience relative vitamin D insufficiency or deficiency. Secondary hyperparathyroidism (SHPT) is a common complication in patients with end-stage renal disease and it is also common in hemodialysis patients. SHPT is an adaptive and in many cases ultimately maladaptive process that develops in response to declining kidney function, impaired phosphate excretion, failure to bioactivate vitamin D and hypocalcemia. SHPT is characterized by persistently elevated levels of parathyroid hormone (PTH) and complicated by important disturbances in mineral metabolism. Maintaining the level of vitamin D and parathyroid hormone concentrations in the target range reduce its associated complications (e.g., fractures, chronic kidney disease and cardiovascular calcification). Effective therapeutic interventions are highly desirable if the morbidity and mortality associated with uncontrolled SHPT are to be reduced. Major renal guidelines recommend use of vitamin D for secondary hyperparathyroidism in chronic kidney disease. However, because of the difficulties associated with lowering PTH while simultaneously controlling serum levels of calcium and phosphorous, traditional therapies for managing SHPT have several limitations. Selective vitamin D receptor activator paricalcitol mainly targets vitamin D receptors (VDR) in the parathyroid glands, has less effect on VDR in the intestine and other tissues, inhibits PTH strongly, triggers less hypercalcemia, and has less effect on intestinal absorption of calcium, phosphorus and bone metabolism and significantly lowers renin levels, albuminuria and blood pressure, which is supported by the results of most studies conducted over these decades. The article is devoted to the problem of treatment of patients with SHPT inpatient with renal replacement therapy with program hemodialysis.

ABSTRACT Introduction For the reduction of PTH levels, two classes of drugs are available in the Brazilian market: non-selective and selective vitamin D receptor activators and calcimimetics. Among the mentioned drugs, the SUS provides oral calcitriol, paricalcitol and cinacalcet. Objectives: Develop cost-effectiveness (CE) and budgetary impact (BI) analysis of cinacalcet versus paricalcitol for patients on dialysis with SHPT, from the perspective of SUS. Methodology: A decision tree model was constructed for CE analysis, which considered the outcome of avoided parathyroidectomy and a time horizon of 1 year. As for the BI analysis, two scenarios were considered, one of which was measured demand and other epidemiological, based on data from the Brazilian Society of Nephrology (BSN). Results: The CE analysis showed that the use of cinacalcet results in one-off savings of R$1,394.64 per year and an incremental effectiveness of 0.08, in relation to avoided parathyroidectomy. The incremental CE ratio (ICER) was - R$ 17,653.67 per avoided parathyroidectomy for cinacalcet, as it was more effective and cheaper compared to paricalcitol. As for the BI analysis, it was estimated that the incremental BI with the expansion of the use of cinacalcet in the SUS will be between - R$ 1,640,864.62 and R$ 166,368.50 in the first year, considering the main and the epidemiological scenarios. At the end of 5 years after the expansion of use, an BI was estimated between - R$ 10,740,743.86 and - R$ 1,191,339.37; considering the same scenarios. Conclusion: Cinacalcet was dominant to avoid parathyroidectomies, being cost-effective.

Simple Summary: Pancreatic carcinoma is one of the malignancies with the highest cancer-specific mortality. While invading the microenvironment and the dense stroma, the immune system plays a key role in the pathological development, as well as in the treatment of pancreatic tumors. In this review, evidence-based treatment options, including standard oncological treatment and integrative therapies, such as hyperthermia, electroporation, intra-tumoral injections, phytochemical preparations or vitamins to improve the prognosis of patients with pancreatic cancer, are presented and discussed. Numerous clinical studies have been conducted to improve the outcomes of patients suffering from pancreatic cancer. Different approaches using targeted therapeutic strategies and precision medicine methods have been investigated, and synergies and further therapeutic advances may be achieved through combinations with integrative methods. For pancreatic tumors, a particular challenge is the presence of a microenvironment and a dense stroma, which is both a physical barrier to drug penetration and a complex entity being controlled by the immune system. Therefore, the state of immunological tolerance in the tumor microenvironment must be overcome, which is a considerable challenge. Integrative approaches, such as hyperthermia, percutaneous irreversible electroporation, intra-tumoral injections, phytotherapeutics, or vitamins, in combination with standard-oncological therapies, may potentially contribute to the control of pancreatic cancer. The combined application of standard-oncological and integrative methods is currently being studied in ongoing clinical trials. An actual overview is given here. [ABSTRACT FROM AUTHOR]

