Adipocyte induced arterial calcification is prevented with sodium thiosulfate

Similarities and Differences of Vascular Calcification in Diabetes and Chronic Kidney Disease

Presently, the mechanism of occurrence and development of vascular calcification (VC) is not fully understood; a range of evidence suggests a positive association between diabetes mellitus (DM) and VC. Furthermore, the increasing burden of central vascular disease in patients with chronic kidney disease (CKD) may be due, at least in part, to VC. In this review, we will review recent advances in the mechanisms of VC in the context of CKD and diabetes. The study further unveiled that VC is induced through the stimulation of pro-inflammatory factors, which in turn impairs endothelial function and triggers similar mechanisms in both disease contexts. Notably, hyperglycemia was identified as the distinctive mechanism driving calcification in DM. Conversely, in CKD, calcification is facilitated by mechanisms including mineral metabolism imbalance and the presence of uremic toxins. Additionally, we underscore the significance of investigating vascular alterations and newly identified molecular pathways as potential avenues for therapeutic intervention.

The application of MDT model for calciphylaxis management in patients with end-stage renal disease

This study focuses on the application of nurse-led multidisciplinary collaborative therapy (MDT) management model for calciphylaxis prevention of patients with terminal renal disease. Through the establishment of a multidisciplinary management team spanning nephrology department, blood purification center, dermatology department, burn and plastic surgery department, infection department, stem cell platform, nutrition department, pain department, cardiology department, hydrotherapy group, dermatology group, and outpatient treatment room, the distribution of duties among team members were clarified to bring out the best advantages of a multidisciplinary teamwork during treatment and nursing. For patients with calciphylaxis symptoms in terminal renal disease, a case-by-case management model was carried out with the focus on personalised problem. We emphasised on personalised wound care, precise medication care, active pain management, psychological intervention and palliative care, the amelioration of calcium and phosphorus metabolism disorder, nutritional supplementation, and the therapeutic intervention based on human amniotic mesenchymal stem cell regeneration. The MDT model effectively compensates for traditional nursing mode and could serve as a novel clinical management modality for calciphylaxis prevention in patients with terminal renal disease.

Influence of sodium thiosulfate on coronary artery calcification of patients on dialysis: a meta-analysis

Coronary artery calcification (CAC) is common in dialysis patients and is associated with a higher risk of future cardiovascular events. Sodium thiosulfate (STS) is effective for calciphylaxis in dialysis patients; however, the influence of STS on CAC in dialysis patients remains unclear. This systematic review and meta-analysis were conducted to evaluate the effects of STS on CAC in patients undergoing dialysis. PubMed, Embase, Cochrane Library, CNKI, and Wanfang databases were searched from inception to 22 March 2023 for controlled studies comparing the influence of STS versus usual care without STS on CAC scores in dialysis patients. A random effects model incorporating the potential influence of heterogeneity was used to pool the results. Nine studies, including two non-randomized studies and seven randomized controlled trials, were included in the meta-analysis. Among these, 365 patients on dialysis were included in the study. Compared with usual care without STS, intravenous STS for 3-6 months was associated with significantly reduced CAC scores (mean difference [MD] = -180.17, 95% confidence interval [CI]: -276.64 to -83.70, p < 0.001, I2 = 0%). Sensitivity analysis limited to studies of patients on hemodialysis showed similar results (MD: -167.33, 95% CI: -266.57 to -68.09, p = 0.001; I2 = 0%). Subgroup analyses according to study design, sample size, mean age, sex, dialysis vintage of the patients, and treatment duration of STS also showed consistent results (p for subgroup differences all > 0.05). In conclusion, intravenous STS may be effective in attenuating CAC in dialysis patients.

Multimodality approach to treat calciphylaxis in end-stage kidney disease patients

A multimodality approach has been proposed as an effective treatment for calciphylaxis in patients with end-stage kidney disease. In this retrospective study, we report the cases of 12 end-stage kidney disease patients from l'Hôtel-Dieu de Québec hospital (Canada) who were diagnosed with calciphylaxis between 2004 and 2012 and treated with a multimodality clinical approach including sodium thiosulfate (STS). Statistical analyses were performed to evaluate the impacts of patients characteristics, the different interventions as well as therapy regimen on the therapeutic response. The majority of patients (n = 9) were hemodialyzed. The patients-associated comorbidities were consistent with previously reported risk factors for calciphylaxis: Diabetes (n = 11), calcium-based phosphate binders use (n = 10), warfarin use (n = 9), obesity (n = 7), female gender (n = 8) and intravenous iron use (n = 8). STS was given for a median duration of 81 days. 75% of the patients had a response (total or partial) including a complete response in 42% of patients. One-year mortality rate was low (25%). STS was used during a mean duration of 83.33 ± 41.52 days and with a total cumulating dose of 1129.00 ± 490.58 g. The recorded mean time before a complete response was 102.20 days (51-143). Pain improvement occurred after a mean time of 8.67 ± 10.06 days. None of the studied factors was statistically associated with a complete or a partial response to the multimodality approach. Although our data have a limited statistical power, they support treating calciphylaxis with a multimodality approach including STS as its effects are independent from important clinical variables.

Calciphylaxis and its co-occurrence with connective tissue diseases

Calciphylaxis, also known as calcific uremic arteriopathy, is a rare calcification syndrome that presents as ischemic skin necrosis and severe pain. It has a high mortality rate and is characterised by calcification of the small and medium arteries and micro-thrombosis. Calciphylaxis mainly occurs in patients with end-stage renal disease. In recent years, there have been an increasing number of cases of calciphylaxis associated with connective tissue diseases. Given the absence of clear diagnostic criteria for calciphylaxis thus far, an early diagnosis is crucial for designing an effective multidisciplinary treatment plan. In this article, we review the research progress on calciphylaxis and describe its characteristics in the context of connective tissue diseases.

