Role of zinc in hemostasis: a review

Enhanced coagulation cascade activation and styptic effects of Zn@SiO2 nanocomposite

Humans often have bleeding, which exerts substantial selective pressure on the coagulation system to optimize hemostasis in a variety of situations. Uncontrolled hemorrhage due to severe trauma leads to morbidity and mortality. Although nonbiological surfaces such as silicates can activate coagulation factor XII (FXII), the presence of Zn (Zinc) in the material stimulates and activates the various steps in the coagulation cascade. This results in blood clotting. The Zn@SiO2 nanocomposite has an excellent hemostatic property that establishes hemostasis by activating the factors responsible for the formation of a stable clot called fibrin mesh. This can be used as a hemostatic agent during surgeries and in any other trauma condition related to bleeding. Zn@SiO2 was synthesized and characterized with XRD, FTIR and HRTEM. It is analyzed for its RBC (Red Blood Corpuscles) aggregation and Platelet adhesion ability, fibrin formation, thrombus formation and prothrombin time (PT), Activated Partial Thromboplastin Time (aPTT), D-dimer for its ability to activate the coagulation cascade to achieve stable clotting.

Clays and Wound Healing

Aluminosilicates, such as montmorillonite, kaolinite, halloysite, and diatomite, have a uniform bidimensional structure, a high surface-to-volume ratio, inherent stiffness, a dual charge distribution, chemical inertness, biocompatibility, abundant active groups on the surface, such as silanol (Si-OH) and/or aluminol (Al-OH) groups. These compounds are on the list of U.S. Food and Drug Administration-approved active compounds and excipients and are used for various medicinal products, such as wound healing agents, antidiarrheals, and cosmetics. This review summarizes the wound healing mechanisms related to the material characteristics and the chemical components. Numerous wound dressings with different active components and multiple forms have been studied. Then, medicinal mineral resources for use in hemostatic materials can be developed.

Combining Multiple Photosensitizer Modules into One Supramolecular System for Synergetic Enhanced Photodynamic Therapy

Photodynamic therapy (PDT), as an emerging cancer treatment, requires the development of highly desirable photosensitizers (PSs) with integrated functional groups to achieve enhanced therapeutic efficacy. Coordination-driven self-assembly (CDSA) would provide an alternative approach for combining multiple PSs synergistically. Here, we demonstrate a simple yet powerful strategy of combining conventional chromophores (tetraphenylethylene, porphyrin, or Zn-porphyrin) with pyridinium salt PSs together through condensation reactions, followed by CDSA to construct a series of novel metallo-supramolecular PSs (S1-S3). The generation of reactive oxygen species (ROS) is dramatically enhanced by the direct combination of two different PSs, and further reinforced in the subsequent ensembles. Among all the ensembles, S2 with two porphyrin cores shows the highest ROS generation efficiency, specific interactions with lysosome, and strong emission for probing cells. Moreover, the cellular and living experiments confirm that S2 has excellent PDT efficacy, biocompatibility, and biosafety. As such, this study will enable the development of more efficient PSs with potential clinical applications.

A cross-sectional analysis of zinc and copper levels and their relationship to cardiovascular disease risk markers in Qatar biobank participants

Cardiovascular diseases (CVD) are the leading cause of mortality and morbidity worldwide. Dietary intake, particularly zinc (Zn) and copper (Cu) has been strongly associated with CVD. These trace elements play a crucial role in human enzyme activity, suppressing inflammation, catalyzing lipid metabolism enzymes, reducing oxidative stress, and regulating glucose metabolism. However, imbalances in these elements are linked to cardiovascular disturbances. Thus, this study aimed to investigate the association between circulating levels of Zn, Cu, and Zn/Cu ratio with CVD risk factors in the Qatari population. Bivariate logistic regression, adjusted for age, nationality, gender, and education was performed to examine the impact of Zn, Cu, and Zn/Cu ratio (as independent variables) on major CVD risk markers (as dependent variables). Participants in the highest Zn tertiles (T2 and T3) were at greater odds ratio (OR) of unfavorable metabolic functions such as elevated HbA1C [OR = 2.5, p = 0.015 (T2) and OR = 3.2, p = 0.002 (T3)], triglycerides [OR = 2.17, p = 0.015 (T2), and TyG index [OR = 2.21, p = 0.004 (T2), and OR = 2.67, p < 0.001 (T3)] compared to T1. Conversely, they had significantly lower ORs for prolonged prothrombin time [OR = 0.37, p = 0.001 (T3)]. Higher levels of Cu (T2 and T3) had higher OR for elevated HDL-C levels [OR = 1.69, p = 0.046 (T2), and OR = 2.27, p = 0.002 (T3)] and lower OR for elevated levels of triglycerides (OR = 0.4, p = 0.009, T3), diastolic blood pressure [OR = 0.41, p = 0.024 (T2), and OR = 0.47, p = 0.049 (T3)], and creatinine kinase (OR = 0.27, p = 0.014, T3) compared to T1. Higher levels of Cu (T2 and T3) were associated with a higher risk for elevated fibrinogen levels [OR = 3.1, p = 0.035 (T2), and OR = 5.04, p = 0.002 (T3)]. Additionally, higher Zn/Cu ratio (T2 and T3) were associated with lower ORs for elevated fibrinogen levels [OR = 0.3, p = 0.005 (T2), and OR = 0.27, p = 0.005 (T3)] compared to T1, indicating a lower risk of developing CVD. The study reveals a link between Zn, Cu, and the Zn/Cu ratio and cardiovascular disease risk. A higher Zn/Cu ratio may protect against CVD, while elevated Cu levels are linked to obesity, fibrinogen levels, and HbA1C. Maintaining optimal levels of these trace elements, either through diet or supplementation, may help reduce CVD risk.

Zamzam Water Mitigates Cardiac Toxicity Risk through Modulation of GUT Microbiota and the Renin-angiotensin System

BACKGROUND

Cardiovascular diseases (CVDs) continue to exert a substantial global influence in specific areas due to population growth, aging, microbiota, and genetic/environmental factors. Drinking water has a strong impact on the health of an individual. Further, emerging evidence has highlighted the therapeutic potential and benefits of Zamzam water (Zam).

OBJECTIVE

We investigated the influence of Zam on doxorubicin-induced cardiac toxicity, elucidating its consequential effects on GUT microbiota dysbiosis and hepatic and renal functions.

METHODS

Male rats were categorized into four groups: Group 1 as Normal control (NC), Group 2 as Zamzam control (ZC), Group 3 Disease control (DC) and Group 4 as Therapeutic control (DZ) treated with Zam against doxorubicin-induced disease at a dose of 1mg/kg boy weight) intraperitoneally (i.p).

