Renal functional and structural integrity in infants with iron deficiency anemia: relation to oxidative stress and response to iron therapy.

BACKGROUND: Iron deficiency anemia (IDA) is the most common nutritional deficiency in the world. The aim of our study was to evaluate and compare renal functional and structural integrity in 50 infants with IDA and 50 healthy controls and to assess the relation between IDA and oxidative stress and response to iron therapy. METHODS: This was a prospective study in which peripheral blood samples were collected from all study subjects and the following laboratory investigations performed: serum iron profile, urinary microalbumin, urinary leucine aminopeptidase (LAP), fractional excretion of sodium (FeNa), serum total antioxidant capacity (TAC), serum malondialdehyde (MDA), serum and urinary trace elements (iron, copper, zinc, calcium and magnesium). All patients received oral iron therapy and were followed-up for 3 months. RESULTS: The levels of baseline urinary markers were higher among the patients with IDA than among the controls (p < 0.05). Patients had a lower pre-therapy TAC and lower serum zinc and magnesium levels than controls as well as higher MDA and serum copper levels (p < 0.05). MDA level was positively correlated to microalbumin and LAP level (p < 0.05). Urinary LAP concentration was positively correlated to urinary trace element concentrations (p < 0.05). A significant decrease in microalbumin, LAP, FeNa, and urinary trace elements was observed post-iron therapy while hemoglobin and ferritin levels were increased (p < 0.05). CONCLUSION: Among the study subjects, IDA had an adverse influence on renal functional and structural integrity which could be reversed with iron therapy. Oxidative stress played an important role in the pathogenesis of renal injury in IDA.

Effect of tramadol addiction alone and its co-abuse with cannabis on urinary excretion of Copper, Zinc, and Calcium among Egyptian addicts.

BACKGROUND: The use of illicit drugs has become a worldwide health problem. Substances with the potential to be abused may have direct or indirect effects on physiologic mechanisms that lead to organ system dysfunction and diseases. OBJECTIVE: The present study aims to investigate the structural and reabsorption integrity of the nephron among Egyptian addicts of tramadol alone and coabused with cannabis. METHODS: Sixty-five males were included in the study, they were classified into control group (G1=19), tramadol addicts group (G2=18), and tramadol coabused with cannabis addicts group (G3=28). Parameters investigated for structural integrity were urinary levels ofleucineaminopeptidase and N-acetyl-ß-D-glucosaminidase, and urinary parameters for reabsorption integrity were levels of copper and zinc as well as calcium, also urinary creatinine was measured. In addition, urinary levels of tramadol and tetrahydrocannabinol were estimated. RESULTS: Among the two addicted groups, all measured parameters were not significantly different in comparison with the control group except for urinary calcium excretion which was found to be significantly increased among the two addicted groups. CONCLUSION: Both tramadol addiction alone or coabused with cannabis causes increased urinary excretion of calcium, indicating reabsorption dysfunction of calcium without affecting structural integrity along the nephron.

Nephrotoxic effects of mercury exposure and smoking among Egyptian workers in a fluorescent lamp factory.

BACKGROUND: It is known that mercury (Hg) has a nephrotoxic effect in exposed workers. This effect is evident when there is advanced damage of kidney tissue. METHODS: A random morning urine sample was collected from each participant for measuring urinary concentrations of total protein (UTP), retinol-binding protein (URBP), creatinine (UCr), Hg (UHg), and the activities of leucine-aminopeptidase (ULAP) and glutathione S-transferase (UGST) as well as N-acetyl-beta-D-glucosaminidase (UNAG). RESULTS: Urinary excretion of the measured parameters was significantly increased among Hg-exposed workers who were smokers and among Hg-exposed workers with work duration >or=11 years than those with

Subclinical nephrotoxicity caused by smoking and occupational silica exposure among Egyptian industrial workers.

BACKGROUND: The aim of the present work was to investigate early signs of subclinical renal alterations due to silica exposure and smoking among non-silicotics and silicotics by measuring urinary indicators of nephrotoxicity. METHODS: The subjects comprised 29 non-silicotics (9 non-smokers, 20 smokers), 24 silicotics (9 non-smokers, 15 smokers), and 28 referents (9 non-smokers, 19 smokers). Measured urinary parameters were concentrations of total protein, microalbumin, retinol-binding protein, and activities of N-acetyl-beta-D-glucosaminidase and glutathione S-transferase. In addition, we measured levels of urinary silicon and creatinine. RESULTS: Compared with referents, both non-silicotics and silicotics excreted significant high levels of all measured parameters. Smokers in each investigated group also showed increased levels (although not significant) of renal parameters in comparison to corresponding non-smokers. Among non-silicotics, the present results showed that elevation of measured urinary parameters was significantly associated with work duration, while only urinary excretion of glutathione S-transferase was associated with work duration among silicotics. CONCLUSIONS: The study confirms that silica may lead to subclinical signs of nephrotoxicity, and that smoking also has a nephrotoxic effect on kidney and is synergistic to nephrotoxicity of silica exposure. Additionally, the study suggests that renal alterations may occur prior to pulmonary involvement.