Calciphylaxis and Kidney Disease: A Review

Calciphylaxis is a life-threatening complication most often associated with chronic kidney disease that occurs as a result of the deposition of calcium in dermal and adipose microvasculature. However, this condition may also be seen in patients with acute kidney injury. The high morbidity and mortality rates associated with calciphylaxis highlight the importance to correctly diagnose and treat this condition. However, calciphylaxis remains a diagnosis that may be clinically challenging to make. Here, we review the literature on uremic calciphylaxis with a focus on its pathophysiology, clinical presentation, advances in diagnostic tools, and treatment strategies. We also discuss the unique histopathological features of calciphylaxis and contrast it with those of other forms of general vessel calcification. This review emphasizes the need for multidisciplinary collaboration including nephrology, dermatology, and palliative care to ultimately provide the best possible care to patients with calciphylaxis.

Calciphylaxis Case Series: A Late Presentation of Chronic Kidney Disease From the Eastern Caribbean

Calcific uremic arteriolopathy (CUA) or calciphylaxis is a rare condition that predominantly affects the dialysis population and is characterized by calcification of cutaneous arterioles accompanied by painful necrotic skin ulcers. At the hemodialysis unit of the Port-of-Spain General Hospital, there have been eight cases between the years 2015-2019 with an incidence of 121 cases per 10,000 patients undergoing renal replacement therapy, quite possibly one of the highest in the world along with an 87.5% mortality when diagnosed with this condition. Risk factors identified in this case series include female gender, obesity, and late presentation of end-stage renal disease. This case series highlights limitations in the diagnosis and management of the disease in a resource-limited setting and intends to raise awareness of this condition in the Caribbean.

Perioperative Management of Calciphylaxis: Literature Review and Treatment Recommendations

Calciphylaxis is a serious and rare medical condition that leads to substantial clinical manifestations including pain, creating perioperative and treatment challenges. No standard treatment protocol exists nor are comprehensive guidelines available for perioperative management of patients with calciphylaxis. In this review, we evaluate existing literature (January 2000 to May 2021) with the aim to offer guidance for treating patients with this challenging disease through the perioperative period. Although no therapies are currently considered standard for treating calciphylaxis, multiple interventions are available for improving symptoms. Preoperative and intraoperative management involves monitoring and optimizing patient comorbid conditions and any possible electrolyte imbalances. Postoperative management can be challenging when potential calciphylaxis triggers are indicated, such as warfarin and corticosteroids. In addition, poor wound healing and difficult pain control are common. Therefore, a multifactorial approach to controlling postoperative pain is recommended that includes the use of nerve blocks, renal-sparing opioids, benzodiazepines, and/or ketamine. We present preoperative, intraoperative, and postoperative recommendations for treating calciphylaxis with levels of evidence when appropriate.

The role of adipose tissue-derived hydrogen sulfide in inhibiting atherosclerosis

Hydrogen sulfide (H₂S) is the third gaseous signaling molecule discovered in the body after NO and CO and plays an important organismal protective role in various diseases. Within adipose tissue, related catalytic enzymes (cystathionine-β-synthetase, cystathionine-γ-lyase, and 3-mercaptopyruvate transsulfuration enzyme) can produce and release endogenous H₂S. Atherosclerosis (As) is a pathological change in arterial vessels that is closely related to abnormal glucose and lipid metabolism and a chronic inflammatory response. Previous studies have shown that H₂S can act on the cardiovascular system, exerting effects such as improving disorders of glycolipid metabolism, alleviating insulin resistance, protecting the function of vascular endothelial cells, inhibiting vascular smooth muscle cell proliferation and migration, regulating vascular tone, inhibiting the inflammatory response, and antagonizing the occurrence and development of As.

Innate Immunity in Calcinosis Cutis

Calcinosis cutis is the deposition of calcium salts in the skin and subcutaneous tissue, manifesting as variably shaped papules, nodules, and plaques that can substantially impair quality of life. The pathophysiology of calcinosis cutis involves dysregulation of proinflammatory cytokines, leukocytes, and other components of the innate immune system. In some conditions associated with calcinosis cutis, elevated serum calcium, phosphate, and vitamin D may also perturb innate immunity. The mechanisms by which these lead to cutaneous and subcutaneous calcification likely parallel those seen in vascular calcification. The role of aberrant innate immunity is further supported by the association between various autoantibodies with calcinosis cutis, such as anti-MDA5, anti-NXP2, anti-centromere, and anti-topoisomerase I. Treatments for calcinosis cutis remain limited and largely experimental, although mechanistically many therapies appear to focus on dampening innate immune responses. Further research is needed to better understand the innate immune pathophysiology and establish treatment options based on randomized-controlled trials.

[Uremic calciphylaxis]

Uremic calciphylaxis is a rare disease that affects patients with chronic end-stage renal disease. It is a pathology of the microvessels of the dermis and hypodermis which are calcified and whose thrombosis leads to skin necrosis. Calciphylaxis lesions can be distal and axial. They lead to pain, infection and are associated with denutrition and in high mortality rate (40-80% at 1 year). This general review describes the clinical and para-clinical presentations of calciphylaxis. It summarizes the current knowledge on its pathogenesis and the therapeutical options that can be proposed to improve the management and attempt to reduce the mortality of patients with uremic calciphylaxis.

CCAAT/Enhancer-Binding Protein Alpha Is a Novel Regulator of Vascular Smooth Muscle Cell Osteochondrogenic Transition and Vascular Calcification

Aims

Vascular calcification is a common clinical complication of chronic kidney disease (CKD), atherosclerosis (AS), and diabetes, which is associated with increased cardiovascular morbidity and mortality in patients. The transdifferentiation of vascular smooth muscle cells (VSMCs) to an osteochondrogenic phenotype is a crucial step during vascular calcification. The transcription factor CCAAT/enhancer-binding protein alpha (C/EBPα) plays an important role in regulating cell proliferation and differentiation, but whether it regulates the calcification of arteries and VSMCs remains unclear. Therefore, this study aims to understand the role of C/EBPα in the regulation of vascular calcification.

