Combined insulin and bicarbonate therapy elicits cerebral edema in a juvenile mouse model of diabetic ketoacidosis

Brain injury in children with diabetic ketoacidosis: Review of the literature and a proposed pathophysiologic pathway for the development of cerebral edema

Cerebral edema (CE) is a potentially devastating complication of diabetic ketoacidosis (DKA) that almost exclusively occurs in children. Since its first description in 1936, numerous risk factors have been identified; however, there continues to be uncertainty concerning the mechanisms that lead to its development. Currently, the most widely accepted hypothesis posits that CE occurs as a result of ischemia-reperfusion injury, with inflammation and impaired cerebrovascular autoregulation contributing to its pathogenesis. The role of specific aspects of DKA treatment in the development of CE continues to be controversial. This review critically examines the literature on the pathophysiology of CE and attempts to categorize the findings by types of brain injury that contribute to its development: cytotoxic, vasogenic, and osmotic. Utilizing this scheme, we propose a multifactorial pathway for the development of CE in patients with DKA.

The therapeutic importance of acid-base balance

Baking soda and vinegar have been used as home remedies for generations and today we are only a mouse-click away from claims that baking soda, lemon juice, and apple cider vinegar are miracles cures for everything from cancer to COVID-19. Despite these specious claims, the therapeutic value of controlling acid-base balance is indisputable and is the basis of Food and Drug Administration-approved treatments for constipation, epilepsy, metabolic acidosis, and peptic ulcers. In this narrative review, we present evidence in support of the current and potential therapeutic value of countering local and systemic acid-base imbalances, several of which do in fact involve the administration of baking soda (sodium bicarbonate). Furthermore, we discuss the side effects of pharmaceuticals on acid-base balance as well as the influence of acid-base status on the pharmacokinetic properties of drugs. Our review considers all major organ systems as well as information relevant to several clinical specialties such as anesthesiology, infectious disease, oncology, dentistry, and surgery.

The activation of retinal HCA2 receptors by systemic beta-hydroxybutyrate inhibits diabetic retinal damage through reduction of endoplasmic reticulum stress and the NLRP3 inflammasome

OBJECTIVE

The role of the hydroxycarboxylic acid receptor 2 (HCA2) in the retinal damage induced by diabetes has never been explored. In this context, the present study highlights an upregulation of retinal HCA2 receptors in diabetic C57BL6J mice. Moreover, we illustrate that HCA2 receptors exert an anti-inflammatory effect on the retinal damage induced by diabetes when activated by the endogenous ligand β-hydroxybutyrate.

METHODOLOGY

Seven-to-10-week-old C57BL6J mice were rendered diabetic by a single intraperitoneal injection of streptozotocin (75 mg/kg of body weight) and monitored intermittently over a 10-week period extending from the initial diabetes assessment. Mice with a fasting blood glucose level higher than 250 mg/dl for 2 consecutive weeks after streptozotocin injection were treated twice a week with intraperitoneal injections of 25-50-100 mg/kg β-hydroxybutyrate.

RESULTS

Interestingly, while the retinal endoplasmic reticulum stress markers (pPERK, pIRE1, ATF-6α) were elevated in diabetic C57BL6J mice, their levels were significantly reduced by the systemic intraperitoneal treatment with 50 mg/kg and 100 mg/kg β-hydroxybutyrate. These mice also exhibited high NLRP3 inflammasome activity and proinflammatory cytokine levels. In fact, the elevated levels of retinal NLRP3 inflammasome activation markers (NLRP3, ASC, caspase-1) and of the relative proinflammatory cytokines (IL-1β, IL-18) were significantly reduced by 50 mg/kg and 100 mg/kg β-hydroxybutyrate treatment. These doses also reduced the high apoptotic cell number exhibited by the diabetic mice in the retinal outer nuclear layer (ONL) and increased the ONL low connexin 43 expression, leading to an improvement in retinal permeability and homeostasis.

