Effect of Zinc Supplementation on Maintenance Hemodialysis Patients: A Systematic Review and Meta-Analysis of 15 Randomized Controlled Trials

Association of serum zinc with mineral stress in chronic kidney disease

Background

The excessive cardiovascular mortality of patients with chronic kidney disease (CKD) could be linked to mineral stress, the biological consequence of calcium-phosphate nanoparticle exposure. This study investigated whether zinc is associated with mineral stress markers in CKD.

Methods

Zinc and T50 (serum calcification propensity) as well as hydrodynamic radius of secondary calciprotein particles (CPP2) were measured in blood donors and CKD patients with/out dialysis.

Results

Serum zinc concentrations and T50 were reduced, while CPP2 radius was increased in CKD patients. Serum zinc levels positively correlated with T50 and inversely correlated with CPP2 radius. In a hierarchical linear regression model, T50 was associated with age, calcium, phosphate, magnesium and albumin. Addition of zinc significantly improved prediction of the model, confirming an additional contribution of zinc to T50. Similar observations were made for the association of zinc and CPP2 radius, but spiking experiments indicated that zinc may stronger modify T50 than CPP2 radius. Also, urinary zinc excretion was increased in patients with kidney disease and correlated to T50 and CPP2 radius. Serum zinc further correlated with markers of arterial stiffness in blood donors and CKD patients, but these associations did not remain significant in a multivariate linear regression model.

Conclusions

Reduced serum zinc levels in CKD appear directly linked to lower T50 and associated with larger CPP2 radius. Further studies on the associations of zinc and mineral stress as well as putative therapeutic benefits of zinc supplementation are required.

Zinc and Diabetes: A Connection between Micronutrient and Metabolism

Diabetes mellitus is a global health problem and a major contributor to mortality and morbidity. The management of this condition typically involves using oral antidiabetic medication, insulin, and appropriate dietary modifications, with a focus on macronutrient intake. However, several human studies have indicated that a deficiency in micronutrients, such as zinc, can be associated with insulin resistance as well as greater glucose intolerance. Zinc serves as a chemical messenger, acts as a cofactor to increase enzyme activity, and is involved in insulin formation, release, and storage. These diverse functions make zinc an important trace element for the regulation of blood glucose levels. Adequate zinc levels have also been shown to reduce the risk of developing diabetic complications. This review article explains the role of zinc in glucose metabolism and the effects of its inadequacy on the development, progression, and complications of diabetes mellitus. Furthermore, it describes the impact of zinc supplementation on preventing diabetes mellitus. The available information suggests that zinc has beneficial effects on the management of diabetic patients. Although additional large-scale randomized clinical trials are needed to establish zinc's clinical utility further, efforts should be made to increase awareness of its potential benefits on human health and disease.

The effect of oral zinc on hemoglobin and dose of erythropoietin in hemodialysis patients

Background

In hemodialysis (HD) patients, low serum zinc level could cause hyporesponsivity to erythropoiesis-stimulating agents and lead to anemia. This study investigated the effects of oral zinc supplements on the required dose of erythropoietin in patients undergoing HD.

Materials and Methods

In a double-blinded randomized trial, 76 HD patients were assigned to 2 groups of 38. One group (intervention) was treated with oral zinc supplements of 210 mg, daily for 6 months, and the other group (control) used placebo capsules for 6 months. The serum zinc level, hemoglobin level, and required dose of erythropoietin, albumin, ferritin, ferrous, and total iron-binding capacity were evaluated 3 and 6 months after intervention.

Results

Repeated measures ANOVA did not show a significant increase in Hb level after 6 months of intervention (P = 0.28). However, the required dose of erythropoietin was decreased, but the changes were not statistically significant (P > 0.05). The changes in the other variables were not statistically significant.

Conclusion

Oral zinc supplementation in HD patients could not increase hemoglobin level irrespective of their serum zinc level.

Progress in the study of nutritional status and selenium in dialysis patients

Malnutrition is very common in patients with chronic kidney disease, especially in those on maintenance dialysis. Malnutrition is one of the major factors affecting survival and death of dialysis patients, and reducing their activity tolerance and immunity. There are numerous and interacting risk factors for malnutrition, such as reduced nutritional intake, increased energy expenditure, hormonal disorders, and inflammation. Selenium, in the form of selenoproteins, is involved in many physiological processes in the body and plays an important role in maintaining redox homeostasis. Oxidative stress and infection are very common in dialysis patients, and selenium levels in dialysis patients are significantly lower than those in the healthy population. It has been shown that there is a correlation between selenium levels in hemodialysis patients and their nutrition-related indicators, and that selenium supplementation may improve malnutrition in patients. However, further studies are needed to support this conclusion and there is a lack of basic research to further characterize the potential mechanisms by which selenium may improve malnutrition in dialysis patients. The purpose of this review is to provide a comprehensive overview of factors associated with malnutrition in dialysis patients and to describe the progress of research on nutritional status and selenium levels in dialysis patients.

Co-Administration of Roxadustat and Zinc Stabilizes Both Serum Copper and Zinc Concentrations in Patients Undergoing Hemodialysis

Patients undergoing hemodialysis often require zinc supplementation owing to hypozincemia, which may reduce serum copper concentrations. However, hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHIs), which are used to treat renal anemia, have been reported to increase serum copper. Therefore, this study investigates the effectiveness of a combination of HIF-PHIs and zinc for the stabilization of serum copper and zinc concentrations during zinc supplementation for patients undergoing hemodialysis with renal anemia and hypozincemia. The serum zinc and copper concentrations were retrospectively compared over an 8-month period in 20 patients being administered roxadustat (an HIF-PHI) and 20 controls. The changes in concentrations were tracked in participants taking roxadustat who initiated or increased zinc supplementation. The serum zinc concentrations of the participants were significantly higher (p < 0.001) during zinc supplementation, regardless of roxadustat administration. Post-roxadustat, the serum copper concentrations were significantly higher than those pre-roxadustat or in non-roxadustat-treated participants, irrespective of zinc supplementation (p < 0.005). Even post-roxadustat, the serum copper concentrations were significantly lower, with no increase during zinc supplementation (p < 0.040). When zinc supplementation was initiated or increased in participants taking roxadustat, copper and zinc concentrations were normalized. Thus, combining zinc supplementation with roxadustat prevents both an excessive increase in serum copper and a decrease in serum zinc.

Zinc Acetate Hydrate Supplementation versus Polaprezinc Supplementation for Improving Hypozincemia in Hemodialysis Patients: A Randomized Clinical Trial

Zinc supplementation may ameliorate zinc deficiency in maintenance hemodialysis patients; however, no standard protocol has been established. This study aimed to investigate the effects of zinc acetate hydrate (ZAH) and polaprezinc (PPZ) as zinc supplements in hemodialysis patients. We enrolled 75 hemodialysis patients with serum zinc levels <60 μg/dL for this study and randomly assigned Zinc supplementation to these 75 patients: 37 received ZAH (50 mg/day), and 38 received PPZ (34 mg/day). Serum zinc levels of both groups were compared every 4 weeks for 1 year. In both groups, serum zinc levels significantly increased at 4-52 weeks. Serum zinc levels were significantly higher in the ZAH group at 4-12 weeks; however, no significant differences were observed between the groups at 16-52 weeks. Adverse events requiring a reduction in the zinc dose, including copper deficiency, occurred significantly more frequently in the ZAH group. In conclusion, PPZ can safely maintain serum zinc levels for 1 year. ZAH provides rapid zinc supplementation but can cause adverse events.