Effective and targeted prevention and treatment methods for acute kidney injury (AKI), a common clinical complication, still needs to be explored. Paricalcitol is a biologically active chemical that binds to vitamin D receptors in the body to exert anti-oxidant and anti-inflammatory effects. However, the molecular mechanism of the effect of paricalcitol on AKI remains unclear. The current study uses a paricalcitol pretreatment with a mouse AKI model induced by cisplatin to detect changes in renal function, pathology and ultrastructure. Results showed that paricalcitol significantly improved renal function in mice and reduced inflammatory cell infiltration and mitochondrial damage in renal tissue. Furthermore, paricalcitol markedly suppressed reactive oxygen species and malondialdehyde levels in the kidneys of AKI mice and increased the levels of glutathione, superoxide dismutase, Catalase and total anti-oxidant capacity. In addition, we detected renal necrosis and inflammation-related proteins in AKI mice by immunofluorescence and Western blot, and found that their levels were markedly decreased after paricalcitol pretreatment. Moreover, paricalcitol promotes nuclear factor erythroid 2-related factor 2 (Nrf2) in the nucleus and activates the Nrf2/heme oxygenase-1 (HO-1) signaling pathway; while HO-1 is inhibited, the protective effect of paricalcitol on the kidney is attenuated. In conclusion, paricalcitol exerts a renoprotective effect by decreasing renal oxidative injury and inflammation through Nrf2/HO-1 signaling, providing a new insight into AKI prevention. [ABSTRACT FROM AUTHOR]

Renal endothelial cell (EC) injury and microvascular dysfunction contribute to chronic kidney disease (CKD). In recent years, increasing evidence has suggested that EC undergoes an endothelial-to-mesenchymal transition (EndoMT), which might promote fibrosis. Adriamycin (ADR) induces glomerular endothelial dysfunction, which leads to progressive proteinuria in rodents. The activation of the vitamin D receptor (VDR) plays a crucial role in endothelial function modulation, cell differentiation, and suppression of the expression of fibrotic markers by regulating the production of nitric oxide (NO) by activating the endothelial NO synthase (eNOS) in the kidneys. This study aimed to evaluate the effect of paricalcitol treatment on renal endothelial toxicity in a model of CKD induced by ADR in rats and explore mechanisms involved in EC maintenance by eNOS/NO, angiopoietins (Angs)/endothelium cell-specific receptor tyrosine kinase (Tie-2, also known as TEK) and vascular endothelial growth factor (VEGF)-VEGF receptor 2 (VEGFR2) axis. The results show that paricalcitol attenuated the renal damage ADR-induced with antiproteinuric effects, glomerular and tubular structure, and function protection. Furthermore, activation of the VDR promoted the maintenance of the function and structure of glomerular, cortical, and external medullary endothelial cells by regulating NO production. In addition, it suppressed the expression of the mesenchymal markers in renal tissue through attenuation of (transforming growth factor-beta) TGF-β1/Smad2/3-dependent and downregulated of Ang-2/Tie-2 axis. It regulated the VEGF/VEGFR2 pathway, which was ADR-deregulated. These effects were associated with lower AT1 expression and VDR recovery to renal tissue after paricalcitol treatment. Our results showed a protective role of paricalcitol in the renal microvasculature that could be used as a target for treating the beginning of CKD. [ABSTRACT FROM AUTHOR]

