Nephrolithiasis

Occupational hazard in urolithiasis patients in Qatar: A single-center cross-sectional study

BACKGROUND

Urolithiasis is one of the most prevalent urological diseases and is associated with a substantial economic burden. Its prevalence varies according to geographical location. Qatar is a Middle Eastern country located in the Afro-Asian Stone Belt. It has a dry and hot climate, which may predispose individuals working in these environments to form kidney stones (KSs).

METHODS

A population sample of 4204 patients was categorized into five occupational classes. The frequencies and correlations of these occupations with KS formation were calculated.

RESULTS

Among the total cases, 2000 presented with KSs, with the majority being of Asian descent (49%), followed by individuals of Middle Eastern descent (35.1%). Technicians accounted for 35.15% of KS cases followed by clerks (29.2%) and executives (14.6%). Among KS cases, 44% had a single stone, 30% had multiple stones, and 26% had two stones. In comparing both KS and non-KS groups, age, gender, occupation, and race were significantly associated with KS formation (p<0.05), while BMI did not show any significant correlation (p>0.05). Asian males aged 31-40, working as technicians, were significantly more prone to urolithiasis. In comparing age, BMI, and gender with stone characteristics, only age was found significantly associated with stone size (p<0.05). Occupation showed an impact on all studied stone characteristics. Clerks and technicians presented more frequently with stones within the 11-15 mm range, while executives more frequently presented with smaller stones (p<0.001). Stone density was more frequently <500 HU in workers, technicians and housewives and >500 HU in executives and clerks (p<0.001).

CONCLUSIONS

Our findings revealed an elevated risk of urolithiasis among certain occupational groups, particularly technicians, who frequently work outdoors in high-temperature environments. Alternatively, the sedentary nature of clerical and executive positions can also contribute to the risk of urolithiasis.

Non-spinal low back pain: Global epidemiology, trends, and risk factors

Background and Aims

Low back pain (LBP) is one of the most debilitating and prevalent disorders. The prevalence of LBP ranges from 30% to 80%, depending on the population, and increases with age. Causes of LBP are typically classified as spinal and non-spinal. The main goal of this study was to investigate the non-spinal causes of LBP, since neglecting these factors leads to increases in the financial, psychological, and physical burden of LBP on individuals as well as on society.

Methods

The data were extracted after searching the PubMed database and Google Scholar search engine up to October 27, 2021. We included all studies that were conducted on a human population and assessed the effects of epidemiological, biological, psychological, and sociodemographic factors on the incidence or progression of LBP.

Results

The most common causes of non-spinal LBP were diseases such as nephrolithiasis, endometriosis, tumors, fibromyalgia, and conditions like psychological disorders and pregnancy. Nevertheless, the perceived intensity of the pain can be affected by factors such as socioeconomic level, genetics, age, habits, diet, and psychological status.

Conclusion

The epidemiology, etiologies, and risk factors associated with LBP should be more clearly recognized to better prevent, diagnose, and treat the underlying disease and to reduce the burden of LBP.

Decoding Hypercalcemia and Renal Stones in a Young Adult: Could it be Dent's Disease?

Dent's disease is a rare genetic kidney disorder characterized by proximal tubular dysfunction, nephrocalcinosis, recurrent nephrolithiasis, and chronic kidney disease. Hypercalcemia is a rare finding in this disease. In this report, we present a case of possible Dent's disease in a young adult male with hypercalcemia and chronic kidney disease. The diagnosis was evoked based on the presence of low-molecular-weight proteinuria, kidney stones, and renal failure. This case underscores the significance of considering Dent's disease as a potential diagnosis, even in patients with chronic renal disease who exhibit hypercalcemia. It also emphasizes the importance of regular monitoring and management of patients with this condition to prevent further complications.

The effectiveness of citrates and pyridoxine in the treatment of kidney stones

The prevalence of nephrolithiasis is increasing across all demographic groups. Apart from the morbidity associated with an acute occurrence, preventative treatment is essential for stone disease, which can become a long-term problem. Simple interventions like fluid intake optimization and dietary modification are effective for most stone types. However, patients with specific metabolic abnormalities may require pharmaceutical therapy if lifestyle changes are insufficient to reduce the risk of stone recurrence. The treatment of citrates and/or pyridoxines may help eliminate or prevent recurrences of kidney stones, especially when they are composed of uric acid, calcium oxalate, calcium phosphate, or the latter two together. In cases of struvite stones, which often necessitate a surgical approach, acetohydroxamic acid emerges as a valuable second-line treatment option. Thiol-binding agents may be needed for cystinuria, as well as lifestyle modifications. Successful treatment reduces stone recurrence and the need to remove stones surgically.

Why is childhood urolithiasis increasing? Etiology, diagnosis and management: a single-center experience

BACKGROUND

Globally, urolithiasis is becoming more and more common among children. We aimed to determine the etiology, and the diagnostic and therapeutic approaches in patients with urolithiasis.

METHODS

This was a retrospective study which included all patients (aged 1 month-18 years) admitted to the pediatric nephrology clinic in Elazığ Fethi Sekin City Hospital with urolithiasis between November 2019 and 2021. Only patients whose diagnosis of urolithiasis was confirmed by urinary ultrasonography were included in the study, while patients with chronic diseases (neurological diseases such as epilepsy, cerebral palsy, chronic bowel diseases, etc.) predisposing to kidney stone formation were not. Demographic characteristics, serum and urine biochemical parameters, urine metabolic and kidney stone metabolic and chemical analyses, urinary tract ultrasonography findings and treatment modalities were collected.

RESULTS

One hundred ninety-seven patients (91 female and 106 male) were included in the study. Hypervitaminosis D was detected in 4 (2%) patients, suppressed parathyroid hormone in 12 (6%) and hypercalcemia in 27 (14%) patients. Metabolic screening showed hypercalciuria in 69 (35%) patients, hypocitraturia in 39 (20%), hyperoxaluria in 15 (8%) and cystinuria in 6 (3%) patients. Eighty three (42%) patients had a positive family history for kidney stones. One hundred eighteen (60%) patients received potassium citrate treatment, 71 (36%) were given hydration and diet recommendations without medical treatment, 6 (3%) received tiopronin treatment, and 2 (1%) patients were treated surgically.

CONCLUSIONS

Our study suggests that Vitamin D supplementation at doses higher than 400 IU/day may be a risk factor for kidney stones in children. We observed that mothers tend not to give water to infants who are breastfed or formula-fed in the first year of life. K-citrate treatment can be a good option for prevention and dissolution of stones by alkalinization.

Meta-data analysis of kidney stone disease highlights ATP1A1 involvement in renal crystal formation

Nephrolithiasis is a complicated disease affected by various environmental and genetic factors. Crystal-cell adhesion is a critical initiation process during kidney stone formation. However, genes regulated by environmental and genetic factors in this process remain unclear. In the present study, we integrated the gene expression profile data and the whole-exome sequencing data of patients with calcium stones, and found that ATP1A1 might be a key susceptibility gene involved in calcium stone formation. The study showed that the T-allele of rs11540947 in the 5'-untranslated region of ATP1A1 was associated with a higher risk of nephrolithiasis and lower activity of a promoter of ATP1A1. Calcium oxalate crystal deposition decreased ATP1A1 expression in vitro and in vivo and was accompanied by the activation of the ATP1A1/Src/ROS/p38/JNK/NF-κB signaling pathway. However, the overexpression of ATP1A1 or treatment with pNaKtide, a specific inhibitor of the ATP1A1/Src complex, inhibited the ATP1A1/Src signal system and alleviated oxidative stress, inflammatory responses, apoptosis, crystal-cell adhesion, and stone formation. Moreover, the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine reversed ATP1A1 down-regulation induced by crystal deposition. In conclusion, this is the first study to show that ATP1A1, a gene modulated by environmental factors and genetic variations, plays an important role in renal crystal formation, suggesting that ATP1A1 may be a potential therapeutic target for treating calcium stones.

Case report: disease mechanisms and medical management of calcium nephrolithiasis in rheumatologic diseases

Background

Nephrolithiasis as a feature of rheumatologic diseases is under recognized. Understanding presenting features, diagnostic testing is crucial to proper management.

