Dietary zinc modulation of COX-2 expression and lingual and esophageal carcinogenesis in rats

The Role of Zinc in Bone Tissue Health and Regeneration-a Review

Zinc is a micronutrient of key importance for human health. An increasing number of studies indicate that zinc plays a significant role in bone tissue's normal development and maintaining homeostasis. Zinc is not only a component of bone tissue but is also involved in the synthesis of the collagen matrix, mineralization, and bone turnover. It has been demonstrated that zinc can stimulate runt-related transcription factor 2 (Runx2) and promote the differentiation of osteoblasts. On the other hand, zinc has been found to inhibit osteoclast-like cell formation and to decrease bone resorption by stimulating osteoclasts' apoptosis. Moreover, zinc regulates the RANKL/RANK/OPG pathway, thereby facilitating bone remodeling. To date, not all mechanisms of Zn activity on bone tissue are well understood and documented. The review aimed to present the current state of research on the role of zinc in bone tissue, its beneficial properties, and its effects on bone regeneration. Since calcium phosphates as bone substitute materials are increasingly enriched in zinc ions, the paper included an overview of research on the potential role of such materials in bone filling and regeneration.

Nutritional practices to manage menstrual cycle related symptoms: a systematic review

Certain nutritional practices may reduce menstrual-related symptoms, but there is no current consensus on what foods/supplements are sufficiently evidenced to warrant promotion to reduce menstrual symptoms of naturally menstruating individuals. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Two online databases were searched for published experimental studies that investigated the effects of foods/supplements on menstrual-related symptoms in eumenorrhoeic women. Extracted data and study characteristics were tabulated and grouped on the basis of food/supplement intervention and dosage compared with UK dietary reference values (DRV) and safe upper limits. In total, twenty-eight studies and twenty-one different foods/supplement interventions were included in the review. None of the studies reported a negative effect on symptoms, twenty-three reported a positive effect and five had no effect. Eighteen different ways of measuring menstrual-related symptoms were described across the studies. The results indicate a lack of consistency in studies to confidently provide information to eumenorrheic, naturally menstruating women regarding the use of foods/supplements to reduce menstrual symptoms. Determination of menstrual-related symptoms varied along with dose and duration of food or supplements provided. These data provide some evidence for the use of vitamin D, calcium, zinc and curcumin to reduce menstrual-related symptoms of non-hormonal contraceptive users, on an individual basis; however, further investigation is required prior to implementation with a focus on robust protocols to determine and measure changes in menstrual symptoms, with interventions adhering to DRV and safe upper limits.

Global comparative transcriptomes uncover novel and population-specific gene expression in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) has a poor prognosis and is one of the deadliest gastrointestinal malignancies. Despite numerous transcriptomics studies to understand its molecular basis, the impact of population-specific differences on this disease remains unexplored.

AIMS

This study aimed to investigate the population-specific differences in gene expression patterns among ESCC samples obtained from six distinct global populations, identify differentially expressed genes (DEGs) and their associated pathways, and identify potential biomarkers for ESCC diagnosis and prognosis. In addition, this study deciphers population specific microbial and chemical risk factors in ESCC.

METHODS

We compared the gene expression patterns of ESCC samples from six different global populations by analyzing microarray datasets. To identify DEGs, we conducted stringent quality control and employed linear modeling. We cross-compared the resulting DEG lists of each populations along with ESCC ATLAS to identify known and novel DEGs. We performed a survival analysis using The Cancer Genome Atlas Program (TCGA) data to identify potential biomarkers for ESCC diagnosis and prognosis among the novel DEGs. Finally, we performed comparative functional enrichment and toxicogenomic analysis.

RESULTS

Here we report 19 genes with distinct expression patterns among populations, indicating population-specific variations in ESCC. Additionally, we discovered 166 novel DEGs, such as ENDOU, SLCO1B3, KCNS3, IFI35, among others. The survival analysis identified three novel genes (CHRM3, CREG2, H2AC6) critical for ESCC survival. Notably, our findings showed that ECM-related gene ontology terms and pathways were significantly enriched among the DEGs in ESCC. We also found population-specific variations in immune response and microbial infection-related pathways which included genes enriched for HPV, Ameobiosis, Leishmaniosis, and Human Cytomegaloviruses. Our toxicogenomic analysis identified tobacco smoking as the primary risk factor and cisplatin as the main drug chemical interacting with the maximum number of DEGs across populations.

CONCLUSION

This study provides new insights into population-specific differences in gene expression patterns and their associated pathways in ESCC. Our findings suggest that changes in extracellular matrix (ECM) organization may be crucial to the development and progression of this cancer, and that environmental and genetic factors play important roles in the disease. The novel DEGs identified may serve as potential biomarkers for diagnosis, prognosis and treatment.

Regulation of COX-2 expression by selected trace elements and heavy metals: Health implications, and changes in neuronal plasticity. A review

Trace elements or trace metals are essential components of enzymes, proteins, hormones and play a key role in biochemical processes, cell growth and differentiation, as well as in neurotransmission, affecting human physiology. In nature there are also heavy metals that exhibit toxic effects on the human body, including the brain. The importance of trace elements has been established in neurodegenerative disorders, schizophrenia, depression among others. In parallel, an important regulatory element in the above diseases is cyclooxygenase-2 (COX-2), a modulator of the arachidonic acid (AA) pathway, and a cause of neuroinflammation, and glutamate (Glu) dysregulation, affecting calcium (Ca) metabolism in cells. This review presents the effects of major trace elements and heavy metals on COX-2 expression. Calcium (Ca), zinc (Zn), cadmium (Cd), vanadium (V), nickel (Ni), copper (Cu), and iron (Fe) can potentially increase COX-2 expression, inducing neuroinflammation and Glu excitotoxicity; while magnesium (Mg), lithium (Li), and selenium (Se) can potentially decrease COX-2 expression. The associated mechanisms are described in the article.

Esophagus cancer and essential trace elements

Numerous epidemiological and laboratory studies on essential trace elements have reported protective associations in developing various cancer types, including esophagus cancer (EC). However, the results are not always consistent. Some essential trace elements could play a vital role in preventing esophagus cancer. Some showed no association with esophageal cancer risk, while others harmed individuals. This article reviews the association between the intake or supplementation of essential trace elements (especially zinc, copper, iron, and selenium) and the risk of esophageal cancer. Generally, zinc intake may decrease the risk of esophageal cancer (EC), especially in high esophageal squamous cell carcinoma (ESCC) prevalence regions. The association between copper supplementation and EC remains uncertain. Total iron consumption is thought to be associated with lower EC risk, while heme iron intake may be associated with higher EC risk. Selenium intake showed a protective effect against EC, especially for those individuals with a low baseline selenium level. This review also prospects the research direction of the association between EC and essential trace elements.

ZIF-8 modified multifunctional injectable photopolymerizable GelMA hydrogel for the treatment of periodontitis

Periodontitis is a chronic inflammatory disease caused by plaque that leads to alveolar bone resorption. In the treatment of periodontitis, it is necessary to reduce the bacterial load and promote alveolar bone regeneration. In this study, zeolitic imidazolate framework-8 (ZIF-8) is used in the treatment of periodontitis, and an injectable photopolymerizable ZIF-8/gelatin methacryloyl (GelMA) composite hydrogel (GelMA-Z) is constructed. We confirm that ZIF-8 nanoparticles are successfully loaded into GelMA, which demonstrates fluidity and photopolymerizability. GelMA-Z continuously releases Zn²⁺ and shows good cytocompatibility. In vitro, GelMA-Z can effectively upregulate the expression of osteogenesis-related genes and proteins, increase alkaline phosphatase activity, promote extracellular matrix mineralization by rat bone mesenchymal stem cells, and exert an obvious antibacterial effect against Porphyromonas gingivalis. In vivo, GelMA-Z reduces the bacterial load, relieves inflammation and promotes alveolar bone regeneration in a rat model. The above results show that GelMA-Z has potential prospects in the treatment of periodontitis. STATEMENT OF SIGNIFICANCE: Various methods have been explored for the treatment of periodontitis. However, current regiments have difficulty achieving ideal alveolar bone regeneration. In this study, we constructed a zeolitic imidazolate framework-8 (ZIF-8)/gelatin methacryloyl (GelMA) composite hydrogel (GelMA-Z). (1) The injectable and photopolymerizable GelMA-Z showed biocompatibility in vitro and in vivo. (2) GelMA-Z continually released zinc ions to promote the osteogenic differentiation of bone mesenchymal stem cells and kill bacteria in vitro. (3) In a rat model, the GelMA-Z pregel solution was used to fill the periodontal pocket and then crosslinked by UV exposure. GelMA-Z can stably remain in the periodontal pocket to reduce the bacterial load, relieve inflammation and promote alveolar bone regeneration. In conclusion, GelMA-Z has great potential for use in the treatment of periodontitis, especially in promoting alveolar bone regeneration.