Methods and Results

Both mRNA and protein expression levels of C/EBPα were significantly increased in calcified arteries from mice treated with a high dose of vitamin D3 (vD3). Upregulation of C/EBPα was also observed in the high phosphate- and calcium-induced VSMC calcification process. The siRNA-mediated knockdown of C/EBPα significantly attenuated VSMC calcification in vitro. Moreover, C/EBPα depletion in VSMCs significantly reduced the mRNA expression of the osteochondrogenic genes, e.g., sex-determining region Y-box 9 (Sox9). C/EBPα overexpression can induce SOX9 overexpression. Similar changes in the protein expression of SOX9 were also observed in VSMCs after C/EBPα depletion or overexpression. In addition, silencing of Sox9 expression significantly inhibited the phosphate- and calcium-induced VSMC calcification in vitro.

Conclusion

Findings in this study indicate that C/EBPα is a key regulator of the osteochondrogenic transdifferentiation of VSMCs and vascular calcification, which may represent a novel therapeutic target for vascular calcification.

Nonuremic Calciphylaxis Associated With Hypercalcemia and Rheumatologic Diseases

Calcific uremic arteriolopathy, termed calciphylaxis, was previously considered a condition that developed mostly in patients requiring dialysis. It has now been described in kidney transplant patients, in advanced chronic kidney disease (CKD) patients not requiring dialysis, and in individuals with maintained kidney function. We describe an individual with CKD stage 3b with hypercalcemia who presented with features highly specific for calciphylaxis based on results of a skin biopsy. The condition has high morbidity and mortality, and thus prompts immediate cessation of the offending agents or treatment of the cause. The following case and literature review demonstrates a need for a detailed assessment of patients’ risks and exposures and expanding the differential diagnosis to include calciphylaxis in nonuremic patients with necrotic ulcers with a plan for early imaging and possible biopsy.

Non-Uremic Calciphylaxis: An Unexpected Complication With Recombinant Human Parathyroid Hormone

Calciphylaxis is a rare syndrome of calcific microvascular occlusion, whereas non-uremic calciphylaxis (NUC) is a subset of this disease in which renal impairment is not observed. Recombinant human parathyroid hormone (rhPTH) (1-84) is a medication approved for the management of hypocalcemia in patients with hypoparathyroidism. We present a case report of a 38-year-old woman with postoperative hypoparathyroidism treated with rhPTH who subsequently developed calciphylactic lesions on her abdomen. Multidisciplinary interventions included intravenous and intralesional sodium thiosulfate therapy, laboratory monitoring, dermatological wound care, and pain management. Calciphylaxis can rarely be precipitated by rhPTH due to its effect on calcium and phosphorus balance even in the setting of normal renal function. The use of calcium and calcitriol supplementation, complicated by factors such as female sex and obesity, may have contributed in this patient’s case. Hence, regular follow-up with tapering off of calcium and calcitriol supplementation is important in patients receiving rhPTH.

Skeletal muscle metabolic responses to physical activity are muscle type specific in a rat model of chronic kidney disease

Chronic kidney disease (CKD) leads to musculoskeletal impairments that are impacted by muscle metabolism. We tested the hypothesis that 10-weeks of voluntary wheel running can improve skeletal muscle mitochondria activity and function in a rat model of CKD. Groups included (n = 12-14/group): (1) normal littermates (NL); (2) CKD, and; (3) CKD-10 weeks of voluntary wheel running (CKD-W). At 35-weeks old the following assays were performed in the soleus and extensor digitorum longus (EDL): targeted metabolomics, mitochondrial respiration, and protein expression. Amino acid-related compounds were reduced in CKD muscle and not restored by physical activity. Mitochondrial respiration in the CKD soleus was increased compared to NL, but not impacted by physical activity. The EDL respiration was not different between NL and CKD, but increased in CKD-wheel rats compared to CKD and NL groups. Our results demonstrate that the soleus may be more susceptible to CKD-induced changes of mitochondrial complex content and respiration, while in the EDL, these alterations were in response the physiological load induced by mild physical activity. Future studies should focus on therapies to improve mitochondrial function in both types of muscle to determine if such treatments can improve the ability to adapt to physical activity in CKD.

Role of Uremic Toxins in Early Vascular Ageing and Calcification

In patients with advanced chronic kidney disease (CKD), the accumulation of uremic toxins, caused by a combination of decreased excretion secondary to reduced kidney function and increased generation secondary to aberrant expression of metabolite genes, interferes with different biological functions of cells and organs, contributing to a state of chronic inflammation and other adverse biologic effects that may cause tissue damage. Several uremic toxins have been implicated in severe vascular smooth muscle cells (VSMCs) changes and other alterations leading to vascular calcification (VC) and early vascular ageing (EVA). The above mentioned are predominant clinical features of patients with CKD, contributing to their exceptionally high cardiovascular mortality. Herein, we present an update on pathophysiological processes and mediators underlying VC and EVA induced by uremic toxins. Moreover, we discuss their clinical impact, and possible therapeutic targets aiming at preventing or ameliorating the harmful effects of uremic toxins on the vasculature.

Positive Association of Leptin and Artery Calcification of Lower Extremity in Patients With Type 2 Diabetes Mellitus: A Pilot Study

OBJECTIVE

We aimed to explore the role and possible mechanism of leptin in lower-extremity artery calcification in patients with type 2 diabetes mellitus (T2DM).

