Zinc: a potential star for regulating peritoneal fibrosis

Peritoneal dialysis (PD) is a commonly used renal replacement therapy for patients with end-stage renal disease (ESRD). During PD, the peritoneum (PM), a semi-permeable membrane, is exposed to nonbiocompatible PD solutions. Peritonitis can occur, leading to structural and functional PM disorders, resulting in peritoneal fibrosis and ultrafiltration failure, which are important reasons for patients with ESRD to discontinue PD. Increasing evidence suggests that oxidative stress (OS) plays a key role in the pathogenesis of peritoneal fibrosis. Furthermore, zinc deficiency is often present to a certain extent in patients undergoing PD. As an essential trace element, zinc is also an antioxidant, potentially playing an anti-OS role and slowing down peritoneal fibrosis progression. This study summarises and analyses recent research conducted by domestic and foreign scholars on the possible mechanisms through which zinc prevents peritoneal fibrosis.

Improving growth in infants with CF

Cystic fibrosis (CF) results in chronic pulmonary infections, inflammation, pancreatic insufficiency, and multiple gastrointestinal manifestations. Malnutrition and poor growth are hallmarks of CF, and strongly associated with poor outcomes. Through newborn screening, many infants can be diagnosed within a few days of life, which allows for early initiation of nutritional counseling and close clinical follow-up. Obstacles to growth for infants with CF start in utero, as newborns with CF can have a lower birth weight than the general population. Improving infant growth has been linked to improved clinical outcomes and survival. It remains a top priority and challenge for caregivers and healthcare teams. An interdisciplinary approach, including registered dietitian and social work support, is essential to optimize health for infants with CF. Remaining barriers to normalcy include deficits in linear growth, lack of accurate nutrition biomarkers, persistence of inequities related to social determinant of health, particularly in the global CF community.

Zinc status in cystic fibrosis patients; a systematic review and meta-analysis

Background

Cystic fibrosis (CF) is an autosomal recessive hereditary disease causes concentration of secretions and this affects the lungs and digestive system. These patients are exposed to zinc (zn) deficiency. In this review, we decided to investigate the status of zn in CF patients compared to control group. Also, the clinical trials that have so far performed zinc supplementation in these patients are examined.

Method

ISI Web of Science, Scopus, PubMed/Medline, and Cochrane database were searched, up to December 2023, for studies that reported the association between zn levels of CF patients compared to a healthy control group. A random-effect model was used to compute the pooled weighted mean difference (WMD) with 95 % confidence intervals (CI). Subgroup analysis was done for region, sample and method of measurement, zinc supplementation and age.

Result

Overall, meta-analysis of 9 studies (n = 383 participants) revealed that the zn levels were significantly lower in children and adolescents with CF compared with healthy subjects (WMD = -11.97 μg/dL, 95 % CI: -22.57 to -1.37; I2 = 92.83 %). Meta-analysis of 8 studies (n = 320 participants) revealed that the serum and plasma level of zn was significantly lower in CF patients compared with healthy subjects (WMD = -14.31 μg/dL, 95 % CI: -25.09 to -3.53; I2 = 88.14 %, P-heterogeneity <0.001) While the zn level in saliva and sputum was significantly higher in CF patients.

Conclusion

CF patients have decreased zn levels in circulatory reservoirs. zn may effective for the diminish the respiratory and gastrointestinal symptoms in CF patients, further well-designed clinical trial studies is required to prove these effects.

Nutritional Care in Children with Cystic Fibrosis

Patients with cystic fibrosis (CF) are prone to malnutrition and growth failure, mostly due to malabsorption caused by the derangement in the chloride transport across epithelial surfaces. Thus, optimal nutritional care and support should be an integral part of the management of the disease, with the aim of ameliorating clinical outcomes and life expectancy. In this report, we analyzed the nutrition support across the different ages, in patients with CF, with a focus on the relationships with growth, nutritional status, disease outcomes and the use of the CF transmembrane conductance regulator (CFTR) modulators. The nutrition support goal in CF care should begin as early as possible after diagnosis and include the achievement of an optimal nutritional status to support the growth stages and puberty development in children, that will further support the maintenance of an optimal nutritional status in adult life. The cornerstone of nutrition in patients with CF is a high calorie, high-fat diet, in conjunction with a better control of malabsorption due to pancreatic enzyme replacement therapy, and attention to the adequate supplementation of fat-soluble vitamins. When the oral caloric intake is not enough for reaching the anthropometric nutritional goals, supplemental enteral feeding should be initiated to improve growth and the nutritional status. In the last decade, the therapeutic possibilities towards CF have grown in a consistent way. The positive effects of CFTR modulators on nutritional status mainly consist in the improvement in weight gain and BMI, both in children and adults, and in an amelioration in terms of the pulmonary function and reduction of exacerbations. Several challenges need to be overcome with the development of new drugs, to transform CF from a fatal disease to a treatable chronic disease with specialized multidisciplinary care.