The lack of therapeutics along with complex pathophysiology made non-alcoholic fatty liver disease (NAFLD) a research hotspot. Studies showed that the deficiency of Vitamin D plays a vital role in NAFLD pathogenesis. While several research studies focused on vitamin D supplementation in NAFLD, there is still a need to understand the regulatory mechanism of direct vitamin D receptor activation in NAFLD. In the present study, we explored the role of direct Vitamin D receptor activation using paricalcitol in choline-deficient high-fat diet-induced NAFLD rat liver and its modulation on protein acetylation. Our results showed that paricalcitol administration significantly reduced the fat accumulation in HepG2 cells and the liver of NAFLD rats. Paricalcitol attenuated the elevated serum level of alanine transaminase, aspartate transaminase, insulin, low-density lipoprotein, triglyceride, and increased high-density lipoprotein in NAFLD rats. Paricalcitol significantly decreased the increased total protein acetylation by enhancing the SIRT1 and SIRT3 expression in NAFLD liver. Further, the study revealed that paricalcitol reduced the acetylation of NFκB and FOXO3a in NAFLD liver along with a decrease in the mRNA expression of IL1β, NFκB, TNFα, and increased catalase and MnSOD. Moreover, total antioxidant activity, glutathione, and catalase were also elevated, whereas lipid peroxidation, myeloperoxidase, and reactive oxygen species levels were significantly decreased in the liver of NAFLD after paricalcitol administration. The study concludes that the downregulation of SIRT1 and SIRT3 in NAFLD liver was associated with an increased acetylated NFκB and FOXO3a. Paricalcitol effectively reversed hepatic inflammation and oxidative stress in NAFLD rats through transcriptional regulation of NFκB and FOXO3a, respectively, by inhibiting their acetylation. Role of paricalcitol in inhibiting oxidative stress and inflammation in NAFLD by regulating acetylation of FOXO3A and NFκB. [Display omitted] [ABSTRACT FROM AUTHOR]

Background Renoprotective effects of vitamin D analogues have been shown in several experimental and clinical studies. The exact mechanism of the therapeutic effectiveness of these analogues in nephrotic syndrome remains unclear, and these are relatively few studies on potential treatment roles for vitamin D analogues in nephrotic-range proteinuria. İndicate similar efficacy of the vitamin D analogues calcitriol and paricalcitol in time-limited amelioration of proteinuria in nephrotic syndrome, yet suggest the likelihood of mechanisms other than direct upregulation of nephrin and podocin in podocytes underlie the renoprotective effects of vitamin D analogues. Objective To investigate the effect of vitamin D analogues calcitriol and paricalcitol on urinary protein/creatinine ratio (UPCR) and renal podocin and nephrin expression in a rat model of puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS). Methods A total of 28 male Wistar Albino rats were separated into 4 groups (n=7 for each) including CON [control; intraperitoneal (IP) saline injection], PAN (NS + IP saline injection), PAN-C (NS + IP 0.4 µg/kg/day calcitriol injection), and PAN-P (NS + IP 240 ng/kg/day paricalcitol injection). Nephrotic syndrome was induced via intravenous (IV) administration of 10mg/100gr PAN. The UPCR as well as histopathological, immuno-histochemical, and real time PCR analyses of kidney tissue specimens were recorded and analyzed among the 4 groups. Results Median UPCR (Day 4) was significantly lower in both the PAN-C [1.45 (range 1.20-1.80)] and PAN-P [1.40 (range 1.10- 1.80)] groups than in the PAN group [2.15 (range 2.00-2.40)] (P<0.01 for each). The PAN group had significantly higher mean UPCR than the CON group [1.75 (range 1.40-2.00); P<0.05]. No significant difference in UPCR was noted between groups on Day 7. Median podocin mRNA expression was significantly higher in the PAN-P group compared to the PAN group [22.55 (range 22.42-23.02) vs. 22.06 (range 21.81-22.06), respectively; (P<0.01)]. Conclusion Seven-day calcitriol and paricalcitol supplementation in a rat model of PAN-induced nephrotic syndrome have similar efficacy, in terms of temporary amelioration of proteinuria. [ABSTRACT FROM AUTHOR]

