Saw, J J

Background Human kidney stones form via repeated events of mineral precipitation, partial dissolution, and reprecipitation, which are directly analogous to similar processes in other natural and manmade environments, where resident microbiomes strongly influence biomineralization. High-resolution microscopy and high-fidelity metagenomic (microscopy-to-omics) analyses, applicable to all forms of biomineralization, have been applied to assemble definitive evidence of in vivo microbiome entombment during urolithiasis. Methods Stone fragments were collected from a randomly chosen cohort of 20 patients using standard percutaneous nephrolithotomy (PCNL). Fourier transform infrared (FTIR) spectroscopy indicated that 18 of these patients were calcium oxalate (CaOx) stone formers, whereas one patient formed each formed brushite and struvite stones. This apportionment is consistent with global stone mineralogy distributions. Stone fragments from seven of these 20 patients (five CaOx, one brushite, and one struvite) were thin sectioned and analyzed using brightfield (BF), polarization (POL), confocal, super-resolution autofluorescence (SRAF), and Raman techniques. DNA from remaining fragments, grouped according to each of the 20 patients, were analyzed with amplicon sequencing of 16S rRNA gene sequences (V1–V3, V3–V5) and internal transcribed spacer (ITS1, ITS2) regions. Results Bulk-entombed DNA was sequenced from stone fragments in 11 of the 18 patients who formed CaOx stones, and the patients who formed brushite and struvite stones. These analyses confirmed the presence of an entombed low-diversity community of bacteria and fungi, including Actinobacteria, Bacteroidetes, Firmicutes , Proteobacteria , and Aspergillus niger . Bacterial cells approximately 1 μm in diameter were also optically observed to be entombed and well preserved in amorphous hydroxyapatite spherules and fans of needle-like crystals of brushite and struvite. Conclusions These results indicate a microbiome is entombed during in vivo CaOx stone formation. Similar processes are implied for brushite and struvite stones. This evidence lays the groundwork for future in vitro and in vivo experimentation to determine how the microbiome may actively and/or passively influence kidney stone biomineralization.

Abstract Background Therapeutic options for management of diabetic gastroparesis are limited. Failure to maintain upregulation of heme oxygenase ( HO 1) leads to loss of interstitial cells of Cajal and delayed gastric emptying ( GE ) in non‐obese diabetic mice. Our hypothesis was that hemin upregulation of HO 1 would restore normal GE in humans with gastroparesis. Aims To compare effects of hemin and placebo infusions on HO 1 activity and protein, GE , autonomic function, and gastrointestinal symptoms in diabetic gastroparesis. Methods In a single‐center, double‐blind, placebo‐controlled, randomized clinical trial, we compared intravenous hemin, prepared in albumin, or albumin alone (placebo) in 20 patients, aged 41 ± 5 ( SEM ) years with diabetic gastroparesis. After infusions on days 1, 3, and 7, weekly infusions were administered for 7 additional weeks. Assessments included blood tests for HO 1 protein and enzyme activity levels, GE with 13 C‐spirulina breath test, autonomic functions (baseline and end), and gastrointestinal symptoms every 2 weeks. Key Results Nine of 11 patients randomized to hemin completed all study procedures. Compared to placebo, hemin increased HO 1 protein on days 3 ( p = 0.0002) and 7 ( p = 0.008) and HO 1 activity on day 3 ( p = 0.0003) but not after. Gastric emptying, autonomic functions, and symptoms did not differ significantly in the hemin group relative to placebo. Conclusions & Inferences Hemin failed to sustain increased HO 1 levels beyond a week and did not improve GE or symptoms in diabetic gastroparesis. Further studies are necessary to ascertain whether more frequent hemin infusions or other drugs would have a more sustained effect on HO 1 and improve GE .

AbstractBackgroundHeme oxygenase 1 (HO‐1) degrades heme and protects against oxidative stress. In vitro and animal models suggest that HO‐1 is beneficial in several diseases (e.g., postoperative ileus, gastroparesis, acute pancreatitis, and colitis). However, the only drugs (i.e., hemin and heme arginate) which pharmacologically upregulate HO‐1 in humans are expensive and can only be administered intravenously. Our aims were to compare the effects of placebo, aspirin, and simvastatin alone, and with α‐lipoic acid, on HO‐1 protein concentration and activity in humans.MethodsThis randomized, double‐blind, placebo‐controlled study compared the effects of three oral regimens administered for 7 days, i.e., placebo; aspirin (325 mg twice daily) and simvastatin (40 mg twice daily); aspirin, simvastatin, and the sodium salt of R‐ α‐lipoic acid (NaRLA, 600 mg three times daily) on markers of HO‐1 activation (i.e., plasma HO‐1 protein concentration and venous monocyte HO‐1 protein activity) in 18 healthy subjects (14 females). Markers of HO‐1 activation were evaluated at baseline, days 2, and 7.Key ResultsBaseline HO‐1 protein concentrations and activity were similar among the three groups. Compared to placebo, aspirin and simvastatin combined, or together with NaRLA did not affect HO‐1 protein concentration or activity at 2 or 7 days. HO‐1 protein concentrations and activity were correlated on day 7 (r = 0.75, p = 0.0004) but not at baseline and on day 2.Conclusions & InferencesAt therapeutic doses, aspirin, simvastatin, and α‐lipoic acid do not increase plasma HO‐1 protein concentration or venous monocyte HO‐1 activity in healthy humans.