Clinical Significance of Trace Element Zinc in Patients with Chronic Kidney Disease

The trace element zinc is essential for diverse physiological processes in humans. Zinc deficiency can impair growth, skin reproduction, immune function, maintenance of taste, glucose metabolism, and neurological function. Patients with chronic kidney disease (CKD) are susceptible to zinc deficiency, which is associated with erythropoiesis-stimulating agent (ESA) hypo-responsive anemia, nutritional problems, and cardiovascular diseases as well as non-specific symptoms such as dermatitis, prolonged wound healing, taste disturbance, appetite loss, or cognitive decline. Thus, zinc supplementation may be useful for the treatment of its deficiency, although it often causes copper deficiency, which is characterized by several severe disorders including cytopenia and myelopathy. In this review article, we mainly discuss the significant roles of zinc and the association between zinc deficiency and the pathogenesis of complications in patients with CKD.

Robotic system for accurate percutaneous puncture guided by 3D-2D ultrasound

PURPOSE

Ultrasound (US)-guided robotic systems can reduce the reliance on the experience and skills of surgeons and enable automatic and accurate percutaneous puncture. Two-dimensional (2D) and three-dimensional (3D) US guidance have various advantages and disadvantages. The planned puncture path in the US data directly affects the puncture quality and tissue injury risk. It is difficult to define the optimal path in 2D US images and achieve accurate and safe puncture under the guidance of 3D US volume. This study aims to propose a robotic system guided by 3D-2D US to realize accurate and safe percutaneous puncture.

METHODS

We proposed a 3D-2D US-guided percutaneous puncture robotic system by integrating a 3D US scanning robotic system and a 2D US-guided puncture robotic system. The optimal spatial puncture path that targets the lesion and avoids other important tissues was determined in the 3D US volume reconstructed through robotic US scanning. Thereafter, the puncture robot was placed at the puncture site determined according to the planned path. The optimal path was mapped to the 2D US image taken at the puncture site. Finally, the 2D US image and puncture path were used to guide the robot in performing an accurate and safe percutaneous puncture.

RESULTS

The proposed robotic system based on the guidance of 3D-2D US exhibits the advantages of both 3D US and 2D US to improve the accuracy of percutaneous puncture and reduce the risk of tissue injury. The experimental results of phantom puncture demonstrate that the mean puncture accuracy of the system is 1.09 ± 0.35 mm, and the puncture success rate with single needle insertion is 100%.

CONCLUSION

A percutaneous puncture robotic system based on 3D-2D US guidance was proposed and tested successfully. The experimental results demonstrate the feasibility of the proposed system for achieving accurate and safe robotic percutaneous puncture.

Serum Zinc Levels in Chronic Kidney Disease Patients, Hemodialysis Patients, and Healthy Controls: Systematic Review and Meta-Analysis

OBJECTIVES

Patients with chronic kidney disease (CKD) are susceptible to changes in zinc homeostasis through anorexia and dietary restrictions, as well as hemodialysis (HD). Changes in zinc homeostasis might predispose CKD and HD patients to specific adverse effects, including erythropoietin-resistant anemia, oxidative stress, atherosclerosis, and cardiovascular disease. Because serum zinc levels are rarely measured in CKD and HD patients, zinc supplementations do not represent a routine therapy for CKD and dialysis patients. Therefore, in this meta-analysis, we aimed to assess serum zinc levels in CKD and HD patients compared with healthy controls (HC). In addition, we investigated whether HD affects serum zinc levels by comparing serum zinc levels in HD versus CKD patients and comparing serum zinc pre- versus post-HD.

DESIGN AND METHODS

A comprehensive search of databases was conducted to identify either observational studies or randomized trials that assessed serum zinc levels in either CKD and/or HD patients in comparison to HC. We conducted a random-effects meta-analysis.

RESULTS

Our meta-analysis included 42 studies with a total of 4,161 participants, of whom 460 were CKD patients, 2,047 were HD patients, and 1,654 were HCs. Both CKD and HD patients showed lower serum zinc levels compared with HC (mean difference = -22.86 μg/dL, 95% CI -33.25 to -12.46; mean difference = -13.64 μg/dL, 95% CI -21.47 to -53.80, respectively). CKD and HD patients showed no significant difference in serum zinc levels (mean difference = 15.39, 95% CI -8.91 to 39.68). Pre-HD serum zinc levels were significantly lower than those post-HD (mean difference = -7.51 μg/dL, 95% CI -14.24 to -0.78).

CONCLUSION

In the current study, the serum zinc levels were lower in CKD and HD patients compared to HCs and appears to be more common than reported in daily clinical practice. It may be beneficial to assess serum zinc levels in CKD and HD patients. More research on zinc in kidney disease is encouraged.

High Blood Cu/Zn Ratio is Associated with Nutritional Risk in Patients Undergoing Maintenance Hemodialysis

Patients undergoing maintenance hemodialysis (MHD) are at risk of an imbalance of copper and zinc homeostasis. We hypothesized that there is an association between the blood copper-zinc (Cu/Zn) ratio and nutritional status in these patients. For this cross-sectional study, blood samples were collected from patients undergoing MHD at Guangzhou Red Cross Hospital in September 2019. Zinc and copper levels were measured using inductively coupled plasma mass spectrometry. The seven-point subjective global assessment (SGA), nutritional risk screening 2002 (NRS2002), and geriatric nutritional risk index (GNRI) were used to evaluate the overall nutritional status. We enrolled 144 MHD patients (men:women = 78:66), with an average age of 64.33 ± 13.39 years and a median dialysis vintage of 33.50 (16.25-57.50) months. Patients with a higher blood Cu/Zn ratio had lower levels of hemoglobin, blood zinc, serum prealbumin, albumin, and creatinine as well as low SGA and GNRI scores, but higher modified Charlson comorbidity index score, serum C-reactive protein level, interleukin-6 level, blood copper level, and NRS2002 score (all p < 0.05). After adjustment for confounding factors in multivariable models, a high blood Cu/Zn ratio was independently associated with nutritional risk defined by all nutritional parameters (SGA, NRS2002, and GNRI). Prospective studies with larger sample sizes are warranted to confirm these results.

Benefits and risks of essential trace elements in chronic kidney disease: a narrative review

Background and Objective

Chronic kidney disease (CKD) is an important public health concern. With the decline of renal function, CKD patients gradually progress to end-stage kidney disease and need to undergo dialysis or kidney transplantation to maintain life, bringing a heavy economic burden to the family and society. Therefore, it is necessary to effectively prevent and delay the progression of CKD. Essential trace elements play an indispensable role in CKD, and the objective of this study is to systematically review their benefits in the disease and summarize the risks of their excess.