RESULTS

Significant dysbiosis in the composition of GM was observed in the DC group along with a significant decrease (p < 0.05) in serum levels of Zinc, interleukin-10 (IL-10), IL-6 and Angiotensin II (Ang II), while C-reactive protein (CRP), fibrinogen, and CKMB increased significantly (restoration of Zinc ions (0.72 ± 0.07 mcg/mL) compared to NC. Treatment with Zamzam exhibited a marked abundance of 18-times to 72% in Romboutsia, a genus of firmicutes, along with lowering of Proteobacteria in DZ followed by significant restoration of Zinc ions (0.72 ± 0.07 mcg/mL), significant (p ˂ 0.05) reduction in CRP (7.22 ± 0.39 mg/dL), CKMB (118.8 ± 1.02 U/L) and Fibrinogen (3.18 ± 0.16 mg/dL), significant (p < 0.05) increase in IL-10 (7.22 ± 0.84 pg/mL) and IL-6 (7.18 ± 0.40 pg/ml), restoration of Ang II (18.62 ± 0.50 nmol/mL/min), marked increase in renin with normal myocyte architecture and tissue orientation of kidney, and restoration of histological architecture of hepatocyte.

CONCLUSION

Zam treatment mitigated cardiac toxicity risk through the modulation of GUT microbiota and the renin-angiotensin system and tissue histology effectively.

Trace Metals and The Hemostatic System

In this narrative review we report the main relationships between trace metals and the hemostatic system since this aspect has seldom attracted the attention of the scientific community. A basic aspect to be considered is the importance of maintaining the fine control of all trace metals' levels since they have an important impact on the pathophysiology of the hemostatic system. It is worth noting that poor diet habits are responsible for most trace metal deficiencies, while pollution is responsible for dangerous exposure to them with a consequent negative impact on the general population. This appears of paramount importance in planning the implementation of food and nutrient support to ameliorate the hidden hunger and the quality of life of people especially in developing countries and limiting poisons both in the air and food. As it often happens, when damage to certain mechanisms takes a very long time to appear, no attention is paid to the importance of a systematic prevention to avoid late negative outcomes.

The enhancement of mechanical properties and uniform degradation of electrodeposited Fe-Zn alloys by multilayered design for biodegradable stent applications

Pure Fe is a potential biodegradable stent material due to its better biocompatibility and mechanical properties, but its degradation rate needs to be improved. Alloying with Zn to form Fe-Zn alloy is anticipated to meet the degradation rate requirements while retaining the iron's inherent properties. Therefore, Fe-Zn alloys with monolayered and multilayered structures were prepared by electrodeposition. The alloys' composition, microstructure, mechanical properties, in vitro degradation and biocompatibility were assessed. Results showed that the Zn content ranged from 2.1 wt% to 11.6 wt%. After annealing at 450°C, all the alloys consisted of α(Fe) solid solution and Zn-rich B2 ordered coherent phase, except for the alloy with 11.6 wt% Zn content, in which a Fe₃Zn₁₀ phase appeared. The layered structure consisted of alternating columnar-grain and nano-grain layers, which compensated for the intrinsic brittleness of electrodeposited metals and improved the galvanic effect of the alloy, thus increasing the strength and plasticity and changing the corrosion from localized to uniform while augmenting the corrosion rate. The yield strength of the multilayered alloy exceeded 350 MPa, its elongation was more than 20%, and its corrosion rate obtained by immersion test in Hank's solution reached 0.367 mm·y^-1. Fe-Zn alloys with lower Zn content had good cytocompatibility with the human umbilical vein endothelial cells and good blood compatibility. The above results verified that the multilayered Fe-Zn alloy prepared by electrodeposition presented enhanced mechanical properties, higher degradation rate, uniform degradation mechanism and good biocompatibility. It should be qualified for the application of biodegradable stents. STATEMENT OF SIGNIFICANCE: A potential biodegradable Fe-Zn alloy, which is difficult to be obtained by the metallurgical method, was prepared by electrodeposition to solve the low degradation rate of iron-based biomaterials. A multilayered microstructure design composed of alternating columnar-grain and nano-grain layers was achieved by changing the electrical parameters. The layered design compensated for the intrinsic poor plasticity of electrodeposited metals. It increased the galvanic effect of the alloy, thus augmenting the corrosion rate and changing the corrosion mode of the alloy from localized to uniform corrosion. The yield strength of multilayered alloy exceeded 350 MPa; its elongation was more than 20%. Moreover, the layered alloy had good cytocompatibility and blood compatibility. It indicates that the alloy is qualified for biodegradable stent application.

Zinc improves antibacterial, anti-inflammatory and cell motility activity of chitosan for wound healing applications

We report the successful preparation and characterization of chitosan-Zn complex (ChiZn) in the form of films, intended to enhance the biological performance of chitosan by the presence of Zn as antibacterial agent and biologically active ion. The influence of Zn chelation on morphology and structure of chitosan was assessed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and infrared spectroscopy. The biodegradability study of ChiZn showed a sustained release of Zn up to 2 mg/mL. No toxic response was observed toward stromal cell line ST-2 in indirect contact with the ChiZn films. The dissolution product of ChiZn showed improved wound closure (88% closure) compared to the positive control group (70% closure). Moreover, ChiZn exhibited antibacterial activity against S. aureus together with a slight increase (~30%) in the secretion of VEGF and moderate decrease in nitric oxide evolution. Our findings indicate that ChiZn could be used as a safe and effective wound healing agent.

In Situ Growth of Zeolitic Imidazolate Framework-L in Macroporous PVA/CMC/PEG Composite Hydrogels with Synergistic Antibacterial and Rapid Hemostatic Functions for Wound Dressing

Although many advances have been made in medicine, traumatic bleeding and wound infection are two of the most serious threats to human health. To achieve rapid hemostasis and prevent infection by pathogenic microbes, the development of new hemostatic and antibacterial materials has recently gained significant attention. In this paper, safe, non-toxic, and biocompatible polyvinyl alcohol (PVA); carboxymethyl cellulose (CMC), which contains several carboxyl and hydroxyl groups; and polyethylene glycol (PEG), which functions as a pore-forming agent, were used to prepare a novel PVA/CMC/PEG-based composite hydrogel with a macroporous structure by the freeze-thaw method and the phase separation technique. In addition, a PVA/CMC/PEG@ZIF-L composite hydrogel was prepared by the in situ growth of zeolitic imidazolate framework-L (ZIF-L). ZIF-L grown in situ on hydrogels released Zn²⁺ and imidazolyl groups. They elicited a synergistic antibacterial effect in hemostasis with PVA and CMC, rendering the PVA/CMC/PEG@ZIF-L hydrogel with a good antibacterial effect against Staphylococcus aureus. At the same time, the macroporous structure enabled the rapid release of Zn²⁺ and imidazolyl groups in ZIF-L and promoted cell proliferation at an early stage, enhancing the coagulation efficiency. A rat liver injury model was used to confirm its rapid hemostasis capacity.