CONCLUSIONS

These data suggest that the systemic treatment of diabetic C57BL6J mice with BHB activates retinal HCA2 and inhibits local damage.

A Rare and Lethal Complication: Cerebral Edema in the Adult Patient with Diabetic Ketoacidosis

Commonly seen in the emergency department, diabetic ketoacidosis is a potentially lethal sequela of uncontrolled diabetes mellitus. In the adult population, a rare complication of diabetic ketoacidosis is cerebral edema. This case report discusses a 26-year-old male with new onset diabetes mellitus who developed cerebral edema leading to death.

Clinical Efficacy of Stem Cell Therapy for Diabetes Mellitus: A Meta-Analysis

BACKGROUND

Stem cell therapy is a promising therapeutic modality for advanced diabetes mellitus (DM). This study presents a meta-analysis of relevant clinical trials to determine the efficacy of stem cell therapy in DM. We aim to critically evaluate and synthesize clinical evidence on the safety and efficiency of different types of stem cell therapy for both T1DM and T2DM.

METHODS AND FINDINGS

We pooled participant-level data from twenty-two eligible clinical trials that satisfied our inclusion criteria, with a total of 524 patients. There were significant differences in the outcome based on the type and source of the infused cells. Out of all T1DM patients who received CD34+ hematopoietic stem cell (HSC) infusion, 58.9% became insulin independent for a mean period of 16 months, whereas the results were uniformly negative in patients who received umbilical cord blood (UCB). Infusion of umbilical cord mesenchymal stem cells (UC-MSCs) provided significantly beneficial outcome in T1DM, when compared to bone-marrow mesenchymal stem cells (BM-MSCs) (P<0.0001 and P = 0.1557). Administration of stem cell therapy early after DM diagnosis was more effective than intervention at later stages (relative risk = 2.0, P = 0.0008). Adverse effects were observed in only 21.72% of both T1DM and T2DM stem cell recipients with no reported mortality. Out of all poor responders, 79.5% were diagnosed with diabetic ketoacidosis.

CONCLUSIONS

Stem cell transplantation can represent a safe and effective treatment for selected patients with DM. In this cohort of trials, the best therapeutic outcome was achieved with CD34+ HSC therapy for T1DM, while the poorest outcome was observed with HUCB for T1DM. Diabetic ketoacidosis impedes therapeutic efficacy.

Simulated diabetic ketoacidosis therapy in vitro elicits brain cell swelling via sodium-hydrogen exchange and anion transport

A common complication of type 1 diabetes mellitus is diabetic ketoacidosis (DKA), a state of severe insulin deficiency. A potentially harmful consequence of DKA therapy in children is cerebral edema (DKA-CE); however, the mechanisms of therapy-induced DKA-CE are unknown. Our aims were to identify the DKA treatment factors and membrane mechanisms that might contribute specifically to brain cell swelling. To this end, DKA was induced in juvenile mice with the administration of the pancreatic toxins streptozocin and alloxan. Brain slices were prepared and exposed to DKA-like conditions in vitro. Cell volume changes were imaged in response to simulated DKA therapy. Our experiments showed that cell swelling was elicited with isolated DKA treatment components, including alkalinization, insulin/alkalinization, and rapid reductions in osmolality. Methyl-isobutyl-amiloride, a nonselective inhibitor of sodium-hydrogen exchangers (NHEs), reduced cell swelling in brain slices elicited with simulated DKA therapy (in vitro) and decreased brain water content in juvenile DKA mice administered insulin and rehydration therapy (in vivo). Specific pharmacological inhibition of the NHE1 isoform with cariporide also inhibited cell swelling, but only in the presence of the anion transport (AT) inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid. DKA did not alter brain NHE1 isoform expression, suggesting that the cell swelling attributed to the NHE1 was activity dependent. In conclusion, our data raise the possibility that brain cell swelling can be elicited by DKA treatment factors and that it is mediated by NHEs and/or coactivation of NHE1 and AT.

