The Interaction of Central Nervous System and Acute Kidney Injury: Pathophysiology and Clinical Perspectives

Incidence and predictors of acute kidney injury among traumatic brain injury patients in Northwest Ethiopia: a cohort study using survival analysis

BACKGROUND

Acute kidney injury (AKI) is a sudden and reversible decrease in kidney function, causing the retention of waste products in the blood and potentially resulting in severe complications or death if not timely managed. Studies on AKI among traumatic brain injury patients in low-income nations like Ethiopia is very critical due to the limited healthcare resources, high burden of trauma-related injuries, and lack of robust data on the incidence and risk factors of AKI in such settings, which hinders effective prevention and treatment strategies tailored to these vulnerable populations Therefore, this study aimed to assess the incidence and predictors of AKI among traumatic brain injury patients.

METHODS

A retrospective cohort study was conducted among 450 adult patients with traumatic brain injuries admitted to Tibebe-Ghion Specialized Hospital in Ethiopia. Kaplan- Meir curve and Log rank test were used to estimate and compare survival probability of different categories. A multivariable Cox proportional hazards model was used to identify determinants of acute kidney injury (AKI).

RESULTS

The incidence of AKI was 10.9%, with a median follow-up period of 42 days. Significant predictors of AKI among traumatic brain injury patients included age (AHR: 1.05, 95% CI: 1.02-1.07), severe head injury (AHR: 1.46, 95% CI: 1.02-2.09), unreactive pupillary response (AHR: 4.82, 95% CI: 1.82-12.72), and hypotension (AHR: 3.45, 95% CI: 1.71-6.96).

CONCLUSIONS

The study found that AKI occurs in more than one in ten patients with traumatic brain injuries, with significant predictors including older age, severe head injury, unreactive pupillary response, and hypotension. These findings highlight the need for careful monitoring and early intervention for high-risk patients to prevent AKI and improve overall outcomes. Implementing targeted prevention and treatment strategies in settings with limited resources can help mitigate the burden of AKI and enhance patient care in vulnerable populations.

A Review of the Risk Factors and Management of Refractory Hypertension: The Role of Carotid Sinus Stimulation and Renal Nerve Denervation

Hypertension (HTN) is a significant health concern, with a recent increase in HTN-related cardiovascular deaths in the United States. Refractory hypertension, a form of treatment-resistant HTN, poses a challenge for physicians and patients due to its association with increased morbidity and mortality. Risk factors for refractory HTN include African ancestry, female gender, younger age, diabetes mellitus, obesity, obstructive sleep apnea, chronic kidney disease, end-stage renal disease, and smoking. While the exact pathophysiology of refractory HTN is not fully understood, sympathetic overdrive appears to be a significant contributing factor. Arterial stiffness, chronic kidney disease, obstructive sleep apnea, obesity, and diabetes mellitus are comorbid conditions associated with increased sympathetic activity and refractory HTN. The knowledge behind carotid sinus stimulation suggested promising outcomes due to the known physiology. However, the introduction of devices, surgical complications, and the development of new antihypertensive soon took over the innovation of these devices. The authors aim to highlight three important aspects related to refractory hypertension: the risk factors for the development of refractory hypertension, the role of surgery in managing hypertension, and the referral systems available for the management of refractory hypertension.

LncTCONS_00058568 is involved in the pathophysiologic processes mediated by P2X7R in the lower thoracic spinal cord after acute kidney injury

Acute kidney injury (AKI), a prevalent clinical syndrome, involves the participation of the nervous system in neuroimmune regulation. However, the intricate molecular mechanism that governs renal function regulation by the central nervous system (CNS) is complex and remains incompletely understood. In the present study, we found that the upregulated expression of lncTCONS_00058568 in lower thoracic spinal cord significantly ameliorated AKI-induced renal tissue injury, kidney morphology, inflammation and apoptosis, and suppressed renal sympathetic nerve activity. Mechanistically, the purinergic ionotropic P2X7 receptor (P2X7R) was overexpressed in AKI rats, whereas lncTCONS_00058568 was able to suppress the upregulation of P2X7R. In addition, RNA sequencing data revealed differentially expressed genes associated with nervous system inflammatory responses after lncTCONS_00058568 was overexpressed in AKI rats. Finally, the overexpression of lncTCONS_00058568 inhibited the activation of PI3K/Akt and NF-κB signaling pathways in spinal cord. Taken together, the results from the present study show that lncTCONS_00058568 overexpression prevented renal injury probably by inhibiting sympathetic nerve activity mediated by P2X7R in the lower spinal cord subsequent to I/R-AKI.