Zinc status and growth in infants and young children with cystic fibrosis

BACKGROUND

Zinc deficiency is associated with poor growth in children without cystic fibrosis (CF), but its impact on growth in children with CF is unknown.

OBJECTIVE

To determine the prevalence of low serum Zn (sZn) and its relationship with growth in the first 3 years of life in children with CF.

METHODS

We utilized data from infants with CF who were enrolled in a longitudinal study of nutrition and lung health and had sZn measured as part of clinical care. Cross-sectional correlations between sZn levels and growth z scores were assessed by Pearson's correlation coefficient. To identify factors associated with sZn status and its association to longitudinal growth patterns, multiple regression analysis with repeated measures were performed using generalized estimating equations.

RESULTS

A total of 106 sZn measurements from 53 infants were identified. Seventeen infants (32%) had intermittent Zn insufficiency, defined as at least one sZn <70 mcg/dl in their first 3 years of life. There were no significant cross-sectional associations between sZn and growth z scores. However, analysis of longitudinal growth patterns revealed that weight- and length-for-age z scores in children with intermittent Zn insufficiency were lower during early infancy and their weight-for-length z scores at age 3 years were also lower compared to those who were always Zn sufficient.

CONCLUSION

Low sZn occurs in one-third of children with CF in the first 3 years of life. Cross-sectional and longitudinal analyses revealed discrepant associations between sZn and growth. Therefore, prospective studies are needed to understand the role of Zn in growth in CF.

Zinc deficiency and its association with treatment-related toxicity in children with cancer

BACKGROUND

Nutritional deficiencies in children with cancer at time of diagnosis and during treatment may negatively affect disease outcome and increase treatment-related toxicity. Yet zinc, an essential nutrient important for supporting immune function and known for reducing diarrheal episodes, is rarely assessed in these children.

PROCEDURES

Fifty children (1 month to 18 years) with recently diagnosed cancer were enrolled in this study. An age and gender matched control group (n = 50) was also recruited. Plasma and urinary zinc, plasma copper, and C-reactive protein (CRP) levels were measured at baseline, 3, and 6 months following diagnosis. A retrospective review of the toxicity profile was performed in the cohort of children with cancer for the first 4 years after initial diagnosis.

RESULTS

CRP and plasma copper (both acute-phase reactants) were elevated in patients with cancer compared to controls at baseline, both p < .03. Plasma zinc levels were not significantly different from controls at baseline, but decreased by 11% in the cancer group over 6 months of treatment, 83.2 ± 15.6 to 74.3 ± 14.8 μg/dl, p = .01. Plasma zinc dropped to deficient levels in 35% of cases over the initial 6 months. Zinc deficiency at 6 months was related to an increased incidence of severe diarrhea during 4 years of follow-up, p < .001.

CONCLUSIONS

Zinc deficiency is an underrecognized problem among patients undergoing treatment for cancer and is associated with severe diarrhea. Further studies are needed to evaluate causes for zinc deficiency, related effects, and a possible role for zinc supplementation.

Nutritional immunity: the impact of metals on lung immune cells and the airway microbiome during chronic respiratory disease

Nutritional immunity is the sequestration of bioavailable trace metals such as iron, zinc and copper by the host to limit pathogenicity by invading microorganisms. As one of the most conserved activities of the innate immune system, limiting the availability of free trace metals by cells of the immune system serves not only to conceal these vital nutrients from invading bacteria but also operates to tightly regulate host immune cell responses and function. In the setting of chronic lung disease, the regulation of trace metals by the host is often disrupted, leading to the altered availability of these nutrients to commensal and invading opportunistic pathogenic microbes. Similarly, alterations in the uptake, secretion, turnover and redox activity of these vitally important metals has significant repercussions for immune cell function including the response to and resolution of infection. This review will discuss the intricate role of nutritional immunity in host immune cells of the lung and how changes in this fundamental process as a result of chronic lung disease may alter the airway microbiome, disease progression and the response to infection.