Case presentation

A 32 year old woman with a history of recurrent complicated nephrolithiasis presented to a rheumatologist for a several month history of fatigue, dry eyes, dry mouth, arthralgias. She had a positive double-stranded DNA, positive SSA and SSB antibodies. She was diagnosed with Systemic Lupus erythematosus (SLE) and Sjogren's syndrome and was started on mycophenalate mofetil. Of relevance was a visit to her local emergency room 4 years earlier with profound weakness with unexplained marked hypokalemia and a non-anion gap metabolic acidosis. Approximately one year after that episode she developed flank pain and nephrocalcinosis. She had multiple issues over the ensuing years with stones and infections on both sides. Interventions included extracorporeal shockwave lithotripsy as well as open lithotomy and eventual auto-transplantation of left kidney for recurrent ureteric stenosis. 24 h stone profile revealed marked hypocitraturia, normal urine calcium, normal urine oxalate and uric acid. She was treated with potassium citrate. Mycophenolate was eventually stopped due to recurrent urinary tract infections and she was started on Belimumab. Because of recurrent SLE flares, treatment was changed to Rituximab (every 6 months) with clinical and serologic improvement. Her kidney stone frequency gradually improved and no further interventions needed although she continued to require citrate repletion for hypocitraturia.

Conclusions

Nephrolithiasis can be a prominent and even presenting feature in Sjogrens syndrome as well as other rheumatologic diseases. Prompt recognition and understanding disease mechanisms is important for best therapeutic interventions for kidney stone prevention as well as treatment of underlying bone mineral disease.

Oxalate secretion is stimulated by a cAMP-dependent pathway in the mouse cecum

Elevated levels of the intracellular second messenger cAMP can stimulate intestinal oxalate secretion however the membrane transporters responsible are unclear. Oxalate transport by the chloride/bicarbonate (Cl-/HCO3-) exchanger Slc26a6 or PAT-1 (Putative Anion Transporter 1), is regulated via cAMP when expressed in Xenopus oocytes and cultured cells but whether this translates to the native epithelia is unknown. This study investigated the regulation of oxalate transport by the mouse intestine focusing on transport at the apical membrane hypothesizing PAT-1 is the target of a cAMP-dependent signaling pathway. Adopting the Ussing chamber technique we measured unidirectional 14C-oxalate and 36Cl- flux ([Formula: see text] and [Formula: see text]) across distal ileum, cecum and distal colon, employing forskolin (FSK) and 3-isobutyl-1-methylxanthine (IBMX) to trigger cAMP production. FSK/IBMX initiated a robust secretory response by all segments but the stimulation of net oxalate secretion was confined to the cecum only involving activation of [Formula: see text] and distinct from net Cl- secretion produced by inhibiting [Formula: see text]. Using the PAT-1 knockout (KO) mouse we determined cAMP-stimulated [Formula: see text] was not directly dependent on PAT-1, but it was sensitive to mucosal DIDS (4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid), although unlikely to be another Cl-/HCO3- exchanger given the lack of trans-stimulation or cis-inhibition by luminal Cl- or HCO3-. The cAMP-activated oxalate efflux was reliant on CFTR (Cystic Fibrosis Transmembrane conductance Regulator) activity, but only in the presence of PAT-1, leading to speculation on the involvement of a multi-transporter regulatory complex. Further investigations at the cellular and molecular level are necessary to define the mechanism and transporter(s) responsible.

Tubeless mini-percutaneous nephrolithotomy to remove a staghorn stone concurrent with proximal ureteral calculus in an elderly patient: A case report

A complex staghorn calculus that is concurrent with an impacted large proximal ureteric calculi is rarely found in elderly patients, and morbidity and mortality rates are much higher if left untreated. We report the case of an 88-year-old female with complex high-volume renal and ureteral calculus who was treated successfully using a tubeless mini-percutaneous nephrolithotomy. The entire stone was retrieved, and the patient fully recovered without any complications.

Vantera Mediated Quantification of Urine Citrate and Creatinine: A New Technology to Assess Risk of Nephrolithiasis

Urine citrate is often used to identify patients at risk of recurrent nephrolithiasis or kidney stones. A high-throughput assay was developed to measure urine citrate and creatinine on the Vantera® Clinical Analyzer, a nuclear magnetic resonance (NMR) instrument designed for the clinical laboratory. Assay performance was evaluated and comparisons between the NMR and chemistry results were conducted. Linearity was demonstrated over a wide range of concentrations for citrate (6 and 2040 mg/L) and creatinine (2.8 and 1308 mg/dL). Intra-and inter-assay precision (%CV) ranged from 0.9 to 3.7% for citrate and 0.4 to 2.1% for creatinine. The correlation coefficients for the comparison between NMR and chemistry results were 0.98 (Y = 1.00X + 5.0) for citrate and 0.96 (Y = 0.968X + 0.97) for creatinine. The reference intervals for both analytes were confirmed. Ten endogenous and exogenous substances were tested and none were found to interfere with the assay results. In conclusion, the newly developed high-throughput NMR assay exhibited robust performance and generated results comparable to the currently utilized chemistry tests, thereby providing an alternative means to simultaneously quantify urine citrate and creatinine for clinical and research use. Furthermore, the NMR assay does not exhibit the same interference limitations as the chemistry tests and it enables multiplexing with other urine metabolite assays which saves time and costs.

Vinegar: A functional ingredient for human health

Vinegar is a well-known natural food product derived from alcoholic and subsequently acetous fermentation of carbohydrate-rich foods. Vinegar is widely used in the food industry; domestically for pickling vegetables and fruits, and as an ingredient in condiments like salad dressings, ketchups, and mayonnaise; and traditionally as a food seasoning and preservative. Historically, vinegar has been used for medicinal purposes such as a cure for stomach aches, wounds, burns, rashes, and oedema conditions. Different types of vinegar are found worldwide such as rice, black, balsamic, grain, and fruit vinegars. These are produced from different raw materials, and using different fermentation methods to give unique tastes and flavours. Vinegar, while enhancing physiological functions such as lipid metabolism, blood glucose level control, and body weight management, also possesses anticancer, antibacterial, antioxidant, and anti-infection properties. It is considered as a good source material for many bioactive compounds including organic acids, melanoidins, polyphenols, ligustrazine, and tryptophol. The pharmacological and metabolic benefits of vinegar are believed to be due to these bioactive compounds present in vinegar. Acetic acid (CH3COOH) is the essential component of vinegar; it is slightly volatile and has a strong and sour aroma and flavour. Regular consumption of vinegar-containing foods is considered important for keeping many life-style related diseases like diabetes, hypertension, hyperlipidaemia, cancers, and obesity in check. Therefore, the present review aims at highlighting the health benefits associated with vinegar consumption for the physiological well-being of an individual.

CAV1 alleviated CaOx stones formation via suppressing autophagy-dependent ferroptosis

Background

Calcium oxalate (CaOx) is the most common type of kidney stone, but the mechanism of CaOx stones formation remains unclear. The injury of renal cells such as ferroptosis and autophagy has been considered a basis for stones formation.

Methods

We conducted transmission electron microscope (TEM), reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), and C11-BODIPY analysis to explore whether CaOx could induce autophagy-dependent ferroptosis in vivo and in vitro. To explore the possible mechanism, we conducted bioinformatic analysis of patients with or without CaOx stones, Western blot and qPCR were used to identify the different genes we found in bioinformatic analysis.

Results

In our study, we found that CaOx could induce autophagy-dependent ferroptosis no matter in vivo or in vitro, which might finally lead to urolithiasis. Bioinformatic analysis of the GSE73680 dataset indicated that the expression of caveolin-1 (CAV1) was higher in control patients than CaOx stone patients, the STRING database indicated that CAV1 might interact with low density lipoprotein receptro-related protein 6 (LRP6), Gene Set Enrichment Analysis (GSEA) showed that the WNT pathway positively associated with the control group while negatively related to the stone group, and LRP6 was the core gene of the WNT pathway. Western blot found that CAV1, LRP6, and Wnt/β-Catenin were decreased in Human Kidney2 (HK2) cells stimulated with CaOx. Furthermore, the WNT pathway was considered to be involved in autophagy and ferroptosis.

Conclusions

We presumed that CAV1 could ameliorate autophagy-dependent ferroptosis through the LRP6/Wnt/β-Catenin axis, and finally alleviate CaOx stone formation.