Stratification of Acute Kidney Injury Risk, Disease Severity, and Outcomes by Electrolyte Disturbances

Acute kidney injury (AKI) affects up to 30% of all hospitalized patients in Central Europe and the USA. New biomarker molecules have been identified in recent years; most studies performed so far however aimed to identify markers for diagnostic purposes. Serum electrolytes such as sodium and potassium are quantified in more or less all hospitalized patients. Aim of the article is to review the literature on the AKI predictive role of four distinct serum electrolytes in evolving/progressing AKI. The following databases were searched for references: PubMed, Web of Science, Cochrane Library, and Scopus. The period lasted from 2010 until 2022. The following terms were utilized: "AKI" AND "sodium" OR "potassium" OR "calcium" OR "phosphate" AND "risk" OR "dialysis" OR "recovery of kidney function" OR "renal recovery" OR "kidney recovery" OR "outcome". Finally, 17 references were selected. The included studies were mostly retrospective in nature. Particularly, hyponatremia has been shown to be associated with an overall poor clinical outcome. The association between dysnatremia and AKI is anything but consistent. Hyperkalemia and potassium variability are most likely AKI predictive. Serum calcium and AKI risk are associated in a U-shaped manner. Higher phosphate levels potentially predict AKI in non-coronavirus disease 2019 (COVID-19) patients. The literature suggests that admission electrolytes can offer valuable information about AKI onset during follow-up. Limited data are however available on follow-up characteristics such as the need for dialysis or the chance of renal recovery. These aspects are of particular interest from the nephrologist's perspective.

Protective Effects of Orexin A in a Murine Model of Cisplatin-Induced Acute Kidney Injury

Cisplatin is a chemotherapeutic agent widely used in the treatment of various cancers, but its application is often limited due to complications such as acute kidney injury (AKI). Orexins are hypothalamic neuropeptides that modulate the sleep-wake cycle, neuroendocrine function, and the autonomic nervous system. Emerging evidence suggests that orexin A (OXA) has anti-inflammatory and neuroprotective effects in animal models of neuroinflammatory diseases of the central nervous system. However, the effect of OXA on kidney diseases has not been examined. Here, we investigated whether OXA has a protective effect in a murine model of cisplatin-induced AKI. Intraperitoneal administration of OXA ameliorated renal dysfunction, and histological abnormalities in mice injected with cisplatin. OXA inhibited cisplatin-induced oxidative stress through the modulation of prooxidant and antioxidant enzymes. This peptide reduced apoptotic cell death by inhibiting the p53-mediated pathway in mice injected with cisplatin. OXA also alleviated cisplatin-induced cytokine production and macrophage infiltration into injured kidneys. Taken together, these results showed that OXA ameliorates cisplatin-induced AKI via antioxidant, anti-apoptotic, and anti-inflammatory actions. This peptide could be a potential therapeutic agent for cisplatin-induced AKI.

CNS and CNS diseases in relation to their immune system

The central nervous system is the most important nervous system in vertebrates, which is responsible for transmitting information to the peripheral nervous system and controlling the body's activities. It mainly consists of the brain and spinal cord, which contains rich of neurons, the precision of the neural structures susceptible to damage from the outside world and from the internal factors of inflammation infection, leading to a series of central nervous system diseases, such as traumatic brain injury, nerve inflammation, etc., these diseases may cause irreversible damage on the central nervous or lead to subsequent chronic lesions. After disease or injury, the immune system of the central nervous system will play a role, releasing cytokines to recruit immune cells to enter, and the immune cells will differentiate according to the location and degree of the lesion, and become specific immune cells with different functions, recognize and phagocytose inflammatory factors, and repair the damaged neural structure. However, if the response of these immune cells is not suppressed, the overexpression of some genes can cause further damage to the central nervous system. There is a need to understand the molecular mechanisms by which these immune cells work, and this information may lead to immunotherapies that target certain diseases and avoid over-activation of immune cells. In this review, we summarized several immune cells that mainly play a role in the central nervous system and their roles, and also explained the response process of the immune system in the process of some common neurological diseases, which may provide new insights into the central nervous system.