The role of mannitol in alleviating renal injury during extracorporeal shock wave lithotripsy

Renal protective effect of N-acetylcysteine with stepwise ramping voltage against extracorporeal shock wave lithotripsy-induced renal injury: a prospective randomized trial

PURPOSE

To evaluate the role of combination of N-acetylcysteine with stepwise ramping voltage in renal protection against the ischemic, vascular and oxidative effects of extracorporeal shock wave lithotripsy.

PATIENTS AND METHODS

A prospective randomized trial on 164 adult patients scheduled for ESWL for single renal stones. Patients with radio-lucent stones, diabetes, hypertension, febrile UTI, and preoperative albuminuria were excluded from the study. Patients were randomized into one of four groups. Group A patients received maximal fixed voltage of ESWL. Group B patients received stepwise ramping voltage of ESWL. Group C patients received fixed maximal voltage with N-acetylcysteine (NAC) 600 mg/bid from 48 h before to 24 h after the procedure. Group D patients received gradual ramping voltage with NAC. Urinary β₂-microglobulin, 24 h albumin and N-acetyl-β-D-glucosaminidase/creatinine ratio at 1 day and 5 days post-ESWL and the stone free rate at 2 weeks were measured.

RESULTS

Group D was the only group that showed no significant difference pre and post ESWL in urinary albumin, β₂-microglobulin and N-acetyl-β-D-glucosaminidase/creatinine ratio. Post hoc analysis revealed no significant difference between group B and group C in albumin, β₂-microglobulin N-acetyl-β-D-glucosaminidase/creatinine ratio, but both of them had significantly lower levels than group A and significantly higher levels than group D. There was no statistically significant difference between all groups in the stone free rate at 2 weeks.

CONCLUSION

N-acetylcysteine protects the kidney against ESWL-induced renal injuries especially if combined with stepwise ramping voltage.

A randomised controlled trial evaluating renal protective effects of selenium with vitamins A, C, E, verapamil, and losartan against extracorporeal shockwave lithotripsy-induced renal injury

OBJECTIVE

To evaluate the protective effects of selenium with vitamins A, C and E (selenium ACE, i.e. antioxidants), verapamil (calcium channel blocker), and losartan (angiotensin receptor blocker) against extracorporeal shockwave lithotripsy (ESWL)-induced renal injury.

PATIENTS AND METHODS

A randomised controlled trial was conducted between August 2012 and February 2015. Inclusion criteria were adult patients with a single renal stone (<2 cm) suitable for ESWL. Patients with diabetes, hypertension, congenital renal anomalies, moderate or marked hydronephrosis, or preoperative albuminuria (>300 mg/L) were excluded. ESWL was performed using the electromagnetic DoLiS lithotripter. Eligible patients were randomised into one of four groups using sealed closed envelopes: Group1, control; Group 2, selenium ACE; Group 3, losartan; and Group 4, verapamil. Albuminuria and urinary neutrophil gelatinase-associated lipocalin (uNGAL) were estimated after 2-4 h and 1 week after ESWL. The primary outcome was differences between albuminuria and uNGAL. Dynamic contrast-enhanced magnetic resonance imaging was performed before ESWL, and at 2-4 h and 1 week after ESWL to compare changes in renal perfusion.

RESULTS

Of 329 patients assessed for eligibility, the final analysis comprised 160 patients (40 in each group). Losartan was the only medication that showed significantly lower levels of albuminuria after 1 week (P < 0.001). For perfusion changes, there was a statistically significant decrease in the renal perfusion in patients with obstructed kidneys in comparison to before ESWL (P = 0.003). These significant changes were present in the control or antioxidant group, whilst in the losartan and verapamil groups renal perfusion was not significantly decreased.

CONCLUSIONS

Losartan was found to protect the kidney against ESWL-induced renal injury by significantly decreasing post-ESWL albuminuria. Verapamil and losartan maintained renal perfusion in patients with post-ESWL renal obstruction.

Shock wave lithotripsy: the new phoenix?

INTRODUCTION

Following its introduction in 1980, shock wave lithotripsy (SWL) rapidly emerged as the first-line treatment for the majority of patients with urolithiasis. Millions of SWL therapies have since been performed worldwide, and nowadays, SWL still remains to be the least invasive therapy modality for urinary stones. During the last three decades, SWL technology has advanced in terms of shock wave generation, focusing, patient coupling and stone localization. The implementation of multifunctional lithotripters has made SWL available to urology departments worldwide. Indications for SWL have evolved as well. Although endoscopic treatment techniques have improved significantly and seem to take the lead in stone therapy in the western countries due to high stone-free rates, SWL continues to be considered as the first-line therapy for the treatment of most intra-renal stones and many ureteral stones.