Determination of Zn2+ in Solid Pharmaceutical Dosage Forms by Means of Spectrophotometry in Micellar Media: Method Validation

In this study, a spectrophotometric method for the quantitative determination of zinc in a dietary supplement was validated. Zinc forms a ternary complex with Xylenol Orange and cetylpyridinium chloride in acetate buffer at pH = 5.5. The complex exhibits an absorption maximum at 560 nm. Linearity (range was 0.5–1.5 µg/mL, and correlation coefficient of the calibration curve was 0.9998), precision (repeatability variation coefficient and reproducibility variation coefficient were 1.57% and 1.77%, respectively), and accuracy (confidence interval of the mean recovery was 98.29–100.55%) of this method fulfil current pharmacopeial requests. Results obtained by spectrophotometric method were statistically compared with ones obtained by atomic absorption spectrometry and good agreement was found. The method can be applied routinely for quality control of solid pharmaceutical dosage forms containing zinc.

Modeling and dynamical analysis of the full-length structure of factor XII with zinc

Zinc (II), the second most abundant transition metal in blood, binds to the initiator of the contact pathway, factor XII (FXII). This binding induces conformational changes in the structure of FXII eventually leading to its activation. Despite many in vitro and in vivo studies on zinc-mediated activation of FXII, its molecular mechanism remains elusive mainly due to absence of a full-length structural model of FXII. To this end, this study investigated the role of zinc in the structure and dynamics of the full-length structure FXII that was obtained through molecular modeling. We have used four structural templates covering more than 70% of the FXII sequence and the remaining interconnecting regions were built by loop modeling. The resulting full-length structure of FXII contained disordered regions, but in comparison to the AlphaFold (AF) prediction, our full-length model represented a more realistic structure because of the disordered regions which were modeled to yield a more compact full-length structure in our model than the AF structure. Other than the disordered regions, our model and AF prediction were highly similar. The resulting full-length FXII structure was used to generate different systems representing the zinc-bound form (holo). Further to assess the contribution of the disulfide bridges, we also analyzed the apo and holo FXII structures with oxidized or reduced cysteine side-chains. Simulations suggested zinc binding conferred rigidity to the structure, particularly to the light chain of FXII. Zinc binding alone was sufficient to limit the backbone flexibility while 15 disulfide bonds, which were scattered throughout the structure, made a less significant contribution to the backbone rigidity. Altogether our results provide insights into the first realistic full-length structure of FXII focusing on the impact of structural zinc and disulfide bridges in the dynamics of this structure.

Influence of physical training on intracellular and extracellular zinc concentrations

Background

Physical exercise affects zinc (Zn) homeostasis. This study aimed to analyze the influence of physical training on extracellular (serum, plasma, and urine) and intracellular (erythrocytes and platelets) concentrations of Zn.

Methods

Forty young men, divided into a training group (TG; n = 20; 18.15 ± 0.27 years; 68.59 ± 4.18 kg; 1.76 ± 0.04 m) and a control group (CG; n = 20; 19.25 ± 0.39 years; 73.45 ± 9.04 kg; 1.79 ± 0.06 m), participated in this study. The TG was formed by semiprofessional soccer players from a youth category with a regular training plan of 10 h/week. The CG was formed by healthy men who did not practice physical exercise and had not followed any specific training plan. Plasma, serum, urine, erythrocyte, and platelet samples of Zn were obtained and analyzed by inductively coupled plasma mass spectrometry.

Results

The TG showed elevated plasma Zn concentrations (p < 0.01) despite similar intakes. However, TG showed reduced absolute (p < 0.01) and relative (p < 0.05) Zn concentrations in erythrocytes.

Conclusions

Athletes who underwent regular physical training showed elevated plasma and reduced erythrocyte Zn concentrations despite similar intakes to the CG.

Metal ion chelation enhances tissue plasminogen activator (tPA)-induced thrombolysis: an in vitro and in vivo study

Stroke is the third leading cause of death in the United States and the leading cause of adult disability. Despite enormous research efforts including many clinical trials, tissue plasminogen activator (tPA) remains the only FDA-approved treatment for acute ischemic stroke. Unfortunately, only 1-3% of stroke patients in the US receive this therapy because of the narrow time window and severe side effects for using tPA. The most deadly and damaging side effect is the risk of intracranial bleeding or hemorrhage. For that reason, the dose of tPA and its overall administration are under tight control, which may compromise the effect of thrombolysis. Studies have been focused on improving the effectiveness of tPA for higher rate of reperfusion, and the safety for less adverse bleeding episode. We studied how metal ions (zinc & iron) affect tPA-induced thrombolysis in vitro and in vivo, and proposed a method to improve the rate of thrombolysis. The amount of hemoglobin in the blood clot lysis was measured by a spectrophotometer. The tPA-induced thrombolysis was measured in vivo in femoral artery. Our results showed that Zn²⁺, Fe³⁺ and Fe²⁺ inhibited tPA-induced thrombolysis, with Zn²⁺ and Fe²⁺ being the most effective. Metal ion chelating agent EDTA when it was co-applied with tPA significantly enhanced the tPA-induced thrombolysis. The chelation alone did not have noticeable thrombolytic effect. In in vivo study of tPA-induced thrombosis following femoral artery thrombosis, the co-application of tPA and EDTA achieved significant higher rate of reperfusion than that by tPA treatment alone, suggesting that ion chelation facilitates tPA-induced thrombolysis and potentially improves the safety of tPA application by reducing the necessary dose of tPA application. Our results suggest that the co-application of a chelator and tPA improves the efficacy and, potentially, safety of tPA application, by reducing the necessary dose of tPA for thrombolysis.

Prolonged blood coagulation time among occupationally exposed automobile technicians in Abeokuta, Nigeria

Automobile technicians in resource-poor settings often work in poor environments and are exposed to chemicals that put them at risk of ill health and disease. These chemical exposures could affect blood coagulation, leading to bleeding disorders or thrombosis. The present study is aimed at assessing prothrombin test (PT) and activated partial thromboplastin test (aPTT) values, serum zinc (Zn) and copper (Cu) concentrations, and blood lead level (BLL) among occupationally exposed automobile technicians compared to unexposed controls. A total of 140 consenting participants comprising 70 automobile technicians and 70 unexposed controls were recruited for this case-control study. A 6-mL blood sample was drawn from each participant for estimation of BLL, serum Zn and Cu concentrations, and PT and aPTT values. Blood lead level, and serum Zn and Cu concentrations were determined using atomic absorption spectrophotometry, while PT and aPTT values were determined using Innovin PT and Actin FS Activated PTT reagents on the Sysmex CA-101 coagulation analyser. Data were analysed using t-tests, chi-square tests, and logistic and multiple linear regression analyses with statistical significance set at p < 0.05. The mean BLL, serum Zn concentration, and PT and aPTT values were significantly higher in automobile technicians compared to controls. Binary logistic regression showed that automobile technicians had higher odds of elevated PT value (OR = 21.769; p = 0.000), aPTT value (OR = 1.348; p = 0.018), BLL (OR = 1.261; p = 0.000) and serum Zn concentration (OR = 1.063; p = 0.005) than unexposed controls. Linear regression showed significant positive association of PT value with BLL and with serum Zn concentration. Higher PT and aPTT values reflect prolonged blood coagulation time among automobile technicians, which indicates impairment of extrinsic and intrinsic coagulation pathways associated with work-related exposures.