Effects of dietary zinc deficiency on esophageal squamous cell proliferation and the mechanisms involved

BACKGROUND

Dietary zinc deficiency has been shown to be associated with the development of esophageal cancer in humans, but the exact mechanism of action is not known

AIM

To observe the effects of dietary zinc deficiency on esophageal squamous cell proliferation.

METHODS

Thirty C57BL/6 mice were randomly divided into three groups: A zinc-sufficient (ZS) group, zinc-deficient (ZD) group, and zinc-replenished (ZR) group. For weeks 1–10, zinc levels in the mice diets were 30.66–30.89 mg/kg in the ZS group and 0.66–0.89 mg/kg in the ZD and ZR groups. During weeks 10–12, the ZR group was switched to the ZS diet; the other two groups had no changes in their diets. Changes in body weight, serum, and esophageal tissue zinc concentrations were assessed as well as differences in the expression of proliferating cell nuclear antigen (PCNA), mitogen-activated protein kinase p38 (p38MAPK), nuclear factor kappa B (NF-κB) p105, NF-κB p65, and cyclooxygenase (COX)-2 proteins in the esophageal mucosa.

RESULTS

The body weight and zinc concentration in the serum and esophageal mucosa were significantly lower in the ZD and ZR groups than in the ZS group (P < 0.05). In ZD mice, there was a marked proliferation of basal cells in the esophageal mucosa, resulting in a disturbance in the arrangement of basal cells in layers 2–4, a thickening of the squamous layer, and a significant increase in the expression of the above-mentioned five proteins involved in proliferation and inflammation in the esophageal mucosa. Two weeks after switching to the ZS diet, the serum zinc concentration in the ZR group increased, and the expression of PCNA, NF-κB p105, and COX-2 decreased, but the concentration of zinc in the esophageal mucosa and the structure of the esophageal mucosa did not display any significant changes

CONCLUSION

The ZD diet decreased the growth rate and promoted the proliferation of esophageal squamous cells in mice. The mechanism of proliferation was related to the induced overexpression of COX-2, P38, PCNA, and NF-κB (p105 and p65), and the ZR diet reduced the expression of PCNA, NF-κB p105, and COX-2, thereby reversing this process.

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Brief Review of Endometriosis and the Role of Trace Elements

Endometriosis is a chronic, estrogen-dependent, inflammatory condition that is defined as the presence of endometrial glands and stroma outside the uterine cavity. Despite the progress in research into the mechanisms leading to the development of endometriosis, its cause has not yet been established. It seems to be possible that the formation of oxidative stress may be one of the main causes of the development of endometriosis. There is much research that studies the potential role of trace elements in the appearance of endometrial-like lesions. Most studies focus on assessing the content of selected trace elements in the blood, urine, or peritoneal fluid in women with endometriosis. Meanwhile, little is known about the content of these elements in endometrial-like implants, which may be helpful in developing the theory of endometriosis. Investigations that are more comprehensive are needed to confirm a hypothesis that some trace elements play a role in the pathomechanism of endometriosis.

Zinc, ω-3 polyunsaturated fatty acids and vitamin D: An essential combination for prevention and treatment of cancers

Zinc, ω-3 polyunsaturated fatty acids (PUFAs) and vitamin D are essential nutrients for health, maturation and general wellbeing. Extensive literature searches have revealed the widespread similarity in molecular biological properties of zinc, ω-3 PUFAs and vitamin D, and their similar anti-cancer properties, even though they have different modes of action. These three nutrients are separately essential for good health, especially in the aged. Zinc, ω-3 PUFAs and vitamin D are inexpensive and safe as they are fundamentally natural and have the properties of correcting and inhibiting undesirable actions without disturbing the normal functions of cells or their extracellular environment. This review of the anticancer properties of zinc, ω-3 PUFAs and vitamin D is made in the context of the hallmarks of cancer. The anticancer properties of zinc, ω-3 PUFAs and vitamin D can therefore be used beneficially through combined treatment or supplementation. It is proposed that sufficiency of zinc, ω-3 PUFAs and vitamin D is a necessary requirement during chemotherapy treatment and that clinical trials can have questionable integrity if this sufficiency is not checked and maintained during efficacy trials.

The Role of Zinc in Selected Female Reproductive System Disorders

Zinc is an essential microelement that plays many important functions in the body. It is crucial for the regulation of cell growth, hormone release, immunological response and reproduction. This review focuses on its importance in the reproductive system of women of reproductive and postmenopausal ages, not including its well described role in pregnancy. Only recently, attention has been drawn to the potential role of zinc in polycystic ovary syndrome (PCOS), dysmenorrhea, or endometriosis. This review is mainly based on 36 randomized, controlled studies on reproductive, pre- and post-menopausal populations of women and on research trying to explain the potential impact of zinc and its supplementation in the etiology of selected female reproductive system disorders. In women with PCOS, zinc supplementation has a positive effect on many parameters, especially those related to insulin resistance and lipid balance. In primary dysmenorrhea, zinc supplementation before and during each menstrual cycle seems to be an important factor reducing the intensity of menstrual pain. On the other hand, little is known of the role of zinc in endometriosis and in postmenopausal women. Therefore, further studies explaining the potential impact of zinc and its supplementation on female reproductive system would be highly advisable and valuable.

Effects of flavonoids on tongue squamous cell carcinoma

Squamous cell carcinoma (SCC) of the tongue is associated with tobacco use, alcohol abuse, and human papillomavirus (HPV) infections. While clinical outcomes have recently improved for HPV-positive patients in general, 50% of patients suffering from tongue cancer die within 5 years of being diagnosed. Flavonoids are secondary plant metabolites with a wide range of biological activities including antioxidant, anti-inflammatory, and anticancer activities. Flavonoids have generated high interest as therapeutic agents owing to their low toxicity and their effects on a large variety of cancer cell types. In this literature review, we evaluate the actions of flavonoids on SCC of the tongue demonstrated in both in vivo and in vitro models.

MicroRNA dysregulation and esophageal cancer development depend on the extent of zinc dietary deficiency

Zinc deficiency (ZD) increases the risk of esophageal squamous cell carcinoma (ESCC), and marginal ZD is prevalent in humans. In rats, marked-ZD (3 mg Zn/kg diet) induces a proliferative esophagus with a 5-microRNA signature (miR-31, -223, -21, -146b, -146a) and promotes ESCC. Here we report that moderate and mild-ZD (6 and 12 mg Zn/kg diet) also induced esophageal hyperplasia, albeit less pronounced than induced by marked-ZD, with a 2-microRNA signature (miR-31, -146a). On exposure to an environmental carcinogen, ∼16% of moderate/mild-ZD rats developed ESCC, a cancer incidence significantly greater than for Zn-sufficient rats (0%) (P ≤ 0.05), but lower than marked-ZD rats (68%) (P < 0.001). Importantly, the high ESCC, marked-ZD esophagus had a 15-microRNA signature, resembling the human ESCC miRNAome, with miR-223, miR-21, and miR-31 as the top-up-regulated species. This signature discriminated it from the low ESCC, moderate/mild-ZD esophagus, with a 2-microRNA signature (miR-31, miR-223). Additionally, Fbxw7, Pdcd4, and Stk40 (tumor-suppressor targets of miR-223, -21, and -31) were downregulated in marked-ZD cohort. Bioinformatics analysis predicted functional relationships of the 3 tumor-suppressors with other cancer-related genes. Thus, microRNA dysregulation and ESCC progression depend on the extent of dietary Zn deficiency. Our findings suggest that even moderate ZD may promote esophageal cancer and dietary Zn has preventive properties against ESCC. Additionally, the deficiency-associated miR-223, miR-21, and miR-31 may be useful therapeutic targets in ESCC.

Knockdown of Zinc Transporter ZIP5 by RNA Interference Inhibits Esophageal Cancer Growth In Vivo

We recently found that SLC39A5 (ZIP5), a zinc transporter, is overexpressed in esophageal cancer. Downregulation of ZIP5 inhibited the proliferation, migration, and invasion of the esophageal cancer cell line KYSE170 in vitro. In this study, we found that downregulation of SLC39A5 (ZIP5) by interference resulted in a significant reduction in esophageal cancer tumor volume and weight in vivo. COX2 (cyclooxygenase 2) expression was decreased and E-cadherin expression was increased in the KYSE170K xenografts, which was caused by the downregulation of ZIP5. However, we did not find that the downregulation of ZIP5 caused a change in the relative expressions of cyclin D1, VEGF (vascular endothelial growth factor), MMP9 (matrix metalloprotein 9), and Bcl-2 (B-cell lymphoma/leukmia-2) mRNA or an alteration in the average level of zinc in the peripheral blood and xenografts in vivo. Collectively, these findings indicate that knocking down ZIP5 by small interfering RNA (siRNA) might be a novel treatment strategy for esophageal cancer with ZIP5 overexpression.