Airway Redox Homeostasis and Inflammation Gone Awry: From Molecular Pathogenesis to Emerging Therapeutics in Respiratory Pathology

As aerobic organisms, we are continuously and throughout our lifetime subjected to an oxidizing atmosphere and, most often, to environmental threats. The lung is the internal organ most highly exposed to this milieu. Therefore, it has evolved to confront both oxidative stress induced by reactive oxygen species (ROS) and a variety of pollutants, pathogens, and allergens that promote inflammation and can harm the airways to different degrees. Indeed, an excess of ROS, generated intrinsically or from external sources, can imprint direct damage to key structural cell components (nucleic acids, sugars, lipids, and proteins) and indirectly perturb ROS-mediated signaling in lung epithelia, impairing its homeostasis. These early events complemented with efficient recognition of pathogen- or damage-associated recognition patterns by the airway resident cells alert the immune system, which mounts an inflammatory response to remove the hazards, including collateral dead cells and cellular debris, in an attempt to return to homeostatic conditions. Thus, any major or chronic dysregulation of the redox balance, the air-liquid interface, or defects in epithelial proteins impairing mucociliary clearance or other defense systems may lead to airway damage. Here, we review our understanding of the key role of oxidative stress and inflammation in respiratory pathology, and extensively report current and future trends in antioxidant and anti-inflammatory treatments focusing on the following major acute and chronic lung diseases: acute lung injury/respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and cystic fibrosis.

Efficacy of a Quail Eggs-Based Dietary Supplement for Allergic Rhinitis: Results of a Single-Arm Trial

Previous data suggested the potential treatment effect of a proprietary quail eggs-based blend on allergic rhinitis (AR) symptoms, induced by allergen challenge. We herein aimed to investigate the efficacy and safety of a similar dietary supplement, comprising the bioactive ingredients of quail eggs and the zinc mineral, in the setting of active AR. Adult patients (n = 77), aged 18- 60 years, with mild, intermittent AR were enrolled in this single-arm, open-label trial. Patients' responses were assessed based on peak nasal inspiratory flow (PNIF) measurements at two visits (Day 1/Visit 1 and Day 7/Visit 2) and self-rating of AR-associated symptoms on a Visual Analog Scale (VAS) throughout the entire 7-day study period. PNIF values at 15, 30, 60, 90 and 120 min (Visit 1) following administration of an oral dose of the study product were the primary efficacy endpoint. PNIF values (Visit 1) gradually increased from baseline (pre-treatment), with statistical significance first reached 30 min later (p = 0.002). VAS scores (Visit 1) for all AR symptoms gradually decreased with statistical significance first reached at 15 min (rhinorrhea, p = 0.042; itchy nose, p = 0.001; sneezing p < 0.001), 30 min (nasal congestion, p < 0.001; itchy eyes, p = 0.003) or 60 min (watery eyes, p = 0.04). PNIF improvement and decline of VAS scores were significantly more apparent at Visit one vs. Visit 2. Treatment-emergent adverse events were limited to cough and muscle strain (one patient each). Our results support the efficacy, rapid mode of action and tolerability of the investigated product for symptomatic treatment of mild intermittent AR.

Fenretinide favorably affects mucins (MUC5AC/MUC5B) and fatty acid imbalance in a manner mimicking CFTR-induced correction

Cystic fibrosis (CF) is the most common genetic disease in Caucasians. CF is manifested by abnormal accumulation of mucus in the lungs, which serves as fertile ground for the growth of microorganisms leading to recurrent infections and ultimately, lung failure. Mucus in CF patients consists of DNA from dead neutrophils as well as mucins produced by goblet cells. MUC5AC mucin leads to pathological plugging of the airways whereas MUC5B has a protective role against bacterial infection. Therefore, decreasing the level of MUC5AC while maintaining MUC5B intact would in principle be a desirable mucoregulatory treatment outcome. Fenretinide prevented the lipopolysaccharide-induced increase of MUC5AC gene expression, without affecting the level of MUC5B, in a lung goblet cell line. Additionally, fenretinide treatment reversed the pro-inflammatory imbalance of fatty acids by increasing docosahexaenoic acid and decreasing the levels of arachidonic acid in a lung epithelial cell line and primary leukocytes derived from CF patients. Furthermore, for the first time we also demonstrate the effect of fenretinide on multiple unsaturated fatty acids, as well as differential effects on the levels of long- compared to very-long-chain saturated fatty acids which are important substrates of complex phospholipids. Finally, we demonstrate that pre-treating mice with fenretinide in a chronic model of P. aeruginosa lung infection efficiently decreases the accumulation of mucus. These findings suggest that fenretinide may offer a new approach to therapeutic modulation of pathological mucus production in CF.