Methods

The keywords "trace elements", "chronic kidney disease", "dialysis", "inflammation", and "fibrosis" and their combinations were used to search for relevant literature published in the PubMed database and Web of Science. We then summarized the role of trace element abnormalities in CKD patients in anemia, oxidative stress, inflammation, and chronic fibrosis, and the risk of their excess.

Key Content and Findings

Imbalance of essential trace elements is a common complication of CKD and a risk factor for CKD progression, cardiovascular events, and death. This article reviews the effects of essential trace elements (iron, zinc, selenium, copper, iodine, and manganese) on CKD. We analyze literature and discuss the advantages and disadvantages of various essential trace elements.

Conclusions

Research shows CKD patients have an imbalance of essential trace elements, and treatment based on these is an important direction for future exploration. A knowledge of the homeostasis of trace elements is important to improving the prognosis of CKD patients and delaying the progression of the disease.

Association of Zinc with Anemia

Zinc is an essential trace element, and anemia is the most common blood disorder. The association of zinc with anemia may be divided into three major forms: (1) zinc deficiency contributing to anemia, (2) excess intake of zinc leading to anemia, and (3) anemia leading to abnormal blood-zinc levels in the body. In most cases, zinc deficiency coexists with iron deficiency, especially in pregnant women and preschool-age children. To a lesser extent, zinc deficiency may cooperate with other factors to lead to anemia. It seems that zinc deficiency alone does not result in anemia and that it may need to cooperate with other factors to lead to anemia. Excess intake of zinc is rare. However, excess intake of zinc interferes with the uptake of copper and results in copper deficiency that leads to anemia. Animal model studies indicate that in anemia, zinc is redistributed from plasma and bones to the bone marrow to produce new red blood cells. Inadequate zinc status (zinc deficiency or excess) could have effects on anemia; at the same time, anemia could render abnormal zinc status in the body. In handling anemia, zinc status needs to be observed carefully, and supplementation with zinc may have preventive and curative effects.

Serum zinc values, ankle brachial index and mortality in hemodialysis patients

Introduction

The atherosclerotic state of haemodialysis (HD) patients may be influenced by heavy metals. The purpose of our study was to assess the relationship between serum zinc (Zn) ankle brachial index (ABI) as a non-invasive diagnostic tool for atherosclerosis, and mortality in chronic haemodialysis (HD) patients.

Methods

Sixty one HD patients were included (mean age 61.2 ± 13.8 years). The ABI was measured with an automated measuring device (ABPI MD, MESI®, Slovenia). Two groups of patients were formed based on the median value of Zn (14.1 mcmol/l). The average observation time was 2.8 years. Comorbidities (arterial hypertension (AH), diabetes mellitus (DM), dyslipidaemia), smoking and oral nutritional supplements (ONS) consumption were noted. Survival rates were analysed by Kaplan–Meier and Cox regression was used to determine the influence of Zn, ABI, AH, DM, dyslipidaemia, smoking and ONS.

Results

Zn values were between 9.2 and 23.5 mcmol/l (14.4 ± 2.34), ABI values ranged from 0.8 to 1.4 (1.14 ± 0.12). Patients with lower Zn values had lower ABI (p = 0.036). Mean survival time of patients with higher Zn values was 985 days ± 277 days and with lower Zn values 1055 ± 143 days. Six (19.4%) patients with lower Zn and five (16.7%) patients with higher Zn died. We found statistically insignificant lower survival in patients with higher Zn. We failed to find any predictor of all-cause mortality, except for ONS consumption (95% CI 1.6–33.3; p = 0.012).

Conclusions

Lower Zn is associated with lower ABI in HD patients, but we found no impact of Zn on patient survival.

Micronutrients and Renal Outcomes: A Prospective Cohort Study

Background: Micronutrients are essential in maintaining normal human physiology. Data regarding the association between micronutrients and renal outcomes in chronic kidney disease (CKD) are lacking. Methods: This prospective observational cohort study enrolled 261 patients with CKD stages 1−5 and 30 subjects with normal renal function. Baseline serum zinc (Zn), selenium (Se), chromium, manganese, and copper, and laboratory tests were performed at enrolment. The primary endpoint was the presence of end-stage renal disease (ESRD) requiring long-term renal replacement therapy. Results: The median follow-up periods of renal and non-renal survivals were 67.78 and 29.03 months, respectively. Multiple linear regression showed that Zn and Se (β ± SE: 24.298 ± 8.616, p = 0.005; 60.316 ± 21.875, p = 0.006, respectively) levels were positively correlated with renal function. Time to ESRD was significantly longer for those with Zn levels ≥1287.24 ng/g and Se levels ≥189.28 ng/g (both p < 0.001). Cox regression analysis identified a higher Zn level as an independently negative predictor of ESRD after adjusting for renal function (hazard ratio, 0.450, p = 0.019). Conclusion: Serum Se and Zn concentrations are positively associated with renal function and better renal outcomes. A higher Zn concentration could independently predict better renal survival.

Nonpharmacological Interventions for the Management of Testosterone and Sperm Parameters: A Scoping Review

PURPOSE

Testosterone replacement and associated pharmacologic agents are effective strategies to treat male hypogonadism; however, nutraceutical agents and lifestyle modification approaches have gained medical interest. The purpose of this scoping review is to highlight the evidence (or lack thereof) of nutraceuticals and lifestyle modification approaches in the management of testosterone levels and sperm parameters.

METHODS

A scoping review of nonpharmacologic interventions (supplements, herbal medicines, diets, sleep, and exercise) with the potential to improve male health was undertaken to elucidate changes in testosterone levels and sperm parameters in men with hypogonadism or infertility compared with healthy patients.

FINDINGS

A multitude of nutraceuticals and functional nutrients are purported to stimulate testosterone production; however, only a select few have had promising results, such as zinc, vitamin D (in case of hypovitaminosis D), l-arginine, mucuna, and ashwagandha, based on well-controlled randomized clinical trials of men with low testosterone levels and related problems. Except for l-arginine, these natural agents, as well as tribulus and ω3 fatty acids, can improve some degree of sperm parameters in infertile men. Before implementing these nutraceutical agents, adequate sleep, exercise, and weight loss in patients with obesity are imperative. The effects of nonpharmacologic interventions on testosterone levels are modest and hence do not directly translate into clinical benefits. Correspondingly, androgen receptor content, but not endogenous androgens, has been regarded as the principal factor in muscle hypertrophy.

IMPLICATIONS

A limited number of supplements and herbal medicines can be considered as adjunctive approaches in the management of testosterone levels and sperm parameters, primarily in men with low testosterone levels and infertility, whereas most nonpharmacologic supplements appear to lack evidence. Although proper physical exercise, sleep, and diet are indisputable approaches because of the general benefits to health, the use of nutraceuticals, if considered, must be personalized by physicians and/or registered dietitians.