The Efficacy of Zinc Administration in the Treatment of Primary Dysmenorrhea

OBJECTIVES

Dysmenorrhea is a common complaint in women. Primary dysmenorrhea is defined as painful menstruation in the absence of pelvic disease and is caused by uterine contractions caused by prostaglandins released from the endometrium. Conventional treatments include nonsteroidal anti-inflammatory drugs and oral contraceptives. We sought to evaluate the efficacy of zinc supplementation in the treatment of primary dysmenorrhea. .

METHODS

Two-hundred participants with primary dysmenorrhea were randomized into one of two groups. The intervention group received zinc and mefenamic acid, and the control group received mefenamic acid and a placebo drug. After three months of treatment, changes in the incidence of dysmenorrhea and the degree of pain were measured in both groups. .

RESULTS

The mean pain score before administration of zinc and mefenamic acid in the intervention group was 5.3±1.8 and after treatment was 1.2±1.9 (p < 0.001). In the control group, the mean pain score before administration of mefenamic acid and placebo was 5.8±2.1 and after treatment was 2.9±2.6 (p < 0.001). The difference in pain levels before and after treatment in the intervention group was 4.1±2.8, and in the control group was 2.9±1.7 (p > 0.050). We also found that 64% of case group and 33% of the control group did not experience dysmenorrhea after treatment (p < 0.001). .

CONCLUSIONS

The use of a zinc supplement in combination with mefenamic acid was superior in reducing primary dysmenorrhea compared to mefenamic acid alone.

The Nail as a Biomonitor of Trace Element Status in Golestan Cohort Study

BACKGROUND

In the Golestan Cohort Study that was launched to investigate the causes of esophageal cancer, a complete biospecimen bank was established for storage of collected blood, urine, hair, and nail samples. The objective of this study was to evaluate the feasibility of nail samples as a biomarker of selected trace elements status.

METHODS

Thirty toenail samples were selected randomly from the participants of Golestan Cohort Study (GCS). The samples were cleaned and analyzed for selenium, mercury, chromium, iron, zinc, and scandium by instrumental neutron activation analysis at the University of Missouri Research Reactor Center. Pearson correlation coefficients were computed for selected trace elements concentration versus scandium concentration to assess terrestrial contamination.

RESULTS

The selenium, zinc, and mercury were not correlated with scandium, suggesting they were free from substantial contamination. The high correlations of scandium with iron and chromium suggest that the iron and chromium levels may be compromised by terrestrial contamination. The coefficients of variation for duplicate samples for selenium and zinc were 2.6% and 7.2%, respectively.

CONCLUSION

The nail samples from Golestan Cohort Study appears to be useable as a biomarker of selenium, zinc, and mercury and could be considered for use in future studies.

Repression of Esophageal Neoplasia and Inflammatory Signaling by Anti-miR-31 Delivery In Vivo

BACKGROUND

Overexpression of microRNA-31 (miR-31) is implicated in the pathogenesis of esophageal squamous cell carcinoma (ESCC), a deadly disease associated with dietary zinc deficiency. Using a rat model that recapitulates features of human ESCC, the mechanism whereby Zn regulates miR-31 expression to promote ESCC is examined.

METHODS

To inhibit in vivo esophageal miR-31 overexpression in Zn-deficient rats (n = 12-20 per group), locked nucleic acid-modified anti-miR-31 oligonucleotides were administered over five weeks. miR-31 expression was determined by northern blotting, quantitative polymerase chain reaction, and in situ hybridization. Physiological miR-31 targets were identified by microarray analysis and verified by luciferase reporter assay. Cellular proliferation, apoptosis, and expression of inflammation genes were determined by immunoblotting, caspase assays, and immunohistochemistry. The miR-31 promoter in Zn-deficient esophagus was identified by ChIP-seq using an antibody for histone mark H3K4me3. Data were analyzed with t test and analysis of variance. All statistical tests were two-sided.

RESULTS

In vivo, anti-miR-31 reduced miR-31 overexpression (P = .002) and suppressed the esophageal preneoplasia in Zn-deficient rats. At the same time, the miR-31 target Stk40 was derepressed, thereby inhibiting the STK40-NF-κΒ-controlled inflammatory pathway, with resultant decreased cellular proliferation and activated apoptosis (caspase 3/7 activities, fold change = 10.7, P = .005). This same connection between miR-31 overexpression and STK40/NF-κΒ expression was also documented in human ESCC cell lines. In Zn-deficient esophagus, the miR-31 promoter region and NF-κΒ binding site were activated. Zn replenishment restored the regulation of this genomic region and a normal esophageal phenotype.

CONCLUSIONS

The data define the in vivo signaling pathway underlying interaction of Zn deficiency and miR-31 overexpression in esophageal neoplasia and provide a mechanistic rationale for miR-31 as a therapeutic target for ESCC.

Dietary intake of minerals and risk of esophageal squamous cell carcinoma: results from the Golestan Cohort Study

BACKGROUND

Dietary factors have been hypothesized to affect the risk of esophageal cancer via different mechanisms, but the intake of minerals is understudied and the evidence is conflicting.

OBJECTIVE

The objective was to evaluate the associations of dietary intake of minerals with risk of esophageal squamous cell carcinoma (ESCC).

DESIGN

We used data from the Golestan Cohort Study, which was launched in a high-risk region for esophageal cancer in Iran. Participants were enrolled in 2004-2008 and were followed to 2014. Intakes of minerals were assessed with a validated food-frequency questionnaire. A Cox proportional hazards model was used to estimate HRs and 95% CIs of ESCC for dietary intakes of selected minerals.

RESULTS

We identified 201 ESCC cases among 47,405 subjects. Calcium intake was significantly inversely associated with the risk of ESCC (HR per 100-mg/d increase: 0.88; 95% CI: 0.81, 0.96; P = 0.005; quartile 4 vs. quartile 1 HR: 0.49; 95% CI: 0.29, 0.82; P-trend = 0.013). Zinc intake was also inversely associated with ESCC, but the quartile association did not reach significance (HR per 1-mg/d increase: 0.87; 95% CI: 0.77, 0.98; P = 0.027; quartile 4 vs. quartile 1 HR: 0.56; 95% CI: 0.28, 1.12; P-trend = 0.097). The relations between dietary intakes of selenium, magnesium, and copper and risk of ESCC were nonlinear (P-nonlinear trend = 0.001, 0.016, and 0.029, respectively). There was no relation between dietary intake of manganese and the risk of ESCC.

CONCLUSION

The results suggest that higher intakes of calcium and zinc are associated with a lower risk of ESCC in a high-risk region of Iran.

A randomised controlled trial of oral zinc sulphate for primary dysmenorrhoea in adolescent females

BACKGROUND

Primary dysmenorrhoea, the most common gynaecologic problem of adolescent females, is commonly treated with nonsteroidal anti-inflammatory drugs or oral contraceptive pills.

AIM

To compare the effect of zinc sulphate with that of placebo on the control of pain severity and duration in adolescent girls with primary dysmenorrhoea.

MATERIALS AND METHODS

In a three-month randomised double-blind placebo-controlled clinical trial, 120 adolescent females with primary dysmenorrhoea were randomly divided into two groups of sixty: an intervention group (zinc) and a control group (placebo). Zinc was administered in the form of a capsule containing 50 mg/day zinc sulphate beginning on the first day of menses and continuing until three days prior to the end of menses. Each month, the duration and severity of primary dysmenorrhoea were determined. Severity scoring was performed by using a 0-10 scaling system.

RESULTS

In the first month, the duration of pain was significantly lower in the zinc group compared with the placebo group (P-value = 0.044), while there was no significant difference in pain severity between the groups (P-value = 0.497). In the second and third month, pain severity and duration in the zinc group were significantly lower than the placebo group (P-value <0.001).

CONCLUSION

Both pain duration and pain severity were decreased by taking oral zinc. The results of our interventional study suggests that zinc may be used to treat primary dysmenorrhoea in adolescents.