Zinc supplementation inhibits the high glucose‑induced EMT of peritoneal mesothelial cells by activating the Nrf2 antioxidant pathway

The high glucose (HG)-induced epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) serves an important role in peritoneal fibrosis (PF) during peritoneal dialysis. Our previous study reported that zinc (Zn) supplementation prevented the HG-induced EMT of rat PMCs in vitro. In the present study, the role of Zn in HG-induced EMT was investigated in vivo using a rat model of PF. Additionally, the molecular mechanisms underlying HG-induced EMT were studied in human PMCs (HPMCs). In the rat model of PF, HG treatment increased the glucose transfer capacity and decreased the ultrafiltration volume. Histopathological analysis revealed peritoneal thickening, increased expression of vimentin and decreased expression of E-cadherin. ZnSO₄ significantly ameliorated the aforementioned changes, whereas Zn inhibition by clioquinol significantly aggravated the effects of HG on rats. The effects of Zn on HPMCs was assessed using western blot analysis, Transwell assays and flow cytometry. It was revealed that Zn also significantly suppressed the extent of the EMT, and reduced reactive oxygen species production and the migratory ability of HG-induced HPMCs, whereas Zn inhibition by N',N',N',N'-tetrakis (2-pyridylmethyl) ethylenediamine significantly potentiated the HG-induced EMT of HPMCs. HG-stimulated HPMCs exhibited increased expression of nuclear factor-like 2 (Nrf2) in the nucleus, and total cellular NAD(P)H quinone dehydrogenase 1 (NQO1) and heme oxygenase-1 (HO-1), the target proteins of the Nrf2 antioxidant pathway. Zn supplementation further promoted nuclear Nrf2 expression, and increased the expression of target proteins of the Nrf2 antioxidant pathway, whereas Zn depletion decreased nuclear Nrf2, NQO1 and HO-1 expression compared with the HG group. In conclusion, Zn supplementation was proposed to suppress the effects of HG on the EMT by stimulating the Nrf2 antioxidant pathway and subsequently reducing oxidative stress in PMCs.

Zinc Nutritional Status in Patients with Cystic Fibrosis

BACKGROUND

Zinc is an essential nutrient for all forms of life and its deficiency affects the normal growth and development of human beings.

OBJECTIVE

The main aim was to investigate zinc nutritional status by serum zinc concentration (SZC) and dietary zinc intake and their association in cystic fibrosis (CF) patients.

METHODS

A cross-sectional study was conducted in CF patients. Anthropometric measurements and respiratory and pancreatic tests were conducted. Hypozincemia was determined by SZC while using atomic absorption spectrophotometry and dietary zinc deficiency by prospective 72-h dietary surveys.

RESULTS

Mean SZC (87.2 ± 16.7 μg/dL) and dietary zinc intake (97 ± 26.9% Dietary Reference Intake) were normal. Three of 17 patients with CF (17.6%) had hypozincemia and four (23.5%) had a dietary zinc deficiency. No patient with dietary zinc deficiency had hypozincemia. A positive and significant association was observed between SZC and Z-score of BMI-for-age (p = 0.048) and weight-for-height (p = 0.012) and between dietary zinc intake and energy intake (EI, p = 0.036) and Z-score of weight-for-high (p = 0.029).

CONCLUSION

SZC was associated with the nutritional status, expressed as BMI (Body Mass Index) and weight-for-height Z score, and dietary zinc intake with EI and weight-for-height Z-score. No patient with hypozincemia had dietary zinc deficiency. This situation should alert us to a marginal zinc deficiency and it may explain why there were no overlapping cases between the two groups. We suggest that probably 41% of the cases in this study would be at elevated risk of zinc deficiency and a zinc supplementation may be considered.

Zinc Deficiency via a Splice Switch in Zinc Importer ZIP2/SLC39A2 Causes Cystic Fibrosis-Associated MUC5AC Hypersecretion in Airway Epithelial Cells

Airway mucus hyperproduction and fluid imbalance are important hallmarks of cystic fibrosis (CF), the most common life-shortening genetic disorder in Caucasians. Dysregulated expression and/or function of airway ion transporters, including cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC), have been implicated as causes of CF-associated mucus hypersecretory phenotype. However, the contributory roles of other substances and transporters in the regulation of CF airway pathogenesis remain unelucidated. Here, we identified a novel connection between CFTR/ENaC expression and the intracellular Zn^2 + concentration in the regulation of MUC5AC, a major secreted mucin that is highly expressed in CF airway. CFTR-defective and ENaC-hyperactive airway epithelial cells specifically and highly expressed a unique, alternative splice isoform of the zinc importer ZIP2/SLC39A2 (ΔC-ZIP2), which lacks the C-terminal domain. Importantly, ΔC-ZIP2 levels correlated inversely with wild-type ZIP2 and intracellular Zn^2 + levels. Moreover, the splice switch to ΔC-ZIP2 as well as decreased expression of other ZIPs caused zinc deficiency, which is sufficient for induction of MUC5AC; while ΔC-ZIP2 expression per se induced ENaC expression and function. Thus, our findings demonstrate that the novel splicing switch contributes to CF lung pathology via the novel interplay of CFTR, ENaC, and ZIP2 transporters.

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Zinc deficiency is a common feature in both CFTR-defective (CF) and ENaC-hyperactive (CF-like) airway epithelial cells.