Objective: Chronic kidney disease is common, irreversible, and associated with high mortality and morbidity. In this study, we aimed to investigate the effects of calcitriol and paricalcitol on chronic kidney disease progression in an adenine induced uremic rat model. Methods: Male Wistar-albino rats were fed a diet containing 0.75% adenine + 1.2% phosphorus for 3 weeks to induce chronic kidney disease. The rats were randomly divided into 6 groups: control group (n = 12), chronic kidney disease group (n = 12), chronic kidney disease+ calcitriol group (n = 12), chronic kidney disease +paricalcitol group (n = 12), calcitriol group (n = 6), paricalcitol group (n = 6). Animals were monitored for weight and systolic blood pressure. The kidney function parameters, parathyroid hormone, monocyte chemoattractant protein-1, and kidney histology were investigated. This research was supported by the Scientific Research Projects Unit (11-TIP-062). Results: Kidney histology proved that the adenine-induced uremic rat model was successfully established. Serum urea, creatinine, and phosphorus were significantly higher in chronic kidney disease, chronic kidney disease + calcitriol, chronic kidney disease +paricalcitol groups compared with the control group (P < .05). Calcitriol and paricalcitol provide effective parathyroid hormone suppression and decrease serum monocyte chemoattractant protein-1 levels in uremic rats. All uremic rats, including the paricalcitol and calcitriol treatment groups, lost weight. Paricalcitol significantly lowered systolic blood pressure in uremic rats (P = .006). Serum calcium was higher in calcitriol group compared with chronic kidney disease group. Paricalcitol caused less hyperphosphatemia in non-uremic rats than calcitriol. Conclusion: Paricalcitol and calcitriol therapy may prevent chronic kidney disease progression in uremic rats as they restore vitamin D metabolism during the disease. [ABSTRACT FROM AUTHOR]

N-Acetylcysteine (NAC) is used for contrast induced acut kidney injury (CI-AKI) prophylaxis because of its antioxidant effects. Paricalcitol, which has reno-protective effects, is likely to provide a more effective prophylaxis when added to NAC treatment. The study was designed based on this hypothesis. The study was organised to include 4 groups each consisting of 7 rats. Group 1 was the control group, and Group 2 included rats with CI-AKI. Rats in Group 3 were administered NAC at a dose of 100 mg/kg via oral gavage once a day for 5 days. Rats in group 4 were administered paricalcitol at a dose of 0.4 mcg/kg once a day for 5 days in addition to NAC. CI-AKI was induced after the treatments in both groups. The study was terminated on the sixth day. Samples were collected from the rats' sera and kidney tissues to study oxidant and antioxidant parameters; kidney function tests were also studied. There were significant differences between the contrast nephropathy group (Group 2) and NAC and NAC+paricalcitol groups with respect to serum urea and creatinine levels. When the same groups were compared regarding oxidant (TOS-MDA) and antioxidant (TAC-Paraoxonase) parameters, we observed that the oxidant parameters increased in serum and kidney tissue samples with NAC use, and that effect was strengthened by the addition of paricalcitol to NAC treatment. However, despite increased antioxidant effectiveness, we observed no decrease in urea and creatinine levels when paricalcitol was added for CI-AKI in rats. There was no significant difference between Group 3 and Group 4. Paricalcitol provides a more potent antioxidant effect in both serum and kidney tissue samples when added to NAC treatment in rats with CI-AKI. Despite increased antioxidant parameters, however, paricalcitol does not provide a significant decrease in urea and creatinine levels. [ABSTRACT FROM AUTHOR]

Introduction:Secondary hyperparathyroidism is considered an unconventional risk factor of vascular calcification in hemodialysis patients (HPs). An important factor of vascular calcification is vitamin D receptor activator used in the treatment of secondary hyperparathyroidism. This study aimed to investigate the change in pulse wave velocity (PWV) and fibroblast growth factor-23 (FGF-23), Klotho, and 25-hydroxyvitamin D [25(OH)D] levels as a result of 1-year treatment with paricalcitol or calcitriol among patients undergoing chronic dialysis.Methods:Eighty HPs were included in the study, and PWV measurements were obtained at the beginning and after 1 year of treatment. Serum Klotho and 25(OH)D levels were evaluated at the end of 1-year treatment with paricalcitol or calcitriol.Results:At the end of 1 year, FGF-23 levels in the paricalcitol group were significantly lower than those in the calcitriol group. Klotho and 25(OH)D levels were significantly higher in the paricalcitol group. The PWV at the beginning of the study was statistically similar between the two groups; in contrast, PWV at 1 year was significantly lower in the paricalcitol group than in the calcitriol group (p=0.002). When the PWV change was considered as the dependent variable, the most powerful determinant in multiple regression analysis was the FGF-23 level.Conclusion:In HPs, paricalcitol has a protective effect against vascular calcification compared with calcitriol treatment, owing to its positive effects on both parathyroid hormone and calcium-phosphorus balance. Therefore, paricalcitol should be the first choice in the treatment of secondary hyperparathyroidism.