METHODS

This paper reviews the fundamentals of SWL physics to facilitate a better understanding about how a lithotripter works and should be best utilized.

RESULTS

Advances in lithotripsy technology such as shock wave generation and focusing, advances in stone localization (imaging), different energy source concepts and coupling modalities are presented. Furthermore adjuncts to improve the efficacy of SWL including different treatment strategies are reviewed.

CONCLUSION

If urologists make use of a more comprehensive understanding of the pathophysiology and physics of shock waves, much better results could be achieved in the future. This may lead to a renaissance and encourage SWL as first-line therapy for urolithiasis in times of rapid progress in endoscopic treatment modalities.

A chronic outcome of shock wave lithotripsy is parenchymal fibrosis

Shock wave lithotripsy (SWL) is widely viewed as an effective noninvasive method to break stones within the kidney and ureter. However, it is a technology that is not without trauma to the kidney--acute vascular, tubular and interstitial damage is often reported that if severe enough can lead to renal fibrosis (scarring) and permanent loss of functional parenchyma. These chronic changes can potentially lead to serious long-term adverse effects. The risk of developing chronic fibrotic lesions after lithotripsy is influenced by the number of shock waves (SWs) administered, SW power, rate of SW delivery and the number of SWL treatment sessions. The interplay between these risk factors is largely unknown, but progress has been made in identifying SWL protocols and pharmacologic therapies that can ameliorate the acute and chronic tissue damage that is an unintended consequence of SWL treatment.

Antioxidant therapy is associated with a reduction in the serum levels of mediators of renal injury following lithotripsy for renal calculi

OBJECTIVE

To investigate the effects of antioxidant therapy on the levels of mediators of shock wave induced renal injury in patients with renal calculi treated with extracorporeal shock wave lithotripsy (ESWL).

PATIENTS AND METHODS

One hundred and twenty patients with renal calculi were divided into three treatment groups: Group A patients (n = 39) served as a control group; Group B patients (n = 41) were given 2 capsules of Nature Made((R)) antioxidants 2 hours before, and 2 and 8 hours after ESWL and Group C patients (n = 40) were given 2 capsules of the antioxidants at 2 and 8 hours after ESWL. Blood and urine samples were obtained from all patients just before the start of treatment with ESWL, and at 2 and 24 hours and on day 7 and 28 after ESWL. Levels of mediators of renal injury such as serum alkaline phosphatase (ALP), C-reactive protein (CRP) and lactate dehydrogenase (LDH) were measured. Urinary levels of albumin and ALP were also determined as measures of renal tubular injury.

RESULTS

Patients given antioxidants had significantly reduced mean serum concentration of ALP (p < 0.001) at 24 hours, lower serum ALP and LDH on day 7 and 28, and lowest CRP on day 28 after ESWL. They also had higher urine albumin (p < 0.001) and ALP (p < 0.001) levels (from 24 hours to day 28) compared with patients who were not given antioxidants.

CONCLUSION

These findings suggest that oral antioxidant therapy prior to lithotripsy may reduce the severity of long term renal injury caused by the shock waves.

Ovarian apoptosis after shock wave lithotripsy for distal ureteral stones

The objective of this study is to identify any apoptotic effect of shock wave lithotripsy (SWL) for distal ureteral stones on ovarian tissue. Twenty-one female New Zealand White rabbits were divided into three groups of seven rabbits each: I (control), and II, III (treated and killed 14 and 28 days after SWL, respectively). The left distal ureteral segment of the anesthetized (ketamine HCl, 20 mg/kg) animals in groups II and III was exposed to 1,500 shock waves at 17 kV. Localization of the distal ureteral segments was achieved following contrast medium (Iohexol 300 mg of I/ml) injection. The animals were killed on day 14 or 28 after SWL, and the ovaries were removed. The follicle number with apoptotic changes in ovarian tissue was compared with control group. Apoptotic changes were determined by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) method. No increased apoptosis was detected in all groups. The mean number of TUNEL-positive follicle in groups I, II and III was 9.3 +/- 2.9, 8.1 +/- 2.6 and 8.7 +/- 2.9, respectively. There were no statistically significant differences among all groups regarding the number of TUNEL-positive follicle (P = 0.647). Also, no histomorphological change other than apoptosis was detected in the study groups. In conclusion, SWL treatment for distal ureteral stones does not induce apoptotic changes on ovarian tissue.