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A splice switch from WT-ZIP2 to ΔC-ZIP2 as well as other ZIPs down-regulation caused zinc deficiency in CF and CF-like cells.

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Lower intracellular Zn^2 + levels contributed to CF-associated MUC5AC hypersecretion in airway epithelial cells.

The role of zinc in the pathogenesis of CF lung disease is not well understood. We utilized human CF patient-derived cell lines and primary cells as well as murine CF model, and identified zinc deficiency as a common characteristic in CF models. Down-regulation of several zinc importers (ZIPs) in CF cells caused zinc deficiency, which is sufficient for induction of MUC5AC, a major secreted mucin that exacerbates CF pathogenesis. Especially, strong contribution of ΔC-ZIP2, a novel ZIP2 splice isoform, in the regulation of CF-associated MUC5AC hypersecretion was clearly demonstrated. The study refined the importance of zinc in airway homeostasis.

Zinc inhibits high glucose-induced NLRP3 inflammasome activation in human peritoneal mesothelial cells

Zinc (Zn) deficiency is important for inducing nucleotide-binding domain and leucine‑rich repeat‑containing family, pyrin domain-containing-3 (NLRP3) inflammasome activation in macrophages. However, its function in the NLRP3 inflammasome activation of peritoneal mesothelial cells (PMCs) remains to be elucidated. In the present study, the human PMC (HPMC) line HMrSV5 was co‑treated with high glucose and either ZnSO4 or a Zn chelator. The activity of the NLRP3/caspase‑1 inflammasome was assessed via western blot analysis, immunofluorescence, reverse transcription‑quantitative polymerase chain reaction and ELISA. In addition, the activity of the nuclear factor erythroid 2‑related factor 2 (Nrf2) pathway was detected using western blotting, and the level of reactive oxygen species (ROS) was assessed by 2,7‑dichlorofluorescein fluorescence and flow cytometry. It was found that Zn supplementation inhibited HG‑induced NLRP3 inflammasome activation in the HPMCs by attenuating ROS production. Further experiments revealed that Zn supplementation inhibited the HG‑induced production of ROS through activation of the Nrf2 antioxidant pathway. These results indicated that Zn inhibited NLRP3 inflammasome activation in the HG‑treated HPMCs by activating the Nrf2 antioxidant pathway and reducing the production of ROS.

Role of divalent metals in infectious disease susceptibility and outcome

BACKGROUND

Divalent metals play important roles in maintaining metabolism and cellular growth of both eukaryotic hosts and invading microbes. Both metal deficiency and overload can result in abnormal cellular function or damage. Given its central role in host-pathogen interactions, subtle alterations of divalent metal homeostasis can occur in the course of infectious diseases which aim, from the host perspective, either to reduce the availability of respective metals to microbes or to use toxic metal accumulation to eliminate pathogens.

AIMS

To provide the reader with background information and clinical data on divalent metal homeostasis in host-pathogen interactions, how this affects the course of infectious disease and whether correction of metal disturbances has shown benefit in infections.

SOURCES

An in-depth analysis of PubMed articles related to the topic of this review published in English between 1970 and 2016 was performed.

CONTENT

From the microbial perspective, divalent metals are essential for growth and pathogenicity and to mount effective protection against antimicrobial host responses, including toxic radical formation. Microbes have evolved multiple strategies to control their access to divalent metals. From the clinical perspective, alterations of divalent metal levels may result in increased or decreased susceptibility to infection and often occur in response to infections. However, keeping in mind the strategies underlying such alterations, for which the term 'nutritional immunity' was coined, the uncritical correction of such divalent metal imbalances may cause harm to patients. This review addresses the role of the divalent metals iron, selenium, zinc, manganese and copper in infectious diseases from a mechanistic and clinical perspective.

IMPLICATIONS

We point out areas of research needed to expand our limited knowledge, hoping to improve the clinical management of patients with infections and to identify promising new targets for treatment by modulation of host or microbe divalent metal metabolism.

Effect of zinc deficiency on mouse renal interstitial fibrosis in diabetic nephropathy

There is emerging evidence that tubulointerstitial fibrosis is the final common pathway of the majority of chronic progressive renal diseases, including diabetic nephropathy (DN). Zinc, an essential dietary element, has been suggested to be important for a number of protein functions during fibrosis in vivo and in vitro. However, the effect of zinc deficiency (ZnD) on renal interstitial fibrosis in DN remains unclear. The present study investigated the effect and the underlying mechanisms of ZnD on renal interstitial fibrosis during DN using an streptozotocin‑induced model of diabetes with immunofluorescence staining and western blot analysis. The present study identified that dietary zinc restriction significantly decreased zinc concentrations in the plasma and mouse kidney. ZnD enhanced albuminuria and extracellular matrix protein expression, associated with diabetic renal interstitial fibrosis by activation of renal interstitial fibroblasts and regulation of the expression of fibrosis‑associated factors, which may be mediated by the activation of fibroblasts via the TGF‑β/Smad signaling pathway. The data indicates that ZnD serves an important role in the pathogenic mechanisms of renal interstitial fibrosis during the development of DN.

