Detection of Cadmium and Lead in Kidney Stones. Associations with Patient Demographics, Stone Composition, and Smoking.

BACKGROUND: Kidney stones are a highly prevalent disease worldwide. Additionally, both environmental and occupational exposure to Pb and Cd continue to be prevalent globally and can result in renal toxicity. The objective of this study was to examine the potential presence of Pb and Cd in kidney stones, and to assess for correlation with demographic factors including smoking, gender, age, and kidney stone matrix composition. METHODS: Patient kidney stones (n = 96) were analyzed using Fourier transform infrared spectroscopy to identify the stone constituents. Cd and Pb concentrations (µg/g) were determined by inductively coupled plasma mass spectrometry. Cd and Pb concentrations were correlated using bivariable and multivariable statistical analysis with demographic factors (age, gender, smoking status), and kidney stone composition. RESULTS: Kidney stone Cd (median 0.092 µg/g, range 0.014 to 2.46) and Pb concentrations (median 0.95 µg/g, range 0.060 to 15.4) were moderately correlated (r = 0.56, P < 0.0001). Cd concentrations were positively associated with patient history of smoking, patient age, and calcium oxalate monohydrate levels while negatively associated with struvite and uric acid/uric acid dihydrate. Pb concentrations were positively associated with females and apatite levels while negatively associated with uric acid/uric acid dihydrate. After holding constant other stone type composition levels, smoking status, and age, both Pb and Cd were positively associated with apatite and negatively associated with uric acid/uric acid dihydrate, struvite, and calcium carbonate. CONCLUSIONS: Cd and Pb kidney stone concentrations are associated with specific kidney stone types. Cd and Pb kidney stone concentrations are both associated with smoking.

Assessment of gadolinium and iodine concentrations in kidney stones and correlation with contrast agent exposure, stone matrix composition, and patient demographic factors.

BACKGROUND: Gadolinium-based contrast agents (GBCAs) and Iodinated contrast media are widely utilized to increase medical imaging sensitivity. With predominant renal elimination, the potential for the incorporation of contrast agent derived gadolinium and iodine into kidney stones remains largely uncharacterized. The study objective was to measure gadolinium and iodine concentrations within kidney stones. Observed elemental concentrations were correlated with prior contrast agent administration, kidney stone composition, age, gender, and smoking status. METHODS: Kidney stones from 96 patients were analyzed by Fourier Transform Infrared Spectroscopy to determine stone composition. Residual kidney stone material was digested and analyzed by Inductively Coupled Plasma Mass Spectrometry to determine gadolinium and iodine concentrations. Univariable and multivariable lognormal linear regression were performed to study the relationship between kidney stone element concentrations and contrast agent administration, kidney stone composition, age, gender, and smoking status. RESULTS: Median iodine and gadolinium stone concentrations were 6.4 (range 0.6-3997) and 0.1 (range ≤0.013-113.5) µg/g respectively. Elevated gadolinium was strongly associated with GBCA history with a hazard rate of 2.20 (95 % CI 1.14-3.25 P < 0.001). Gadolinium was positively associated with smoking, as well as stones comprised of apatite and calcium oxalate. Iodine concentrations were negatively associated with uric acid stones. CONCLUSION: Gadolinium, but not iodine, concentrations in kidney stones was strongly correlated with contrast exposure history. Stone matrix composition and demographic factors, particularly smoking, can influence observed kidney stone elemental concentrations. Additional studies are needed to determine if exposure to gadolinium and iodine promote the formation of stone matrix and/or reflect exposure history.

Myocardial Cobalt Levels Are Elevated in the Setting of Total Hip Arthroplasty.

BACKGROUND: Arthroplasty implants commonly contain elemental metal that may undergo wear-related release. Recently, cases of hip implant-associated myocardial injury have been reported. However, we are not aware of any previous study that has systematically measured myocardial metal levels or examined the relationship with total hip arthroplasty (THA). METHODS: Archives of our institution were queried for autopsies of individuals who had undergone THA between 1990 and 2013. Myocardial tissue samples were analyzed for cobalt (Co) and chromium (Cr) levels with inductively coupled plasma mass spectroscopy. Seventy-five Co/Cr-on-polyethylene THA cases were included (mean age at time of death = 77.4 years; 49% women) as were 73 non-arthroplasty controls matched for age, sex, and history of hypertension and diabetes mellitus. RESULTS: Significantly higher median myocardial concentrations of Co were observed in individuals with THA compared with controls (0.12 versus 0.06 µg/g, p < 0.0001). The median Co concentration was 69% higher in patients who had undergone THA revision (0.169 µg/g) than in those who underwent primary THA (0.100 µg/g; p = 0.004). In general, higher Co levels were observed in those with multiple replaced joints, although this finding only trended toward significance. Cardiomegaly, interstitial fibrosis, and decreased ejection fraction were observed more frequently in the postmortem samples of patients with implants than in those of controls (p = 0.0002, 0.044, and 0.0039, respectively). CONCLUSIONS: We believe this to be the first study to quantify metal levels in cardiac tissue in patients with and without joint replacement. The elevated Co levels, in concert with cardiomegaly and increased interstitial fibrosis found during autopsy, in the arthroplasty cohort are novel, important findings. Although Co levels were significantly elevated above those in controls, the majority were below those seen in clinical case reports of death from Co cardiotoxicity associated with metal-on-metal prostheses. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.