Efficient synthesis of NIR emitting bis[2-(2'-hydroxylphenyl)benzoxazole] derivative and its potential for imaging applications

Unassymetric bis[2-(2'-hydroxyphenylbenzoxole)] bis(HBO) derivatives with a DPA functionality for zinc binding have been developed with an efficient synthetic route, using the retrosynthetic analysis. Comparison of bis(HBO) derivatives with different substitution patterns allows us to verify and optimize their unique fluorescence properties. Upon binding zinc cation, bis(HBO) derivatives give a large fluorescence turn-on in both visible (λ_em ≈ 536 nm) and near-infrared (NIR) window (λ_em ≈ 746 nm). The probes are readily excitable by a 488 nm laser, making this series of compounds a suitable imaging tool for in vitro and in vivo study on a confocal microscope. The application of zinc binding-induced fluorescence turn-on is successfully demonstrated in cellular environments and thrombus imaging.

Zn2+ and Cu2+ complexes of a fluorescent scorpiand-type oxadiazole azamacrocyclic ligand: crystal structures, solution studies and optical properties

A ligand comprised of a macrocyclic pyridinophane core having a pendant arm containing a secondary amine group linked through a methylene spacer to a pyridyl-oxadiazole-phenyl (PyPD) fluorescent system has been prepared (L). The crystal structures of [ZnL](ClO₄)₂ and [CuL](ClO₄)₂ show that M²⁺ is coordinated to all the nitrogen atoms of the macrocyclic core, the secondary amine of the pendant arm and the nitrogen atom of the pyridine group of the fluorescent moiety, the latter bond being clearly weaker than the one with the pyridine of the macrocycle. Solution studies showed the formation of a highly stable Cu²⁺ complex with 1 : 1 stoichiometry, whereas with Zn²⁺ least stable complexes were formed and, given the right conditions, a [Zn₃L₂]⁶⁺ species was also detected, but it was not possible to isolate this species in the solid state. Following Zn²⁺ coordination, a strong chelation-induced enhancement of fluorescence was observed, a behaviour that was not observed with any of the other metal cations tested.

Zinc Homeostasis in Platelet-Related Diseases

Zn²⁺ deficiency in the human population is frequent in underdeveloped countries. Worldwide, approximatively 2 billion people consume Zn²⁺-deficient diets, accounting for 1-4% of deaths each year, mainly in infants with a compromised immune system. Depending on the severity of Zn²⁺ deficiency, clinical symptoms are associated with impaired wound healing, alopecia, diarrhea, poor growth, dysfunction of the immune and nervous system with congenital abnormalities and bleeding disorders. Poor nutritional Zn²⁺ status in patients with metastatic squamous cell carcinoma or with advanced non-Hodgkin lymphoma, was accompanied by cutaneous bleeding and platelet dysfunction. Forcing Zn²⁺ uptake in the gut using different nutritional supplementation of Zn²⁺ could ameliorate many of these pathological symptoms in humans. Feeding adult rodents with a low Zn²⁺ diet caused poor platelet aggregation and increased bleeding tendency, thereby attracting great scientific interest in investigating the role of Zn²⁺ in hemostasis. Storage protein metallothionein maintains or releases Zn²⁺ in the cytoplasm, and the dynamic change of this cytoplasmic Zn²⁺ pool is regulated by the redox status of the cell. An increase of labile Zn²⁺ pool can be toxic for the cells, and therefore cytoplasmic Zn²⁺ levels are tightly regulated by several Zn²⁺ transporters located on the cell surface and also on the intracellular membrane of Zn²⁺ storage organelles, such as secretory vesicles, endoplasmic reticulum or Golgi apparatus. Although Zn²⁺ is a critical cofactor for more than 2000 transcription factors and 300 enzymes, regulating cell differentiation, proliferation, and basic metabolic functions of the cells, the molecular mechanisms of Zn²⁺ transport and the physiological role of Zn²⁺ store in megakaryocyte and platelet function remain elusive. In this review, we summarize the contribution of extracellular or intracellular Zn²⁺ to megakaryocyte and platelet function and discuss the consequences of dysregulated Zn²⁺ homeostasis in platelet-related diseases by focusing on thrombosis, ischemic stroke and storage pool diseases.

Bioinorganics and Wound Healing

Wound dressings and the healing enhancement (increasing healing speed and quality) are two components of wound care that lead to a proper healing. Wound care today consists mostly of providing an optimal environment by removing waste and necrotic tissues from a wound, preventing infections, and keeping the wounds adequately moist. This is however often not enough to re-establish the healing process in chronic wounds; with the local disruption of vascularization, the local environment is lacking oxygen, nutrients, and has a modified ionic and molecular concentration which limits the healing process. This disruption may affect cellular ionic pumps, energy production, chemotaxis, etc., and will affect the healing process. Biomaterials for wound healing range from simple absorbents to sophisticated bioactive delivery vehicles. Often placing a material in or on a wound can change multiple parameters such as pH, ionic concentration, and osmolarity, and it can be challenging to pinpoint key mechanism of action. This article reviews the literature of several inorganic ions and molecules and their potential effects on the different wound healing phases and their use in new wound dressings.

Long-lasting antidepressant-like activity of the GPR39 zinc receptor agonist TC-G 1008

BACKGROUND

The discovery of the zinc-sensing receptor, has provided new possibilities for explaining the neurobiology of zinc. Recent studies indicate that the GPR39 zinc receptor may play an important role in the pathogenesis of depression as well as in the antidepressant mechanism of action.

METHODS

In this study we evaluated the time-course of the antidepressant response of the GPR39 agonist (TC-G 1008), imipramine, ZnCl₂ and MK-801 in the forced swim test in mice 30 min, 3 h, 6 h and 24 h after acute drug administration as well as after 14-day treatment. Zinc level was measured in serum of mice. BDNF protein level was evaluated in hippocampus following both acute and chronic TC-G 1008 treatment.

RESULTS

A single administration of the GPR39 agonist caused an antidepressant-like effect lasting up to 24 h following the injection, which is longer than the effect of imipramine, ZnCl₂ and MK-801. Chronic treatment with these compounds caused a decrease in immobility time in the FST. Serum zinc concentrations showed an increased level following chronic ZnCl₂ administration, but not following administration of TC-G 1008, imipramine or MK-801. We also observed some tendencies for increased BDNF following acute TC-G 1008 treatment.