Zinc Attenuates Tubulointerstitial Fibrosis in Diabetic Nephropathy Via Inhibition of HIF Through PI-3K Signaling

Evidence has demonstrated that hypoxia may have a central pathogenic mechanism in the development of diabetic nephropathy (DN). Epithelial-to-mesenchymal transition (EMT) of mature tubular epithelial cells in kidney is a contributor to the renal accumulation of matrix protein in DN and is highly associated with the progression of tubulointerstitial fibrosis. Zinc (Zn) has anti-fibrosis effects in liver and lungs. In the present study, we aimed to investigate the effect of Zn on renal tubulointerstitial fibrosis especially under hypoxic conditions and its association with DN. We found that Zn treatment blockaded tubular EMT and attenuated renal tubulointerstitial fibrosis by downregulation of hypoxia-inducible factor alpha (HIF-1α) in the kidneys of diabetic streptozotocin-treated mice. High glucose (HG)/hypoxic conditions stimulated EMT in renal tubular cells as indicated by the significant decrease in epithelial marker E-cadherin and ZO-1 while the increase in mesenchymal markers α-smooth muscle actin (α-SMA). Zn supplement mainly prevented HG/hypoxic-induced HIF-1α accumulation and EMT marker changes. In co-treatment Zn with PI3K/Akt/GSK-3β signaling pathway, inhibitor LY294002 prevented HG/hypoxic-induced HIF-1α increase and EMT changes, suggesting that Zn may mediate HG/hypoxic-induced EMT through PI3K/Akt/GSK-3β pathway. Therefore, we concluded that Zn had an important anti-fibrosis role under HG/hypoxic conditions, and a novel mechanism contributing to Zn protection on renal tubular epithelial cells from HG/hypoxia-induced EMT through activation of PI3K/Akt/GSK-3β signaling pathway, which subsequently leads to the downregulation of the expression of HIF-1α.

Zinc Supplementation Increases Procollagen Type 1 Amino-Terminal Propeptide in Premenarcheal Girls: A Randomized Controlled Trial

BACKGROUND

Data have shown that healthy children and adolescents have an inadequate intake of zinc, an essential nutrient for growth. It is unclear whether zinc supplementation can enhance bone health during this rapid period of growth and development.

OBJECTIVE

The primary aim of this study was to determine the effect of zinc supplementation on biochemical markers of bone turnover and growth in girls entering the early stages of puberty. The secondary aim was to test moderation by race, body mass index (BMI) classification, and plasma zinc status at baseline.

METHODS

One hundred forty seven girls aged 9-11 y (46% black) were randomly assigned to a daily oral zinc tablet (9 mg elemental zinc; n = 75) or an identical placebo (n = 72) for 4 wk. Fasting plasma zinc, procollagen type 1 amino-terminal propeptide (P1NP; a bone formation marker), carboxy-terminal telopeptide region of type 1 collagen (ICTP; a bone resorption marker), and insulin-like growth factor I (IGF-I) were assessed at baseline and post-test. Additional markers of bone formation (osteocalcin) and resorption (urinary pyridinoline and deoxypyridinoline) were also measured.

RESULTS

Four weeks of zinc supplementation increased plasma zinc concentrations compared with placebo [mean change, 1.8 μmol/L (95% CI: 1.0, 2.6) compared with 0.2 μmol/L (95% CI: -0.3, 0.7); P < 0.01]. Zinc supplementation also increased serum P1NP concentrations compared with placebo [mean change, 23.8 μmol/L (95% CI: -14.9, 62.5) compared with -31.0 μmol/L (95% CI: -66.4, 4.2); P = 0.04). There was no effect from zinc supplementation on osteocalcin, ICTP, pyridinoline, deoxypyridinoline, or IGF-I. There was no moderation by race, BMI classification, or plasma zinc status at baseline.

CONCLUSIONS

Our data suggest that 4 wk of zinc supplementation increases bone formation in premenarcheal girls. Further studies are needed to determine whether supplemental zinc can improve childhood bone strength. This trial was registered at clinicaltrials.gov as NCT01892098.

Serum zinc concentration in cystic fibrosis patients with CFTR I1234V mutation associated with pancreatic sufficiency

OBJECTIVE

To determine serum zinc (Zn) level among cystic fibrosis (CF) patients with homozygous CFTR I1234V mutation associated with pancreatic sufficiency (PS).