Adjuvant therapy after surgical stone management

The aim of this article was to review the most widely researched adjuvant medical therapies for the surgical management of urolithiasis. Articles were identified and reviewed from PubMed and Medline databases with MeSH headings focusing on the various surgical treatments of urolithiasis and adjuvant therapy. Additional articles were retrieved from references and conference proceedings. Surgical treatments reviewed included shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. Adjuvant therapy was considered medical or complementary therapy as an adjunct to these surgical interventions. Adjuvant therapy for the surgical management of urolithiasis has been documented to increase stone-free rates, reduce stone remission rates, prevent renal damage, and decrease postoperative morbidity. A variety of agents have been studied, ranging from antioxidants to alpha-blockers and to alkalinizing agents. Additionally, there is increasing interest in complementary adjuvant therapy (ie, acupuncture). Adjuvant therapy is a fertile area for research in the surgical management of urolithiasis. The optimal agents have yet to be determined and therefore further investigation is warranted and necessary.

Treatment of renal calculi by lithotripsy: minimizing short-term shock wave induced renal damage by using antioxidants

Treatment with extracorporeal shock wave lithotripsy (ESWL), the preferred method of treating kidney stones <3 cm in size, has been shown to induce silent and often self-limiting acute and chronic lesions in the kidneys and adjacent organs. We conducted a randomized clinical trial to determine whether ESWL produces ischaemia and reperfusion injury in the kidneys and whether oral administration of antioxidants reduces the degree of short-term renal injury in patients treated with ESWL. The study included 120 patients with renal stones (1-3 cm in size) treated with ESWL. The patients were divided into three groups--patients in group A (n=39) served as a control group and were not given any antioxidants; patients in group B (n=41) were given two capsules of antioxidants "Nature Made R: " 2 h before ESWL, and 2 and 8 h after ESWL; and patients in group C (n=40) were given two capsules of the antioxidants 2 and 8 h after ESWL. Double 'J' stents were inserted in patients before treatment with ESWL. Blood and urine samples were obtained from all patients just before the start of treatment with ESWL, and at 2 and 24 h and on 7th and 28th day after ESWL. Serum levels of malondialdehyde (MDA), alpha-tocopherol, cholesterol, albumin and ascorbic acid, and alpha-tocopherol/cholesterol ratio were determined. Urinary levels of albumin and beta(2) microglobulin were also determined as measures of renal tubular injury. At 24 h after ESWL, patients given antioxidants (groups B + C) had significantly reduced mean serum concentration of MDA (P<0.001); higher levels of serum ascorbic acid (P<0.001) and serum albumin (P<0.001); lower alpha-tocopherol/cholesterol ratio, lower urinary albumin and beta(2 )microglobulin levels compared with patients who did not receive antioxidants (group A). These findings suggest that treatment with ESWL generates free radicals through ischaemic/reperfusion injury mechanism, and that oral administration of antioxidant may protect these patients from short term renal injury caused by ESWL.

New concepts in shock wave lithotripsy

This monograph reviews the basic principles of shock wave lithotripsy. The focus is on new research on stone fragmentation and tissue injury and how this improved understanding of shock-wave technology is leading to modifications in lithotripsy that will allow this therapy to be a safer, more effective treatment for nephrolithiasis.

Pyrrolidine dithiocarbamate attenuate shock wave induced MDCK cells injury via inhibiting nuclear factor-kappa B activation