Analysis and Characterization of Lactobacillus paragasseri and Lacticaseibacillus paracasei: Two Probiotic Bacteria that Can Degrade Intestinal Oxalate in Hyperoxaluric Rats

In the present study, we characterized the probiotic properties of two commercially available bacterial strains, Lactobacillus paragasseri UBLG-36 and Lacticaseibacillus paracasei UBLPC-87, and evaluated their ability to degrade oxalate in vitro and in a hyperoxaluria-induced nephrolithiasis rat model. UBLG-36 harboring two oxalate catabolizing genes, oxalyl coenzyme A decarboxylase (oxc) and formyl coenzyme A transferase (frc), was previously shown to degrade oxalate in vitro effectively. Here, we show that UBLPC-87, lacking both oxc and frc, could still degrade oxalate in vitro. Both these strains harbored several potential putative probiotic genes that may have conferred them the ability to survive in low pH and 0.3% bile, resist antibiotic stress, show antagonistic activity against pathogenic bacteria, and adhere to epithelial cell surfaces. We further evaluated if UBLG-36 and UBLPC-87 could degrade oxalate in vivo and prevent hyperoxaluria-induced nephrolithiasis in rats. We observed that rats treated with 4.5% sodium oxalate (NaOx) developed hyperoxaluria and renal stones. However, when pre-treated with UBLG-36 or UBLPC-87 before administering 4.5% NaOx, the rats were protected against several pathophysiological manifestations of hyperoxaluria. Compared to the hyperoxaluric rats, the probiotic pre-treated rats showed reduced urinary excretion of oxalate and urea (p < 0.05), decreased serum blood urea nitrogen and creatinine (p < 0.05), alleviated stone formation and renal histological damage, and an overall decrease in renal tissue oxalate and calcium content (p < 0.05). Taken together, both UBLG-36 and UBLPC-87 are effective oxalate catabolizing probiotics capable of preventing hyperoxaluria and alleviating renal damage associated with nephrolithiasis.

Comprehensive Analysis of the Herbal Mixture Made of Juniperus oxycedrus L. Berries, Inner Bark of Betula pendula Roth., and Grains of Avena sativa L

This is the first report of the high-performance liquid chromatography and gas chromatography–mass spectrometry profile of a herbal mixture (HM) made of Juniperus oxycedrus L. (redberry juniper) berries, inner bark of Betula pendula Roth. (silver birch), and grains of Avena sativa L. (oat), and its effect on the No. of micronuclei (MN) in human lymphocytes and toxicity toward Artemia salina. Constituents represented by over 1000 µg per g of methanol dry extract were gallic acid, protocatechuic acid, and amentoflavone. The methanol extract of the HM at a concentration of 2.0 μg/mL decreased MN frequency by 38.3%, which was more than 3 times greater than that of the radioprotectant amifostine. The essential oil isolated from the HM was composed mainly of β-myrcene (32%) and showed weaker toxicity toward Artemia salina than the positive control after both incubation periods (24 h and 48 h). These findings suggest that the examined HM, beside its ethnopharmacological relevance on the elimination of renal calculi, also significantly reduces the No. of MN in human lymphocytes.

Fresh lemon juice supplementation for the prevention of recurrent stones in calcium oxalate nephrolithiasis: A pragmatic, prospective, randomised, open, blinded endpoint (PROBE) trial

BACKGROUND

Standard diet with normal calcium and reduced animal proteins and salt content reduces stone recurrence in calcium oxalate nephrolithiasis. Whether lemon juice supplementation further reduces recurrence rate is unknown.

METHODS

In this single-centre, prospective, randomised, open, blinded endpoint trial (Clinical Trials gov NCT01217372) we evaluated the effects of fresh lemon juice supplementation (60 mL twice daily) versus no supplementation, on time to stone recurrence in 203 patients with recurrent idiopathic calcium oxalate nephrolithiasis who were all prescribed a standard diet. Patients were included between July 2009 and March 2017 at the Nephrology Unit of the Papa Giovanni XXIII hospital in Bergamo, Italy. Time to stone recurrence at 2 years of follow-up was the primary outcome. Analyses were by intention-to-treat.

FINDINGS

During two years of follow-up 21 of 100 patients randomised to lemon juice supplementation and 32 of 103 controls randomised to no supplementation had stone recurrence [HR (95% CI): 0·62 (0·35-1·07), p = 0·089]. Patient adherence to lemon juice supplementation, however, progressively decreased from 68% at one-year to 48% at two-year follow-up. At explorative analyses restricted at one-year follow-up, ten patients with supplementation versus 22 controls had stone recurrence [0·43 (0·20-0·89), p = 0·028]. After adjustment by age, sex and normo or hypocitraturia, the HR (95%) was still significant [0·45 (0·20-0·93), p = 0·036]. At six months, 24 hour urinary sodium excretion decreased by 8·60±65·68 mEq/24 h in patients receiving lemon juice supplementation and increased by 3·88±64·78 mEq/24 h in controls. Changes significantly differed between groups (p = 0·031). This difference was subsequently lost. Treatment was safe. In patients with lemon juice supplementation gastrointestinal disorders were more frequent (p<0·001). Renal and urinary tract disorders were similar between groups (p = 0·103).

INTERPRETATION

Explorative analyses suggest that fresh lemon juice supplementation to standard diet might prevent stone recurrence in patients with calcium-oxalate nephrolithiasis. However, treatment effect was likely reduced by progressively declining adherence to lemon juice supplementation.

FUNDING

This study received no funding.

Role of Nox4 in High Calcium-Induced Renal Oxidative Stress Damage and Crystal Deposition

Aims: We aimed at exploring the role of nicotinamide adenine dinucleotide phosphate oxidase subunit 4 (Nox4) in the regulation of hypercalciuria-induced renal oxidative damage and crystal depositions. Results: High calcium activated Nox4 expression through protein kinase C (PKC). Downregulation of Nox4 expression attenuated hypercalciuria-induced osteoblast-associated protein expression, oxidative stress injury, and crystal deposition in rat kidneys of 1,25-dihydroxyvitamin D3 (VitD) urolithiasis model. Further, calcium-induced activation of mitogen-activated protein kinase (MAPK), overexpression of osteoblast-associated protein, oxidative stress injury, apoptosis, and calcium salt deposition in normal rat kidney epithelial-like (NRK-52E) cells were reversed by downregulating Nox4 expression but were enhanced by upregulating Nox4 expression in vitro. Moreover, calcium-induced increases of osteoblast-associated protein expression were attenuated by the c-Jun-N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) inhibitors. Innovation: Our results demonstrated the effect of Nox4 in the pathological process of kidney stones in in vitro and in vivo studies for the first time. Calcium aggravates renal oxidative stress injury and crystal deposition by activating the Nox4-related reactive oxygen species (ROS)-ERK/JNK pathway in the rat kidney. This study is expected to provide a new theoretical basis for the prevention and treatment of kidney stones. Conclusion: Nox4-derived ROS induced by calcium through PKC caused oxidative stress damage and apoptosis in renal tubular epithelial cells; in addition, Nox4-derived ROS induced by calcium mediated abnormal activation of the bone morphogenetic protein 2 (BMP2) signaling pathway through the MAPK signaling pathway, which induced renal tubular epithelial cells to transdifferentiate into osteoblast-like cells, resulting in the formation of a kidney stone. Antioxid. Redox Signal. 36, 15-38.

Oxalate Flux Across the Intestine: Contributions from Membrane Transporters

Epithelial oxalate transport is fundamental to the role occupied by the gastrointestinal (GI) tract in oxalate homeostasis. The absorption of dietary oxalate, together with its secretion into the intestine, and degradation by the gut microbiota, can all influence the excretion of this nonfunctional terminal metabolite in the urine. Knowledge of the transport mechanisms is relevant to understanding the pathophysiology of hyperoxaluria, a risk factor in kidney stone formation, for which the intestine also offers a potential means of treatment. The following discussion presents an expansive review of intestinal oxalate transport. We begin with an overview of the fate of oxalate, focusing on the sources, rates, and locations of absorption and secretion along the GI tract. We then consider the mechanisms and pathways of transport across the epithelial barrier, discussing the transcellular, and paracellular components. There is an emphasis on the membrane-bound anion transporters, in particular, those belonging to the large multifunctional Slc26 gene family, many of which are expressed throughout the GI tract, and we summarize what is currently known about their participation in oxalate transport. In the final section, we examine the physiological stimuli proposed to be involved in regulating some of these pathways, encompassing intestinal adaptations in response to chronic kidney disease, metabolic acid-base disorders, obesity, and following gastric bypass surgery. There is also an update on research into the probiotic, Oxalobacter formigenes, and the basis of its unique interaction with the gut epithelium. © 2021 American Physiological Society. Compr Physiol 11:1-41, 2021.