Consortium of plant growth-promoting rhizobacteria enhances oilseed rape (Brassica napus L.) growth under normal and saline conditions

A preparation development, which stimulates plant growth under normal and saline conditions, and protects against fungal infections, would increase crop yields and reduce damage in agriculture. This study was conducted using bacterial isolates from rape rhizosphere as a plant growth promoter and an alternative to chemical fertilizers. Three from fifty bacterial isolates: B14 (Pseudomonas sp.), B16 (Sphingobacterium sp.), and B19 (Microbacterium sp.) showed the best in vitro plant growth-promoting (PGP) characteristics. B14 strain had the best antifungal activity against phytopathogens inhibiting growth of B. cinerea, C. acutatum, and P. lingam. Moreover, B14, B16 and B19 isolates coded for several genes involved in PGP activities, aimed at improving nutrient availability, resistance to abiotic stress, and fungal pathogen suppression. Microbial consortium (B14, B16, and B19) had the best effect on rape growth, significantly increasing number of live leaves, compared to the untreated control and single inoculant treatments. Moreover, the consortium induced significant increase in shoots length and chlorophyll content in comparison to Pseudomonas sp. B14 and Microbacterium sp. B19. The consortium also induced plants tolerance to salt stress. The genomic information as well as the observed traits, and beneficial attributes towards rape, make the rhizobacterial consortium an ideal candidate for further development as biofertilizers.

Impact of Serum Zinc Level and Oral Zinc Supplementation on Clinical Outcomes in Patients Undergoing Infrainguinal Bypass for Chronic Limb-Threatening Ischemia

BACKGROUND

Zinc (Zn) has been reported to play an important role in wound healing (WH). Nevertheless, the effect of Zn in chronic limb-threatening ischemia (CLTI) patients is unclear. This study investigated the effect of Zn on the clinical outcomes of CLTI patients undergoing bypass surgery.

METHODS AND RESULTS

This study reviewed 111 consecutive patients who underwent an infrainguinal bypass from 2012 to 2020. Patients with Zn deficiency (serum Zn level <60 μg/dL) received oral Zn supplementation and maintained a normal level until WH. This study aimed to explore: (1) the effect of Zn deficiency; and (2) Zn supplementation in Zn-deficient patients on the clinical outcomes of this cohort. Patients with Zn deficiency, Zn supplementation, and no Zn supplementation despite Zn deficiency accounted for 48, 21, and 42 patients, respectively. (1) Zn deficiency was associated with WH (HR, 0.47; 95% CI, 0.29-0.78: P=0.003), major adverse limb events (MALE) (HR, 2.53; 95% CI, 1.26-5.09: P=0.009), and major amputation or death (HR, 3.17; 95% CI, 1.51-6.63: P=0.002). (2) Zn supplementation was positively related to WH (HR, 2.30; 95% CI, 1.21-4.34: P=0.011). This result was confirmed using propensity score matching (HR, 2.24; 95% CI, 1.02-4.87: P=0.043).

CONCLUSIONS

The current study revealed that Zn level was associated with clinical outcomes in CLTI patients after bypass surgery. Oral Zn supplementation could improve WH in these patients.

Diet-Related Inflammation is Associated with Malnutrition-Inflammation Markers in Maintenance Hemodialysis Patients: Results of a Cross-Sectional Study in China Using Dietary Inflammatory Index

Purpose

This cross-sectional study aimed to explore the association between the inflammation potential of the diet and malnutrition-inflammation status in Chinese maintenance hemodialysis (MHD) patients.

Methods

Dietary Inflammatory Index (DII) was computed based on a semi-quantitative food frequency questionnaire. Malnutrition-inflammation status was assessed by six indexes, including C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), hemoglobin (HB), albumin (ALB) and malnutrition-inflammation score (MIS). Multivariable linear regression and logistic regression were employed adjusting for covariables including age, gender, body mass index and dialysis vintage.

Results

A total of 161 Chinese MHD patients with an average age of 60.0 ± 13.6 years were enrolled. The median (IQR) DII score among participants was 0.60 (−0.80, 2.32), revealing a generally pro-inflammatory diet. DII was positively associated with MIS score (β= 0.61, 95% CI: 0.51, 0.69, p < 0.0001) and CRP (β = 0.54, 95% CI: 0.46, 0.63, p < 0.0001). A negative relationship between DII and NLR (β = −0.37, 95% CI: −0.61, −0.13, p = 0.008) was found in the most anti-inflammatory diet. Multivariable logistic regression showed that each unit increase in DII was linked with 3.06 (95% CI: 1.39, 6.69, p = 0.005) times increased odds of MIS.

Conclusion

Diet with a higher DII score may act as a potential trigger contributing to the development of malnutrition-inflammation status. Further studies for verification and for developing strategies to decrease the dietary inflammation burden are warranted.

Role of Zinc in Diabetic Kidney Disease

Diabetic Kidney Disease (DKD) represents the most common cause of Chronic Kidney Disease (CKD) in developed countries. Approximately 30% to 40% of diabetes mellitus (DM) subjects develop DKD, and its presence significantly increases the risk for morbidity and mortality. In this context, Zinc seems to have a potential role in kidney and body homeostasis in diabetic individuals as well as in patients at a high risk of developing this condition. This essential element has functions that may counteract diabetes-related risk factors and complications, which include stabilization of insulin hexamers and pancreatic insulin storage and improved glycemic control. In our review, we analyzed the current knowledge on the role of zinc in the management of renal impairment in course of DM. Several studies underline the critical role of zinc in reducing oxidative stress levels, which is considered the common denominator of the mechanisms responsible for the progression of kidney disease. Reaching and maintaining a proper serum zinc level could represent a valuable target to reduce symptoms related to DM complications and contrast the progression of kidney impairment in patients with the high risk of developing end-stage renal disease. In conclusion, analyzing the beneficial role of zinc in this review would advance our knowledge on the possible strategies of DM and DKD treatment.

Efficacy of Zinc Acetate Treatment for Patients with Decompensated Liver Cirrhosis Complicated by Hypozincemia

The aim of this study was to evaluate the efficacy of zinc acetate treatment for patients with decompensated liver cirrhosis complicated by hypozincemia. We retrospectively analyzed 49 patients with decompensated liver cirrhosis complicated by hypozincemia who received zinc acetate treatment from August 2017 to March 2020. The relationships between serum zinc levels and several parameters including the prognosis, sarcopenia, and immunity were evaluated. Serum zinc levels measured at 3 months post-treatment and the incidence of adverse events were also determined. The median age was 69.0 years (IQR:59.5-78.8) and the male to female ratio was 29:20. Twenty-seven patients had a Child-Pugh classification of B and 22 had a Child-Pugh classification of C; the median Child-Pugh score was 9.0 (IQR, 8.0-11.0). The median serum zinc levels measured at 3 months post-treatment (74.7 (IQR, 50.0-101.0) μg/dL) were significantly elevated in comparison to the pre-treatment levels (43.0 (IQR, 34.0-51.0) μg/dL, P < 0.0001). The overall survival of patients with pre-treatment serum zinc levels of ≥60 μg/dL was significantly better than that of those with pre-treatment serum zinc levels of <60 μg/dL (P = 0.013). The survival of patients with zinc levels of ≥70 μg/dL at 3 months post-treatment was significantly better than those with levels of <70 μg/dL (P = 0.013). The serum albumin level, Child-Pugh score, albumin-bilirubin (ALBI) score and model for end-stage liver disease (MELD) score were identified as factors predicting a good response at 3 months post-treatment. There were no significant relations between the pretreatment serum zinc levels and skeletal muscle mass, lymphocyte count, and neutrophil lymphocyte ratio. There were no obvious problematic adverse events in patients who received zinc acetate treatment. The patients with higher basal zinc levels and good responders to zinc acetate treatment had a better prognosis. Zinc acetate was useful and safe for patients with decompensated liver cirrhosis complicated by hypozincemia.

