Approach to Acute Kidney Injuries in the Emergency Department

Insights into the protective capacity of human dental pulp stem cells and its secretome in cisplatin-induced nephrotoxicity: effects on oxidative stress and histological changes

OBJECTIVES

Acute renal injury (AKI) is a major limiting factor for cisplatin administration. Recent evidence suggests the potential contribution of mesenchymal stem cells (MSCs) to rehabilitation from several disorders via both direct and indirect routes. Thus, the present study aimed, for the first time, to explore and compare the reno-protective potential of human dental pulp-derived stem cells (hDPSCs) vs. hDPSC-conditioned medium (hDPSC-CM) in recovery of impaired kidney tissues in a rat animal model of cisplatin-induced AKI.

METHODS

AKI was induced via cisplatin injection (n=36). One day after, 24 rats were treated with either hDPSCs or hDPSC-CM (n=12). An extra set of rats (n=12) served as sham group. On days 2 or 7 (n=6), rats were humanly sacrificed for further analysis. Renal injury was explored via measuring serum creatinine and BUN. Renal level of oxidative stress was assessed by determining malondialdehyde, and enzymatic activities of superoxide dismutase and catalase. Renal histopathological changes were scored for comparison among different experimental groups.

RESULTS

A single dose of cisplatin resulted in considerable renal dysfunction and oxidative stress. Treatment with hDPSCs or hDPSC-CM resulted in significantly restored renal function, reduced level of oxidative stress, and improved histopathological manifestations. Furthermore, as compared to hDPSC-CM, administration of hDPSCs led to superior results in AKI-induced animals.

CONCLUSIONS

The current study described the first comparative evidence of reno-protective potential of hDPSCs and their CM against cisplatin-induced nephrotoxicity in an AKI rat model, proposing them as useful adjunctive therapy in AKI. Yet, future explorations are still needed.

Phenotype and genotype of 197 British patients with McArdle disease: An observational single-centre study

McArdle disease is caused by recessive mutations in PYGM gene. The condition is considered to cause a "pure" muscle phenotype with symptoms including exercise intolerance, inability to perform isometric activities, contracture, and acute rhabdomyolysis leading to acute renal failure. This is a retrospective observational study aiming to describe phenotypic and genotypic features of a large cohort of patients with McArdle disease between 2011 and 2019. Data relating to genotype and phenotype, including frequency of rhabdomyolysis, fixed muscle weakness, gout and comorbidities, inclusive of retinal disease (pattern retinal dystrophy) and thyroid disease, were collected. Data from 197 patients are presented. Seven previously unpublished PYGM mutations are described. Exercise intolerance (100%) and episodic rhabdomyolysis (75.6%) were the most common symptoms. Fixed muscle weakness was present in 82 (41.6%) subjects. Unexpectedly, ptosis was observed in 28 patients (14.2%). Hyperuricaemia was a common finding present in 88 subjects (44.7%), complicated by gout in 25% of cases. Thyroid dysfunction was described in 30 subjects (15.2%), and in 3 cases, papillary thyroid cancer was observed. Pattern retinal dystrophy was detected in 15 out of the 41 subjects that underwent an ophthalmic assessment (36.6%). In addition to fixed muscle weakness, ptosis was a relatively common finding. Surprisingly, dysfunction of thyroid and retinal abnormalities were relatively frequent comorbidities. Further studies are needed to better clarify this association, although our finding may have important implication for patient management.

Acetylbritannilactone attenuates contrast-induced acute kidney injury through its anti-pyroptosis effects