Nucleation kinetics of calcium oxalate monohydrate as a function of pH, magnesium, and osteopontin concentration quantified with droplet microfluidics

A droplet-based microfluidic platform is presented to study the nucleation kinetics of calcium oxalate monohydrate (COM), the most common constituent of kidney stones, while carefully monitoring the pseudo-polymorphic transitions. The precipitation kinetics of COM is studied as a function of supersaturation and pH as well as in the presence of inhibitors of stone formation, magnesium ions (Mg2+), and osteopontin (OPN). We rationalize the trends observed in the measured nucleation rates leveraging a solution chemistry model validated using isothermal solubility measurements. In equimolar calcium and oxalate ion concentrations with different buffer solutions, dramatically slower kinetics is observed at pH 6.0 compared to pHs 3.6 and 8.6. The addition of both Mg2+ and OPN to the solution slows down kinetics appreciably. Interestingly, complete nucleation inhibition is observed at significantly lower OPN, namely, 3.2 × 10-8 M, than Mg2+ concentrations, 0.875 × 10-4 M. The observed inhibition effect of OPN emphasizes the often-overlooked role of macromolecules on COM nucleation due to their low concentration presence in urine. Moreover, analysis of growth rates calculated from observed lag times suggests that inhibition in the presence of Mg2+ cannot be explained solely on altered supersaturation. The presented study highlights the potential of microfluidics in overcoming a major challenge in nephrolithiasis research, the overwhelming physiochemical complexity of urine.

Head and tail pancreatic duct stones mimicking duplex staghorn renal calculi: A rare case

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Head and tail Pancreatic Duct stone mimically bilateral staghorn renal stone is rare.

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Bilateral lumbar pain same in renal and pancreatic process due to dermatomal distribution.

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Similar radiologic appearance pancreatic head and tail due to same topography of kidney.

Introduction

Pancreatolithiasis is an uncommon disease and the diagnosis of pancreatic duct stones is challenging. The radiological findings of pancreatic duct stones may mimic other diseases, such as renal stones.

Case presentation

A 42-year-old male came with chief complaint of recurrent bilateral flank pain accompanied by fever which worsen 7 days before admission. The patient was diagnosed as gastritis and received analgesics in several hospitals. Ultrasonography and IVP examinations showed stones in both kidneys. CT-scan was not performed due to limitation in the hospital. Patient was diagnosed bilateral staghorn nephrolithiasis. The patient underwent bilateral bivalve nephrotomy for staghorn renal stone performed by urologist, but intraoperatively, no stones were found. The patient was then consulted intraoperatively to the digestive surgeon and get immediate median laparotomy. Intraoperatively, stones were palpated in the head and tail of the pancreas. The stones were evacuated. The symptoms were relieved, neither recurrence, nor pain, nor postoperative leakage was found. Patient was discharged uneventfully 4 days after the procedure and had no complaints in further follow-ups.

Discussion

The symptoms of pancreatolithiasis may overlap with nephrolithiasis and gastritis. The presented case was unique because from the history taking, clinical symptoms, USG, and IVP findings supported the diagnosis of nephrolithiasis, but intraoperative findings reveal pancreatic duct stones.

Conclusion

For patient diagnosed with renal calculi based on sonography and IVP findings, differential diagnosis of pancreatic stone should be considered especially if no underlying cause is detected. In such circumstances relying on IVP and sonographic findings alone can be misleading.

Metabolomic Alteration in the Mouse Distal Colonic Mucosa after Oral Gavage with Oxalobacter formigenes

Oxalobacter formigenes has been investigated for years due to its proposed ability to produce a secretagogue compound that initiates net intestinal oxalate secretion, thereby theoretically reducing circulating oxalate and risk of kidney stone formation. Strains which have been shown to exhibit this function in vivo across native tissue include the human strain, HC1, and the wild rat strain, OxWR. While previous work on these secretagogue-relevant strains has focused on profiling their metabolome and lipidome in vitro, efforts to characterize their influence on host intestinal mucosal biochemistry in vivo are yet to be reported. Much work has been done over the years with O. formigenes in relation to the secretagogue hypothesis, but it has never been clearly demonstrated that this microorganism is capable of inducing metabolic changes in native host tissue, which would be expected with the production of a transport-inducing compound. In this work, we show how the distal colonic mucosal metabolomic profile in a mouse model exhibited significant changes in the levels of a variety of metabolites as a result of oral gavage with O. formigenes HC1. Among these significant metabolites was nicotinic acid, an essential nutrient shown in past work to be produced in the gut by the native microbiome. Our finding that the in vivo biochemical state of the distal colon was altered with O. formigenes lends support to the secretagogue hypothesis and serves as a pioneering step in characterizing the biochemical interplay between O. formigenes and the mammalian host.

A Combined Experimental and Modelling Study on Solubility of Calcium Oxalate Monohydrate at Physiologically Relevant pH and Temperatures

Accurate Calcium Oxalate Monohydrate (COM) solubility measurements are essential for elucidating the physiochemical mechanism behind the formation of kidney stones, nephrolithiasis. Yet the reported solubility values of COM in ultrapure water, arguably the simplest solvent relevant for nephrolithiasis, vary significantly depending on implemented method. To address this variation, we present an experimental study of the solubility of COM validated by a model based on the Debye–Hückel theory describing the solution chemistry and the complex formation. We also carefully monitor potential pseudopolymorphic/hydrate transitions during the solubility measurements with in-situ and ex-situ methods. Our results indicate that the solubility of COM in ultrapure water is a weak function of temperature. However, the measured solubility varies significantly in buffer solutions across physiologically relevant pH values at body temperature. The proposed model explains observed trends as a combined effect of ionic strength, protonation reactions, and soluble complex formation. Moreover, it predicts solubility of COM in buffer solutions remarkably well using our measurements in ultrapure water as input, demonstrating the consistency of presented approach. The presented study parleying experiments and modelling provides a solid stepping stone to extend the physiochemical understanding of nephrolithiasis to more realistic solutions laden with biological complexity.

Utility of blood tests in screening for metabolic disorders in kidney stone disease

OBJECTIVES

To determine the clinical utility of blood tests as a screening tool for metabolic abnormalities in patients with kidney stone disease.

SUBJECTS AND METHODS

Clinical and biochemical data from 709 patients attending the Oxford University Hospitals NHS Foundation Trust for assessment and treatment of kidney stones were prospectively collected between April 2011 and February 2017. Data were analysed to determine the utility of serum calcium, parathyroid hormone (PTH), urate, chloride, bicarbonate, potassium and phosphate assays in screening for primary hyperparathyroidism, normocalcaemic hyperparathyroidism, hyperuricosuria, distal renal tubular acidosis (dRTA) and hypercalciuria.

RESULTS

An elevated serum calcium level was detected in 2.3% of patients. Further investigations prompted by this finding resulted in a diagnosis of primary hyperparathyroidism in 0.2% of men and 4.6% of women for whom serum calcium was recorded. An elevated serum PTH level in the absence of hypercalcaemia was detected in 15.1% of patients. Of these patients, 74.6% were vitamin D-insufficient; no patients were diagnosed with normocalcaemic hyperparathyroidism. Hyperuricosuria was present in 21.6% of patients and hypercalciuria in 47.1%. Hyperuricaemia was not associated with hyperuricosuria, nor was hypophosphataemia associated with hypercalciuria. No patient was highlighted as being at risk of dRTA using serum chloride and bicarbonate as screening tests.

CONCLUSION

This study indicates that individuals presenting with renal calculi should undergo metabolic screening with a serum calcium measurement alone. Use of additional blood tests to screen for metabolic disorders is not cost-effective and may provide false reassurance that metabolic abnormalities are not present. A full metabolic assessment with 24-h urine collection should be undertaken in recurrent stone formers and in those at high risk of future stone disease to identify potentially treatable metabolic abnormalities.