3D ultrasound navigation system for screw insertion in posterior spine surgery: a phantom study

PURPOSE

Posterior spinal fusion surgery is required to correct severe idiopathic scoliosis. The surgery involves insertion of screws which requires high accuracy to prevent neurologic damage to the spinal cord. Although conventional CT navigation can reduce this risk, 3D-ultrasound-based navigation could achieve this without added ionizing radiation and usage of expensive and bulky equipment. This study aimed to evaluate the accuracy of a 3D ultrasound navigation system for posterior spine surgery.

METHODS

A custom 3D ultrasound (3DUS) with model-to-surface registration algorithm was developed and integrated into a 3D navigation environment. A CT scan of an adolescent spine (T3-T11) was segmented and 3D printed for experiments. A probe with reflective markers was placed in vertebral pedicles 684 times in varying levels, positions in the capture space and orientation of vertebra, and the entrypoint and trajectory accuracies were measured.

RESULTS

Among 684 probe placements in vertebral levels T3 to T11 in the phantom spine, 95.5% were within 1 mm and 5° of accuracy, with an average accuracy of 0.4 ± 0.4 mm and 2.1 ± 0.9°, requiring 8.8 s to process. Accuracies were statistically significantly affected by vertebral orientation and position in the capture volume, though this was still within the targeted accuracies of 1 mm and 5°.

CONCLUSION

This preliminary ultrasound-based navigation system is accurate and fast enough for guiding placement of pedicle screws into the spine in posterior fusion surgery. The current results are limited to phantom spines, and future study in animal or human cadavers is needed to investigate soft tissue effects on registration accuracy.

Zinc Deficiency, Plasma Fatty Acid Profile and Desaturase Activities in Hemodialysis Patients: Is Supplementation Necessary?

Background: Desaturation and elongation are critical processes in endogenous metabolic fatty acid pathways. Zinc (Zn) is a cofactor for desaturases and elongases enzymes. There is limited evidence regarding the relationships between biomarkers of Zn status, nutritional intake, plasma phospholipid fatty acid profile and clinical outcomes among patients undergoing hemodialysis (HD). Objective: To examine the relationships between dietary and serum levels of Zn and Cu/Zn ratio and to explore associations of these micronutrients with PUFA profile and estimated desaturase and elongase enzyme activities in serum phospholipids among HD patients. Methods: This study included 40 adult patients undergoing hemodialysis treatment. Repeated 24-h recalls were applied for dietary intake assessment. Serum concentration of Zn and Cu were determined using inductively coupled plasma mass spectrometry and fatty acid composition by gas-liquid chromatography. Desaturase and elongase activities were calculated from product-precursor fatty acid ratios. Results: Inadequate dietary Zn intake was found in 55% of HD patients. They all had serum Zn concentration below the reference value of 60 μg/dL (mean 38.8 ± 7.72 μg/dL). Adequate zinc intake was accompanied with significantly higher intake of energy, total fats, SFA, MUFA and proteins. There was no correlation between Zn serum status and Zn intake estimates. Serum Cu/Zn ratio was high, (2.76 ± 0.68), directly and significantly associated with HD period, CRP, BMI, VFA, and inversely with Kt/V, albumin, iron, and iPTH. The n-6/n-3 ratio in plasma phospholipids was elevated (12.25 ± 3.45) and patients with inadequate Zn intake had lower n-3 PUFA intake and status compared to those with adequate intake. Serum Zn concentrations were inversely correlated with linoleic/dihomo-γ-linolenic acid ratio (LA/DGLA) (p = 0.037), related to D6-desaturase activity (p = 0.033) and directly with DGLA relative abundances (p = 0.024). Cu status was inversely associated with EPA level (p = 0.03) and estimates of elongase activity (p = 0.001). Furthermore, positive relationship was found between the Cu/Zn ratio and determined elongase value (p = 0.01). Conclusion: Findings of this study underpin the high prevalence of Zn deficiency and inadequate n-3 PUFA intake and status among subjects undergoing HD. The results obtained indicate that the assessment of Zn status should be a standard parameter of nutritional status screening in HD patients while emphasizing the importance of Cu/Zn determination. Although further research is warranted, Zn and-n-3 PUFA supplementation in HD patients might be beneficial for the prevention and attenuation of adverse health outcomes.

Zinc Deficient Intake in Hemodialysis Patients: A Path to a High Mortality Risk

BACKGROUND

Zinc is essential for human nutrition and plays an important role in hemodialysis (HD) patients. The aim of this study is to analyze the relationship between zinc intake and mortality in HD patients.

METHODS

This is a longitudinal, prospective, multicenter study with 582 HD patients from 37 dialysis centers. We recorded clinical and body composition parameters. Dietary intake and physical activity data were obtained using the Food Frequency Questionnaire and International Physical Activity Questionnaire. All statistical tests were performed using SPSS 24.0 software. A P value lower than 0.05 was considered statistically significant.

RESULTS

Patients' mean age was 67.8 ± 17.7 years and median HD vintage was 65 (43-104) months. About 53.6% of the patients presented a deficient daily intake of zinc. Patients with the highest zinc intake were those who had a higher lean tissue index (P = .022), energy (P < .001), and protein (p = .022) intakes. Zinc intake was positively correlated with energy (r = 0.709) and protein intake (r = 0.805) and negatively correlated with the malnutrition screening tool score (r = -0.087). A higher energy, protein, and lower carbohydrates intake, as well as lower HD vintage and higher lean tissue index were predictors of zinc intake. A higher mortality risk was observed in patients with zinc intake below the recommended values, even after the adjustment for age, presence of diabetes, gender, dialysis vintage, albumin, lean tissue index, energy intake/kilogram, and level of physical activity (P = .021).

CONCLUSION

There is a high prevalence of HD patients with an inadequate zinc intake, which is related to worse nutritional and body composition parameters and with a higher mortality risk.

CT findings of non-neoplastic central airways diseases

Non-neoplastic lesions of central airways are uncommon entities with different etiologies, with either focal or diffuse involvement of the tracheobronchial tree. Clinical symptoms of non-neoplastic tracheobronchial diseases are non-specific, and diagnosis is difficult, especially in the early stages. Three-dimensional computed tomography (3D-CT) is an evaluable tool as it allows to assess and characterize tracheobronchial wall lesions and meanwhile it enables the evaluation of airways surrounding structures. Multiplanar reconstructions (MPR), minimum intensity projections (MinIP), and 3D Volume Rendering (VR) (in particular, virtual bronchoscopy) also provide information on the site and of the length of airway alterations. This review will be discussed about (1) primary airway disorders, such as relapsing polychondritis, tracheobronchophathia osteochondroplastica, and tracheobronchomegaly, (2) airway diseases, related to granulomatosis with polyangiitis, Chron's disease, Behcet's disease, sarcoidosis, amyloidosis, infections, intubation and transplantation, (3) tracheobronchial malacia, and (4) acute tracheobronchial injury. 3D-CT findings, especially with MPR and 3D VR reconstructions, allows us to evaluate tracheobronchial disease morphologically in detail.