METHODS

We recruited 59 male patients with T2DM and 39 non-diabetic male participants. All participants underwent computed tomography scan of lower-extremity arteries. The calcification scores (CSs) were analyzed by standardized software. Plasma leptin level was determined by radioimmunoassay kits. Human vascular smooth muscle cells (VSMCs) calcification model was established by beta-glycerophosphate and calcium chlorideinduction. Calcium deposition and mineralization were measured by the o-cresolphthalein complexone method and Alizarin Red staining. The mRNA expression of bone morphogenic protein 2 (BMP2), runt-related transcription factor 2 (Runx2), osteocalcin (OCN) and osteopontin (OPN) was determined by quantitative RT-PCR. The protein levels of BMP2, Runx2, α-smooth muscle actin (α-SMA) and (p)-Akt was determined by Western-blot analysis, and α-SMA was also measured by immunofluorescence analysis.

RESULTS

Compared with controls, patients with T2DM showed higher median calcification score in lower-extremity artery [286.50 (IQR 83.41, 1082.00) vs 68.66 (3.41, 141.30), p<0.01]. Plasma leptin level was higher in patients with calcification score ≥300 than ≥100 (252.67 ± 98.57 vs 189.38 ± 44.19 pg/ml, p<0.05). Compared with calcification medium, intracellular calcium content was significantly increased in VSMCs treated by leptin (200, 400 and 800 ng/ml) combined with calcification medium [11.99 ± 3.63, 15.18 ± 4.55, and 24.14 ± 5.85 mg/ml, respectively, vs 7.27 ± 1.54 mg/ml, all p<0.01]. Compared with calcification medium, Alizarin Red staining showed calcium disposition was more obvious, and the mRNA level of BMP2, Runx2 and OCN was significantly increased, and immunofluorescence and Western blot analysis showed that the expression of α-SMA was downregulated in VSMCs treated by leptin (400 ng/ml) combined with calcification medium, respectively. Compared with calcification medium, the protein level of BMP2 and Runx2 was upregulated in VSMCs treated by leptin (400 ng/ml) combined with calcification medium. Moreover, blocking PI3K/Akt signaling pathway can decrease the protein expression of BMP2 and Runx2 in VSMCs treated by leptin (400 ng/ml) combined with calcification medium.

CONCLUSIONS

Leptin promoted lower-extremity artery calcification of T2DM by upregulating the expression of BMP2 and Runx2, and regulating phenotypic switch of VSMCs via PI3K/Akt signaling pathway.

Management of Cutaneous Calciphylaxis

Calciphylaxis is a deadly, painful disease with a 1-year mortality of up to 50%. The disease is commonly associated with patients with end-stage kidney disease (ESKD), but it can manifest in non-uremic patients as well. In patients who are undergoing dialysis, the incidence of calciphylaxis can range from 0.04% to 4%. The progressive arterial calcification seen in calciphylaxis can affect multiple body organs, including the skin, brain, lungs, and muscle. In cutaneous calciphylaxis, painful and non-healing nodules, plaques, and ulcers may appear, increasing morbidity for patients. Diagnosis can be difficult, and the condition can clinically appear similar to other dermatological diseases, especially in non-uremic patients. Currently, skin biopsy with histological analysis is the most reliable method to help diagnose the condition. In certain cases, the use of medical imaging may be helpful. Treatment of pain in this condition can be difficult and should be multimodal and include wound care as well as modification of risk factors. Analgesic options include opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), as well as analgesic options that are targeted for specific patients. There are currently multiple clinical trials underway that are studying targeted therapies for this condition.

Uremic Toxins and Vascular Calcification-Missing the Forest for All the Trees

The cardiorenal syndrome relates to the detrimental interplay between the vascular system and the kidney. The uremic milieu induced by reduced kidney function alters the phenotype of vascular smooth muscle cells (VSMC) and promotes vascular calcification, a condition which is strongly linked to cardiovascular morbidity and mortality. Biological mechanisms involved include generation of reactive oxygen species, inflammation and accelerated senescence. A better understanding of the vasotoxic effects of uremic retention molecules may reveal novel avenues to reduce vascular calcification in CKD. The present review aims to present a state of the art on the role of uremic toxins in pathogenesis of vascular calcification. Evidence, so far, is fragmentary and limited with only a few uremic toxins being investigated, often by a single group of investigators. Experimental heterogeneity furthermore hampers comparison. There is a clear need for a concerted action harmonizing and standardizing experimental protocols and combining efforts of basic and clinical researchers to solve the complex puzzle of uremic vascular calcification.

Emerging functions of adipokines in linking the development of obesity and cardiovascular diseases

Increasing evidence shows that obesity is the critical factor in shaping cardio-metabolic phenotypes. However, the pathogenic mechanisms remain incompletely clarified. According to the published reports, adipose tissue communicates with several diverse organs, such as heart, lungs, and kidneys through the secretion of various cytokines named adipokines. The adipocytes isolated from obese mice or humans are dysfunctional with aberrant production of pro-inflammatory adipokines, which subsequently induce both acute and chronic inflammatory reaction and facilitate the process of cardio-metabolic disorder complications. Furthermore, the microenvironment within adipose tissue under obese status also influence the secretion of adipokines. Recently, given that several important adipokines have been completely researched and causally involved in various diseases, we could make a conclusion that adipokines play an essential role in modulating the development of cardio-metabolic disorder diseases, whereas several novel adipokines continue to be explored and elucidated. In the present review, we summarized the current knowledge of the microenvironment of adipose tissue and the published mechanisms whereby adipocytes affects obesity and cardiovascular diseases. On the other hand, we also provide the evidence to elucidate the functions of adipokines in controlling and regulating the inflammatory reactions which contribute to obesity and cardiovascular disease.