SEM-EDX linear scanning: a new tool for morpho-compositional analysis of growth bands in urinary stones

The genesis and growth of calculi are imprinted in their structure, so the pathogenesis of lithiasis could potentially be read via proper analytical techniques. In this study, electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) is used to obtain a description of the morphology and compositional structure of a single bladder stone. This technique establishes the chemical and crystalline architecture of the urolith to assess the effect of the chemical environment on its growth. Scanning electron microscopy-backscattered electrons (SEM-BSE) images clearly show that the stone has a multilayered structure. These layers and Liesegang ring-like structures are characterized by one predominant chemical component but also by slighter compositional changes. The mean crystalline components are determined by X-ray diffraction (DRX), infrared spectroscopy (FT-IR), and Raman analysis (RMN). Elemental analysis along a radial trajectory of the calculus by EDX linear scanning (EDX-LS) also reveals the compositional structure of the layers and the spatial distribution of the main chemical components. EDX-LS data processing reveals concentration profiles that clearly show morpho-compositional growth bands, which correspond to precipitation waves and urinary concentration peaks. The width of the growth bands is independent of the radial position, layer, and element analyzed. We conclude that the bands observed are a consequence of slight changes in the biochemical composition of the urine and consequently reflect a short-term biological cycle of the renal system. This non-specific growth rate suggests that stone formation is a kinetically controlled phenomenon in which promoters of crystal cluster aggregation may have played a key role.

Intradermal sterile water injection versus diclofenac sodium in acute renal colic pain: A randomized controlled trial

OBJECTIVES

We aimed to evaluate the efficacy of intracutaneous sterile water injection (ISWI) to relieve the pain of acute renal colic compared with diclofenac and placebo.

METHODS

The study included 150 patients presented to the Emergency Department with renal colic randomized into 3 groups: control group received intracutaneous injections of 0.5 cm³ isotonic saline in the flank, group A received intracutaneous injections of 0.5 cm³ ISWI in the flank, and group B received an intramuscular injection of 75 mg Diclofenac in the gluteal region. The severity of the pain was assessed by a visual analogue scale system at baseline and 30, 45 min, and 60 min after injections. Subjects with inadequate pain relief at 1 h received rescue analgesia.

RESULTS

The mean baseline pain score was 9.6 ± 0.61 in the ISWI group, 9.72 ± 0.64 in the diclofenac group and 9.26 ± 0.89 in the control group. The mean pain score at 30 min of the control group was reduced to 6.9 ± 1.56. This mean at 30 min after ISWI and diclofenac injections were reduced to 1.98 ± 1.41 and 1.88 ± 1.19 respectively. The mean of pain sore of the ISWI and diclofenac group at 45 and 60 min was constant. Rescue analgesics at 1 h were required by 47 patients receiving the saline injection and by 4 patients and by 7 patients receiving ISWI and diclofenac injection respectively.

CONCLUSIONS

ISWI and diclofenac were equally effective for the pain relief of acute renal colic.

Lithotriptic effect of Safūf Hajar-al Yahūd in patients of Hasat-ul Kilya (Nephrolithiasis) - an open prospective clinical validation trial

BACKGROUND

Hasat-ul Kilya (Nephrolithiasis) is one of the most common chronic conditions and has been known to the mankind since antiquity. The incidence is increasing globally with geographic, racial and gender variation in its occurrence. Medical management of Nephrolithiasis still poses a considerable challenge for modern medical practice. Unani drugs possessing lithotriptic activity are not only cost effective but also have least side effects. Safūf Hajar-al Yahūd has been used since long for the treatment of Hasat-ul Kilya (Nephrolithiasis) but no documentary evidence based on scientific parameters as to its safety and efficacy are available.

OBJECTIVE

To validate the safety and efficacy of Safūf Hajar-al Yahūd in the treatment of Hasat-ul Kilya.

METHODOLOGY

An open prospective clinical trial was carried out on 107 subjects of renal calculi of 3-7 mm diameter diagnosed by Ultrasonogram-KUB (USG-KUB). Subjects were evaluated by clinical history & examination, laboratory investigations followed by USG-KUB for confirmation. The safety was assessed by reporting of adverse events and by pathological and biochemical investigations. Assessment of efficacy was based on improvement observed in VAS score and expulsion/reduction of stone size as detected by USG-KUB.

RESULTS

Substantial reduction (53%) in the size of calculi confirmed by USG-KUB and considerable lowering of VAS score (75%) were observed with the active intervention in majority of the cases.

CONCLUSION

The trial has revealed that the Unani pharmacopoeal formulation Safūf Hajar-al Yahūd was well tolerated and has the therapeutic potential in the reduction and expulsion of renal calculi.

Update on cystine stones: current and future concepts in treatment

Cystine stones are relatively uncommon compared with other stone compositions, constituting just 1% to 2% of adult urinary tract stone diseases, and accounting for up to 10% of pediatric stone diseases. Two responsible genes of cystinuria have been identified, the SLC3A1 and the SLC7A9. Cystinuria is diagnosed by family history, stone analysis, or by measurement of urine cystine excretion. Current treatments for cystinuria include increased fluid intake to increase cystine solubility by maintaining daily urine volume of greater than 3 Liter (L). Limiting sodium and protein intake can decrease cystine excretion. When conservative therapy fails, then pharmacologic therapy may be effective. Alkaline urine pH in the 7.0-7.5 range will reduce cystine solubility and can be achieved by the addition of alkali therapy. If these measures fail, cystine-binding thiol drugs such as tiopronin and D-penicillamine are considered. These compounds bind cysteine and prevent the formation of less soluble cystine. These drugs, however, have poor patient compliance due to adverse effects. Captopril can be useful in the treatment of cystine stones but the drug has not been tested in rigorous clinical trials. Novel potential therapies such as alpha-lipoic acid and crystal growth inhibitors (L-cystine dimethyl ester (L-CDME) and L-cystine methyl ester (L-CME)) were developed and tested in animals. Those therapies showed promising results. Compliance with treatment was associated with a lower rate of cystine stone formation.

A new intrasurgical technique to safely and reproducibly induce partial unilateral urinary obstruction and renal scarring in a Rat Model

OBJECTIVE

Irreversible electroporation (IRE) uses microsecond-long electric pulses to kill cells through membrane permeabilization, without affecting surrounding extracellular structures. We evaluated whether IRE can be used to induce urinary obstruction for a rat model of renal scarring.

MATERIALS AND METHODS

Intrasurgical IRE (2000 V/cm, 90 pulses, 100 μs) with caliper electrodes was performed in the right proximal ureter in male rats (n = 24) which were euthanized at 2, 5, or 10 days post-treatment, following contrast-enhanced magnetic resonance imaging. Complete urinary tract (bilateral kidneys, ureter and bladder) was extracted, and scored on a five-point scale for renal dilation, ureteral dilation and hydronephrosis. Whole kidney sections underwent immunohistochemistry to quantify levels of macrophages (CD68), activated fibroblasts [α-smooth muscle actin (α-SMA)], collagen (Masson's Trichrome) and Hematoxylin and Eosin. Change in renal pelvis diameter and the number of glomeruli in the treated and contralateral urinary tract was also computed.

RESULTS

Intrasurgical IRE performed with non-invasive caliper electrodes resulted in immediate loss of peristalsis in the treated ureteral segment, and cell death in the ureteral muscularis along with urothelial sloughing. Dilation of the ureter was observed on gross anatomic evaluation and histopathology. Magnetic resonance imaging indicated partial stricture and urinary obstruction in IRE-treated urinary tract, without evidence of urinoma, leakage or fistula formation. Enlargement of the kidney with progressive renal dilation and hydronephrosis was evident between Day 2 and Day 10 post-treatment. Obstructed kidney demonstrated scarring with elevated levels of tissue collagen, macrophages and α-SMA-positive fibroblasts. There was a steady decrease in the number of glomeruli in the obstructed kidney, while glomeruli numbers in the contralateral kidney remained unchanged through the 10-day observation period.

CONCLUSION

IRE provides a safe and reproducible technique to induce partial ureteral obstruction and renal fibrosis in rat model without the need for ligation or its associated complications.