Essential sufficiency of zinc, ω-3 polyunsaturated fatty acids, vitamin D and magnesium for prevention and treatment of COVID-19, diabetes, cardiovascular diseases, lung diseases and cancer

Despite the development of a number of vaccines for COVID-19, there remains a need for prevention and treatment of the virus SARS-CoV-2 and the ensuing disease COVID-19. This report discusses the key elements of SARS-CoV-2 and COVID-19 that can be readily treated: viral entry, the immune system and inflammation, and the cytokine storm. It is shown that the essential nutrients zinc, ω-3 polyunsaturated fatty acids (PUFAs), vitamin D and magnesium provide the ideal combination for prevention and treatment of COVID-19: prevention of SARS-CoV-2 entry to host cells, prevention of proliferation of SARS-CoV-2, inhibition of excessive inflammation, improved control of the regulation of the immune system, inhibition of the cytokine storm, and reduction in the effects of acute respiratory distress syndrome (ARDS) and associated non-communicable diseases. It is emphasized that the non-communicable diseases associated with COVID-19 are inherently more prevalent in the elderly than the young, and that the maintenance of sufficiency of zinc, ω-3 PUFAs, vitamin D and magnesium is essential for the elderly to prevent the occurrence of non-communicable diseases such as diabetes, cardiovascular diseases, lung diseases and cancer. Annual checking of levels of these essential nutrients is recommended for those over 65 years of age, together with appropriate adjustments in their intake, with these services and supplies being at government cost. The cost:benefit ratio would be huge as the cost of the nutrients and the testing of their levels would be very small compared with the cost savings of specialists and hospitalization.

Lower Levels of Blood Zinc Associated with Intradialytic Hypertension in Maintenance Hemodialysis Patients

Intradialytic hypertension (iHTN) has been related with an increased risk of mortality, with imbalances in trace elements being frequent in maintenance hemodialysis (MHD) patients. The aim of this study was to analyze the relationships between the levels of blood trace elements and iHTN in MHD patients. A total of 144 MHD patients were enrolled in September, 2019 (66 females; 5616 hemodialysis treatments), with a mean age of 64.33 ± 13.39 years and median vintage of 33.50 (16.25-57.50) months. Patients exhibited an average peridialytic systolic blood pressure (SBP) change of - 4.18 ± 20.22 mm Hg in the next 3 months. Thirty-four (23.6%) patients had persistent iHTN (piHTN). These patients were characterized by older age, higher rate of hypozincemia, and modified Charlson comorbidity score, whereas lower blood zinc and hemoglobin, at the time of their recruitment. No significant difference in the levels of other blood trace elements was observed between groups. A general linear mixed (GLM) model showed that with every mg/L point lower mean blood zinc at baseline, the peridialytic SBP change was increased by 4.524 mm Hg (P < 0.001). Binary logistic model in modulate of the GLM model revealed that the lower level of blood zinc was associated with piHTN (OR = 0.433, 95 % CI 0.295 to 0.637, P < 0.001). Multivariate analysis confirmed both above results. Our study indicated that lower blood zinc was independently associated with piHTN in patients undergoing MHD, but prospective studies with larger population are still needed.

Association of Zinc Deficiency with Development of CVD Events in Patients with CKD

Deficiency of the micronutrient zinc is common in patients with chronic kidney disease (CKD). The aim of this review is to summarize evidence presented in literature for consolidation of current knowledge regarding zinc status in CKD patients, including those undergoing hemodialysis. Zinc deficiency is known to be associated with various risk factors for cardiovascular disease (CVD), such as increased blood pressure, dyslipidemia, type 2 diabetes mellitus, inflammation, and oxidative stress. Zinc may protect against phosphate-induced arterial calcification by suppressing activation of nuclear factor kappa light chain enhancer of activated B. Serum zinc levels have been shown to be positively correlated with T₅₀ (shorter T₅₀ indicates higher calcification propensity) in patients with type 2 diabetes mellitus as well as those with CKD. Additionally, higher intake of dietary zinc was associated with a lower risk of severe abdominal aortic calcification. In hemodialysis patients, the beneficial effects of zinc supplementation in relation to serum zinc and oxidative stress levels was demonstrated in a meta-analysis of 15 randomized controlled trials. Thus, evidence presented supports important roles of zinc regarding antioxidative stress and suppression of calcification and indicates that zinc intake/supplementation may help to ameliorate CVD risk factors in CKD patients.

Automatic ultrasound scanning robotic system with optical waveguide-based force measurement

PURPOSE

The three-dimensional (3D) ultrasound (US) imaging realized by continuous scanning of a region is of great value for medical diagnosis and robot-assisted needle insertion. During scanning, the contact force and posture between the probe and skin of the patient are crucial factors that determine the quality of US imaging. We propose a robotic system for automatic scanning of curved surfaces with a stable contact force and vertical contact posture (the probe is parallel to the normal of the surface at the contact point).

METHODS

A 6-DOF robotic arm is used to hold and drive a two-dimensional (2D) US probe to complete automatic scanning. Further, a path-planning strategy is proposed to generate the scan path covering the selected area automatically. We also developed a novel force-measuring device based on optical waveguides to measure the distributed contact force and contact posture. Based on the measured force and posture, the robotic arm automatically adjusts the position and orientation of the probe and maintains a stable contact force and vertical contact posture at each scan point.

RESULTS

The novel force-measuring device is easy to fabricate, integrates with the probe and has the capacity of measuring the force distributed on the contact surface and estimating the contact posture. The experimental results of automatic scanning of a US phantom and parts of the human body demonstrate that the proposed system performs well in automatically scanning curved surfaces, maintaining a stable contact force and vertical contact posture and producing a good quality 3D US volume.

CONCLUSION

An automatic US scanning robotic system with an optical waveguide-based force-measuring device was developed and tested successfully. Experimental results demonstrated the feasibility of the proposed system to scan the human body.

Zinc in Dog Nutrition, Health and Disease: A Review

Simple Summary

This work compiles the current state of knowledge regarding zinc requirements of healthy dogs and biomarkers of zinc status. To ensure an adequate zinc status, it is important to know the zinc content of foods and their bioavailability to assess the need and the ideal supplementation strategy regarding levels and sources of additives in complete dog foods. As zinc is required for enzymatic, structural, and regulatory functions in the animal body, its nutritional status has been associated with several pathologies that may be due to, or exacerbated by, a deficit of dietary zinc supply.