Molecular mechanisms of ethanol-associated oro-esophageal squamous cell carcinoma

Alcohol drinking is a major etiological factor of oro-esophageal squamous cell carcinoma (OESCC). Both local and systemic effects of ethanol may promote carcinogenesis, especially among chronic alcoholics. However, molecular mechanisms of ethanol-associated OESCC are still not well understood. In this review, we summarize current understandings and propose three mechanisms of ethanol-associated OESCC: (1) Disturbance of systemic metabolism of nutrients: during ethanol metabolism in the liver, systemic metabolism of retinoids, zinc, iron and methyl groups is altered. These nutrients are known to be associated with the development of OESCC. (2) Disturbance of redox metabolism in squamous epithelial cells: when ethanol is metabolized in oro-esophageal squamous epithelial cells, reactive oxygen species are generated and produce oxidative damage. Meanwhile, ethanol may also disturb fatty-acid metabolism in these cells. (3) Disturbance of signaling pathways in squamous epithelial cells: due to its physico-chemical properties, ethanol changes cell membrane fluidity and shape, and may thus impact multiple signaling pathways. Advanced molecular techniques in genomics, epigenomics, metabolomics and microbiomics will help us elucidate how ethanol promotes OESCC.

Zinc and gastrointestinal disease

This review is a current summary of the role that both zinc deficiency and zinc supplementation can play in the etiology and therapy of a wide range of gastrointestinal diseases. The recent literature describing zinc action on gastrointestinal epithelial tight junctions and epithelial barrier function is described. Zinc enhancement of gastrointestinal epithelial barrier function may figure prominently in its potential therapeutic action in several gastrointestinal diseases.

Zinc and human disease

The vast knowledge of the physiologic functions of zinc in at least 3000 proteins and the recent recognition of fundamental regulatory functions of zinc(II) ions released from cells or within cells links this nutritionally essential metal ion to numerous diseases. However, this knowledge so far has had remarkably limited impact on diagnosing, preventing, and treating human diseases. One major roadblock is a lack of suitable biomarkers that would detect changes in cellular zinc metabolism and relate them to specific disease outcomes. It is not only the right amount of zinc in the diet that maintains health. At least as important is the proper functioning of the dozens of proteins that control cellular zinc homeostasis, regulate intracellular traffic of zinc between the cytosol and vesicles/organelles, and determine the fluctuations of signaling zinc(II) ions. Cellular zinc deficiencies or overloads, a term referring to zinc concentrations exceeding the cellular zinc buffering capacity, compromise the redox balance. Zinc supplementation may not readily remedy zinc deficiency if other factors limit the capability of a cell to control zinc. The role of zinc in human diseases requires a general understanding of the wide spectrum of functions of zinc, how zinc is controlled, how it interacts with the metabolism of other metal ions, in particular copper and iron, and how perturbation of specific zinc-dependent molecular processes causes disease and influences the progression of disease.

Targeted expression of ornithine decarboxylase antizyme prevents upper aerodigestive tract carcinogenesis in p53-deficient mice

Upper aerodigestive tract (UADT) cancers of the oral cavity and esophagus are a significant global health burden, and there is an urgent need to develop relevant animal models to identify chemopreventive and therapeutic strategies to combat these diseases. Antizyme (AZ) is a multifunctional negative regulator of cellular polyamine levels, and here, we evaluate the susceptibility of keratin 5 (K5)-AZ transgenic mice to tumor models that combine chemical carcinogenesis with dietary and genetic risk factors known to influence human susceptibility to UADT cancer and promote UADT carcinogenesis in mice. First, p53(+/-) and K5-AZ/p53(+/-) (AZ/p53(+/-)) mice were placed on a zinc-deficient (ZD) or zinc-sufficient (ZS) diet and chronically exposed to 4-nitroquinoline 1-oxide. Tongue tumor incidence, multiplicity and size were substantially reduced in both ZD and ZS AZ/p53(+/-) mice compared with p53(+/-). AZ expression also reduced progression to carcinoma in situ or invasive carcinoma and decreased expression of the squamous cell carcinoma biomarkers K14, cyclooxygenase-2 and metallothionein. Next, AZ-expressing p53(+/-) and p53 null mice were placed on the ZD diet and treated with a single dose of N-nitrosomethylbenzylamine. Regardless of p53 status, forestomach (FST) tumor incidence, multiplicity and size were greatly reduced with AZ expression, which was also associated with a significant decrease in FST epithelial thickness along with reduced proliferation marker K6 and increased differentiation marker loricrin. These studies demonstrate the powerful tumor suppressive effects of targeted AZ expression in two distinct and unique mouse models and validate the polyamine metabolic pathway as a target for chemoprevention of UADT cancers.

Targeting COX-2/PGE(2) pathway in HIPK2 knockdown cancer cells: impact on dendritic cell maturation

Background

Homeodomain-interacting protein kinase 2 (HIPK2) is a multifunctional protein that exploits its kinase activity to modulate key molecular pathways in cancer to restrain tumor growth and induce response to therapies. For instance, HIPK2 knockdown induces upregulation of oncogenic hypoxia-inducible factor-1 (HIF-1) activity leading to a constitutive hypoxic and angiogenic phenotype with increased tumor growth in vivo. HIPK2 inhibition, therefore, releases pathways leading to production of pro-inflammatory molecules such as vascular endothelial growth factor (VEGF) or prostaglandin E2 (PGE₂). Tumor-produced inflammatory mediators other than promote tumour growth and vascular development may permit evasion of anti-tumour immune responses. Thus, dendritic cells (DCs) dysfunction induced by tumor-produced molecules, may allow tumor cells to escape immunosurveillance. Here we evaluated the molecular mechanism of PGE₂ production after HIPK2 depletion and how to modulate it.

Methodology/Principal findings

We show that HIPK2 knockdown in colon cancer cells resulted in cyclooxygenase-2 (COX-2) upregulation and COX-2-derived PGE₂ generation. At molecular level, COX-2 upregulation depended on HIF-1 activity. We previously reported that zinc treatment inhibits HIF-1 activity. Here, zinc supplementation to HIPK2 depleted cells inhibited HIF-1-induced COX-2 expression and PGE₂/VEGF production. At translational level, while conditioned media of both siRNA control and HIPK2 depleted cells inhibited DCs maturation, conditioned media of only zinc-treated HIPK2 depleted cells efficiently restored DCs maturation, seen as the expression of co-stimulatory molecules CD80 and CD86, cytokine IL-10 release, and STAT3 phosphorylation.

Conclusion/Significance

These findings show that: 1) HIPK2 knockdown induced COX-2 upregulation, mostly depending on HIF-1 activity; 2) zinc treatment downregulated HIF-1-induced COX-2 and inhibited PGE₂/VEGF production; and 3) zinc treatment of HIPK2 depleted cells restored DCs maturation.

Effects of cigarette smoke and ethanol intake on mouse oesophageal mucosa changes induced by dietary zinc deficiency and deoxycholic acid supplementation

The noxious effects of dietary zinc deficiency (ZD) and deoxycholic bile acid (DCA) supplementation in the oesophagus were investigated. The additional influence of cigarette smoke and ethanol intake on the changes in the oesophageal mucosa induced by dietary ZD plus DCA was also assessed. Male C57BL/6 mice were allocated into four groups: Group 1 was fed control diet and groups 2-4 were fed ZD plus DCA diet. After 5 weeks, groups 3 and 4 were exposed to 10% ethanol intake or cigarette smoke for 15 weeks, respectively. All animals were euthanized at the end of week 20, and the oesophagus, lung, liver and colon were collected and analysed by conventional morphology. Cell proliferation was assessed in the oesophageal mucosa by Ki-67 immunohistochemistry and cyclooxygenase 2 (COX-2) protein by Western blotting. Dietary ZD plus DCA treatment induced mild hyperkeratosis and hyperplasia, increased cell proliferation index and COX-2 protein expression in the oesophagus, and intranuclear inclusion, karyocytomegaly and microvesicular fatty change in the liver. Cigarette smoke increased COX-2 protein expression in oesophageal mucosa and irregular enlargement of alveolus and alveolar ductal air spaces, while ethanol enhanced liver damage induced by ZD plus DCA diet. These findings indicate that dietary ZD plus DCA treatment during 20 weeks induces a pattern of chemical oesophageal injury but not Barrett's-like lesions.