Physiology, Development, and Disease Modeling in the Drosophila Excretory System

The insect excretory system contains two organ systems acting in concert: the Malpighian tubules and the hindgut perform essential roles in excretion and ionic and osmotic homeostasis. For over 350 years, these two organs have fascinated biologists as a model of organ structure and function. As part of a recent surge in interest, research on the Malpighian tubules and hindgut of Drosophila have uncovered important paradigms of organ physiology and development. Further, many human disease processes can be modeled in these organs. Here, focusing on discoveries in the past 10 years, we provide an overview of the anatomy and physiology of the Drosophila excretory system. We describe the major developmental events that build these organs during embryogenesis, remodel them during metamorphosis, and repair them following injury. Finally, we highlight the use of the Malpighian tubules and hindgut as accessible models of human disease biology. The Malpighian tubule is a particularly excellent model to study rapid fluid transport, neuroendocrine control of renal function, and modeling of numerous human renal conditions such as kidney stones, while the hindgut provides an outstanding model for processes such as the role of cell chirality in development, nonstem cell-based injury repair, cancer-promoting processes, and communication between the intestine and nervous system.

Current insights into the mechanisms and management of infection stones

Infection stones are complex aggregates of crystals amalgamated in an organic matrix that are strictly associated with urinary tract infections. The management of patients who form infection stones is challenging owing to the complexity of the calculi and high recurrence rates. The formation of infection stones is a multifactorial process that can be driven by urine chemistry, the urine microenvironment, the presence of modulator substances in urine, associations with bacteria, and the development of biofilms. Despite decades of investigation, the mechanisms of infection stone formation are still poorly understood. A mechanistic understanding of the formation and growth of infection stones - including the role of organics in the stone matrix, microorganisms, and biofilms in stone formation and their effect on stone characteristics - and the medical implications of these insights might be crucial for the development of improved treatments. Tools and approaches used in various disciplines (for example, engineering, chemistry, mineralogy, and microbiology) can be applied to further understand the microorganism-mineral interactions that lead to infection stone formation. Thus, the use of integrated multidisciplinary approaches is imperative to improve the diagnosis, prevention, and treatment of infection stones.

Matting Calcium Crystals by Melamine Improves Stabilization and Prevents Dissolution

Melamine induces calcium phosphate (CaP) and calcium oxalate (CaOx) crystal formation; however, the physicochemical mechanism is not clear. Recently, we found that melamine has a discriminatory effect on CaP, CaOx, and CaP + CaOx (Mixed) crystal dissolution. Thus, to delineate the mechanism, we examined crystal interactions through birefringence analysis and found that CaP becomes increasingly birefringent when bound to melamine, while the birefringence of CaOx decreases when it forms CaOx-melamine cocrystals. We also confirmed the feasibility of such melamine-CaP/CaOx co-crystallization at the nanomicromolar range. Interestingly, ammeline, which is a similar triazine, did not accelerate CaP/CaOx/Mixed crystal formation and growth, indicating the specificity of crystal interaction by melamine. Furthermore, melamine stabilizes the CaP/CaOx/Mixed crystals when exposed to a crystal inhibitor (etidronic acid) or dissolution agents (citrate analogues), while it induces crystal growth by increasing crystal retention, suggesting melamine's interference with conventional dissolution remedies. Morphological and elemental analysis of melamine-CaP/CaOx/Mixed co-crystals using scanning electron microscopy further revealed that melamine harbors such crystals by creating a nucleation site. Finally, we confirmed the physiological relevance of melamine exposure using artificial urine to show the induction, stabilization, and retention of mixed crystals in the presence of crystal-inhibitor/dissolution agent and thus established potential causes of recurrence of kidney stones.

Metabolomic profiling of oxalate-degrading probiotic Lactobacillus acidophilus and Lactobacillus gasseri

Oxalate, a ubiquitous compound in many plant-based foods, is absorbed through the intestine and precipitates with calcium in the kidneys to form stones. Over 80% of diagnosed kidney stones are found to be calcium oxalate. People who form these stones often experience a high rate of recurrence and treatment options remain limited despite decades of dedicated research. Recently, the intestinal microbiome has become a new focus for novel therapies. Studies have shown that select species of Lactobacillus, the most commonly included genus in modern probiotic supplements, can degrade oxalate in vitro and even decrease urinary oxalate in animal models of Primary Hyperoxaluria. Although the purported health benefits of Lactobacillus probiotics vary significantly between species, there is supporting evidence for their potential use as probiotics for oxalate diseases. Defining the unique metabolic properties of Lactobacillus is essential to define how these bacteria interact with the host intestine and influence overall health. We addressed this need by characterizing and comparing the metabolome and lipidome of the oxalate-degrading Lactobacillus acidophilus and Lactobacillus gasseri using ultra-high-performance liquid chromatography-high resolution mass spectrometry. We report many species-specific differences in the metabolic profiles of these Lactobacillus species and discuss potential probiotic relevance and function resulting from their differential expression. Also described is our validation of the oxalate-degrading ability of Lactobacillus acidophilus and Lactobacillus gasseri, even in the presence of other preferred carbon sources, measuring in vitro 14C-oxalate consumption via liquid scintillation counting.

The Role of Ultrasonography in Patients Referring to the Emergency Department with Acute Abdominal Pain

CONTEXT

Acute abdominal pain is a common clinical problem in emergency and non-emergency cases accounting for 5 to 10% of all referrals to the emergency department. Studies have indicated that these widely differentiated diagnoses are common to these complaints. Considering the high prevalence of this complaint in the patients and the wide range of its differential diagnosis, this review study was designed and evaluated aiming at investigating the causes of acute abdominal pain with a focus on assessing the position of ultrasound as a diagnostic tool in the emergency department.

EVIDENCE ACQUISITION

This article was conducted as a narrative review of selected articles from 2005 through 2019. By comparing them, a comprehensive review of ultrasound role was conducted in patients with acute abdominal pain referring to the emergency department.

RESULTS

In this review study, we attempted to use the articles of the clinical approach, the required laboratory tests, the disadvantages and advantages of each imaging technique, the differential diagnosis for acute abdominal pain according to the location of the pain, and the position of ultrasound as a diagnostic aid tool. Eventually, the proposed protrusion will be considered in dealing with a patient with acute abdominal pain.

CONCLUSION

Regarding the wide range of causes providing multiple differential diagnosis, as well as the limited time of the health team in the emergency department for diagnostic and therapeutic measures, particularly in time-sensitive clinical conditions, ultrasound offered by emergency medicine specialists as a diagnostic aid is considered to improve the overall diagnosis and treatment of patients, thereby reducing complications.

Metabolomic and lipidomic characterization of Oxalobacter formigenes strains HC1 and OxWR by UHPLC-HRMS

Diseases of oxalate, such as nephrolithiasis and primary hyperoxaluria, affect a significant portion of the US population and have limited treatment options. Oxalobacter formigenes, an obligate oxalotrophic bacterium in the mammalian intestine, has generated great interest as a potential probiotic or therapeutic treatment for oxalate-related conditions due to its ability to degrade both exogenous (dietary) and endogenous (metabolic) oxalate, lowering the risk of hyperoxaluria/hyperoxalemia. Although all oxalotrophs degrade dietary oxalate, Oxalobacter formigenes is the only species shown to initiate intestinal oxalate secretion to draw upon endogenous, circulating oxalate for consumption. Evidence suggests that Oxalobacter regulates oxalate transport proteins in the intestinal epithelium using an unidentified secreted bioactive compound, but the mechanism of this function remains elusive. It is essential to gain an understanding of the biochemical relationship between Oxalobacter and the host intestinal epithelium for this microbe to progress as a potential remedy for oxalate diseases. This investigation includes the first profiling of the metabolome and lipidome of Oxalobacter formigenes, specifically the human strain HC1 and rat strain OxWR, the only two strains shown thus far to initiate net intestinal oxalate secretion across native gut epithelia. This study was performed using untargeted and targeted metabolomics and lipidomics methodologies utilizing ultra-high-performance liquid chromatography-mass spectrometry. We report our findings that the metabolic profiles of these strains, although largely conserved, show significant differences in their expression of many compounds. Several strain-specific features were also detected. Discussed are trends in the whole metabolic profile as well as in individual features, both identified and unidentified. Graphical abstract ᅟ.