Multidisciplinary management of calciphylaxis: a series of 5 patients at a single facility

Calciphylaxis is a rare and severe disease that manifests with painful skin ulceration and necrosis. Herein, we report five patients of hemodialysis patients with skin biopsy-proven calciphylaxis at a single facility. One patient had undergone parathyroidectomy (PTx) due to severe secondary hyperparathyroidism, four had been treated with vitamin D receptor activators, and two were on warfarin therapy. All patients had hyperphosphatemia, and one had hypercalcemia. The intact parathyroid hormone level at diagnosis was 2 pg/ml in the patient after PTx, while three patients were within the target range. The average period after diagnosis of calciphylaxis was 2 months. Skin lesions were present on the thighs and lower legs in two patients, and on the dorsum of the foot in one patient. In skin biopsy, calcification was found in the arteriolar media in four patients, and calcium (Ca) was deposited in the dermal lesion in one patient. All patients received local cures, surgical debridement, antibiotics to control infectious diseases, and strict control of serum Ca and phosphate. Calcimimetics were used in all patients except one who had undergone PTx one month before, sodium thiosulfate was used in 4 patients, and low Ca dialysate was used in three patients. The average follow-up period was 7.4 months. Four patients were cured, and one died due to infection. We suggest that multidisciplinary management for infectious diseases, surgical debridement, strict control of mineral and bone markers from the early stage, and elimination of risk factors may improve the course of calciphylaxis, which is a life-threatening disease.

Natural and non-natural antioxidative compounds: potential candidates for treatment of vascular calcification

Vascular calcification (VC) is highly prevalent in patients with advanced age, or those with chronic kidney disease and diabetes, accounting for substantial global cardiovascular burden. The pathophysiology of VC involves active mineral deposition by transdifferentiated vascular smooth muscle cells exhibiting osteoblast-like behavior, building upon cores with or without apoptotic bodies. Oxidative stress drives the progression of the cellular phenotypic switch and calcium deposition in the vascular wall. In this review, we discuss potential compounds that shield these cells from the detrimental influences of reactive oxygen species as promising treatment options for VC. A comprehensive summary of the current literature regarding antioxidants for VC is important, as no effective therapy is currently available for this disease. We systematically searched through the existing literature to identify original articles investigating traditional antioxidants and novel compounds with antioxidant properties with regard to their effectiveness against VC in experimental or clinical settings. We uncovered 36 compounds with antioxidant properties against VC pathology, involving mechanisms such as suppression of NADPH oxidase, BMP-2, and Wnt/β-catenin; anti-inflammation; and activation of Nrf2 pathways. Only two compounds have been tested clinically. These findings suggest that a considerable opportunity exists to harness these antioxidants for therapeutic use for VC. In order to achieve this goal, more translational studies are needed.

Calciphylaxis: Approach to Diagnosis and Management

Calciphylaxis is a rare disorder of poor prognosis that can lead to intense, painful lesions involving the skin and subcutaneous tissue. Although mostly described in dialysis patients, it can affect patients with normal kidney function. The diagnosis of calciphylaxis is complicated by the absence of a gold standard marker of disease such as a clear histopathological finding. Late diagnosis and advanced lesions can significantly shorten life expectancy. Calciphylaxis wounds can have a major influence on the quality of life of patients, usually due to the immense unbearable pain these patients suffer from. The management of calciphylaxis mainly comprises aggressive wound care and symptomatic management. Therapeutic options are few and far between and are limited to off-label uses. Recent understanding of the pathogenesis of lesions has enabled development of novel therapeutic options, some of which are being studied in clinical trials (sodium thiosulfate, vitamin K). Vascular calcification and thrombosis underlie development of these lesions and research has been aimed at studying drugs that counteract such processes. Future research is required to establish clear causal pathways and improve on the treatment options currently available to patients.

The role of the gasotransmitter hydrogen sulfide in pathological calcification

Calcification is the deposition of minerals, mainly hydroxyapatite, inside the cell or in the extracellular matrix. Physiological calcification is central for many aspects of development including skeletal and tooth growth; conversely, pathological mineralization occurs in soft tissues and is significantly associated with malfunction and impairment of the tissue where it is located. Various mechanisms have been proposed to explain calcification. However, this research area lacks a more integrative, systemic, and global perspective that could explain both physiological and pathological processes. In this review, we propose such an integrated explanation. Hydrogen sulfide (H₂ S) is a newly recognized multifunctional gasotransmitters and tis actions have been studied in different physiological and pathological contexts, but little is known about its potential role on calcification. Interestingly, we found that H₂ S promotes calcification under physiological conditions and has an inhibitory effect on pathological processes. This makes H₂ S a potential therapy for diseases related to pathological calcification. LINKED ARTICLES: This article is part of a themed section on Hydrogen Sulfide in Biology & Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.4/issuetoc.

Review: update on the management of calciphylaxis

Calciphylaxis is a disease of significant morbidity and mortality, predominantly affecting dialysis patients. The term 'calciphylaxis' was coined by Seyle et al. in 1961 to describe calcium deposition in the skin and subcutaneous soft tissue of uremic rats in response to 'triggers' (e.g. trauma, metallic salts) after exposure to 'sensitizing agents' (e.g. vitamin D and parathyroid hormone). In humans, calciphylaxis, however, is not a disorder of induced hypersensitivity. Instead, it is a disorder of cutaneous microvascular occlusion caused by thrombosis and calcification. Progressive, excruciatingly painful, non-healing wounds develop in these patients, pre-disposing them to high risk of sepsis and death. Calciphylaxis has no approved therapies. Increased awareness and research in this field have facilitated identification of risk factors and causation pathways. Development of therapeutic options and wound care management, however, are still at a nascent stage. Certain therapies have shown a promise that needs evaluation in prospective clinical trials. It is hoped that ongoing research will help us better understand the pathogenesis of this complex disease and develop efficacious treatment options. In this review, we outline the components involved in calciphylaxis diagnosis and treatment.