Dysregulation of miR-31 and miR-21 induced by zinc deficiency promotes esophageal cancer

Zinc deficiency (ZD) increases the risk of esophageal squamous cell carcinoma (ESCC). In a rat model, chronic ZD induces an inflammatory gene signature that fuels ESCC development. microRNAs regulate gene expression and are aberrantly expressed in cancers. Here we investigated whether chronic ZD (23 weeks) also induces a protumorigenic microRNA signature. Using the nanoString technology, we evaluated microRNA profiles in ZD esophagus and six additional tissues (skin, lung, pancreas, liver, prostate and peripheral blood mononuclear cells [PBMC]). ZD caused overexpression of inflammation genes and altered microRNA expression across all tissues analyzed, predictive of disease development. Importantly, the inflammatory ZD esophagus had a distinct microRNA signature resembling human ESCC or tongue SCC miRNAomes with miR-31 and miR-21 as the top-up-regulated species. Circulating miR-31 was also the top-up-regulated species in PBMCs. In ZD esophagus and tongue, oncogenic miR-31 and miR-21 overexpression was accompanied by down-regulation of their respective tumor-suppressor targets PPP2R2A and PDCD4. Importantly, esophageal miR-31 and miR-21 levels were directly associated with the appearance of ESCC in ZD rats, as compared with their cancer-free Zn-sufficient or Zn-replenished counterparts. In situ hybridization analysis in rat and human tongue SCCs localized miR-31 to tumor cells and miR-21 to stromal cells. In regressing tongue SCCs from Zn-supplemented rats, miR-31 and miR-21 expression was concomitantly reduced, establishing their responsiveness to Zn therapy. A search for putative microRNA targets revealed a bias toward genes in inflammatory pathways. Our finding that ZD causes miR-31 and miR-21 dysregulation associated with inflammation provides insight into mechanisms whereby ZD promotes ESCC.

The immunological contribution of NF-κB within the tumor microenvironment: a potential protective role of zinc as an anti-tumor agent

Over decades, cancer treatment has been mainly focused on targeting cancer cells and not much attention to host tumor microenvironment. Recent advances suggest that the tumor microenvironment requires in-depth investigation for understanding the interactions between tumor cell biology and immunobiology in order to optimize therapeutic approaches. Tumor microenvironment consists of cancer cells and tumor associated reactive fibroblasts, infiltrating non-cancer cells, secreted soluble factors or molecules, and non-cellular support materials. Tumor associated host immune cells such as Th(1), Th(2), Th17, regulatory cells, dendritic cells, macrophages, and myeloid-derived suppressor cells are major components of the tumor microenvironment. Accumulating evidence suggests that these tumor associated immune cells may play important roles in cancer development and progression. However, the exact functions of these cells in the tumor microenvironment are poorly understood. In the tumor microenvironment, NF-κB plays an important role in cancer development and progression because this is a major transcription factor which regulates immune functions within the tumor microenvironment. In this review, we will focus our discussion on the immunological contribution of NF-κB in tumor associated host immune cells within the tumor microenvironment. We will also discuss the potential protective role of zinc, a well-known immune response mediator, in the regulation of these immune cells and cancer cells in the tumor microenvironment especially because zinc could be useful for conditioning the tumor microenvironment toward innovative cancer therapy.

Dietary zinc deficiency fuels esophageal cancer development by inducing a distinct inflammatory signature

Chronic inflammation is implicated in the pathogenesis of esophageal squamous cell carcinoma (ESCC). The causes of inflammation in ESCC, however, are undefined. Dietary zinc (Zn)-deficiency (ZD) increases the risk of ESCC. We have previously shown that short-term ZD (6 weeks) in rats induces overexpression of the proinflammatory mediators S100a8 and S100a9 in the esophageal mucosa with accompanying esophageal epithelial hyperplasia. Here we report that prolonged ZD (21 weeks) in rats amplified this inflammation that when combined with non-carcinogenic low doses of the environmental carcinogen, N-nitrosomethylbenzylamine (NMBA) elicited a 66.7% (16/24) incidence of ESCC. With Zn-sufficiency, NMBA produced no cancers (0/21) (P<0.001). At tumor endpoint, the neoplastic ZD esophagus, as compared with Zn-sufficient esophagus, had an inflammatory gene signature with upregulation of numerous cancer-related inflammation genes (CXC and CC chemokines, chemokine receptors, cytokines and Cox-2) in addition to S100a8 and S100a9. This signature was already activated in the earlier dysplastic stage. Additionally, time-course bioinformatics analysis of expression profiles at tumor endpoint and before NMBA exposure revealed that this sustained inflammation was due to ZD rather than carcinogen exposure. Importantly, Zn replenishment reversed this inflammatory signature at both the dysplastic and neoplastic stages of ESCC development, and prevented cancer formation. Thus, the molecular definition of ZD-induced inflammation as a critical factor in ESCC development has important clinical implications with regard to development and prevention of this deadly disease.

Advances in rodent models of human esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a common form of malignant disease. Appropriate animal models recapitulating human cancers, which are powerful not only for the elucidation of in vivo process and relevant mechanisms of the diseases but also for the evaluation of efficacy and safety of new drugs and management concepts, are critical for the success of translational research. In this context, compared with other malignancies, the present situation for human ESCC that novel discoveries for either diagnostic markers or therapeutic targets as well as the clinical application are out of step (laggard) is largely attributed to the lack of suitable in vivo animal model for this human disease. This article provides an overview of the currently available animal models established for human ESCC, encompassing chemically induced and genetically engineered rodents. Genetically engineered mice coupling induction with 4-nitroquinoline-1-oxide (4NQO) are discussed in more detail.

The role of Pea3 group transcription factors in esophageal squamous cell carcinoma

The transcription factors Pea3, Erm, and Er81 can promote cancer initiation and progression in various types of solid tumors. However, their role in esophageal squamous cell carcinoma (ESCC) has not been elucidated. In this study, we found that the expression levels of Pea3 and Erm, but not that of Er81, were significantly higher in ESCC compared with nontumor esophageal epithelium. A high level of Pea3 expression was significantly correlated with a shorter overall survival in a cohort of 81 patients with ESCC and the subgroup with N1 stage tumor (Wilcoxon-Gehan test, P = 0.016 and P = 0.001, respectively). Pea3 was overexpressed in seven ESCC cell lines compared with two immortalized esophageal cell lines. Pea3 knockdown reduced cell proliferation and suppressed nonadherent growth, migration, and invasion in ESCC cells in vitro. In addition, Pea3 knockdown in ESCC cells resulted in a down-regulation of phospho-Akt and matrix metalloproteinase 13, whereas a significant positive correlation in the expression levels was observed between Pea3 and phospho-Akt (r = 0.281, P < 0.013) and between Pea3 and matrix metalloproteinase 13 in the human specimens (r = 0.462, P < 0.001). Moreover, Pea3 modulated the sensitivity of EC109 cells to doxorubicin, probably via reduced activity of the phosphatidylinositol 3-kinase-Akt-mammalian target of Rapamycin complex 1 pathway on Pea3 knockdown. In conclusion, our results suggest that Pea3 plays an important role in the progression of ESCC.

Zinc supplementation suppresses 4-nitroquinoline 1-oxide-induced rat oral carcinogenesis

Dietary zinc (Zn) deficiency is implicated in the pathogenesis of human oral-esophageal cancers. In rats, Zn deficiency causes increased cell proliferation and cyclooxygenase-2 (COX-2) overexpression and enhances oral carcinogenesis by 4-nitroquinoline 1-oxide (NQO). Zn replenishment reverses all these effects. We questioned whether Zn has antitumor efficacy in a Zn-sufficient animal by investigating in Zn-sufficient rats (i) the efficacy of Zn supplementation on the progression of tongue squamous cell carcinogenesis induced by drinking water exposure to high (20-30 p.p.m.) and low (10 p.p.m.) doses of NQO and (ii) the modulating effects of Zn supplementation on biomarker expression in tongue lesions by immunohistochemistry. In rats exposed to high doses of NQO, Zn supplementation significantly reduced the incidence of papillomas from 100 to 64.7% (P=0.018) and invasive carcinomas from 93.8 to 52.9% (P=0.017). In rats exposed to low doses of NQO, where only minimally invasive carcinomas developed, Zn supplementation significantly reduced tumor multiplicity, incidence of tumors (1-2 mm), hyperplasia, dysplasia, papillomas and progression to carcinoma. Immunohistochemical analysis of carcinomas showed that Zn supplementation caused a shift to a less proliferative/aggressive cancer phenotype by reducing cell proliferation, stimulating apoptosis and decreasing expression of the key tumor markers cyclin D1, p53 and COX-2. Additionally, Zn supplementation significantly reduced cell proliferation in non-lesional tongue squamous epithelia, thereby suppressing tumor development. Together, the results demonstrate that Zn supplementation has chemopreventive efficacy against oral carcinogenesis in nutritionally complete animals. Our data suggest that Zn supplementation may be efficacious in the chemoprevention of human oral cancer.