LIMITATIONS

TC-G 1008 is new drug designed to study GPR39 therefore additional pharmacodynamic and pharmacokinetic properties in preclinical studies are required.

CONCLUSION

This study shows for the first time the long-lasting antidepressant effect of the GPR39 agonist in comparison with imipramine, ZnCl2 and MK-801. Our findings suggest that GPR39 should be considered as a target in efforts to develop new antidepressant drugs.

Biophysical and structural characterization of a zinc-responsive repressor of the MarR superfamily

The uptake of zinc, which is vital in trace amounts, is tightly controlled in bacteria. For this control, bacteria of the Streptococcaceae group use a Zn(II)-binding repressor named ZitR in lactococci and AdcR in streptococci, while other bacteria use a Zur protein of the Ferric uptake regulator (Fur) superfamily. ZitR and AdcR proteins, characterized by a winged helix-turn-helix DNA-binding domain, belong to the multiple antibiotic resistance (MarR) superfamily, where they form a specific group of metallo-regulators. Here, one such Zn(II)-responsive repressor, ZitR of Lactococcus lactis subspecies cremoris strain MG1363, is characterized. Size Exclusion Chromatography-coupled to Multi Angle Light Scattering, Circular Dichroism and Isothermal Titration Calorimetry show that purified ZitR is a stable dimer complexed to Zn(II), which is able to bind its two palindromic operator sites on DNA fragments. The crystal structure of ZitR holo-form (Zn(II)4-ZitR2), has been determined at 2.8 Å resolution. ZitR is the fourth member of the MarR metallo-regulator subgroup whose structure has been determined. The folding of ZitR/AdcR metallo-proteins is highly conserved between both subspecies (cremoris or lactis) in the Lactococcus lactis species and between species (Lactococcus lactis and Streptococcus pneumoniae or pyogenes) in the Streptococcaceae group. It is also similar to the folding of other MarR members, especially in the DNA-binding domain. Our study contributes to better understand the biochemical and structural properties of metallo-regulators in the MarR superfamily.

ZnII Complexes for Bioimaging and Correlated Applications

Zinc is a biocompatible element that exists as the second most abundant transition metal ion and an indispensable trace element in the human body. Compared to traditional metal-organic complexes systems, d¹⁰ metal Zn^II complexes not only exhibit a large Stokes shift and good photon stability but also possess strong emission and low cytotoxicity with a relatively small molecular weight. The use of Zn^II complexes has emerged in the last decade as a versatile and convenient tool for numerous biological applications, including bioimaging, molecular and protein recognition, as well as photodynamic therapy. Herein, we review recent developments involving Zn^II metal complexes applied as specific subcellular compartment imaging probes and their correlated utilizations.

Influence of zinc on glycosaminoglycan neutralisation during coagulation

Heparan sulfate (HS), dermatan sulfate (DS) and heparin are glycosaminoglycans (GAGs) that serve as key natural and pharmacological anticoagulants. During normal clotting such agents require to be inactivated or neutralised. Several proteins have been reported to facilitate their neutralisation, which reside in platelet α-granules and are released following platelet activation. These include histidine-rich-glycoprotein (HRG), fibrinogen and high-molecular-weight kininogen (HMWK). Zinc ions (Zn2+) are also present in α-granules at a high concentration and participate in the propagation of coagulation by influencing the binding of neutralising proteins to GAGs. Zn2+ in many cases increases the affinity of these proteins to GAGs, and is thus an important regulator of GAG neutralisation and haemostasis. Binding of Zn2+ to HRG, HMWK and fibrinogen is mediated predominantly through coordination to histidine residues but the mechanisms by which Zn2+ increases the affinity of the proteins for GAGs are not yet completely clear. Here we will review current knowledge of how Zn2+ binds to and influences the neutralisation of GAGs and describe the importance of this process in both normal and pathogenic clotting.

Comparisons of the spectroscopic and microbiological activities among coumarin-3-carboxylate, o-phenanthroline and zinc(II) complexes

Coumarins (2H-chromen-2-one) are oxygen-containing heterocyclic compounds that belong to the benzopyranones family. In this work we have synthesized different coordination complexes with coumarin-3-carboxylic acid (HCCA), o-phenanthroline (phen) and zinc(II). In the reported [Zn(CCA)₂(H₂O)₂] complex, coumarin-3-carboxylate (CCA) is acting as a bidentate ligand while in the two prepared complexes, [Zn(phen)₃]CCA(NO₃) (obtained as a single crystal) and [Zn(CCA)₂phen].4H₂O, CCA is acting as a counterion of the complex cation [Zn(phen)₃]⁺² or coordinated to the metal center along with phen, respectively. These compounds were characterized on the basis of elemental analysis and thermogravimetry. NMR, FTIR and Raman spectroscopies of the compounds and the CCA potassium salt (KCCA) allow to determine several similarities and differences among them. Finally, their behavior against alkaline phosphatase enzyme and their antimicrobial activities were also measured.

Zinc: An important cofactor in haemostasis and thrombosis

There is mounting evidence that zinc, the second most abundant transition metal in blood, is an important mediator of haemostasis and thrombosis. Prompted by the observation that zinc deficiency is associated with bleeding and clotting abnormalities, there now is evidence that zinc serves as an effector of coagulation, anticoagulation and fibrinolysis. Zinc binds numerous plasma proteins and modulates their structure and function. Because activated platelets secrete zinc into the local microenvironment, the concentration of zinc increases in the vicinity of a thrombus. Consequently, the role of zinc varies depending on the microenvironment; a feature that endows zinc with the capacity to spatially and temporally regulate haemostasis and thrombosis. This paper reviews the mechanisms by which zinc regulates coagulation, platelet aggregation, anticoagulation and fibrinolysis and outlines how zinc serves as a ubiquitous modulator of haemostasis and thrombosis.

Importance of zinc for the human body in the aspect of zinc supplementation

Cynk jest jednym z głównych pierwiastków śladowych organizmu, spełniającym rolę katalityczną, strukturalną i regulacyjną. Jest niezbędny do podziałów komórkowych i różnicowania powstających komórek, uczestniczy w homeostazie, reakcjach odpornościowych, w apoptozie i starzeniu się organizmu. Cynk jest również składnikiem wielu enzymów i białek oraz odgrywa ważną rolę w spermatogenezie i syntezie hormonów steroidowych. Niedostateczna podaż cynku dotyczy ok. 30% ludności świata. Oprócz niedostatecznej podaży z pokarmem, przyczyną niedoboru cynku mogą być niektóre schorzenia oraz nieprawidłowe wchłanianie tego pierwiastka. Schorzenia, wynikające z niedoboru tego pierwiastka, mogą występować zarówno u dzieci, jak i dorosłych. Suplementacja diety preparatami cynku w wielu przypadkach jest niezbędna, jednak samodzielne jego stosowanie, bez stwierdzonego niedoboru i bez konsultacji z lekarzem, może doprowadzić do występowania działań niepożądanych w wyniku jego nadużywania, w tym także niebezpiecznych interakcji z innymi stosowanymi preparatami i żywnością.