Effects of smoking and lead exposure on proximal tubular integrity among Egyptian industrial workers.

BACKGROUND: The hazards of occupational lead exposure are well documented. Tissue damage produced by lead is slow and progressive. The renal system is one of the systems primarily affected by lead. The present study aimed to evaluate renal proximal tubular functional and structural integrity among lead-exposed and cigarette-smoking male Egyptian workers. This study was extended to investigate the effect of lead exposure and cigarette smoking on urinary excretion of copper (Cu) and zinc (Zn). METHODS: Participants included in the present study were 156 male workers grouped as follows: i) 75 lead non-exposed workers subgrouped into G1 that consisted of 36 non-smokers (age, 39.08+/-6.65 years) and G2, which included 39 smokers (age, 43.87+/-9.93 years); ii) 45 lead-exposed workers (work duration <20 years) subgrouped into G3 that consisted of 25 non-smokers (age, 37.40+/-3.76 years) and G4, which included 20 smokers (age, 38.40+/-4.95 years), and iii) 36 lead-exposed workers (work duration > or =20 years) subgrouped into G5 that consisted of 16 non-smokers (age, 45.94+/-4.19 years) and G6 which included 20 smokers (age, 45.70+/-2.25 years). Functional integrity of proximal tubules was studied by determining urinary level of low-molecular-weight protein alpha1-microglobulin (alpha1M), and structural integrity was investigated by measuring urinary activities of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase (NAG) and the cytoplasmic enzyme glutathione S-transferase (GST). Urinary concentrations of Pb, Cu, Zn, and creatinine were also determined. RESULTS: Data of the present investigation showed increased urinary excretion of all measured urinary parameters among lead-exposed workers in comparison with non-exposed workers whether they were non-smokers or smokers (G3 vs. G1, G5 vs. G1, G4 vs. G2, and G6 vs. G2), with greater elevation among lead-exposed smokers than among lead-exposed non-smokers (G4 vs. G3, G6 vs. G5). In addition, there was a greater increase in levels of all urinary parameters among workers with work duration > or =20 years than in those with <20 years' work duration (G6 vs. G4, G5 vs. G3). CONCLUSIONS: Lead exposure in Egyptian workers causes damage to renal proximal tubules and results in its dysfunction. Cigarette smoking has a nephrotoxic effect and also is synergistic to lead nephrotoxicity on urinary excretion of GST and NAG, as well as Pb.

Effect of silica exposure on urinary excretion of copper and zinc.

BACKGROUND: Occupational exposure to silica could lead to renal histological alterations in the glomeruli and proximal tubules. We investigated urinary excretion of copper and zinc and its possible relationship to renal alterations and work duration among nonsmoking, silica-exposed workers. METHODS: Thirty-six control subjects (age, 39.08 +/- 6.65 years) and 48 silica-exposed workers (age, 36.79 +/- 7.33 years) were included in the present study. The exposed workers were grouped into workers with <10 years' work duration (n = 9; age, 29.0 +/- 1.50 years) and workers with > or =10 years' work duration (n = 39; age, 38.59 +/- 6.94 years). Glomerular function was assessed by measuring urinary level of microalbumin, and proximal tubular reabsorption function was assessed by measuring urinary level of alpha1-microglobulin. Structural integrity of proximal tubules was studied by measuring urinary activity of cytosolic enzyme glutathione S-transferase (GST). Also, urinary levels of copper, zinc, and creatinine were measured. RESULTS: All measured urinary parameters were significantly increased among silica-exposed workers compared with control subjects. A significant correlation was observed between urinary levels of each of copper and zinc with the glomerular and proximal tubular functional and structural urinary parameters as well as work duration. CONCLUSIONS: Occupational silica exposure may lead to increased urinary loss of copper and zinc as protein-metal complex, and the urinary level of these essential trace elements may be a marker for renal dysfunction. The urinary excretion of GST may be a useful marker for proximal tubular injury.

Evaluation of renal glomerular and tubular functional and structural integrity in neonates.

BACKGROUND: Renal cells are not fully differentiated at birth, representing a major risk in preterm infants. We evaluated glomerular and tubular functional integrity as well as structural integrity of renal tubules among healthy full-term and preterm infants as well as diseased preterm infants. METHODS: A total of 50 newborns (10 healthy full-term, 10 healthy preterm, and 30 diseased preterm, at 38.9 +/- 1.10, 34.2 +/- 0.92, and 32 +/- 2.47 weeks gestational age, respectively) were included in the present study. Glomerular function was assessed by measuring urinary levels of both microalbumin and immunoglobulin G as well as serum creatinine levels, whereas the proximal tubular function was investigated by measuring the urinary levels of both alpha1-microglobulin and beta2-microglobulin as well as retinol-binding protein. Also, distal tubular reabsorption capacity was investigated by assessing fractional excretion of sodium. Moreover, the structural integrity of renal proximal tubules was studied by measuring the urinary activities of both the brush-border membrane enzyme leucine-aminopeptidase (LAP) and the lysosomal enzyme N-acetyl-beta-D-glucosaminidase. The preceding investigations were done on both the first and third days of life of all 50 newborns. RESULTS: Glomerular and tubular function and structure was relatively impaired at birth among both healthy and diseased preterm as well as healthy full-term neonates and improved rapidly thereafter. The diseased preterm neonates showed worse renal function and structure with minimal improvement regardless of the underlying sickness. CONCLUSION: Renal insufficiency and renal immaturity could be evaluated using enzymuria and low- and high-molecular-weight proteinuria as noninvasive methods.