Effect of zinc supplementation on N-nitrosomethylbenzylamine-induced forestomach tumor development and progression in tumor suppressor-deficient mouse strains

Zinc deficiency is associated with high incidences of esophageal and other cancers in humans and leads to a highly proliferative hyperplastic condition in the upper gastrointestinal tract in laboratory rodents. Zn replenishment reduces the incidence of lingual, esophageal and forestomach tumors in Zn-deficient rats and mice. While previous animal studies focused on Zn deficiency, we have investigated the effect of Zn supplementation on carcinogenesis in Zn-sufficient mice of wild-type and tumor suppressor-deficient mouse strains. All mice received N-nitrosomethylbenzylamine and half the mice of each strain then received Zn supplementation. At killing, mice without Zn supplementation had developed more tumors than Zn-supplemented mice: wild-type C57BL/6 mice developed an average of 7.0 versus 5.0 tumors for Zn supplemented (P < 0.05); Zn-supplemented Fhit-/- mice averaged 5.7 versus 8.0 for control mice (P < 0.01); Zn-supplemented Fhit-/-Nit1-/- mice averaged 5.4 versus 9.2 for control mice (P < 0.01) and Zn-supplemented Fhit-/-Rassf1a-/- (the murine gene) mice averaged 5.9 versus 9.1 for control mice (P < 0.01). Zn supplementation reduced tumor burdens by 28% (wild-type) to 42% (Fhit-/-Nit1-/-). Histological analysis of forestomach tissues also showed significant decreases in severity of preneoplastic and neoplastic lesions in Zn-supplemented cohorts of each mouse strain. Thus, Zn supplementation significantly reduced tumor burdens in mice with multiple tumor suppressor deficiencies. When Zn supplementation was begun at 7 weeks after the final carcinogen dose, the reduction in tumor burden was the same as observed when supplementation began immediately after carcinogen dosing, suggesting that Zn supplementation may affect tumor progression rather than tumor initiation.

Zinc deficiency activates S100A8 inflammation in the absence of COX-2 and promotes murine oral-esophageal tumor progression

Zinc (Zn)-deficiency (ZD) is implicated in the pathogenesis of human oral-esophageal cancers. Previously, we showed that in ZD mice genetic deletion of cyclooxygenase-2 (Cox-2) enhances N-nitrosomethylbenzylamine-induced forestomach carcinogenesis. By contrast, Cox-2 deletion offers protection in Zn-sufficient (ZS) mice. We hypothesize that ZD activates pathways insensitive to COX-2 inhibition, thereby promoting carcinogenesis. This hypothesis is tested in a Cox-2^−/− mouse tongue cancer model that mimics pharmacologic blockade of COX-2 by firstly examining transcriptome profiles of forestomach mucosa from Cox-2^−/− and wild-type mice on a ZD vs. ZS diet, and secondly investigating the roles of identified markers in mouse forestomach/tongue preneoplasia and carcinomas. In Cox-2^−/− mice exposed to the tongue carcinogen 4-nitroquinoline 1-oxide, dietary ZD elicited tongue/esophagus/forestomach carcinomas that were prevented by ZS. The precancerous ZD:Cox-2^−/−vs. ZS:Cox-2^−/− forestomach had an inflammatory signature with upregulation of the proinflammation genes S100a8 and S100a9. Bioinformatics analysis revealed overrepresentation of inflammation processes comprising S100a8/a9 and an nuclear factor (NF)-κB network with connectivity to S100A8. Immunohistochemistry revealed co-overexpression of S100A8, its heterodimeric partner S100A9, the receptor for advanced glycation end-products (RAGE), NF-κB p65, and cyclin D1, in ZD:Cox-2^−/− forestomach/tongue preneoplasia and carcinomas, evidence for the activation of a RAGE-S100A8/A9 inflammatory pathway. Accumulation of p53 in these carcinomas indicated activation of additional inflammatory pathways. Zn-replenishment in ZD:Cox-2^−/−mice reversed the inflammation and inhibited carcinogenesis. Thus, ZD activates alternative inflammation-associated cancer pathways that fuel tumor progression and bypass the antitumor effect of Cox-2 ablation. These findings have important clinical implications, as combination cancer therapy that includes Zn may improve efficacy.

Prevention of mutation, cancer, and other age-associated diseases by optimizing micronutrient intake

I review three of our research efforts which suggest that optimizing micronutrient intake will in turn optimize metabolism, resulting in decreased DNA damage and less cancer as well as other degenerative diseases of aging. (1) Research on delay of the mitochondrial decay of aging, including release of mutagenic oxidants, by supplementing rats with lipoic acid and acetyl carnitine. (2) The triage theory, which posits that modest micronutrient deficiencies (common in much of the population) accelerate molecular aging, including DNA damage, mitochondrial decay, and supportive evidence for the theory, including an in-depth analysis of vitamin K that suggests the importance of achieving optimal micronutrient intake for longevity. (3) The finding that decreased enzyme binding constants (increased Km) for coenzymes (or substrates) can result from protein deformation and loss of function due to an age-related decline in membrane fluidity, or to polymorphisms or mutation. The loss of enzyme function can be compensated by a high dietary intake of any of the B vitamins, which increases the level of the vitamin-derived coenzyme. This dietary remediation illustrates the importance of understanding the effects of age and polymorphisms on optimal micronutrient requirements. Optimizing micronutrient intake could have a major effect on the prevention of cancer and other degenerative diseases of aging.

Optimal micronutrients delay mitochondrial decay and age-associated diseases

Three of our research efforts are reviewed, which suggest that optimizing metabolism will delay aging and the diseases of aging in humans. (1) Research on delay of the mitochondrial decay of aging by supplementing rats with lipoic acid and acetyl carnitine. (2) The triage theory, which posits that modest micronutrient deficiencies (common in much of the population) accelerate molecular aging, including mitochondrial decay, and supportive evidence, including an analysis in depth of vitamin K, that suggests the importance of achieving optimal micronutrient intake for longevity. (3) The finding that decreased enzyme binding constants (increased Km) for coenzymes (or substrates) can result from protein deformation and loss of function due to loss of membrane fluidity with age, or to polymorphisms or mutation. The loss of enzyme function can be ameliorated by high doses of a B vitamin, which raises coenzyme levels, and indicates the importance of understanding the effects of age, or polymorphisms, on micronutrient requirements.

Zinc picolinate in the prevention of leiomyoma in Japanese quail

Epidemiologic studies suggest that zinc deficiency may be associated with increased risk of cancer. We investigated the effects of zinc picolinate supplementation on the development of leiomyomas, malondialdehyde (MDA), 8-isoprostane, 4-hydroxyalkenal (HAE), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, and heat shock protein 70 (Hsp70) expression in Japanese quails. One hundred fifty quails (6 months old) were assigned to three treatment groups consisting of 50 birds in each group. Birds were fed either a basal diet or the basal diet supplemented with 30 mg or 60 mg of zinc/kg of diet. The animals were sacrificed after 350 days, and the tumors were identified. Zinc picolinate supplementation did not affect the number of leiomyomas compared to control birds (P > .05). However, the tumors in zinc-fed birds were smaller than those found in control birds (P = .01) Serum MDA, 8-isoprostane, and HAE levels were lower in the treatment groups than in the control group: MDA, 1.95 versus 0.93 micromol/L; 8-isoprostane, 108 versus 85 pg/mL; HAE, 1.55 versus 0.96 micromol/L (P = .01 for all three parameters). The concentrations of serum 8-OHdG, which is a marker of oxidative damage, in the groups were 28.5, 23.6, and 20.1 ng/mL, respectively (P = .01). Hsp70 expression was significantly decreased in zinc-treated birds (P < .01). The results indicate that dietary zinc picolinate supplementation reduces the growth of spontaneously occurring leiomyomas of the oviduct in the Japanese quail. Clinical trials should be conducted to investigate the efficacy of zinc supplementation in the prevention and treatment of uterine leiomyoma in humans.

The ubiquitous role of zinc in health and disease

OBJECTIVE

To review zinc physiology and pathophysiology and the importance of zinc toxicity and deficiency in veterinary patients.

DATA SOURCES

A review of human and veterinary medical literature.

HUMAN DATA SYNTHESIS

There is a significant amount of original research in humans and animals on the role of zinc in multiple organ systems. There is also significant data available on human patients with zinc abnormalities.

VETERINARY DATA SYNTHESIS

Zinc deficiency has been studied in dogs with genetic disease and dietary deficiency leading to dermatological disease and immune deficiency. Zinc toxicity has been described after ingestion of metallic foreign bodies containing zinc.