The vitamin D receptor (VDR) is associated with antioxidative and anti-inflammatory effects and modulation of the renin-angiotensin-aldosterone system. This study evaluated whether VDR agonist paricalcitol protects renal ischemia-reperfusion (IR) induced tubular injury in rats by evaluating: 1) ATP-dependent tubular Na+ transport; 2) renal redox signaling; 3) renal content of proinflammatory cytokines TNF-α and IL-6; and 4) renal content of renin and angiotensin II receptor type 1 (AT 1 R). Paricalcitol prevented IR-induced tubular injury, evidenced by the prevention of histopathological changes and renal fibrosis with preservation of the activity of ATP-dependent Na+ transporters in the renal cortex. Paricalcitol decreased renal oxidative stress by reducing NADPH oxidase activity and increasing catalase. Paricalcitol also decreased the renal content of TNF-α, IL-6, and AT 1 R. The NADPH oxidase inhibitor apocynin did not present additive protection to paricalcitol-induced effects. The protective effects of paricalcitol on tubular injury induced by renal IR may dependent on the modulation of redox and proinflammatory signaling and renal angiotensin II/AT 1 R signaling. [Display omitted] • The renal ischemia-reperfusion (IR) impairs ATP-dependent Na+ transport. • The vitamin D receptor (VDR) may be a therapeutic target in renal injury. • The VDR agonist Paricalcitol decreased renal oxidative stress. • Paricalcitol decreased renal content of inflammatory cytokines and AT1R. • Paricalcitol protected ATP-dependent Na+ transport from IR induced changes. [ABSTRACT FROM AUTHOR]

Abstract Introduction: Hyperparathyroidism (SHPT) secondary to chronic kidney disease (CKD) is characterized by high levels of parathyroid hormone (PTH), hyperplasia of the parathyroid glands and cardiovascular disease. Selective and non-selective and selective vitamin D-receptor activators, calcimimetics, are available in the Brazilian market to reduce PTH levels. Objectives: To develop a cost-effectiveness (C/E) and budgetary impact (BI) analysis of intravenous paricalcitol vs. oral calcitriol for patients on dialysis with SHPT, from the perspective of the Brazilian Public Health Care System (SUS). Methodology: We built a decision-tree model to analyze C/E, which considered the outcome of avoided death and a time horizon of 1 year. As for the BI analysis, two scenarios were considered, one of demand and one of epidemiological approach, based on data from the Brazilian Society of Nephrology. Results: The analysis showed that the C/E ratio was R$ 1,213.68 per year, and an incremental effectiveness of 0.032, referring to avoided death. The incremental C/E ratio was R$37,927.50 per death averted by paricalcitol. It was estimated that the incremental BI with the expansion of paricalcitol use will be between R$1,600,202.28 and R$4,128,565.65 in the first year, considering the main and epidemiological scenarios. At the end of 5 years after the expansion of its use, an incremental BI was estimated between R$ 48,596,855.50 and R$ 62,90,555.73. Conclusion: Intravenous paricalcitol has superior efficacy and similar safety to oral calcitriol, reducing the overall mortality of dialysis patients, although it implies a higher cost.

Mineral and bone disorders in chronic kidney disease (CKD) is a systemic disorder of mineral and bone metabolism due to CKD manifested by either one or a combination of the following: abnormalities of calcium, phosphorus, PTH, or vitamin D metabolism (secondary hyperparathyroidism); abnormalities in bone turnover, mineralization, volume, linear growth, or strength; or vascular or other soft tissue calcification. Decreasing 1,25(OH)2D (calcitriol) and rising parathyroid hormone (PTH) levels occur on early stages of CKD. Secondary hyperparathyroidism contributes to the high morbidity and mortality noted in this population. Long-term decompensation of secondary hyperparathyroidism in patients with impaired renal function leads to irreversible changes in multiple organ systems, resistance to conservative treatment and the requirement for surgical intervention. Suppress of renal CYP27B1 and the calcitriol deficiency play a major role in the development of mineral and bone disorders in CKD, thus VDR activators are widely used for management of secondary hyperparathyroidism. These medications are effective in suppression of PTH and demonstrate the positive effects on bone metabolism. There is evidence of pleiotropic effects of VDR activators that are crucial for the prevention of renal fibrosis and extraskeletal calcification. This review focuses on the involvement of vitamin D in the pathogenesis of mineral and bone disorders and the role of paricalcitol in their correction. The efficacy of paricalcitol in patients with various stages of CKD has been evaluated in a large number of observational and randomized clinical trials, the comparative effectiveness of paricalcitol therapy has been summarized in several metanalyses.