Shock wave lithotripsy (SWL)-induced renal damage appears to be multifactorial. Recent data indicated that the mechanism of renal tissue damage secondary to SWL is similar to that of ischemia reperfusion injury. Nuclear factor-kappa B (NFkappaB) and its target genes, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), have been demonstrated to play a very important role in a variety of cells or tissues ischemia reperfusion injuries. Thus in the present study, using an in vitro model MDCK cells, we investigated the role of NFkappaB and its target cytotoxic enzyme in shock wave-induced renal cellular damage. We also examined whether inhibition this pathway by pyrrolidine dithiocarbamate (PDTC) is contributed to alleviate SWL-caused cell damage. Suspensions of MDCK cells were placed in containers for shock wave exposure. Three groups of six containers each were examined: control group, no shock wave treatment and SWL group, which received 100 shocks at 18 kV; 3 SWL + PDTC group. PDTC were added to the suspensions before shock wave exposure. After shock wave 0, 2, 4, 6 and 8 h, respectively, the cell supernatants were detected for the level of MDA and release of LDH. At post-shock wave 8 h, cells were harvested to detect the nuclear translocation of NFkappaBp65 by immunofluorescence staining. Degradation of IkappaB-a (an inhibitor protein of NFkappaB) and expression of iNOS and COX-2 were also examined by western blotting. Our results indicated that shock wave initiated the apparent activation of NFkappaB, which in turn induced high expression of iNOS and COX-2. Blocking degradation of IkappaB-a by PDTC was contributed to decrease the expression of iNOS. And the level of MDA and the release of LDH were also significantly reduced by using PDTC. However, the degree of COX-2 expression does not differ significantly between SWL and SWL + PDTC groups. Activation of NFkappaB and subsequent expression of its target cytotoxic enzyme have been demonstrated to be a potential and crucial mechanism in SWL-induced renal cell damage. Blocking this pathway by PDTC is contributed to protect against cellular damage from shock wave.

Rapid communication: renal apoptosis after shockwave application in rabbit model

PURPOSE

To identify any apoptotic effect of shockwave lithotripsy (SWL) on renal tubular and glomerular cells.

MATERIALS AND METHODS

Thirty-five male New Zealand White rabbits were divided into five groups of seven rabbits each: I (control), II (sham), and III, IV, and GV (treated and sacrificed 1, 7, and 28 days after SWL, respectively). Intramuscular anesthetic agent (ketamine HCl; 20 mg/kg) and intravenous contrast medium (iohexol 300 mg of I/mL) were administered to animals in group II. The left kidneys of animals in groups III, IV, and V were exposed to 2000 shockwaves at 18 kV after administration of anesthesia and contrast medium. The animals were sacrificed on day 1, 7, or 28 after SWL, and the kidneys were removed. Apoptotic and proliferative indices of renal tubular and glomerular cells were determined by terminal deoxynucleotidyl transferase dUTP nick and label (TUNEL) and Ki-67 labeling methods, respectively, counting 1000 cells in each preparation.

RESULTS

No apoptosis was detected in glomerular cells in any group. The mean apoptotic indices of the tubular cells in animals in groups I and II were 483.0 +/- 85 and 484.4 +/- 105, respectively with no significant difference between the groups. In groups III and IV, the mean apoptotic indices were 343.4 +/- 89 and 358.4 +/- 61, respectively. There were no statistically significant differences between groups III and IV and the control group. Similarly, there were no significant differences in the apoptotic indices in groups III and IV. However, the apoptotic index in group V was 821.4 +/- 57, significantly higher than in the control group. The proliferative indices of all SWL groups were lower than that of the control group.

CONCLUSION

Shockwave lithotripsy has an apoptotic effect on renal tubular cells that can be detected 4 weeks after the procedures, but no apoptotic effect on glomerular cells. Treatment with SWL also attenuates the proliferation of both tubular and glomerular cells.

The effect of shock wave lithotripsy on nitric oxide and malondialdehyde levels in plasma and urine samples

Shock wave lithotripsy (SWL) is accepted as the first treatment choice for most urinary stones, but it has adverse effects on the kidneys. The mechanisms underlying shock wave-induced renal injury have been discussed and include shear stress, thermal and cavitation effects and free radical formation. We investigated the effects of SWL on plasma and urinary nitrite, a stable metabolite of nitric oxide (NO), and malondialdehyde (MDA) concentrations. Between February and October 2004, 12 men and 8 women with renal calculi were treated using a Dornier MPL-9000 lithotriptor. The ages ranged from 22 to 45 years (average age: 33.7 years). Plasma and urinary NO and MDA levels were analysed before, immediately after, 30 and 60 min and 24 h after SWL. Plasma NO levels were higher than baseline levels immediately, and at 30, 60 min and 24 h after treatment (p = 0.016, p = 0.031, p = 0.033 and p = 0.045, respectively). Simultaneously, the mean urinary NO levels also showed significant elevation after SWL compared with baseline values, except for 24 h (p = 0.021, p = 0.023 and p = 0.048, respectively). The mean levels of plasma MDA showed statistically significant elevation immediately, and 30 and 60 min after SWL termination compared with pre-SWL values (p = 0.012, p = 0.008 and p = 0.012, respectively). Urinary MDA levels obtained immediately (p = 0.035), and 30 (p = 0.006) and 60 (p = 0.045) min after SWL were increased compared to pre-SWL values. We speculate that SWL treatment causes oxidative stress caused by renal ischemia-reperfusion (I/R) injury. Additionally, the increase of NO production may have prevented renal damage caused by vasoconstriction.