CONCLUSIONS

Historically, the role of zinc in health and disease has been studied through patients with toxicity or severe deficiency with obvious clinical signs. As the ubiquitous contribution of zinc to structure and function in biological systems was discovered, clinically significant but subtle deficiency states have been revealed. In human medicine, mild zinc deficiencies are currently thought to cause chronic metabolic derangement leading to or exacerbating immune deficiency, gastrointestinal problems, endocrine disorders, neurologic dysfunction, cancer, accelerated aging, degenerative disease, and more. Determining the causal relationships between mild zinc deficiency and concurrent disease is complicated by the lack of sensitive or specific tests for zinc deficiency. The prevalence of zinc deficiency and its contribution to disease in veterinary patients is not well known. Continued research is warranted to develop more sensitive and specific tests to assess zinc status, to determine which patients are at risk for deficiency, and to optimize supplementation in health and disease.

Zinc replenishment reverses overexpression of the proinflammatory mediator S100A8 and esophageal preneoplasia in the rat

BACKGROUND & AIMS

Zinc deficiency is implicated in the pathogenesis of human esophageal cancer. In the rat esophagus, it induces cell proliferation, modulates genetic expression, and enhances carcinogenesis. Zinc-replenishment reverses proliferation and inhibits carcinogenesis. The zinc-deficient rat model allows the identification of biological differences affected by zinc during early esophageal carcinogenesis.

METHODS

We evaluated gene expression profiles of esophageal epithelia from zinc-deficient and replenished rats vs zinc-sufficient rats using microarray analysis. We characterized the role of the top-up-regulated gene S100A8 in esophageal hyperplasia/reversal and in chemically induced esophageal carcinogenesis in zinc-modulated animals by immunohistochemistry and real-time quantitative polymerase chain reaction.

RESULTS

The hyperplastic-deficient esophagus has a distinct expression signature with the proinflammation genes S100 calcium binding protein A8 (S100A8) and A9 (S100A9) up-regulated 57-fold and 5-fold, respectively. Zinc replenishment rapidly restored to control levels the expression of S100A8/A9 and 27 other genes and reversed the hyperplastic phenotype. With its receptor for advanced glycation end products (RAGE), colocalization and overexpression of S100A8 protein occurred in the deficient esophagus that overexpressed nuclear factor kappaBeta p65 and cyclooxygenase-2 (COX-2) protein. Zinc replenishment, but not a COX-2 inhibitor, reduced the overexpression of these 4 proteins. Additionally, esophageal S100A8/A9 messenger RNA levels were associated directly with the diverse tumorigenic outcome in zinc-deficient and zinc-replenished rats.

CONCLUSIONS

In vivo zinc regulates S100A8 expression and modulates the link between S100A8-RAGE interaction and downstream nuclear factor kappaBeta/COX-2 signaling. The finding that zinc regulates an inflammatory pathway in esophageal carcinogenesis may lead to prevention and therapy for this cancer.

Our genes are not our destiny: incorporating molecular medicine into clinical practice

In many developed nations, the state of publicly administered health care is increasingly precarious as a result of escalating numbers of chronically ill patients, inadequate medical personnel and hospital facilities, as well as sparse funding for ongoing upgrades to state-of-the-art diagnostic and therapeutic technology - an increased emphasis on aetiology-centred medicine should be considered in order to achieve improved health for patients and populations. Medical practice patterns which are designed to provide quick and effective amelioration of signs and symptoms are frequently not an enduring solution to many health afflictions and chronic disease states. Recent scientific discovery has rendered the drug-oriented algorithmic paradigm commonly found in contemporary evidence-based medicine to be a reductionist approach to clinical practice. Unfolding evidence appears to support a genetic predisposition model of health and illness rather than a fatalistic predestination construct - modifiable epigenetic and environmental factors have enormous potential to influence clinical outcomes. By understanding and applying fundamental clinical principles relating to the emerging fields of molecular medicine, nutrigenomics and human exposure assessment, doctors will be empowered to address causality of affliction when possible and achieve sustained reprieve for many suffering patients.

Prevention of upper aerodigestive tract cancer in zinc-deficient rodents: inefficacy of genetic or pharmacological disruption of COX-2

Zinc deficiency in humans is associated with an increased risk of upper aerodigestive tract (UADT) cancer. In rodents, zinc deficiency predisposes to carcinogenesis by causing proliferation and alterations in gene expression. We examined whether in zinc-deficient rodents, targeted disruption of the cyclooxygenase (COX)-2 pathway by the COX-2 selective inhibitor celecoxib or by genetic deletion prevent UADT carcinogenesis. Tongue cancer prevention studies were conducted in zinc-deficient rats previously exposed to a tongue carcinogen by celecoxib treatment with or without zinc replenishment, or by zinc replenishment alone. The ability of genetic COX-2 deletion to protect against chemically-induced forestomach tumorigenesis was examined in mice on zinc-deficient versus zinc-sufficient diet. The expression of 3 predictive biomarkers COX-2, nuclear factor (NF)-kappa B p65 and leukotriene A(4) hydrolase (LTA(4)H) was examined by immunohistochemistry. In zinc-deficient rats, celecoxib without zinc replenishment reduced lingual tumor multiplicity but not progression to malignancy. Celecoxib with zinc replenishment or zinc replenishment alone significantly lowered lingual squamous cell carcinoma incidence, as well as tumor multiplicity. Celecoxib alone reduced overexpression of the 3 biomarkers in tumors slightly, compared with intervention with zinc replenishment. Instead of being protected, zinc-deficient COX-2 null mice developed significantly greater tumor multiplicity and forestomach carcinoma incidence than wild-type controls. Additionally, zinc-deficient COX-2-/- forestomachs displayed strong LTA(4)H immunostaining, indicating activation of an alternative pathway under zinc deficiency when the COX-2 pathway is blocked. Thus, targeting only the COX-2 pathway in zinc-deficient animals did not prevent UADT carcinogenesis. Our data suggest zinc supplementation should be more thoroughly explored in human prevention clinical trials for UADT cancer.

A novel rasH2 mouse carcinogenesis model that is highly susceptible to 4-NQO-induced tongue and esophageal carcinogenesis is useful for preclinical chemoprevention studies

We investigated the susceptibility of 4-nitroquinoline 1-oxide (4-NQO)-induced tongue carcinogenesis in male CB6F1-Tg-rasH2 @Jcl mice (Tg mice). The Tg mice were administered 4-NQO (20 p.p.m. in drinking water) for 2, 4, 6 or 8 weeks, and thereafter they were untreated up to week 24. At week 24, a higher incidence (80%) of tongue neoplasm with dysplasia was noted in the mice that received 4-NQO for 8 weeks in comparison with the other groups (20% incidence for each) treated with 4-NQO for 2, 4 and 6 weeks. Esophageal tumors also developed in the Tg mice were 4-NQO. Immunohistochemical observation revealed that the EP receptors, especially EP(1) and EP(2), expressed in the tongue and esophageal lesions induced by 4-NQO, thus suggesting the involvement of prostaglandin (PG) E(2) and EP(1,2) receptors in the tongue and esophageal carcinogenesis. Using this animal model, we investigated the potential chemopreventive ability of pitavastatin (1, 5 and 10 p.p.m. in diet for 15 weeks), starting 1 week after the cessation of 4-NQO-exposure (20 p.p.m. in drinking water for 8 weeks). Dietary pitavastatin at 10 p.p.m. significantly reduced the incidence and multiplicity of the tongue, but not esophageal neoplasms by the modulation of prostaglandin E2 biosynthesis, EP(1) and EP(2) expression and proliferation. Our results thus suggest that a rasH2 mouse model of 4-NQO-induced tongue and esophageal carcinogenesis can be utilized for investigating the pathogenesis of cancer development in these tissues and may well prove to be useful for identifying candidate cancer chemopreventive agents for the upper digestive organs.

Mass spectrometry in nutrition: understanding dietary health effects at the molecular level

In modern nutrition research, mass spectrometry has developed into a tool to assess health, sensory as well as quality and safety aspects of food. In this review, we focus on health-related benefits of food components and, accordingly, on biomarkers of exposure (bioavailability) and bioefficacy. Current nutrition research focuses on unraveling the link between dietary patterns, individual foods or food constituents and the physiological effects at cellular, tissue and whole body level after acute and chronic uptake. The bioavailability of bioactive food constituents as well as dose-effect correlations are key information to understand the impact of food on defined health outcomes. Both strongly depend on appropriate analytical tools to identify and quantify minute amounts of individual compounds in highly complex matrices--food or biological fluids--and to monitor molecular changes in the body in a highly specific and sensitive manner. Based on these requirements, mass spectrometry has become the analytical method of choice with broad applications throughout all areas of nutrition research. The current review focuses on selected areas of application: protein and peptide as well as nutrient and metabolite analysis.