Abstract

Zinc is an essential trace element, required for enzymatic, structural, and regulatory functions. As body reserves are scarce, an adequate zinc status relies on proper dietary supply and efficient homeostasis. Several biomarkers have been proposed that enable the detection of poor zinc status, but more sensitive and specific ones are needed to detect marginal deficiencies. The zinc content of commercial dry dog foods has great variability, with a more frequent non-compliance with the maximum authorized limit than with the nutritional requirement. The bioavailability of dietary zinc also plays a crucial role in ensuring an adequate zinc status. Despite controversial results, organic zinc sources have been considered more bioavailable than inorganic sources, albeit the zinc source effect is more evident after a restriction period of dietary zinc. Many disorders have been associated with inadequate zinc status, not being clear whether the occurrence of the disease is the consequence or the cause. This review presents data on zinc requirements and biomarkers for zinc status, that can be applied for the development of supplementation strategies of zinc in complete pet foods. Moreover, it provides an understanding of the role zinc plays in the health of dogs, and how altered zinc status affects diseases in dogs.

Trace element imbalances in patients undergoing chronic hemodialysis therapy - Report of an observational study in a cohort of Portuguese patients

INTRODUCTION

Patients with end-stage renal disease undergoing hemodialysis therapy are at risk of developing deficiencies of essential trace elements and/or overload of toxic trace elements, both of which may significantly affect their clinical status of. Those imbalances may result from the disease itself but also from the quality of the therapeutic process, namely the hemodialysis process, which has greatly evolved in the last decades. Thus, old observations that have been assumed as very well-proven have been recently questioned. In this case-control study we evaluate the current trace elements status in a group of Portuguese patients under hemodialysis therapy.

MATERIAL AND METHODS

Serum samples from patients (n = 93), collected for the routine periodic control of Al levels, were analyzed for a wide panel of trace elements (Li, Al, Mn, Co, Ni, Cu, Zn, Se, Rb, Sr, Mo, Cd, Ba, Pb) using inductively coupled plasma mass spectrometry technique (hemodialysis patients' group). For comparison purposes, samples of individuals with no evidence of renal disease according to standard laboratory analytical criteria (n = 50) were also analyzed (control group).

RESULTS

The results showed significant differences between the two groups, with higher values in hemodialysis patients group for Al (14.6 vs. 9.5 μg/L), Co, Ni, Sr, Mo (4.5 vs. 1.4 μg/L), Cd (0.058 vs. 0.025 μg/L) and Pb (0.55 vs. 0.30 μg/L); and lower values in hemodialysis patients group for Li (4.0 vs. 75.8 μg/L), Mn, Cu (943.5 vs. 1038.5 μg/L), Zn (943.5 vs. 1038.5 μg/L), Se (71.5 vs. 103.8 μg/L), Rb (202.4 vs. 300.3 μg/L) and Ba (0.65 vs. 8.7 μg/L).

CONCLUSION

This study confirms that hemodialysis patients tend to present significant trace elements imbalances, which may be related to the higher morbidity and mortality observed in this specific patients' group.

Serum trace metal association with response to erythropoiesis stimulating agents in incident and prevalent hemodialysis patients

Alterations in hemodialysis patients' serum trace metals have been documented. Early studies addressing associations levels of serum trace metals with erythropoietic responses and/or hematocrit generated mixed results. These studies were conducted prior to current approaches for erythropoiesis stimulating agent (ESA) drug dosing guidelines or without consideration of inflammation markers (e.g. hepcidin) important for regulation of iron availability. This study sought to determine if the serum trace metal concentrations of incident or chronic hemodialysis patients associated with the observed ESA response variability and with consideration to ESA dose response, hepcidin, and high sensitivity C-reactive protein levels. Inductively-coupled plasma-mass spectrometry was used to measure 14 serum trace metals in 29 incident and 79 prevalent dialysis patients recruited prospectively. We compared these data to three measures of ESA dose response, sex, and dialysis incidence versus dialysis prevalence. Hemoglobin was negatively associated with ESA dose and cadmium while positively associated with antimony, arsenic and lead. ESA dose was negatively associated with achieved hemoglobin and vanadium while positively associated with arsenic. ESA response was positively associated with arsenic. Vanadium, nickel, cadmium, and tin were increased in prevalent patients. Manganese was increased in incident patients. Vanadium, nickel, and arsenic increased with time on dialysis while manganese decreased. Changes in vanadium and manganese were largest and appeared to have some effect on anemia. Incident and prevalent patients' chromium and antimony levels exceeded established accepted upper limits of normal.

Association between Serum Zinc Levels and Clinical Index or the Body Composition in Incident Hemodialysis Patients

Background: The relationships between serum zinc levels and body composition or clinical outcomes of incident hemodialysis (HD) patients remain unclear. Methods: This prospective observational study examined the relationships between serum zinc levels and clinical indexes, including body composition, in 142 incident HD patients using a bioelectrical impedance analysis. Patients were divided into three groups according to baseline serum zinc levels: tertile, <45, 45–59, and ≥60 µg/dL. The reference group was set as ≥60 µg/dL. Cox’s regression analysis was performed to investigate the relationships between serum zinc categories and cardiovascular events and all-cause mortality after adjustments for potential confounders. Results: Serum zinc levels positively correlated with the nutritional index and negatively correlated with fluid volume markers. In a mean follow-up of 2.5 years, there were 20 cases of cardiovascular events and 15 of all-cause mortality. In the Cox’s regression analysis for cardiovascular events and all-cause mortality, the hazard ratio increased with a decrease in serum zinc levels, but was not significant. Conclusion: Serum zinc levels were associated with nutritional and fluid volume markers in incident HD patients. To clarify the relationship between serum zinc levels and cardiovascular events or mortality, further studies with a larger number of cases will be necessary.

Pharmaconutrition in the Clinical Management of COVID-19: A Lack of Evidence-Based Research But Clues to Personalized Prescription

A scientific interest has emerged to identify pharmaceutical and nutritional strategies in the clinical management of coronavirus disease 2019 (COVID-19). The purpose of this narrative review is to critically assess and discuss pharmaconutrition strategies that, secondary to accepted treatment methods, could be candidates in the current context of COVID-19. Oral medicinal doses of vitamin C (1-3 g/d) and zinc (80 mg/d elemental zinc) could be promising at the first signs and symptoms of COVID-19 as well as for general colds. In critical care situations requiring parenteral nutrition, vitamin C (3-10 g/d) and glutamine (0.3-0.5 g/kg/d) administration could be considered, whereas vitamin D3 administration (100,000 IU administered intramuscularly as a one-time dose) could possess benefits for patients with severe deficiency. Considering the presence of n-3 polyunsaturated fatty acids and arginine in immune-enhancing diets, their co-administration may also occur in clinical conditions where these formulations are recommended. However, despite the use of the aforementioned strategies in prior contexts, there is currently no evidence of the utility of any nutritional strategies in the management of SARS-CoV-2 infection and COVID-19. Nevertheless, ongoing and future clinical research is imperative to determine if any pharmaconutrition strategies can halt the progression of COVID-19.

Effects of zinc supplementation on lipid profile in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIM

Findings on the effects of zinc supplementation on the lipid profile in patients with type 2 diabetes mellitus (T2DM) are conflicting. The current comprehensive systematic review and meta-analysis aimed to summarize available evidence in this regard.