How can cerebral edema during treatment of diabetic ketoacidosis be avoided?

Cerebral edema during diabetic ketoacidosis (DKA) is a rare complication but it can be devastating, with significant mortality and long-term morbidity. Certain risk factors have been teased out with some large case-control studies, but more research needs to be done to make management guidelines safer. This article will discuss how DKA might be prevented from occurring in the first instance, known risk factors for cerebral edema, fluid and insulin management, the importance of careful monitoring during DKA treatment, and the importance of recognizing and acting on the earliest symptoms to prevent long-term harm.

CXCL1/CXCL8 (GROα/IL-8) in human diabetic ketoacidosis plasma facilitates leukocyte recruitment to cerebrovascular endothelium in vitro

Diabetic ketoacidosis (DKA) in children is associated with intracranial vascular complications, possibly due to leukocyte-endothelial interactions. Our aim was to determine whether DKA-induced inflammation promoted leukocyte adhesion to activated human cerebrovascular endothelium. Plasma was obtained from children with type 1 diabetes either in acute DKA or in an insulin-controlled state (CON). Plasma concentrations of 21 inflammatory analytes were compared between groups. DKA was associated with altered circulating levels of ↑CXCL1 (GROα), ↑CXCL8 (IL-8), ↑IL-6, ↑IFNα2, and ↓CXCL10 (IP-10) compared with CON. These plasma analyte measurements were then used to create physiologically relevant cytokine mixtures (CM). Human cerebral microvascular endothelial cells (hCMEC/D3) were stimulated with either plasma (DKA-P or CON-P) or CM (DKA-CM or CON-CM) and assessed for polymorphonuclear leukocyte (PMN) adhesion. Stimulation of hCMEC/D3 with DKA-P or DKA-CM increased PMN adhesion to hCMEC/D3 under "flow" conditions. PMN adhesion to hCMEC/D3 was suppressed with neutralizing antibodies to CXCL1/CXCL8 or their hCMEC/D3 receptors CXCR1/CXCR2. DKA-P, but not DKA-CM, initiated oxidative stress in hCMEC/D3. Expression of ICAM-1, VCAM-1, and E-selectin were unaltered on hCMEC/D3 by either DKA-P or DKA-CM. In summary, DKA elicits inflammation in children associated with changes in circulating cytokines/chemokines. Increased CXCL1/CXCL8 instigated PMN adhesion to hCMEC/D3, possibly contributing to DKA-associated intracranial vascular complications.

Diabetic ketoacidosis elicits systemic inflammation associated with cerebrovascular endothelial cell dysfunction

OBJECTIVE

To determine if the DKA-induced inflammation in juvenile mice provokes activation and dysfunction of CVECs.

METHODS

DKA in juvenile mice was induced with administration of STZ and ALX. Blood from DKA mice was assessed for cytokines and soluble cell adhesion proteins, and either DKA plasma or exogenous compounds were applied to immortalized bEND3.

RESULTS

DKA increased circulating levels of IL-6, IL-8(KC), MCP-1, IL-10, sE-selectin, sICAM-1, and sVCAM-1. Stimulation of bEND3 with DKA plasma caused cellular activation (increased ROS and activation of NF-κΒ), upregulation of a proadhesive phenotype (E-selectin, ICAM-1, and VCAM-1), and increased leukocyte-bEND3 interaction (leukocyte rolling/adhesion). TEER, a measure of bEND3 monolayer integrity, was decreased by DKA plasma. Activation and dysfunction of bEND3 with DKA plasma were suppressed by plasma heat treatment (56°C, 1 hour) and replicated with the application of DKA recombinant cytomix (IL-6, IL-8[KC], MCP-1, and IL-10), implicating circulating inflammatory protein(s) as mediators. Treatment of bEND3 with β-OH-butyrate, the main ketone elevated in DKA, failed to mimic the DKA plasma-induced activation and dysfunction of bEND3.