In our previous work, we evaluated the therapeutic effects of 1α,25-Dihydroxyvitamin D3, the biologically active form of vitamin D, in the context of bleomycin-induced lung fibrosis. Contrary to the expected, vitamin D supplementation increased the DNA damage expression and cellular senescence in alveolar epithelial type II cells and aggravated the overall lung pathology induced in mice by bleomycin. These effects were probably due to an alteration in the cellular DNA double-strand breaks' repair capability. In the present work, we have evaluated the effects of two hypocalcemic vitamin D analogs (calcipotriol and paricalcitol) in the expression of DNA damage in the context of minilungs derived from human embryonic stem cells and in the cell line A549. [ABSTRACT FROM AUTHOR]

Rationale & Objective: Mineral and bone disorder in chronic kidney disease (CKD) is associated with progression of coronary artery calcification (CAC). Mineral and bone disorder often is treated with calcitriol and other vitamin D receptor activators, including paricalcitol, agents that may have differential effects on calcium, phosphate, and parathyroid hormone levels. Accordingly, we investigated whether these agents have differential effects on CAC progression in patients with CKD. Study Design: Randomized, double-concealed, 48-week clinical trial. Setting & Participants: CKD stage 3 or 4 with secondary hyperparathyroidism with CAC score > 0 and no prior treatment with activated vitamin D. Intervention: Calcitriol versus paricalcitol. Outcomes: The primary outcome was log-transformed CAC change. Secondary outcomes included percent change in CAC volume, valvular calcifications, and bone mineral metabolism markers. Results: Among 44 individuals randomly assigned, mean age was 65 years and mean estimated glomerular filtration rate was 27 mL/min/1.73 m2. Median CAC score was 140 (IQR, 55-277) Agatston units at baseline. There was no significant difference in CAC progression between treatment arms (P = 0.06). After adjustment for baseline CAC score (log), treatment group remains nonsignificant (P = 0.08). Further adjustment for creatinine level and/or CKD stage did not change the association. In secondary analyses adjusting for dose level of activated vitamin D, treatment group was significant (P = 0.01), and when dose level was also included in the model, the coefficient for individuals in the paricalcitol group was significantly associated with CAC progression (P = 0.02). An interaction term between dosing level and CKD stage was significant at the highest dosing level (P = 0.04). Limitations: Pilot single-center study. Conclusions: In patients with CKD with secondary hyperparathyroidism naive to activated vitamin D therapy, there was no difference in CAC or valvular progression in participants receiving calcitriol compared with paricalcitol during a 48-week period. Funding: Abbvie, Inc. Trial Registration: NCT00752102

Abstract Background Paricalcitol is known to attenuate ischemic-reperfusion injury of various organs. However, it is not known whether paricalcitol prevents neuronal injury after global cerebral ischemia. The purpose of this study is to investigate the neuroprotective effect of paricalcitol in a rat model of transient global cerebral ischemia. Methods This is a prospective, randomized experimental study. Male Sprague-Dawley rats that survived 10 min of four-vessel occlusion were randomly assigned to two treatment groups: one group was treated with paricalcitol 1 μg/kg IP, and the other was given an equivalent volume of normal saline IP. Drugs were administered at 5 min, 1 day, 2 days, and 3 days after ischemia. Neurologic function was assessed at 2 h, 1 day, 2 days, 3 days, and 4 days after ischemia. We tested motor function 3 days after ischemia using the rotarod test. Also, we tested memory function 4 days after ischemia using the passive avoidance test. We assessed neuronal degeneration in the hippocampus of surviving rats 4 days after ischemia. Results Eight rats were allocated to each group. No significant differences were found between the groups in terms of survival rate, motor coordination, or memory function. The neurological function score 2-h post-ischemia was significantly higher in the paricalcitol group (p = 0.04). Neuronal degeneration was significantly less in the paricalcitol group compared with the control group (p = 0.01). Conclusions Paricalcitol significantly attenuated neuronal injury in the hippocampus. Although motor coordination, memory function, and survival rate were not significantly improved by paricalcitol treatment in this study, paricalcitol remains a potential neuroprotective drug after global cerebral ischemia.