The potential effects of dietary food and beverage intakes on the risk of kidney stone formation

ABSTRACT Objective To determine the effect of nutritional habits on kidney stone formation and recurrence. Methods This study was conducted on 44 healthy individuals and 44 patients diagnosed with nephrolithiasis and aging between 20 and 65 years. Participants shared their salt consumption habits, daily fluid consumption amounts and general information about themselves in a questionnaire form. In addition, food and beverage consumption frequencies of participants were recorded through a food frequency questionnaire. Results Salt consumption frequencies of patients are higher than that of healthy individuals in both genders (p<0.05). It was found out that male individuals in the patient group salt dishes without tasting more frequently (p<0.05). Daily total water consumption of both genders in patient group is lower than that of healthy individuals (p<0.05). Meat consumption of male patients (51.6±31.35g/day) was found to be higher than that of healthy group (34.1±22.58g/day) (p<0.05). Additionally, individuals in the patient group consume less stinging nettle, corn, plum, loquat, orange juice and lemonade than healthy individuals (p<0.05). Conclusion Results of the study showed that total fluid intake, salt consumption habits, and vegetable, fruit and beverage consumption may be correlated with stone formation risk and nutrition habits may affect stone recurrence.

Hereditary hypophosphatemic rickets with hypercalciuria: pathophysiology, clinical presentation, diagnosis and therapy

Hereditary hypophosphatemic rickets with hypercalciuria (HHRH; OMIM: 241530) is a rare autosomal recessive disorder with an estimated prevalence of 1:250,000 that was originally described by Tieder et al. Individuals with HHRH carry compound-heterozygous or homozygous (comp/hom) loss-of-function mutations in the sodium-phosphate co-transporter NPT2c. These mutations result in the development of urinary phosphate (Pi) wasting and hypophosphatemic rickets, bowing, and short stature, as well as appropriately elevated 1,25(OH)₂D levels, which sets this fibroblast growth factor 23 (FGF23)-independent disorder apart from the more common X-linked hypophosphatemia. The elevated 1,25(OH)₂D levels in turn result in hypercalciuria due to enhanced intestinal calcium absorption and reduced parathyroid hormone (PTH)-dependent calcium-reabsorption in the distal renal tubules, leading to the development of kidney stones and/or nephrocalcinosis in approximately half of the individuals with HHRH. Even heterozygous NPT2c mutations are frequently associated with isolated hypercalciuria (IH), which increases the risk of kidney stones or nephrocalcinosis threefold in affected individuals compared with the general population. Bone disease is generally absent in individuals with IH, in contrast to those with HHRH. Treatment of HHRH and IH consists of monotherapy with oral Pi supplements, while active vitamin D analogs are contraindicated, mainly because the endogenous 1,25(OH)₂D levels are already elevated but also to prevent further worsening of the hypercalciuria. Long-term studies to determine whether oral Pi supplementation alone is sufficient to prevent renal calcifications and bone loss, however, are lacking. It is also unknown how therapy should be monitored, whether secondary hyperparathyroidism can develop, and whether Pi requirements decrease with age, as observed in some FGF23-dependent hypophosphatemic disorders, or whether this can lead to osteoporosis.

Diagnostic performance of advanced modeled iterative reconstruction applied images for detecting urinary stones on submillisievert low-dose computed tomography

Background Repeated computed tomography (CT) scans may be an issue in young adults with urinary stones. Therefore, it is important to know how far the dose can be reduced while maintaining the diagnostic performance. Purpose To generate a hypothesis that it is feasible to decrease the radiation dose to a sub-millisievert (mSv) level with the addition of advanced modeled iterative reconstruction (ADMIRE) while maintaining the sensitivity to standard-dose CT (SDCT) for the detection of urinary stones. Material and Methods Ninety-two consecutive patients with urinary stones underwent non-enhanced CT that consisted of standard (120 kVp, 200 mAs) and lose-dose (LDCT) (80 kVp, 60 mAs). The LDCT images were reconstructed separately with five different strengths of ADMIRE (hereafter, S1-S5) and filtered back projection (FBP). Two blinded radiologists independently recorded a number of urinary stones in the six LDCT datasets and SDCT. The sensitivity of each set for detecting urinary stones was compared using the McNemar test. Results A total of 240 urinary stones were analyzed. The sensitivities of the six LDCT datasets showed no difference (FBP, S1-S5, for reader 1: 78%, 79%, 79%, 80%, 80%, and 80%; for reader 2: 64%, 63%, 64%, 64%, 65%, and 66%, P > 0.05, respectively), which were lower than those of SDCT for both readers (reader 1: 88%; reader 2: 81%, P < 0.0001, respectively). Conclusion Despite the addition of ADMIRE, it may not be feasible to decrease the radiation dose to a sub-mSv level while maintaining the sensitivity to SDCT for the detection of urinary stones.

Uric acid stones, clinical manifestations and therapeutic considerations

Uric acid stones account for 10%-15% of all urinary stones. Changes in dietary habits, environment or both can result in the increase of uric acid stones. The formation of uric acid stones is related to hyperuricosuria, low urinary volume and persistently low urinary pH. Diabetes and obesity also significantly increase the risk of stone formation. Dual-energy CT provides a convenient and reliable method for diagnosis. Stone composition analysis and 24-hour urine metabolic evaluations should be considered for further evaluation. Most small uric acid stones (diameter <2 cm) can be treated by pharmacotherapy or extracorporeal shock wave lithotripsy. However, ureteroscopy and other minimally invasive procedures should be reserved for larger stones (diameter ≥2 cm), or patients with concomitant urinary tract obstruction and/or infections. Additionally, adjustment of potential pathophysiologic defects by pharmacotherapy and dietary modification is strongly recommended for the prevention of uric stone recurrence.

Loss-of-function mutations of SCN10A encoding NaV1.8 α subunit of voltage-gated sodium channel in patients with human kidney stone disease

Human kidney stone disease (KSD) causes significant morbidity and public health burden worldwide. The etiology of KSD is heterogeneous, ranging from monogenic defects to complex interaction between genetic and environmental factors. However, the genetic defects causing KSD in the majority of affected families are still unknown. Here, we report the discovery of mutations of SCN10A, encoding Na_V1.8 α subunit of voltage-gated sodium channel, in families with KSD. The region on chromosome 3 where SCN10A locates was initially identified in a large family with KSD by genome-wide linkage analysis and exome sequencing. Two mutations (p.N909K and p.K1809R) in the same allele of SCN10A co-segregated with KSD in the affected family. Additional mutation (p.V1149M) of SCN10A was identified in another affected family, strongly supporting the causal role of SCN10A for KSD. The amino acids at these three positions, N909, K1809, and V1149, are highly conserved in vertebrate evolution, indicating their structural and functional significances. Na_V1.8 α subunit mRNA and protein were found to express in human kidney tissues. The mutant proteins expressed in cultured cells were unstable and causing reduced current density as analyzed by whole-cell patch-clamp technique. Thus, loss-of-function mutations of SCN10A were associated with KSD in the families studied.

Prevalence, pathophysiological mechanisms and factors affecting urolithiasis

The formation of urinary stone, urolithiasis, is one the oldest known disease affecting human throughout different civilizations and times. The exact pathophysiological mechanism of urolithiasis is not yet clear, as these calculi are of various types and too complex for simple understanding. A single theory cannot explain its formation; therefore, different theories are presented in various times for its explanation like free particle, fixed particle, Randall's plaque theory. In addition, various factors and components are identified that play an important role in the formation of these urinary calculi. In this review, composition of kidney stones, its prevalence/incidence, explanation of pathophysiological mechanisms and role of various factors; urinary pH, uric acid, parathyroid hormone, citrate, oxalate, calcium and macromolecules; osteopontin, matrix Gla protein, kidney injury molecules, urinary prothrombin fragment-1, Tamm-Horsfall protein, inter-α-inhibitors, have been discussed in detail.