CONCLUSIONS

DKA elicits systemic inflammation associated with CVEC activation and dysfunction, possibly contributing to DKA-associated intracranial microvascular complications.

GPR109A as an anti-inflammatory receptor in retinal pigment epithelial cells and its relevance to diabetic retinopathy

PURPOSE

Retinal pigment epithelium (RPE) expresses GPR109A, a receptor for the vitamin niacin and the ketone body β-hydroxybutyrate (β-HB). Because diabetes results in elevated levels of β-HB, here we studied expression of the receptor in diabetic retina. We also investigated its functional relevance in RPE.

METHODS

Retinal expression of GPR109A in diabetic mice and postmortem human eyes was evaluated by quantitative PCR (qPCR). ARPE-19 cells and primary wild-type and Gpr109a(-/-) mouse RPE cells were exposed to TNF-α in the presence or absence of niacin or β-HB, followed by analysis of IL-6 and Ccl2 expression via real-time qPCR and ELISA.

RESULTS

GPR109A expression was increased in diabetic mouse and human retina. TNF-α increased the expression and secretion of IL-6 and Ccl2 in ARPE-19 cells. Niacin and β-HB suppressed these effects, implicating GPR109A as the target responsible for mediation of the observed effects. Primary RPE cells from wild-type mice behaved similarly. In contrast, GPR109A ligands failed to suppress TNF-α-induced expression and secretion of IL-6 and Ccl2 in primary RPE cells from Gpr109a(-/-) mice, confirming that the observed anti-inflammatory effects were mediated specifically by Gpr109a.

CONCLUSIONS

GPR109A plays an anti-inflammatory role in RPE and its expression is upregulated in diabetes. Inflammation is a key causative factor in the pathogenesis of diabetic retinopathy. We speculate that the increased expression of GPR109A and elevation of its ligand β-HB in diabetes are mechanisms by which the tissue attempts to fight inflammation in this disease. Pharmacological activation of GPR109A may therefore have therapeutic potential in clinical management of diabetic retinopathy.

Risk factors for cerebral edema in diabetic ketoacidosis in a developing country: role of fluid refractory shock

OBJECTIVES

To study the clinical profile and risk factors of cerebral edema in children with diabetic ketoacidosis with specific reference to fluid refractory shock.

DESIGN

Retrospective review of medical records.

SETTING

Twelve-bed pediatric intensive care unit of a teaching hospital.

PATIENTS

Seventy-seven patients admitted to pediatric intensive care unit with a diagnosis of diabetic ketoacidosis over 5 yrs.

INTERVENTION

Medical records were reviewed, and data with respect to patients' age, clinical features, biochemical profile (blood glucose, osmolality, electrolytes, urea, creatinine, arterial pH, PaCO(2), and HCO(3) at admission, 6-12 hrs, 24 hrs, and beyond 24 hrs), cerebral edema, presence of sepsis and shock, treatment details, and primary outcome in terms of survival or death were retrieved. Patients with and without cerebral edema were compared. Variables that were significant on univariate analysis were entered in a multiple logistic regression analysis to determine the predictors for cerebral edema. Odds ratio and 95% confidence interval were calculated using SPSS version 15.

MEASUREMENTS AND MAIN RESULTS

Mean age of the patients was 5.6 (standard deviation, 3.8) years. Fifty-five (71.4%) patients had new-onset diabetes mellitus. Cerebral edema was seen in 20 patients (26%). Blood glucose, serum osmolality, and CO(2) values at admission and rate of decline in glucose and osmolality during the first 12 hrs were similar in the cerebral edema and noncerebral edema groups. On multiple logistic regression analysis, fluid refractory shock (odds ratio, 7.3; 95% confidence interval, 1.3-41; p = .025) and presence of azotemia (odds ratio, 4.3; 95% confidence interval, 1.1-16; p = .034) at admission were predictors for development of cerebral edema. Mortality in cerebral edema group was 25% as compared to 3% in the noncerebral edema group.