Relationship between Cd and Zn concentration in the kidneys, liver, and muscles of moose (Alces alces) from north-eastern Poland

The aim of the study was to evaluate the cadmium and zinc content in the kidneys and liver of moose from north-eastern Poland. Animals were divided with respect to their age. The mean concentration of cadmium in the kidneys of moose studied was 11.31 mg kg^-1, while in the liver it amounted to 2.68 mg kg^-1. Age had a significant effect on the content of cadmium in both organs. In the muscles of most animals studied, the cadmium concentrations were below the detection limit. Elevated concentrations were found in three individuals only. Older animals had over six times higher concentrations of cadmium in both kidneys and liver than younger individuals. The cadmium content in kidneys increased with animals' age while no such relationship was found for zinc. Although older animals had higher mean concentrations of zinc in kidneys, liver, and muscles, the two age groups did not differ significantly. The mean concentration of zinc in the kidneys of moose studied was 38.83 mg kg^-1, while in the liver it amounted to 29.03 mg kg^-1. The cadmium concentration in the kidneys was significantly correlated with the cadmium concentration in the liver (r = 0.53, p ≤ 0.01) and with the zinc concentration in the kidneys (r = 0.52, p ≤ 0.01). The data obtained within study correspond with analyses results of the organs of healthy moose in Sweden.

The contribution of zinc to platelet behaviour during haemostasis and thrombosis

Platelets are the primary cellular determinants of haemostasis and pathological thrombus formation leading to myocardial infarction and stroke. Following vascular injury or atherosclerotic plaque rupture, platelets are recruited to sites of damage and undergo activation induced by a variety of soluble and/or insoluble agonists. Platelet activation is a multi-step process culminating in the formation of thrombi, which contribute to the haemostatic process. Zinc (Zn(2+)) is acknowledged as an important signalling molecule in a diverse range of cellular systems, however there is limited understanding of the influence of Zn(2+) on platelet behaviour during thrombus formation. This review evaluates the contributions of exogenous and intracellular Zn(2+) to platelet function and assesses the potential pathophysiological implications of Zn(2+) signalling. We also provide a speculative assessment of the mechanisms by which platelets could respond to changes in extracellular and intracellular Zn(2+) concentration.

Accelerating degradation rate of pure iron by zinc ion implantation

Pure iron has been considered as a promising candidate for biodegradable implant applications. However, a faster degradation rate of pure iron is needed to meet the clinical requirement. In this work, metal vapor vacuum arc technology was adopted to implant zinc ions into the surface of pure iron. Results showed that the implantation depth of zinc ions was about 60 nm. The degradation rate of pure iron was found to be accelerated after zinc ion implantation. The cytotoxicity tests revealed that the implanted zinc ions brought a slight increase on cytotoxicity of the tested cells. In terms of hemocompatibility, the hemolysis of zinc ion implanted pure iron was lower than 2%. However, zinc ions might induce more adhered and activated platelets on the surface of pure iron. Overall, zinc ion implantation can be a feasible way to accelerate the degradation rate of pure iron for biodegradable applications.

Binding Analysis of Human Immunoglobulin G as a Zinc-Binding Protein

Human immunoglobulin G (IgG) binding with zinc ions was examined using zinc ions immobilized on chelating Sepharose beads (Zn-beads). Human IgG bound to Zn-beads but not to Sepharose beads (control beads). Mouse, rat, bovine and equine IgGs also bound to Zn-beads, similar to human IgG. The human IgG F(c) fragment showed zinc ion–binding activity whereas the Fab fragment did not. Ethylenediaminetetraacetic acid (EDTA)-treated Zn-beads no longer bound human IgG; however, washing the beads, followed by the addition of zinc ions, restored the binding activity towards human IgG. Zn-beads saturated with human fibrinogen could bind human IgG, and Zn-beads saturated with human IgG could bind fibrinogen. These results suggest that animal IgGs, including human, specifically bind zinc ions, probably through a zinc-binding site in the F(c) fragment and not in the Fab fragment. In addition, IgG and fibrinogen interact with each other and/or bind zinc ions through different mechanisms.

A comprehensive study of the harmful effects of ZnO nanoparticles using Drosophila melanogaster as an in vivo model

This study planned to determine the range of biological effects associated with ZnO-NP exposure using Drosophila melanogaster as an in vivo model. In addition, ZnCl2 was used to determine the potential role of Zn ions alone. Toxicity, internalization through the intestinal barrier, gene expression changes, ROS production, and genotoxicity were the end-points evaluated. No toxicity or oxidative stress induction was observed in D. melanogaster larvae, whether using ZnO-NPs or ZnCl2. Internalization of ZnO-NPs through the intestinal barrier was observed. No significant changes in the frequency of mutant clones (wing-spot test) or percentage of DNA in tail (comet assay) were observed although significant changes in Hsp70 and p53 gene expression were detected. Our study shows that ZnO-NPs do not induce toxicity or genotoxicity in D. melanogaster, although uptake occurs and altered gene expression is observed.

Association of serum zinc levels with liver function and survival in patients awaiting liver transplantation

PURPOSE

Zinc is an important trace element with catalytic and defensive functions. We assessed the impact of zinc deficiency in patients with end-stage liver disease awaiting liver transplantation.

METHODS

Serum zinc levels were measured at the time of evaluation for liver transplantation (n = 368). Patients were dichotomized in two groups based on low and normal zinc serum levels.

RESULTS

Serum zinc levels are tightly associated with liver function as patients with low zinc levels (n = 226) had a higher Model for End-Stage Liver Disease (MELD) score (15.0 [5.0-40.0]) than patients with normal zinc (n = 142) levels (9.0 [6.0-34.0]; p < 0.00). Multivariate analysis demonstrated that serum zinc levels function as an independent predictor of hepatic decompensation (hydropic decompensation: odds ratio [OR] 0.82; 95% confidence interval [CI] 0.70-0.96; p = 0.015; hepatic encephalopathy: OR 0.80; 95% CI 0.71-0.90; p = 0.000; spontaneous bacterial peritonitis: OR 0.85; 95% CI 0.72-1.00; p = 0.047; hepatorenal syndrome: OR 0.83; 95% CI 0.72-0.95; p = 0.011). Actuarial survival free of liver transplantation was reduced for low-zinc patients (26.7 ± 4.0 months; 95% CI 18.8-34.6) compared to patients with normal zinc levels (30.9 ± 3.0 months; 95% CI 24.9-36.9; p = 0.008). Reduction of zinc levels for patients on the transplantation list resulted in a 28.3-fold increased risk of death/liver transplantation (95% CI 3.2-244.8, p < 0.001).