Kidney Stone Disease: An Update on Current Concepts

Kidney stone disease is a crystal concretion formed usually within the kidneys. It is an increasing urological disorder of human health, affecting about 12% of the world population. It has been associated with an increased risk of end-stage renal failure. The etiology of kidney stone is multifactorial. The most common type of kidney stone is calcium oxalate formed at Randall's plaque on the renal papillary surfaces. The mechanism of stone formation is a complex process which results from several physicochemical events including supersaturation, nucleation, growth, aggregation, and retention of urinary stone constituents within tubular cells. These steps are modulated by an imbalance between factors that promote or inhibit urinary crystallization. It is also noted that cellular injury promotes retention of particles on renal papillary surfaces. The exposure of renal epithelial cells to oxalate causes a signaling cascade which leads to apoptosis by p38 mitogen-activated protein kinase pathways. Currently, there is no satisfactory drug to cure and/or prevent kidney stone recurrences. Thus, further understanding of the pathophysiology of kidney stone formation is a research area to manage urolithiasis using new drugs. Therefore, this review has intended to provide a compiled up-to-date information on kidney stone etiology, pathogenesis, and prevention approaches.

Effects of a high-sodium/low-potassium diet on renal calcium, magnesium, and phosphate handling

The distal convoluted tubule (DCT) of the kidney plays an important role in blood pressure regulation by modulating Na⁺ reabsorption via the Na⁺-Cl^- cotransporter (NCC). A diet containing high salt (NaCl) and low K⁺ activates NCC, thereby causing Na⁺ retention and a rise in blood pressure. Since high blood pressure, hypertension, is associated with changes in serum calcium (Ca²⁺) and magnesium (Mg²⁺) levels, we hypothesized that dietary Na⁺ and K⁺ intake affects Ca²⁺ and Mg²⁺ transport in the DCT. Therefore, the present study aimed to investigate the effect of a high-Na⁺/low-K⁺ diet on renal Ca²⁺ and Mg²⁺ handling. Mice were divided in four groups and fed a normal-Na⁺/normal-K⁺, normal-Na⁺/low-K⁺, high-Na⁺/normal-K⁺, or high-Na⁺/low-K⁺ diet for 4 days. Serum and urine were collected for electrolyte and hormone analysis. Gene and protein expression of electrolyte transporters were assessed in kidney and intestine by qPCR and immunoblotting. Whereas Mg²⁺ homeostasis was not affected, the mice had elevated urinary Ca²⁺ and phosphate (P_i) excretion upon high Na⁺ intake, as well as significantly lower serum Ca²⁺ levels in the high-Na⁺/low-K⁺ group. Alterations in the gene and protein expression of players involved in Ca²⁺ and P_i transport indicate that reabsorption in the proximal tubular and TAL is affected, while inducing a compensatory response in the DCT. These effects may contribute to the negative health impact of a high-salt diet, including kidney stone formation, chronic kidney disease, and loss of bone mineral density.

The role of trapped bubbles in kidney stone detection with the color Doppler ultrasound twinkling artifact

The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice bubbles on the kidney stone surface cause twinkling; however, the hypothesis is not fully accepted because the bubbles have not been directly observed. In this paper, the micron or submicron-sized bubbles predicted by the crevice bubble hypothesis are enlarged in kidney stones of five primary compositions by exposure to acoustic rarefaction pulses or hypobaric static pressures in order to simultaneously capture their appearance by high-speed photography and ultrasound imaging. On filming stones that twinkle, consecutive rarefaction pulses from a lithotripter caused some bubbles to reproducibly grow from specific locations on the stone surface, suggesting the presence of pre-existing crevice bubbles. Hyperbaric and hypobaric static pressures were found to modify the twinkling artifact; however, the simple expectation that hyperbaric exposures reduce and hypobaric pressures increase twinkling by shrinking and enlarging bubbles, respectively, largely held for rough-surfaced stones but was inadequate for smoother stones. Twinkling was found to increase or decrease in response to elevated static pressure on smooth stones, perhaps because of the compression of internal voids. These results support the crevice bubble hypothesis of twinkling and suggest the kidney stone crevices that give rise to the twinkling phenomenon may be internal as well as external.

Antiurolithiatic Potential of Neeri against Calcium-Oxalate Stones by Crystallization Inhibition, Free Radicals Scavenging, and NRK-52E Cell Protection from Oxalate Injury

Background

Neeri is a well-established polyherbal formulation prescribed for renal stones by the physicians but has not been experimentally evaluated for its antiurolithiatic potential using cell-lines.

Objective

This study is aimed to scientifically substantiate the antiurolithiatic effect of Neeri extract (NRE) through calcium oxalate (CaOx) crystallization inhibition, scavenging of free radicals, and protection of renal tubular epithelial NRK-52E cells from oxalate-induced injury.

Materials and Methods

The crystallization inhibition was studied by turbidimetric assay while the free radical scavenging potential was determined for superoxide and nitric oxide (NO) radicals. The cytoprotective effect against oxalate-induced injury was assessed by estimating lactate dehydrogenase (LDH) leakage and determining cell viability using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.

Results

NRE significantly inhibited the CaOx crystallization in a concentration-dependent manner and also scavenged superoxide (IC₅₀ 302.88 μg/ml) and NO (IC₅₀ 300.45 μg/ml) free radicals. It did not show any significant cytotoxicity for NRK-52E cells till the highest dose (500 μg/ml) and found to be safe. When NRK-52E cells, injured by exposing to oxalate crystals for 24 h, were treated with NRE, it appreciably prevented the cell injury in a dose-dependent manner. It significantly decreased the elevated LDH leakage toward normal range and improved renal cell viability (82.37% ± 0.87%), hence, prevented growth and retention of crystals.

Conclusion

The experimental findings concluded that Neeri is a potent antiurolithiatic formulation that inhibited CaOx crystallization and prevented tubular retention of crystals by protecting the renal cells against oxalate-induced injury as well as reducing the oxidative stress by scavenging free radicals.

SUMMARY

Neeri extract significantly (P < 0.001) inhibited the in vitro crystallization (88.11% ± 7.70%) of calcium oxalateIt reduced oxidative stress by scavenging superoxide and nitric oxide free radicalsIt significantly (P < 0.001) improved the cell viability by inhibiting the leakage of lactate dehydrogenase in a dose-dependent manner. Abbreviations used: A_c: Absorbance of control, A_t: Absorbance of test, ANOVA: Analysis of variance, CaOx: Calcium oxalate, DMEM: Dulbecco's Modified Eagle's Medium, DMSO: Dimethyl sulfoxide, EDTA: Ethylenediaminetetraacetic acid, FBS: Fetal bovine serum, INT: Iodonitrotetrazolium, LDH: Lactate dehydrogenase, M: Molar, ml: Milliliter, mM: Millimolar, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, NAD: Nicotinamide adenine dinucleotide, NADPH: Nicotinamide adenine dinucleotide phosphate, NBT: Nitro blue tetrazolium, nm: Nanometer, NO: Nitric oxide, NRE: Neeri extract, PMS: Phenazine methosulfate, ROS: Reactive oxygen species, S_c: Slope of the graph of control, SEM: Standard error of mean, S_i: Slope of the graph with inhibitor, U/I: International unit, mg: Microgram, ml: Microliter.

Determining normal values of urinary phosphorus excretion in 3913 healthy children aged 2-18 to aid early diagnosis and treatment for urolithiasis

AIM

This study determined the specific reference values for urinary phosphorus excretion in healthy children and adolescents aged 2-18 years and evaluated whether they changed with age during growth and were gender dependent.

METHODS

We enrolled 3913 healthy children and adolescents aged 2-18 years to this study. The study population was divided into age groups, and the analysis was performed in one-year periods, separately for boys and girls. Urinary phosphorus excretion was analysed using four categories: P1 in mmol/24 hour units, P2 in mmol/kg/24 hours, P3 in mmol/1.73 m² /24 hours and P4 in mmol/mmol creatinine.

RESULTS

Clear differences in urinary exertion for girls and boys were observed as well as systematic changes with age. The boys presented with significantly higher daily urinary phosphorus excretion independent of its manner of expression (p < 0.001). The median urinary phosphorus (P1) rose with age (p < 0.001). Percentile tables of phosphorous exertion are presented.

CONCLUSION

This was the largest study of urinary phosphate excretion based on a randomly selected sample of girls and boys aged 2-18 years. It highlights the importance of determining phosphorus reference values for children of different ages to provide early diagnosis and treatment for urolithiasis.