Backward: Cardiovascular events are the major cause of morbidity and mortality in patients with chronic kidney disease (CKD). Inflammation and mineral-bone disorder are pathological conditions that have been associated with an increased cardiovascular risk. Objective: Show paricalcitol regulation overinflammatory, fibrotic and mineral disorder parameters in CKD. Material and methods: Prospective study in 46 CKD stages III–V patients without dialysis patients with elevated parathormone in which we introduced paricalcitol. We evaluated classic and newest mineral and bone metabolism serum parameters (calcium, phosphorus, parathormone, fibroblast growth factor-23 [FGF-23], Klotho, calcidiol), inflammatory-fibrosis and anticalcifying parameters (interleukin-6 and 10, tumor necrosis factor-α [TNF-α], transforming growth factor-β [TGF-β], bone morphogenic protein-7 [BMP-7] and fetuin-A) for four months. Results: At the end of study soluble Klotho increased (p = 0.001), FGF-23 remained stable, calcium and phosphorus levels were not increased, calcidiol increased (p = 0.010) and PTH decreased (p = 0.002). Inflammation-fibrosis and calcification parameters showed positive regulation after paricalcitol treatment: interleukin-6 decreased significantly (p = 0.001) and also TNF-α did (p = 0.005), on the contrary, interleukin-10 and fetuin-A increased (p = 0.001 for both). Anti-fibrosis marker BMP-7 increased (p = 0.001) and TGF-β decreased (p = 0.001). We did not find significant changes in renal function. Conclusions: Paricalcitol treatment might be profitable in regulating inflammatory and anticalcificant parameters, unmodified calcium or phosphorus seric levels and preserving kidney function in renal patients with no dialysis. Our selected parameters could indicate paricalcitol effects in mineral and endothelial disorder related to renal disease. Resumen: Antecedentes: La principal causa de morbimortalidad en el paciente con enfermedad renal crónica (ERC) es la cardiovascular. La inflamación y las alteraciones en el metabolismo óseo-mineral en estos pacientes conllevan aumento del riesgo cardiovascular. Objetivos: Valorar el papel de paricalcitol sobre distintos parámetros séricos relacionados con inflamación, fibrosis y enfermedad óseo-mineral en la ERC. Material y métodos: Estudio prospectivo, no controlado en 46 pacientes con ERC estadios III-V sin diálisis, con niveles elevados de paratohormona, según su estadio de ERC, por lo que se introdujo tratamiento con el análogo de vitamina D paricalcitol. Durante 4 meses de tratamiento valoramos los parámetros clásicos y novedosos del metabolismo óseo-mineral en suero (calcio, fósforo, paratohormona, factor de crecimiento fibroblástico-23 [FGF-23], Klotho y calcidiol) y parámetros relacionados con el proceso de inflamación-fibrosis y anticalcificantes (interleucina-6 y 10, factor de necrosis tumoral alfa [TNF-a], factor de crecimiento transformante beta [TGF-b], proteína ósea morfogénica-7 [BMP-7], y fetuína-A). Resultados: Tras el uso de paricalcitol los niveles de Klotho aumentaron (p = 0,001) y los de FGF-23 se mantuvieron estables al igual que los de calcio y fósforo; calcidiol aumentó de forma significativa (p = 0,010) y paratohormona descendió (p = 0,002). Los parámetros de inflamación, fibrosis y calcificación mostraron una regulación benigna con descenso significativo de interleucina-6 (p = 0,001), TNF-α (p = 0,005) y TGF-β (p = 0,001) y aumento de BMP-7 (p = 0,001), fetuína-A (p = 0,001) e interleucina-10 (p = 0,001). El filtrado glomerular y la proteinuria se mantuvieron estables. Conclusiones: El tratamiento con paricalcitol en el paciente renal sin diálisis parece ser beneficioso en la regulación de los parámetros inflamatorios y anticalcificantes, preservando la función renal y el eje óseo-mineral. Los marcadores elegidos en nuestro estudio podrían indicarnos un efecto positivo de paricalcitol a nivel vascular.