Veterinary aspects and perspectives of nutrigenomics: a critical review

Nutrigenomics examines nutrient-gene interactions on a genome-wide scale. Increased dietary fat or higher non-esterified fatty acids (NEFA) from starvation-induced mobilisation may enhance hepatic oxidation and decrease esterification of fatty acids by reducing the expression of the fatty acid synthase gene. The key factors are the peroxisome proliferator-activated receptors (PPARs). Dietary carbohydrates--both independently and through insulin effect--influence the transcription of the fatty acid synthase gene. Oleic acid or n-3 fatty acids downregulate the expression of leptin, fatty acid synthase and lipoprotein lipase in retroperitoneal adipose tissue. Protein-rich diets entail a shortage of mRNA necessary for expression of the fatty acid synthase gene in the adipocytes. Conjugated linoleic acids (CLAs) are activators of PPAR and also induce apoptosis in adipocytes. Altered rumen microflora produces CLAs that are efficient inhibitors of milk fat synthesis in the mammary gland ('biohydrogenation theory'). Oral zinc or cadmium application enhances transcription rate in the metallothionein gene. Supplemental CLA in pig diets was found to decrease feed intake and body fat by activating PPARgamma-responsive genes in the adipose tissue. To prevent obesity and type II diabetes, the direct modulation of gene expression by nutrients is also possible. Nutrigenomics may help in the early diagnosis of genetically determined metabolic disorders and in designing individualised diets for companion animals.

Zinc treatment prevents dysmenorrhea

Primary dysmenorrhea, menstrual cramps in otherwise well women, produces mild to debilitating cramping of the uterus. More than half, and by some estimates 90% of all American women experience menstrual cramps during the first several days of menstruation. About one in ten women are unable to perform their normal routine for one to three days each menstrual cycle due to severe uterine cramping. Although the uterus contracts and relaxes routinely, during menstruation the contractions are much stronger producing pain and "cramps". Women with dysmenorrhea have high levels of prostaglandins, hormones believed to cause menstrual cramping. Prostaglandins are believed to temporarily reduce or stop blood supply to the uterus, thus depriving the uterus of oxygen resulting in contractions and pain. One would expect zinc, like the non-steroidal anti-inflammatory drugs used to treat cramping, to reduce the production of prostaglandins. Zinc inhibits the metabolism of prostaglandins ruling out this mechanism of action, suggesting erroneously that zinc deficiency would prevent cramping. However, it is shown by case histories that zinc, in 1-3 30-mg doses given daily for one to four days prior to onset of menses, prevents essentially all to all warning of menses and all menstrual cramping. One hypothesis for a mechanism of action is that a precursor (COX-2) or metabolite of prostaglandins causes menstrual cramping and not prostaglandins themselves. Another hypothesis is that zinc has antioxidant and anti-inflammatory actions in the uterus. Improvement in micro-vessel circulation by zinc may help prevent cramping and pain. In patients consuming 31 mg of zinc per day, premenstrual tension (PMT) symptoms did not occur, while in patients consuming 15 mg of zinc, PMT symptoms did occur (P<0.001). Protocols using 30 mg of zinc once to three times a day for one to four days immediately prior to menses to prevent dysmenorrhea are described and they are recommended for additional study. The side effect from the absence of all warning of pending menses due to zinc treatment was concern of possible pregnancy. The United States RDA for zinc appears to be too low to optimize women's health and prevent menstrual cramps.

Low micronutrient intake may accelerate the degenerative diseases of aging through allocation of scarce micronutrients by triage

Inadequate dietary intakes of vitamins and minerals are widespread, most likely due to excessive consumption of energy-rich, micronutrient-poor, refined food. Inadequate intakes may result in chronic metabolic disruption, including mitochondrial decay. Deficiencies in many micronutrients cause DNA damage, such as chromosome breaks, in cultured human cells or in vivo. Some of these deficiencies also cause mitochondrial decay with oxidant leakage and cellular aging and are associated with late onset diseases such as cancer. I propose DNA damage and late onset disease are consequences of a triage allocation response to micronutrient scarcity. Episodic shortages of micronutrients were common during evolution. Natural selection favors short-term survival at the expense of long-term health. I hypothesize that short-term survival was achieved by allocating scarce micronutrients by triage, in part through an adjustment of the binding affinity of proteins for required micronutrients. If this hypothesis is correct, micronutrient deficiencies that trigger the triage response would accelerate cancer, aging, and neural decay but would leave critical metabolic functions, such as ATP production, intact. Evidence that micronutrient malnutrition increases late onset diseases, such as cancer, is discussed. A multivitamin-mineral supplement is one low-cost way to ensure intake of the Recommended Dietary Allowance of micronutrients throughout life.

OMICS-driven biomarker discovery in nutrition and health

While traditional nutrition research has dealt with providing nutrients to nourish populations, it nowadays focuses on improving health of individuals through diet. Modern nutritional research is aiming at health promotion and disease prevention and on performance improvement. As a consequence of these ambitious objectives, the disciplines "nutrigenetics" and "nutrigenomics" have evolved. Nutrigenetics asks the question how individual genetic disposition, manifesting as single nucleotide polymorphisms, copy-number polymorphisms and epigenetic phenomena, affects susceptibility to diet. Nutrigenomics addresses the inverse relationship, that is how diet influences gene transcription, protein expression and metabolism. A major methodological challenge and first pre-requisite of nutrigenomics is integrating genomics (gene analysis), transcriptomics (gene expression analysis), proteomics (protein expression analysis) and metabonomics (metabolite profiling) to define a "healthy" phenotype. The long-term deliverable of nutrigenomics is personalised nutrition for maintenance of individual health and prevention of disease. Transcriptomics serves to put proteomic and metabolomic markers into a larger biological perspective and is suitable for a first "round of discovery" in regulatory networks. Metabonomics is a diagnostic tool for metabolic classification of individuals. The great asset of this platform is the quantitative, non-invasive analysis of easily accessible human body fluids like urine, blood and saliva. This feature also holds true to some extent for proteomics, with the constraint that proteomics is more complex in terms of absolute number, chemical properties and dynamic range of compounds present. Apart from addressing the most complex "-ome", proteomics represents the only platform that delivers not only markers for disposition and efficacy but also targets of intervention. The Omics disciplines applied in the context of nutrition and health have the potential to deliver biomarkers for health and comfort, reveal early indicators for disease disposition, assist in differentiating dietary responders from non-responders, and, last but not least, discover bioactive, beneficial food components. This paper reviews the state-of-the-art of the three Omics platforms, discusses their implication in nutrigenomics and elaborates on applications in nutrition and health such as digestive health, allergy, diabetes and obesity, nutritional intervention and nutrient bioavailability. Proteomic developments, applications and potential in the field of nutrition have been specifically addressed in another review issued by our group.

Zinc deficiency potentiates induction and progression of lingual and esophageal tumors in p53-deficient mice

Upper aerodigestive tract (UADT) cancer, including oral and esophageal cancer, is an important cause of cancer deaths worldwide. Patients with UADT cancer are frequently zinc deficient (ZD) and show a loss of function of the pivotal tumor suppressor gene p53. The present study examined whether zinc deficiency in collaboration with p53 insufficiency (p53+/-) promotes lingual and esophageal tumorigenesis in mice exposed to low doses of the carcinogen 4-nitroquinoline 1-oxide. In wild-type mice, ZD significantly increased the incidence of lingual and esophageal tumors from 0% in zinc sufficient (ZS) ZS:p53+/+ mice to approximately 40%. On the p53+/- background, ZD:p53+/- mice had significantly greater tumor incidence and multiplicity than ZS:p53+/- and ZD:p53+/+ mice, with a high frequency of progression to malignancy. Sixty-nine and 31% of ZD:p53+/- lingual and esophageal tumors, respectively, were squamous cell carcinoma versus 19 and 0% of ZS:p53+/- tumors (tongue, P = 0.003; esophagus, P = 0.005). Immunohistochemical analysis revealed that the increased cellular proliferation observed in preneoplastic lingual and esophageal lesions, as well as invasive carcinomas, was accompanied by overexpression of cytokeratin 14, cyclooxygenase-2 and metallothionein. In summary, a new UADT cancer model is developed in ZD:p53+/- mouse that recapitulates aspects of the human cancer and provides opportunities to probe the genetic changes intrinsic to UADT carcinogenesis and to test strategies for prevention and reversal of this deadly cancer.