A novel antioxidant agent, astragalosides, prevents shock wave-induced renal oxidative injury in rabbits

Extracorporeal shock-wave lithotripsy (ESWL)-induced renal damage can occur as a result of multiple mechanisms, including small vessel injury and free radical formation. Our previous studies have demonstrated that Astragalus membranaceus (AM), a traditional Chinese herb, could significantly alleviate shock wave-induced renal oxidative injury, and its renoprotective effects were superior to those of varapamil, a calcium antagonist, which were considered to be a powerful agent in treating renal damage during ESWL. However, the effective antioxidant ingredient of this herb in the setting of lithotripsy remains unclear. Astragalosides, the major components of AM, was demonstrated to have superior antioxidation properties both in vitro and in vivo. Therefore, in this study we further investigate the potential effects of astragalosides on the shock wave-induced oxidative stress in rabbit kidney. Thirty male rabbits were randomly assigned to two groups, each consisting of 15 rabbits: (1) control group, (2) astragaloside-treated group. Each group of animals underwent 1,500 shock waves to the right kidney. Peripheral blood, urine and kidney tissue samples were collected pre- and post-ESWL. The level of urinary N-acetyl-beta-glucosaminidase (NAG), serum creatinine, serum or homogenates malondialdehyde (MDA) and superoxide dismutase (SOD), respectively, were detected. Histological alterations were also examined through light microcopy and transmission electron microscopy. In the control group, shock wave significantly increased the level of MDA and decreased SOD activity in both blood and renal homogenates (P<0.05, respectively). The comparison between the control and astragalosides group demonstrated that astragalosides could significantly decrease the level of MDA (P<0.05) and inhibit the decline of SOD activity (P<0.05). After exposure to shock waves, the activity of urinary NAG increased significantly in the control group (P<0.05). However, the concentration of serum creatinine did not change significantly. The comparison between the control and astragalosides group demonstrated that astragalosides significantly reduced the shock wave-induced leakage of NAG into the urine (P<0.05). Histological examination also showed that renal morphological impairments were much milder in astragaloside-treated rabbits than those of the control group. Our results indicated that astragaloside treatment provided significant protection against shock wave-induced renal oxidative injury.

Morphological changes induced in the pig kidney by extracorporeal shock wave lithotripsy: nephron injury

While shock wave lithotripsy (SWL) is known to cause significant damage to the kidney, little is known about the initial injury to cells along the nephron. In this study, one kidney in each of six juvenile pigs (6-7 weeks old) was treated with 1,000 shock waves (at 24 kV) directed at a lower pole calyx with an unmodified HM-3 lithotripter. Three pigs were utilized as sham-controls. Kidneys were fixed by vascular perfusion immediately after SWL or sham-SWL. Three of the treated kidneys were used to quantitate lesion size. Cortical and medullary samples for light (LM) and transmission electron microscopy (TEM) were taken from the focal zone for the shock waves (F2), the contralateral kidney, and the kidneys of sham-SWL pigs. Because preservation of the tissue occurred within minutes of SWL, the initial injury caused by the shock waves could be separated from secondary changes. No tissue damage was observed in contralateral sham-SWL kidneys, but treated kidneys showed signs of injury, with a lesion of 0.2% +/- 0.1% of renal volume. Intraparenchymal hemorrhage and injury to tubules was found at F2 in both the cortex and medulla of SWL-treated kidneys. Tubular injury was always associated with intraparenchymal bleeding, and the range of tissue injury included total destruction of tubules, focal cellular fragmentation, necrosis, cell vacuolization, and membrane blebbing. The initial injury caused by SWL was cellular fragmentation and necrosis. Cellular vacuolization, membrane blebbing, and disorganization of apical brush borders appear to be secondary changes related to hypoxia.