CONCLUSIONS

Patients with fluid refractory shock and azotemia at admission had higher odds for development of cerebral edema. Initial blood glucose, effective osmolality, or decline in glucose and osmolality had no association with cerebral edema.

Sodium concentration in rehydration fluids for children with ketoacidotic diabetes: effect on serum sodium concentration

OBJECTIVES

To analyze in a retrospective cohort if sodium concentration in the rehydration fluids influence natremia in children with diabetic ketoacidosis (DKA).

STUDY DESIGN

Consecutive episodes of diabetic ketoacidosis admitted in a tertiary care referral center from 2000 to 2005. Rehydration was programmed for 48 hours with a 2-bag system. Initial rehydration was performed with isotonic fluids and thereafter with variable tonicity. Analysis of the influence of the different factors on natremia was performed with a multivariate linear regression analysis.

RESULTS

Forty-two episodes of DKA were reviewed. Increased sodium content in rehydration fluids behaved as an independent variable, causing a positive tendency of natremia (P < .008).

CONCLUSIONS

Sodium concentration in the rehydration fluids behaves as an independent factor that influences positively the trend of the serum concentration of sodium during DKA rehydration. We propose the use of isotonic solutions for rehydration in diabetic ketoacidosis.

An evaluation of the outside therapy of diabetic ketoacidosis in pediatric patients

BACKGROUND

Despite literature outlining suggested initial therapy for pediatric patients with diabetic ketoacidosis (DKA), our impression has been that there may be variations from these recommendations during the initial therapy of pediatric patients with DKA. In order to improve education initiatives, an understanding of the deviations from current practice is required.

METHODS

Patients admitted to the pediatric intensive care unit with a diagnosis of DKA were identified from the admission log. The pre-pediatric intensive care unit care including laboratory evaluation, insulin dosing, and fluid therapy was recorded.

RESULTS

The study cohort included 135 episodes of DKA in 127 patients (age range: 10 months to 21 years). A complete blood count was obtained in 83.7% of the patients. Serum electrolytes, blood urea nitrogen, and creatinine were obtained in 89.6%, and a serum pH was obtained in 58%. Seventy-two patients received a bolus dose of insulin. The insulin bolus was < or =0.05 units/kg in 1 patient, >0.05 to < or =0.1 units/kg in 13 patients, >0.1 to < or =0.2 units/kg in 27 patients, and >0.2 units/kg in 31 patients. The route of administration for the insulin bolus was intravenous (IV) in 58 patients, a combination of IV and subcutaneous in 7 patients, subcutaneous in 6, and a combination of intramuscular and IV in 1 patient. Fluid administered before transport ranged from 0 to 60.6 mL/kg. Sixteen patients did not receive a fluid bolus. Normal saline was used in 115 patients, Ringer's lactate solution in 3, and 5% glucose in (1/2) normal saline in 1. Seventeen patients (12.6%) received IV sodium bicarbonate.

CONCLUSIONS

Major issues with the prehospital care of children and adolescents with DKA included lack of appropriate laboratory evaluation, excessive insulin dosing (both bolus doses and infusion rates), lack of fluid resuscitation, use of inappropriate fluids for resuscitation, and the use of sodium bicarbonate.

Diabetic ketoacidosis in the pediatric ICU

Diabetic ketoacidosis (DKA) is a common, life-threatening complication of diabetes mellitus in children. Central nervous system changes seen in DKA include the altered sensorium seen commonly in DKA and loosely characterized as diabetic coma and the uncommon but worrisome progressively deepening coma caused by cerebral edema, which has both a high morbidity and mortality. This article discusses the assessment and treatment of DKA in the setting of the pediatric ICU.