Glomerular and tubular dysfunction in children with congenital cyanotic heart disease: effect of palliative surgery.

BACKGROUND: Nephropathy has long been recognized as a potential complication of congenital cyanotic heart disease (CCHD). The present study was undertaken to investigate some aspects of glomerular function by measuring urinary total protein, microalbumin, and tubular function by assessing urinary alpha-1-microglobulin. The structural integrity of the renal proximal tubules was also studied by measuring urinary activities of the brush-border enzyme leucine-aminopeptidase and the lysosomal enzyme -acetyl-beta-d-glucosaminidase. The levels of hematocrit (Hct) and oxygen saturation were also investigated as predisposing factors for renal impairment in CCHD. METHODS: These investigations were done by recruiting 86 children who were grouped as follows: the control group (G1 ) consisted of 14 children (aged 4-12 years); the other 72 children with CCHD were divided according to age (ie, duration of cyanosis) into 4 equal groups, each containing 18 patients: G2 (age <1 year), G3 (age > or = 1 year and <5 years), G4 (age > or = 5 years and <10 years), and G5 (age > or = 10 years). In addition, 10 of the 72 patients underwent a palliative surgery and were included as G6 (regardless of age: 2 from G3, 4 from G4, and 4 from G5 ) to study the effect of the palliative surgery on the above-mentioned parameters. RESULTS: Results of the present work showed that with increasing duration of cyanosis (ie, on going from G2 to G5 ) among the studied children with CCHD, there was a significant elevation in the urinary excretion of the investigated functional and structural parameters of the glomeruli and proximal tubules compared with the control children. The data also showed a significant increase in Hct, whereas oxygen saturation was significantly decreased. Results of G6 after the palliative surgery demonstrated a significant decrease in the urinary excretion of the investigated parameters of the kidney, with a significant decrease in Hct and increase in oxygen saturation levels, compared with the results of the patients of this group before the palliative surgery. CONCLUSIONS: These results suggest impairment of both glomerular and tubular functions as well as structure of the proximal tubules among children with CCHD and that the palliative surgery has significantly improved this impairment.

Effect of mercury vapour exposure on urinary excretion of calcium, zinc and copper: relationship to alterations in functional and structural integrity of the kidney.

BACKGROUND: The kidney has a remarkable capacity to concentrate mercury (Hg) and as such is a primary target organ when exposure to Hg occurs, and it is also an organ for Hg excretion. OBJECTIVE: The present work aims to investigate the effect of occupational Hg vapour exposure on the urinary excretion of calcium (Ca), zinc (Zn) and copper (Cu), and the possible association of this excretion to work duration as well as renal alterations. METHODS: 83 non-smoker participants (36 referents, age: 35.6 +/- 9.5 years; 27 Hg vapour-exposed workers with < or = 10 years work duration, age: 33.0 +/- 5.1 years; and 20 Hg vapour-exposed workers with > or = 11 years work duration, age: 39.50 +/- 8.50 years) were included in the present study. Urinary levels of microalbumin (U-Malb) and retinol-binding protein (U-RBP) as well as cytosolic glutathione S-transferase activity (U-GST) were measured to assess the glomerular and proximal tubular reabsorption functions as well as structural integrity of proximal tubules; respectively. In addition, blood Hg (B-Hg), serum levels of Hg (S-Hg) and Ca (S-Ca), and urinary levels of Hg (U-Hg), Ca (U-Ca), Zn (U-Zn), Cu (U-Cu) and creatinine (U-cr) were estimated. RESULTS: In comparison to referents, all investigated parameters showed significant increase (except S-Ca and U-Zn/U-Cu ratio that significantly decreased among the workers as one group, S-Ca and U-Zn/U-Cu ratio that significantly and nonsignificantly decreased; respectively among workers with < or = 10 years work duration, S-Ca and U-Zn/U-Cu ratio that significantly decreased among workers with > or = 11 years work duration). In addition, B-Hg was nonsignificantly increased and S-Ca was significantly decreased; also, both U-Hg and U-Zn/U-Cu were nonsignificantly decreased among workers with > or = 11 years work duration in comparison to those with < or = 10 years work duration. Also, each of U-Hg, U-Ca, U-Zn and U-Cu was related to one another, while each of U-Ca, U-Zn and U-Cu was related to each of U-Malb, U-RBP and U-GST (except U-Zn was not related to U-GST). CONCLUSION: Hg vapour exposure leads to renal alterations which may parallel the change in proteinuria and enzymuria as well as the increased loss in urine of each of Ca, Zn and Cu. The urinary assessment of these metals may be used as a good indicator for renal dysfunction.