METHODS

A cross-sectional study was conducted including both pediatric and adult CF patients. Data on age, weight, height, body mass index (BMI), BMI Z-score, FEV1, and chronic Pseudomonas aeruginosa infection were collected. Serum Zn, albumin, and total proteins were measured and analyzed.

RESULTS

Forty-five CF patients with homozygous CFTR I1234V mutation belonging to a large Arab kindred tribe and eight CF patients with other mutations associated with pancreatic insufficiency (PI). Patient's age ranged from 2 to 49 years with a mean age of 15.1 ± 9.1 years and mean plasma Zn of 0.78 ± 0.15 mcg/mL. Seven (13.2%) patients with CFTR I1234V and PS had low Zn levels (<0.6 mcg/mL). Mean age among Zn deficient group was significantly older. The mean FEV1 in the deficient group was found to be insignificant low. Persistent P. aeruginosa colonization was more prevalent in Zn deficient group. BMI Z-scosre of CF patients were positively correlated with Zn levels. Forty-five healthy subjects belonging to the same Arab tribe were selected in order to assess their Zn levels and their mean plasma Zn of 0.84 ± 0.11 mcg/mL (range 0.65-1.1 mcg/mL) with mean age 20.4 ± 10.1 years (range 6-40 years).

CONCLUSION

These findings suggest that Zn deficiency can occur in CF patients with PS. The association of Zn levels and the frequency of P. aeruginosa isolated in CF patients need further investigation.

Changes in Mineral Micronutrient Status During and After Pulmonary Exacerbation in Adults With Cystic Fibrosis

BACKGROUND

Patients with cystic fibrosis (CF) may be at risk for micronutrient depletion, particularly during periods of illness and infection. The purpose of this study was to investigate serum micronutrient status over time in adults with CF initially hospitalized with a pulmonary exacerbation.

MATERIALS AND METHODS

This was an ancillary study of a multicenter trial investigating the role of high-dose vitamin D supplementation in 24 adults with CF (mean age, 29.6 ± 7.3 years). We measured serum concentrations of copper (Cu), iron (Fe), calcium (Ca), magnesium (Mg), potassium (K), and sulfur (S) in subjects at the beginning of a pulmonary exacerbation and again at 3 months.

RESULTS

Serum concentrations of Cu, Fe, and Ca were significantly lower at baseline compared with 3 months following the pulmonary exacerbation (Cu: baseline, 1.5 ± 0.6 vs 3 months, 1.6 ± 0.6 µg/mL, P = .027; Fe: 0.8 ± 0.3 vs 1.3 ± 1.1 µg/mL, P = .026; Ca: 9.7 ± 0.8 vs 10.8 ± 2.0 mg/dL, P = .024). Serum concentrations of K, Mg, and S did not change over time (K: baseline, 4.9 ± 0.3 vs 3 months, 5.1 ± 0.5 mEq/L; Mg: 1.8 ± 0.2 vs 2.0 ± 0.3 mg/dL; S: 1288.6 ± 343 vs 1309.9 ± 290 µg/mL; P > .05 for all).

CONCLUSION

Serum concentrations of Cu, Fe, and Ca increased significantly several months following recovery from acute pulmonary exacerbation in adults with CF. This may reflect decreased inflammation, improved food intake, and/or increased absorption following recovery.

Plasma zinc in adults with cystic fibrosis: correlations with clinical outcomes

BACKGROUND

Zinc status has been previously documented in cystic fibrosis (CF) infants, children and adolescents. However, despite the increasing life expectancy observed in CF populations, data regarding zinc status of CF adults are surprisingly lacking. The objectives of this study were to (1) characterize zinc status and (2) explore associations between zinc status and clinical outcomes of CF adult patients.

METHODS

A retrospective chart review was performed for patients who had their plasma zinc measured between 2009 and 2012. Data included demographics, clinical characteristics, biochemical parameters and co-morbid conditions.

RESULTS

A total of 304 CF patients were included in the study. These patients displayed a good nutritional status (mean BMI±SD: 22.7±3.5) and moderate lung disease (mean FEV1±SD: 66.3±22.2). Low plasma zinc concentration (<9.2μmol/L) was found in 68 out of 304 CF patients (22.4%). Compared to patients with normal zinc, those with low zinc had significantly lower forced vital capacity and forced expiratory volume in one second. 72% of CF adults with low zinc suffered from bone disease (vs 49% with normal zinc, p=0.037) and 79% had impaired glycemic status (vs 58%, p=0.016). Accordingly, negative correlations were found between plasma zinc and glucose (r=-0.139, p=0.0001), HbA1c (r=-0.237, p=0.0001) and fructosamine (r=-0.134, p=0.034). In multiple linear regression, albumin and glycemic status were significant predictors of plasma zinc.