Renal mitochondria can withstand hypoxic/ischemic injury secondary to renal failure in uremic rats pretreated with sodium thiosulfate

BACKGROUND:

Sodium thiosulfate (STS) is a potent drug used to treat calcific uremic arteriopathy in dialysis patients and its mode of action is envisaged by calcium chelation and antioxidant potential. STS's action on mitochondrial dysfunction, one of the major players in the pathology of vascular calcification is yet to be explored.

METHODS:

Adenine (0.75%, 28 days)-treated vascular calcified rat kidney was used to isolate mitochondria, where the animal was administered with or without STS for 28 days. Isolated mitochondria were subjected to physiological oxidative stress by nitrogen gas purging (hypoxia/ischemia-reperfusion injury) to assess mitochondrial recovery extent due to STS treatment in vascular calcified rat kidney.

RESULTS:

The results confirmed an elevated oxidative stress and deteriorated mitochondrial enzyme activities in all groups except the drug-treated group.

CONCLUSION:

The STS treatment, besides rendering renal protection against adenine-induced renal failure, also helped to maintain mitochondrial functional integrity in a later insult due to hypoxia/ischemia-reperfusion injury.

Modulating Cell Fate as a Therapeutic Strategy

In injured tissues, regeneration is often associated with cell fate plasticity, in that cells deviate from their normal lineage paths. It is becoming increasingly clear that this plasticity often creates alternative strategies to restore damaged or lost cells. Alternatively, cell fate plasticity is also part and parcel of pathologic tissue transformations that accompany disease. In this Perspective, we summarize a few illustrative examples of physiologic and aberrant cellular plasticity. Then, we speculate on how one could enhance endogenous plasticity to promote regeneration and reverse pathologic plasticity, perhaps inspiring interest in a new class of therapies targeting cell fate modulation.

Metabolic acidosis after sodium thiosulfate infusion and the role of hydrogen sulfide

Sodium thiosulfate (STS), first-line treatment for calcific uremic arteriolopathy, causes a mild asymptomatic acidosis in many patients. However, severe, life-threatening acidosis out of proportion with the expected acid load of STS may occur, potentially due to metabolism of STS to hydrogen sulfide.

The Use of Antidotes for Calcium Gluconate Extravasation: An Experimental Study in Mice

BACKGROUND

Calcium gluconate extravasation is a process that can cause serious lesions, such as necrosis and calcification of the soft tissues. The aim of the present study was to analyze the beneficial effects of four possible local antidotes for calcium gluconate extravasation: hyaluronidase, sodium thiosulfate, triamcinolone acetonide, and physiologic saline solution.

METHODS

Seventy-four BALB/c mice were used in the study. The substances selected for use in this study were calcium gluconate (4.6 mEq/ml), hyaluronidase (1500 IU/ml), sodium thiosulfate (25%), triamcinolone acetonide (40 mg/ml 0.5 mg/kg), and saline solution 0.9%. Five minutes were allowed to lapse after the calcium gluconate infiltration, and then an antidote was infiltrated. After 3 weeks, a skin biopsy was performed and a radiographic and histologic study was carried out.

RESULTS

Only in the group infiltrated with sodium thiosulfate did all skin lesions disappear after the 3-week period after infiltration. In the radiographic study, calcium deposits larger than 0.5 mm were observed in 40 percent of cases without an antidote, in 33 percent with triamcinolone acetonide, in 13 percent with a saline solution, and in none with thiosulfate and hyaluronidase. In the histologic study, calcium deposits were found in 53 percent of cases without antidote, 100 percent of cases with triamcinolone acetonide, 33 percent of cases with saline solution, and 13 percent of cases with sodium thiosulfate or hyaluronidase.

CONCLUSION

Sodium thiosulfate and hyaluronidase prevent the development of calcium deposits after calcium gluconate extravasation.

A 71-Year-Old Female with Myocardial Infarction and Long-Standing Ulcers on the Thigh

Calciphylaxis is most commonly encountered in patients with end-stage renal disease; however, it is increasingly observed in nonuremic patients as well. It is important to consider and diagnose nonuremic calciphylaxis early, as prompt treatment and mitigation of associated risk factors is essential to improve long-term outcomes for these patients. Here, we present the case of a 71-year-old woman with atrial fibrillation on warfarin, but without renal disease, who presented with two long-standing ulcers on her thigh and was diagnosed with the aid of biopsy with calciphylaxis. We review the existing literature on the subject and offer this case as a representative report of a clinicopathologic correlation for this disorder.

MiR-4638-5p inhibits castration resistance of prostate cancer through repressing Kidins220 expression and PI3K/AKT pathway activity

MicroRNAs (miRNAs) are short, conserved segments of non-coding RNA which play a significant role in prostate cancer development and progression. To identify miRNAs associated with castration resistance, we performed miRNA microarray analysis comparing castration resistant prostate cancer (CRPC) with androgen dependent prostate cancer (ADPC). We identified common underexpression of miR-4638-5p in CRPC compared to ADPC samples, which were further confirmed by quantitative PCR analysis. The role of miR-4638-5p in prostate cancer androgen-independent growth has been demonstrated both in vitro and in vivo. We also identified Kidins220 as a target gene directly regulated by miR-4638-5p and shRNA-mediated knockdown of Kidins220 phenocopied miR-4638-5p restoration. Subsequently, we revealed that Kidins220 activates PI3K/AKT pathway, which plays a key role in CRPC. Loss of miR- 4638-5p may lead to CRPC through the activity of Kidins220 and PI3K/AKT pathway. Furthermore, we found that miR-4638-5p, through regulating Kidins220 and the downstream activity of VEGF and PI3K/AKT pathway, influences prostate cancer progression via angiogenesis. The identification of miR-4638-5p down-regulation in CRPC and the understanding of the functional role of miR-4638-5p and its downstream genes/pathways have the potential to develop biomarkers for CRPC onset and to identify novel targets for novel forms of treatments of this lethal form of PCa.