Contrast-induced acute kidney injury (CI-AKI) is a severe complication caused by intravascular applied radial contrast media (CM). Pyroptosis is a lytic type of cell death inherently associated with inflammation response and the secretion of pro-inflammatory cytokines following caspase-1 activation. The aim of the present study was to investigate the protective effects of acetylbritannilactone (ABL) on iopromide (IOP)-induced acute renal failure and reveal the underlying mechanism. In vivo and in vitro, IOP treatment caused renal damage and elevated the caspase-1 (+) propidium iodide (PI) (+) cell count, interleukin (IL)-1β and IL-18 levels, lactate dehydrogenase (LDH) release, and the relative expression of nucleotide-binding domain, leucine-rich repeat containing protein 3 (NLRP3), apoptosis-associated speck-like protein (ASC), and gasdermin D (GSDMD), suggesting that IOP induces AKI via the activation of pyroptosis. Furthermore, the pretreatment of ABL partly mitigated the CI-AKI, development of pyroptosis, and subsequent kidney inflammation. These data revealed that ABL partially prevents renal dysfunction and reduces pyroptosis in CI-AKI, which may provide a therapeutic target for the treatment of CM-induced AKI.

Genitourinary Emergencies in Older Adults

Older adults are frequently seen in the emergency department for genitourinary complaints, necessitating that emergency physicians are adept at managing a myriad of genitourinary emergencies. Geriatric patients may present with acute kidney injury, hematuria, or a urinary infection and aspects of how managing these presentations differs from their younger counterparts is emphasized. Older adults may also present with acute urinary retention or urinary incontinence as a result of genitourinary pathology or other systemic etiologies. Finally, genital complaints as they pertain to older adults are briefly highlighted with emphasis on emergent management and appropriate referrals.

Toll-like receptor 4: An attractive therapeutic target for acute kidney injury

Acute kidney injury (AKI) is a progressive renal complication which significantly affects the patient's life with huge economic burden. Untreated acute kidney injury eventually progresses to a chronic form and end-stage renal disease. Although significant breakthroughs have been made in recent years, there are still no effective pharmacological therapies for the treatment of acute kidney injury. Toll-like receptor 4 (TLR4) is a well-characterized pattern recognition receptor, and increasing evidence has shown that TLR4 mediated inflammatory response plays a pivotal role in the pathogenesis of acute kidney injury. The expression of TLR4 has been seen in resident renal cells, including podocytes, mesangial cells, tubular epithelial cells and endothelial cells. Activation of TLR4 signaling regulates the transcription of numerous pro-inflammatory cytokines and chemokines, resulting in renal inflammation. Therefore, targeting TLR4 and its downstream effectors could serve as an effective therapeutic intervention to prevent renal inflammation and subsequent kidney damage. For the first time, this review summarizes the literature on acute kidney injury from the perspective of TLR4 from year 2010 to 2020. In the current review, the role of TLR4 signaling pathway in AKI with preclinical evidence is discussed. Furthermore, we have highlighted several compounds of natural and synthetic origin, which have the potential to avert the renal TLR4 signaling in preclinical AKI models and have shown protection against AKI. This scientific review provides new ideas for targeting TLR4 in the treatment of AKI and provides strategies for the drug development against AKI.

Immunopathophysiology of trauma-related acute kidney injury

Physical trauma can affect any individual and is globally accountable for more than one in every ten deaths. Although direct severe kidney trauma is relatively infrequent, extrarenal tissue trauma frequently results in the development of acute kidney injury (AKI). Various causes, including haemorrhagic shock, rhabdomyolysis, use of nephrotoxic drugs and infectious complications, can trigger and exacerbate trauma-related AKI (TRAKI), particularly in the presence of pre-existing or trauma-specific risk factors. Injured, hypoxic and ischaemic tissues expose the organism to damage-associated and pathogen-associated molecular patterns, and oxidative stress, all of which initiate a complex immunopathophysiological response that results in macrocirculatory and microcirculatory disturbances in the kidney, and functional impairment. The simultaneous activation of components of innate immunity, including leukocytes, coagulation factors and complement proteins, drives kidney inflammation, glomerular and tubular damage, and breakdown of the blood-urine barrier. This immune response is also an integral part of the intense post-trauma crosstalk between the kidneys, the nervous system and other organs, which aggravates multi-organ dysfunction. Necessary lifesaving procedures used in trauma management might have ambivalent effects as they stabilize injured tissue and organs while simultaneously exacerbating kidney injury. Consequently, only a small number of pathophysiological and immunomodulatory therapeutic targets for TRAKI prevention have been proposed and evaluated.