CONCLUSION

Our data indicated that nearly one quarter of CF adults with good nutritional status and moderate lung disease had low plasma zinc concentration and that low zinc status was associated with worse clinical outcomes.

Zinc transporter 7 induced by high glucose attenuates epithelial-to-mesenchymal transition of peritoneal mesothelial cells

Zinc (Zn) is an essential micronutrient and cytoprotectant involved in preventing many types of epithelial-to-mesenchymal transition (EMT)-driven fibrosis in vivo. The zinc-transporter family SLC30A (ZnT) is a pivotal factor in the regulation of Zn homeostasis. However, its function in EMT in peritoneal mesothelial cells (PMCs) remains unknown. This study explored the regulation of zinc transporters and the role they play in cell EMT, particularly in rat peritoneal mesothelial cells (RPMCs), surrounding glucose concentrations and the molecular mechanism involved. The effects of high glucose (HG) on zinc transporter gene expression were measured in RPMCs by real-time PCR. We explored ZnT7 (Slc30A7): the effect of ZnT7 over-expression and siRNA-mediated knock-down on HG-induced EMT was investigated as well as the underlying molecular mechanisms. Over-expression of ZnT7 resulted in significantly inhibited HG-induced EMT in RPMCs, while inhibition of ZnT7 expression using a considerable siRNA-mediated knock-down of RPMCs increased the levels of EMT. Furthermore, over-expression of ZnT7 is accompanied by down-regulation of TGF-β/Smad pathway, phospho-Smad3,4 expression levels. The finding suggests that the zinc-transporting system in RPMCs is influenced by the exposure to HG. The ZnT7 may account for the inhibition of HG-induced EMT in RPMCs, likely through targeting TGF-β/Smad signaling.

Zinc supplementation attenuates high glucose-induced epithelial-to-mesenchymal transition of peritoneal mesothelial cells

Zinc (Zn) plays an important role in preventing many types of epithelial-to-mesenchymal transition (EMT)-driven fibrosis in vivo. But its function in the EMT of the peritoneal mesothelial cells (PMCs) remains unknown. Here, we studied the Zn effect on the high glucose (HG)-induced EMT in the rat PMCs (RPMCs) and the underlying molecular mechanisms. We found that Zn supplementation significantly inhibited TGF-β1 and ROS production, and attenuated the HG-induced EMT in the RPMCs, likely through inhibition of MAPK, NF-κB, and TGF-β/Smad pathways.

Sputum zinc concentration and clinical outcome in older asthmatics

BACKGROUND AND OBJECTIVE

Mouse models of asthma show that zinc deficiency is associated with airway inflammation (AI), which is attenuated by zinc supplements. Whether zinc has a similar role in the human airway remains controversial, with studies demonstrating both high and low plasma zinc concentrations [Zn] in asthmatic patients compared with control subjects. This variability may reflect the inability of plasma measurements to accurately assess airway zinc levels. Examination of induced sputum is an established technique for measuring AI and mediators of inflammation. Recent advances allow measurement of the rapidly exchangeable (labile) and total zinc pools in sputum. The aims of this study were to measure labile and total [Zn] in sputum and plasma of subjects with or without asthma, and second to correlate [Zn] with symptoms, asthma severity, lung function (FEV(1)) and airway hyper-responsiveness.

METHODS

A total of 163 subjects (114 with asthma) completed a single visit for sputum induction and a blood test. Labile and total [Zn] were measured by Zinquin fluorescence and atomic absorption spectrophotometry.

RESULTS

The mean (SD) age of subjects with and without asthma was 55 (14) and 57 (14) years, respectively. Baseline FEV(1) was significantly lower in subjects with asthma (94.2 (16)%) than in those without asthma (103 (16.6)%). Sputum total and labile [Zn] were lower in subjects with asthma compared with control subjects, with median (interquartile range) values of 31.8 (117) versus 50 (188.5), P = 0.02 and 0 (48) versus 26 (84.5) µg/L, P = 0.05, respectively. Increased frequency of wheeze, as well as asthma severity and reduced FEV(1), was associated with significantly lower labile sputum [Zn].

CONCLUSIONS

These findings suggest that sputum [Zn] reflect clinical outcomes and underlying AI, suggesting a potential role for zinc as a biomarker in asthma.

Nutrition management of pediatric patients who have cystic fibrosis

Since the identification of cystic fibrosis (CF) in the 1940s, nutrition care of patients who have CF has been a challenge. Through optimal caloric intake and careful management of malabsorption, patients are expected to meet genetic potential for growth. Yet factors beyond malabsorption, including nutrient activity at the cellular level, may influence growth and health. This article reviews nutrition topics frequently discussed in relationship to CF and presents intriguing new information describing nutrients currently being studied for their impact on overall health of patients who have CF.