Predictive microRNAs for lymph node metastasis in endoscopically resectable submucosal colorectal cancer

Accurate prediction of regional lymph node metastasis (LNM) in endoscopically resected T1-stage colorectal cancers (CRCs) can reduce unnecessary surgeries. To identify miRNA markers that can predict LNM in T1-stage CRCs, the study was conducted in two phases; (I) miRNA classifier construction by miRNA-array and quantitative reverse transcription PCR (qRT-PCR) using 36 T1-stage CRC samples; (II) miRNA classifier validation in an independent set of 20 T1-stage CRC samples. The expression of potential downstream target genes of miRNAs was assessed by immunohistochemistry. In the discovery analysis by miRNA microarray, expression of 66 miRNAs were significantly different between LNM-positive and negative CRCs. After qRT-PCR validation, 11 miRNAs were consistently significant in the combined classifier construction set. Among them, miR-342-3p was the most significant one (P=4.3×10-4). Through logistic regression analysis, we developed a three-miRNA classifier (miR-342-3p, miR-361-3p, and miR-3621) for predicting LNM in T1-stage CRCs, yielding the area under the curve of 0.947 (94% sensitivity, 85% specificity and 89% accuracy). The discriminative ability of this system was consistently reliable in the independent validation set (83% sensitivity, 64% specificity and 70% of accuracy). Of the potential downstream targets of the three-miRNAs, expressions of E2F1, RAP2B, and AKT1 were significantly associated with LNM. In conclusion, this classifier can predict LNM more accurately than conventional pathologic criteria and our study results may be helpful to avoid unnecessary bowel surgery after endoscopic resection in early CRC.

The Role of Hemoproteins: Hemoglobin, Myoglobin and Neuroglobin in Endogenous Thiosulfate Production Processes

Thiosulfate formation and biodegradation processes link aerobic and anaerobic metabolism of cysteine. In these reactions, sulfite formed from thiosulfate is oxidized to sulfate while hydrogen sulfide is transformed into thiosulfate. These processes occurring mostly in mitochondria are described as a canonical hydrogen sulfide oxidation pathway. In this review, we discuss the current state of knowledge on the interactions between hydrogen sulfide and hemoglobin, myoglobin and neuroglobin and postulate that thiosulfate is a metabolically important product of this processes. Hydrogen sulfide oxidation by ferric hemoglobin, myoglobin and neuroglobin has been defined as a non-canonical hydrogen sulfide oxidation pathway. Until recently, it appeared that the goal of thiosulfate production was to delay irreversible oxidation of hydrogen sulfide to sulfate excreted in urine; while thiosulfate itself was only an intermediate, transient metabolite on the hydrogen sulfide oxidation pathway. In the light of data presented in this paper, it seems that thiosulfate is a molecule that plays a prominent role in the human body. Thus, we hope that all these findings will encourage further studies on the role of hemoproteins in the formation of this undoubtedly fascinating molecule and on the mechanisms responsible for its biological activity in the human body.

Efficacy of intralesional sodium thiosulfate injections for disabling tumoral calcinosis: Two cases

INTRODUCTION

Tumoral calcinosis (TC) is a difficult-to-treat complication that can occur during several diseases such as dermatomyositis or genetic hyperphosphatemia. It is a painful and disabling condition that can lead to local complications including joint mobility reduction, cutaneous ulceration and superinfection. For the largest lesions, the treatment relies essentially on surgery. Intravenous sodium thiosulfate (STS) is efficient to treat calciphylaxis in patients undergoing hemodialysis. Local injections of STS seem efficient in superficial calcifications.

OBJECTIVE

To report the efficacy and safety of intra-lesional injections of STS in tumoral calcinosis.

RESULTS

We report two cases of successful intra-lesional injections of STS. A 44-year-old woman, with a history of dermatomyositis, presenting large subcutaneous calcifications in the right elbow, and a 42-year-old man, with a history of familial tumoral calcinosis, presenting large intramuscular calcifications in the right buttock, received weekly intra-lesional of 1-3g STS injections for 12 and 21 months, respectively. In both cases, the treatment relieved pain and greatly reduced the tumoral calcinosis with a very significant functional improvement without specific adverse effects. In case 1, TC size decreased from 28.7*56.0mm at baseline to 21.5*30.6mm at M12 treatment (59% reduction). In case 2, TC reduced from 167.5*204.3mm at baseline to 86.2*85.2mm at M21 treatment (79% reduction).

CONCLUSION

Local injection of STS could be a promising therapeutic strategy for large and deep TC lesions and could therefore be an alternative to surgery.

Intravenous sodium thiosulfate for treating tumoral calcinosis associated with systemic disorders: Report of four cases

Intravenous sodium thiosulfate (ivSTS) is a promising new therapeutic option for calciphylaxis related to end-stage renal disease. However, its effect on tumoral calcinosis (TC) complicating autoimmune connective-tissue diseases has been scarcely described. We report here 4 cases (3 adults and 1 child) of TC treated with ivSTS. TC was secondary to CREST syndrome, dermatomyositis (1 adult and 1 child) and systemic erythematous lupus and involved multiple sites in all cases. In all 4 patients, TC was responsible for joint pain, reduced mobility, inflammatory flares and skin fistulations. One patient experienced difficulty sitting due to the pain induced by calcified lesions on the buttock; another patient had major disability, moved only with wheelchair and was under opioid treatment for pain. For all patients, treatment with several medications before STS was unsuccessful. The 3 adults received at least 6 cycles of ivSTS (20g/d, 5 days/month) and the child received a daily infusion of 17g STS during 1 month then a 9-g/d infusion during 3 months. Two adults and the child showed clinical improvement with STS treatment and the third adult felt disappointed and stopped STS treatment after 6 months. The child also stopped STS after 6 months due to vomiting. In one patient, an intensive regimen of ivSTS (20g every 2 days) controlled recurrent flares and fistulations. Unfortunately, TC remained unchanged. Further studies are needed to decipher how STS modulates ectopic calcification, the optimal regimen and posology.