CONCLUSIONS

Serum zinc levels are associated with reduced survival in end-stage liver disease patients. Whether or not zinc supplementation might be beneficial for patients on a liver transplantation list requires further study.

Zinc delays clot lysis by attenuating plasminogen activation and plasmin-mediated fibrin degradation

Zinc circulates free in plasma at a concentration of 0.1-2 µM, but its levels increase locally when it is released from activated platelets. Although zinc influences many processes in haemostasis, its effect on fibrinolysis has not been thoroughly investigated. Using a fluorescent zinc-binding probe, we demonstrated that zinc binds tissue-type plasminogen activator (tPA) and plasmin with high affinity (Kd values of 0.2 µM), and surface plasmon resonance studies revealed that zinc binds fibrin with a Kd of 12.8 µM. Zinc had no effect on the affinity of plasminogen or plasmin for fibrin, but increased the affinity of tPA by two-fold. In the presence of 5 µM zinc, the catalytic efficiency of plasminogen activation by tPA was reduced by approximately two-fold, both in the absence or presence of fibrin. Zinc attenuated plasmin-mediated degradation of the fibrinogen alpha-chain by 43 %, but had no effect on trypsin degradation. tPA-mediated fibrin clot lysis was prolonged 2.5-fold by zinc in a concentration-dependent fashion, and tPA-mediated plasma clot lysis was attenuated by 1.5-fold. Therefore, our data indicate that zinc modulates fibrinolysis by attenuating tPA-mediated plasminogen activation and plasmin-induced fibrin degradation. These findings suggest that local release of zinc by platelets attenuates fibrinolysis.

ZIP1 and zinc inhibits fluoride-induced apoptosis in MC3T3-E1 cells

Excess fluoride intake could induce apoptosis in the cells. As an essential micronutrient and cytoprotectant, zinc is involved in many types of apoptosis. Here, we studied the effects of zinc and ZIP1 on fluoride-induced apoptosis in mouse MC3T3-E1 cells and examined the underlying molecular mechanisms. Our study found that fluoride not only inhibited cell proliferation and increased the intracellular reactive oxygen species (ROS) but also induced cell apoptosis. Whereas pretreatment with zinc significantly attenuated fluoride-induced ROS production and partly protected cells against fluoride-induced apoptosis through MAPK/ERK signaling pathway. Our study also found that fluoride upregulated the expression of ZIP1 in a time-dependent manner. Moreover, overexpression of ZIP1 also inhibited fluoride-induced apoptosis by activation of PI3K/Akt pathway. This cytoprotective effect of zinc and ZIP1 may be new factors that affect the physiological activity of fluoride and need study further.

Zn2+ mediates high affinity binding of heparin to the αC domain of fibrinogen

The nonspecific binding of heparin to plasma proteins compromises its anticoagulant activity by reducing the amount of heparin available to bind antithrombin. In addition, interaction of heparin with fibrin promotes formation of a ternary heparin-thrombin-fibrin complex that protects fibrin-bound thrombin from inhibition by the heparin-antithrombin complex. Previous studies have shown that heparin binds the E domain of fibrinogen. The current investigation examines the role of Zn(2+) in this interaction because Zn(2+) is released locally by platelets and both heparin and fibrinogen bind the cation, resulting in greater protection from inhibition by antithrombin. Zn(2+) promotes heparin binding to fibrinogen, as determined by chromatography, fluorescence, and surface plasmon resonance. Compared with intact fibrinogen, there is reduced heparin binding to fragment X, a clottable plasmin degradation product of fibrinogen. A monoclonal antibody directed against a portion of the fibrinogen αC domain removed by plasmin attenuates binding of heparin to fibrinogen and a peptide analog of this region binds heparin in a Zn(2+)-dependent fashion. These results indicate that the αC domain of fibrinogen harbors a Zn(2+)-dependent heparin binding site. As a consequence, heparin-catalyzed inhibition of factor Xa by antithrombin is compromised by fibrinogen to a greater extent when Zn(2+) is present. These results reveal the mechanism by which Zn(2+) augments the capacity of fibrinogen to impair the anticoagulant activity of heparin.

Deorphanization and target validation of cross-tick species conserved novel Amblyomma americanum tick saliva protein

We previously identified a cross-tick species conserved tick feeding stimuli responsive Amblyomma americanum (Aam) AV422 gene. This study demonstrates that AamAV422 belongs to a novel group of arthropod proteins that is characterized by 14 cysteine amino acid residues: C(23)-X7/9-C(33)-X23/24-C(58)-X8-C(67)-X7-C(75)-X23-C(99)-X15-C(115)-X10-C(126)-X24/25/33-C(150)C(151)-X7-C(159)-X8-C(168)-X23/24-C(192)-X9/10-C(202) predicted to form seven disulfide bonds. We show that AamAV422 protein is a ubiquitously expressed protein that is injected into the host within the first 24h of the tick attaching onto the host as revealed by Western blotting analyses of recombinant (r)AamAV422, tick saliva and dissected tick organ protein extracts using antibodies to 24 and 48 h tick saliva proteins. Native AamAV422 is apparently involved with mediating tick anti-hemostasis and anti-complement functions in that rAamAV422 delayed plasma clotting time in a dose responsive manner by up to ≈ 160 s, prevented platelet aggregation by up to ≈ 16% and caused ≈ 24% reduction in production of terminal complement complexes. Target validation analysis revealed that rAamAV422 is a potential candidate for a cocktail or multivalent tick vaccine preparation in that RNA interference (RNAi)-mediated silencing of AamAV422 mRNA caused a statistically significant (≈ 44%) reduction in tick engorgement weights, which is proxy for amounts of ingested blood. We speculate that AamAV422 is a potential target antigen for development of the highly desired universal tick vaccine in that consistent with high conservation among ticks, antibodies to 24h Ixodes scapularis tick saliva proteins specifically bound rAamAV422. We discuss data in this study in the context of advancing the biology of tick feeding physiology and discovery of potential target antigens for tick vaccine development.