METHODS AND RESULTS

After a systematic search in the online databases, we included the randomized controlled trials (RCTs) investigating the effect of zinc supplementation on lipid profile [total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG)] in patients with T2DM. Altogether, 9 studies with a total sample size of 424 patients with T2DM were included in the analysis. Combining 9 effect sizes from 9 RCTs, we found a significant lowering effect of zinc supplementation on serum levels of TG (weighted mean difference (WMD): -17.08, 95% CI: -30.59, -3.58 mg/dL, P = 0.01) and TC (WMD: -26.16, 95% CI: -49.69, -2.62 mg/dL, P = 0.02). Although the overall effect of zinc supplementation on LDL-C levels was not significant, a beneficial effect was seen in studies that administered <100 mg/d zinc. Based on the non-linear dose-response analysis, a greater reduction in serum levels of TC and LDL-C following zinc supplementation was seen at <12 weeks' duration of intervention. Unlike the overall effect size, we found a significant increasing effect of zinc supplementation on serum HDL-C concentrations in most subgroups of RCTs according to the subgroup analyses.

CONCLUSION

We found that zinc supplementation may beneficially influence lipid profile in patients with T2DM.

Effects of Zinc Supplementation on Nutritional Status in Children with Chronic Kidney Disease: A Randomized Trial

BACKGROUND

Zinc is an essential micronutrient for human beings and its deficiency affects their normal growth and development.

OBJECTIVE

The main aim was to evaluate the effect of two doses of zinc supplementation (ZS) on the nutritional status in chronic kidney disease (CKD) children.

METHODS

A randomized-trial multicentric study was conducted in 48 CKD (23 females) patients under 18-years-old, for a year. At random, participants took 30 or 15 mg/day of ZS, respectively. Anthropometric measurements and biochemical analysis were performed. Hypozincemia was determined by serum zinc concentration (SZC) using atomic absorption spectrophotometry. The positive or negative change in patients' body mass index (BMI) Z-score, serum albumin, zinc and C-reactive protein (CRP) levels were used to evaluate the effect of ZS.

RESULTS

Mean SZC was normal before and after ZS. Despite ZS, there were no significant changes in serum albumin, zinc and CRP levels. A positive and significant association was observed between SZC and serum albumin before (p = 0.000) and after (p = 0.007) ZS. In both groups of ZS, there was a small but positive and significant change in body mass and normalization in BMI Z-score, hypoalbuminemia, hypozincemia and high CRP, especially with 30 mg/day of ZS.

CONCLUSIONS

Zinc supplementation may be beneficial for nutritional status in children and adolescents with CKD.

Effect of Zinc Supplementation on Renal Anemia in 5/6-Nephrectomized Rats and a Comparison with Treatment with Recombinant Human Erythropoietin

Anemia is a severe complication in patients with chronic kidney disease (CKD). Treatment with exogenous erythropoietin (EPO) can correct anemia in many with CKD. We produced 5/6-nephrectomized rats that became uremic and anemic at 25 days post surgery. Injection of the anemic 5/6-nephrectomized rats with 2.8 mg zinc/kg body weight raised their red blood cell (RBC) levels from approximately 85% of the control to 95% in one day and continued for 4 days. We compared the effect of ZnSO4 and recombinant human erythropoietin (rHuEPO) injections on relieving anemia in 5/6-nephrectomized rats. After three consecutive injections, both the ZnSO4 and rHuEPO groups had significantly higher RBC levels (98 ± 6% and 102 ± 6% of the control) than the saline group (90 ± 3% of the control). In vivo, zinc relieved anemia in 5/6-nephrectomized rats similar to rHuEPO. In vitro, we cultured rat bone marrow cells supplemented with ZnCl2, rHuEPO, or saline. In a 4-day suspension culture, we found that zinc induced erythropoiesis similar to rHuEPO. When rat bone marrow cells were supplement-cultured with zinc, we found that zinc stimulated the production of EPO in the culture medium and that the level of EPO produced was dependent on the concentration of zinc supplemented. The production of EPO via zinc supplementation was involved in the process of erythropoiesis.

Role of parathyroid hormone in anorexia on maintenance hemodialysis patients

BACKGROUND AND AIM

Anorexia, which is a common condition in patients on hemodialysis (HD), is characterized by impaired appetite, a subjective condition that hinders anorexia diagnosis. Anorexia is frequently associated with protein energy wasting and inflammation, increasing morbidity and mortality risk. The aim of the study was to evaluate the association between appetite and nutritional, inflammatory, hormonal, and dietary intake parameters in patients on maintenance HD.

METHODS

Cross-sectional study with clinical, laboratory, and anthropometric parameters, body composition, muscle function, and dietary intake assessment. To evaluate appetite, a three simple questions questionnaire previously validated was used. After appetite classification, the sample was dichotomized in "normal appetite" and "impaired appetite" and compared. Multiple logistic regression was used to identify association between variables and outcome.

RESULTS

125 patients on HD were included, aged 60.6 ± 14.12 years old, median HD vintage 35.5 months. In dichotomized sample, 78.4% patients showed "normal appetite", and 21.6% "impaired appetite". "Impaired appetite" was independently associated with increased serum PTH (OR 1.001; 95% CI 1.000-1.002; p = 0.03), low zinc intake (OR 0.860; 95% CI 0.746-0.991; p = 0.03) and lower urea serum (OR 0.982; 95% CI 0.965-0.999; p = 0.04). Both groups showed insufficient dietary intake.

CONCLUSIONS

Appetite was independently associated with increased serum of PTH, low serum concentration of urea, and low zinc intake which may infer association of appetite with mineral bone disease, protein intake and zinc deficiency.

Antioxidant Supplementation in Renal Replacement Therapy Patients: Is There Evidence?

The disruption of balance between production of reactive oxygen species and antioxidant systems in favor of the oxidants is termed oxidative stress (OS). To counteract the damaging effects of prooxidant free radicals, all aerobic organisms have antioxidant defense mechanisms that are aimed at neutralizing the circulating oxidants and repair the resulting injuries. Antioxidants are either endogenous (the natural defense mechanisms produced by the human body) or exogenous, found in supplements and foods. OS is present at the early stages of chronic kidney disease, augments progressively with renal function deterioration, and is further exacerbated by renal replacement therapy. End-stage renal disease patients, on hemodialysis (HD) or peritoneal dialysis (PD), suffer from accelerated OS, which has been associated with increased risk for mortality and cardiovascular disease. During HD sessions, the bioincompatibility of dialyzers and dialysate trigger activation of white blood cells and formation of free radicals, while a significant loss of antioxidants is also present. In PD, the bioincompatibility of solutions, including high osmolality, elevated lactate levels, low pH, and accumulation of advanced glycation end-products trigger formation of prooxidants, while there is significant loss of vitamins in the ultrafiltrate. A number of exogenous antioxidants have been suggested to ameliorate OS in dialysis patients. Vitamins B, C, D, and E, coenzyme Q10, L-carnitine, a-lipoic acid, curcumin, green tea, flavonoids, polyphenols, omega-3 polyunsaturated fatty acids, statins, trace elements, and N-acetylcysteine have been studied as exogenous antioxidant supplements in both PD and HD patients.