A Nationally Representative Study of Calcific Uremic Arteriolopathy Risk Factors

Accurate identification of risk factors for calcific uremic arteriolopathy (CUA) is necessary to develop preventive strategies for this morbid disease. We investigated whether baseline factors recorded at hemodialysis initiation would identify patients at risk for future CUA in a matched case-control study using data from a large dialysis organization. Hemodialysis patients with newly diagnosed CUA (n=1030) between January 1, 2010, and December 31, 2014, were matched by age, sex, and race in a 1:2 ratio to hemodialysis patients without CUA (n=2060). Mean ages for patients and controls were 54 and 55 years, respectively; 67% of participants were women and 49% were white. Median duration between hemodialysis initiation and subsequent CUA development was 925 days (interquartile range, 273-2185 days). In multivariable conditional logistic regression analyses, diabetes mellitus; higher body mass index; higher levels of serum calcium, phosphorous, and parathyroid hormone; and nutritional vitamin D, cinacalcet, and warfarin treatments were associated with increased odds of subsequent CUA development. Compared with patients with diabetes receiving no insulin injections, those receiving insulin injections had a dose-response increase in the odds of CUA involving lower abdomen and/or upper thigh areas (odds ratio, 1.49; 95% confidence interval, 1.03 to 2.51 for one or two injections per day; odds ratio, 1.88; 95% confidence interval, 1.30 to 3.43 for 3 injections per day; odds ratio, 3.74; 95% confidence interval, 2.28 to 6.25 for more than three injections per day), suggesting a dose-effect relationship between recurrent skin trauma and CUA risk. The presence of risk factors months to years before CUA development observed in this study will direct the design of preventive strategies and inform CUA pathobiology.

MicroRNA-1225-5p inhibits proliferation and metastasis of gastric carcinoma through repressing insulin receptor substrate-1 and activation of β-catenin signaling

Emerging evidence has linked aberrantly expressed microRNAs (miRNAs) with oncogenesis and malignant development in various human cancers. However, their specific roles and functions in gastric carcinoma (GC) remain largely undefined. In this study we identify and report a novel miRNA, miR-1225-5p, as tumor suppressor in GC development and progression. Microarray analysis revealed that there were fifty-six differentially expressed miRNAs (thirty-two upregulated and twenty-four downregulated) in GC tumor samples compared to their corresponding nontumorous tissues. Downregulation of miR-1225-5p was frequently detected in GC and strongly correlated with more aggressive phenotypes and poor prognosis. Functional assays demonstrated that ectopic overexpression of miR-1225-5p could inhibit cell proliferation, colony formation, migration and invasion in vitro, as well as suppress tumor growth and metastasis in nude mice. Further integrative and functional studies suggested insulin receptor substrate 1 (IRS1) as a downstream effector of miR-1225-5p which acted through β-catenin signaling pathway. These results demonstrate that miR-1225-5p serves to constrain GC growth and metastatic potential via inhibition of IRS1 and β-catenin signaling. Therefore, downregulation of miR-1225-5p is likely to be one of major molecular mechanisms accounting for the development and progression of GC.

Sodium thiosulfate is effective in calcific uremic arteriolopathy complicating chronic hemodialysis

BACKGROUND

Calcific uremic arteriolopathy (CUA) or calciphylaxis is a severe complication of advanced chronic kidney disease (CKD) and dialysis. Few effective treatments are available and the mortality rate is high. We report 4 cases in which sodium thiosulfate therapy was rapidly effective.

CASES

Sodium thiosulfate therapy was given to 4 Caucasian patients (3 females and 1 male aged 49 to 91 years) with CUA. The causes of end-stage CKD were nephroangiosclerosis (n=2) and diabetic nephropathy (n=2). The lesions developed 1 to 6.5 years after the initiation of hemodialysis and involved the lower limbs in 2 patients, the fingers in 1 patient, and a breast in the remaining patient. They were responsible for pain and skin necrosis in all 4 patients. Local superinfection occurred in 3 patients. Intravenous sodium thiosulfate was given in a dosage of 12.5 to 25g after each hemodialysis session, for 12 to 24 weeks. The pain and trophic disorders resolved fully in all 4 patients. The side effects consisted of nausea and vomiting (n=2) and a moderate blood pressure decrease (n=1). No recurrences were noted during the follow-up of 5 to 17 months after treatment discontinuation.

CONCLUSION

The findings from this small case-series suggest that sodium thiosulfate may hold promise for the treatment of CUA.

Calciphylaxis: risk factors, diagnosis, and treatment

Calciphylaxis is a rare but devastating condition that has continued to challenge the medical community since its early descriptions in the scientific literature many decades ago. It is predominantly seen in patients with chronic kidney failure treated with dialysis (uremic calciphylaxis) but is also described in patients with earlier stages of chronic kidney disease and with normal kidney function. In this review, we discuss the available medical literature regarding risk factors, diagnosis, and treatment of both uremic and nonuremic calciphylaxis. High-quality evidence for the evaluation and management of calciphylaxis is lacking at this time due to its rare incidence and poorly understood pathogenesis and the relative paucity of collaborative research efforts. We hereby provide a summary of recommendations developed by a multidisciplinary team for patients with calciphylaxis.