Dietary zinc depletion and repletion affects plasma proteins: an analysis of the plasma proteome

Zinc (Zn) deficiency is a problem world-wide. Current methods for assessing Zn status are limited to measuring plasma or serum Zn within populations suspected of deficiency. Despite the high prevalence of Zn deficiency in the human population there are no methods currently available for sensitively assessing Zn status among individuals. The purpose of this research was to utilize a proteomic approach using two-dimensional gel electrophoresis (2DE) and mass spectrometry to identify protein biomarkers that were sensitive to changes in dietary Zn levels in humans. Proteomic analysis was performed in human plasma samples (n = 6) obtained from healthy adult male subjects that completed a dietary Zn depletion/repletion protocol, current dietary zinc intake has a greater effect on fractional zinc absorption than does longer term zinc consumption in healthy adult men. Chung et al. (Am J Clin Nutr 87 (5):1224-1229, 2008). After a 13 day Zn acclimatization period where subjects consumed a Zn-adequate diet, the male subjects consumed a marginal Zn-depleted diet for 42 days followed by consumption of a Zn-repleted diet for 28 days. The samples at baseline, end of depletion and end of repletion were pre-fractionated through immuno-affinity columns to remove 14 highly abundant proteins, and each fraction separated by 2DE. Following staining by colloidal Coomassie blue and densitometric analysis, three proteins were identified by mass spectrometry as affected by changes in dietary Zn. Fibrin β and chain E, fragment double D were observed in the plasma protein fraction that remained bound to the immunoaffinity column. An unnamed protein that was related to immunoglobulins was observed in the immunodepleted plasma fraction. Fibrin β increased two-fold following the Zn depletion period and decreased to baseline values following the Zn repletion period; this protein may serve as a viable biomarker for Zn status in the future.

Alteration of the platelet transcriptome in chronic kidney disease

Bleeding and thrombotic disorders are major complications affecting patients with chronic kidney disease (CKD). Exposure of circulating platelets to uraemic toxins and contact with artificial surfaces during dialysis induce platelet abnormalities and alter the platelet proteome. We hypothesised that these changes may be subsequent to changes in the composition and/or regulation of the platelet transcriptome. In this study, we investigated the circulating platelets of 10 CKD patients (i.e. five chronic haemodialysis patients and five stage 4 CKD uraemic patients) and five age- and sex-matched healthy subjects. We observed an alteration of the platelet messenger RNA (mRNA) and microRNA transcriptome in CKD patients. Impaired in uraemic platelets, the levels of some mRNAs and of most microRNAs appeared to be corrected by dialysis, which is consistent with a beneficial effect of dialysis and a mRNA regulatory role of platelet microRNAs. Reduced in platelets of uraemic patients, phosphatidylcholine transfer protein (PCTP) and WD repeat-containing protein 1 (WDR1) were found to be regulated by microRNAs, the latter of which involving hsa-miR-19b, a microRNA increased in platelets of uraemic patients and involved in platelet reactivity. These results suggest that an alteration of microRNA-based mRNA regulatory mechanisms may underlie the platelet response to uremia and entail the development of platelet-related complications in CKD.

A molecular mechanism for modulating plasma Zn speciation by fatty acids

Albumin transports both fatty acids and zinc in plasma. Competitive binding studied by isothermal titration calorimetry revealed that physiologically relevant levels of fatty acids modulate the Zn-binding capacity of albumin, with far-reaching implications for biological zinc speciation. The molecular mechanism for this effect is likely due to a large conformational change elicited by fatty acid binding to a high-affinity interdomain site that disrupts at least one Zn site. Albumin may be a molecular device to "translate" certain aspects of the organismal energy state into global zinc signals.

Human serum albumin: from bench to bedside

Human serum albumin (HSA), the most abundant protein in plasma, is a monomeric multi-domain macromolecule, representing the main determinant of plasma oncotic pressure and the main modulator of fluid distribution between body compartments. HSA displays an extraordinary ligand binding capacity, providing a depot and carrier for many endogenous and exogenous compounds. Indeed, HSA represents the main carrier for fatty acids, affects pharmacokinetics of many drugs, provides the metabolic modification of some ligands, renders potential toxins harmless, accounts for most of the anti-oxidant capacity of human plasma, and displays (pseudo-)enzymatic properties. HSA is a valuable biomarker of many diseases, including cancer, rheumatoid arthritis, ischemia, post-menopausal obesity, severe acute graft-versus-host disease, and diseases that need monitoring of the glycemic control. Moreover, HSA is widely used clinically to treat several diseases, including hypovolemia, shock, burns, surgical blood loss, trauma, hemorrhage, cardiopulmonary bypass, acute respiratory distress syndrome, hemodialysis, acute liver failure, chronic liver disease, nutrition support, resuscitation, and hypoalbuminemia. Recently, biotechnological applications of HSA, including implantable biomaterials, surgical adhesives and sealants, biochromatography, ligand trapping, and fusion proteins, have been reported. Here, genetic, biochemical, biomedical, and biotechnological aspects of HSA are reviewed.

Zinc modulates the interaction of protein C and activated protein C with endothelial cell protein C receptor

Zinc is an essential trace element for human nutrition and is critical to the structure, stability, and function of many proteins. Zinc ions were shown to enhance activation of the intrinsic pathway of coagulation but down-regulate the extrinsic pathway of coagulation. The protein C pathway plays a key role in blood coagulation and inflammation. At present there is no information on whether zinc modulates the protein C pathway. In the present study we found that Zn(2+) enhanced the binding of protein C/activated protein C (APC) to endothelial cell protein C receptor (EPCR) on endothelial cells. Binding kinetics revealed that Zn(2+) increased the binding affinities of protein C/APC to EPCR. Equilibrium dialysis with (65)Zn(2+) revealed that Zn(2+) bound to the Gla domain as well as sites outside of the Gla domain of protein C/APC. Intrinsic fluorescence measurements suggested that Zn(2+) binding induces conformational changes in protein C/APC. Zn(2+) binding to APC inhibited the amidolytic activity of APC, but the inhibition was reversed by Ca(2+). Zn(2+) increased the rate of APC generation on endothelial cells in the presence of physiological concentrations of Ca(2+) but did not further enhance increased APC generation obtained in the presence of physiological concentrations of Mg(2+) with Ca(2+). Zn(2+) had no effect on the anticoagulant activity of APC. Zn(2+) enhanced APC-mediated activation of protease activated receptor 1 and p44/42 MAPK. Overall, our data show that Zn(2+) binds to protein C/APC, which results in conformational changes in protein C/APC that favor their binding to EPCR.

Frequency of hospitalization for angina pectoris, stroke, and peripheral venous thrombosis and its relationship to elements in rainwater in Opole Voivodship, Poland, during 2000-2002

The content of elements in rainwater is an indirect indicator of its occurrence in air dust. This is sometimes referred to as rain fallout and is investigated in applied environmental pollution monitoring schemes. The annual content of elements in rainwater may be recognized as good index for assessing influence of those environmental factors on human body. The possible relationship between the concentrations of selected elements in rainwater and the frequency of hospitalization by reason of angina pectoris, stroke, and peripheral venous thrombosis was investigated in the Opole Voivodship (Poland) area during the period 2000-2002. There is a relatively high or partly significant correlation between frequency of hospitalization by reason of these conditions and content of lead, cadmium, chromium, zinc, and chloride in rainwater. Significant gender-dependent differences were observed only in peripheral venous thrombosis, where important correlations with lead, cadmium, and chromium were found only in men.

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.