Liver involvement in dengue viral infections

Nine fatal cases of dengue: a case series from an intensive care unit in Sri Lanka

BACKGROUND

The case fatality rate of untreated dengue is 20%; it can be reduced to less than 1% with optimal management. The leading causes of death in dengue patients are shock, bleeding, and acute liver injury. We describe the clinical features of patients who died of dengue and discuss the therapeutic challenges and pitfalls of complicated dengue.

METHODS

This retrospective study was done in the intensive care unit (MICU) of the National Hospital of Sri Lanka over 30 months between 2021 and 2023. All patients who died of serologically confirmed dengue were incorporated.

RESULTS

Of the 1722 ICU admissions, 44 (2.6%) patients were treated for dengue-of them, 11 (25.0%) died. Two patients were excluded as their deaths were not directly linked to dengue. Six were females. The average age was 40.2 years. The leading causes of death included shock (n = 5), acute liver failure (n = 6), intracranial bleeding (n = 2), and pulmonary embolism (n = 1). Patient 1 had concomitant leakage and bleeding, which did not respond to fluids or blood products. He developed fluid overload and acute liver failure (ALF) and died of multiorgan dysfunction. Patients 2-5 were in shock for a prolonged period due to leakage ± bleeding. Patients 2-5 developed ALF and lactic acidosis followed by multiorgan dysfunction. Patient 8 developed acute hepatitis and ALF without preceding shock. The patient was treated with immunosuppressants for myasthenia gravis. Patients 6 and 7 experienced intracranial bleeding. Patient 9 died of pulmonary embolism after prolonged ventilation for dengue encephalitis.

CONCLUSIONS

Prolonged shock, fluid overload and acute liver failure were common causes of dengue related deaths, in our study. Fluid overload occurred when vigorous crystalloid resuscitation was continued in patients who were poorly responding. A prompt switch to colloids or blood could have prevented overload. Patients who were in shock for a prolonged period become unresponsive to fluid resuscitation. How to manage dengue in patients who take anti-inflammatory drugs, immunomodulators, or antiplatelets is not known. Balancing the bleeding risk of dengue in patients predisposed to bleeding or thrombosis is a challenge.

New biomarkers for liver involvement by dengue infection in adult Vietnamese patients: a case-control study

Liver injury with marked elevation of aspartate aminotransferase enzyme (AST) is commonly observed in dengue infection. To understand the pathogenesis of this liver damage, we compared the plasma levels of hepatic specific, centrilobular predominant enzymes (glutamate dehydrogenase, GLDH; glutathione S transferase-α, αGST), periportal enriched 4-hydroxyphenylpyruvate dioxygenase (HPPD), periportal predominant arginase-1 (ARG-1), and other non-specific biomarkers (paraoxonase-1, PON-1) in patients with different outcomes of dengue infection. This hospital-based study enrolled 87 adult dengue patients, stratified into three groups based on plasma AST levels (< 80, 80-400, > 400 U/L) in a 1:1:1 ratio (n = 40, n = 40, n = 40, respectively. The new liver enzymes in the blood samples from the 4th to 6th days of their illness were measured by commercial enzyme-linked immunosorbent assay (ELISA) or colorimetric kits. Based on the diagnosis at discharge days, our patients were classified as 40 (46%) dengue without warning signs (D), 35 (40.2%) dengue with warning signs (DWS), and 11 (12.6%) severe dengue (SD) with either shock (two patients) or AST level over 1000 U/L (nine patients), using the 2009 WHO classification. The group of high AST (> 400 U/L) also had higher ALT, GLDH, ARG-1, and HPPD than the other groups, while the high (> 400 U/L) and moderate (80-400 U/L) AST groups had higher ALT, αGST, ARG-1, and HPPD than the low AST group (< 80 U/L). There was a good correlation between AST, alanine aminotransferase enzyme (ALT), and the new liver biomarkers such as GLDH, αGST, ARG-1, and HPPD. Our findings suggest that dengue-induced liver damage initiates predominantly in the centrilobular area toward the portal area during the dengue progression. Moreover, these new biomarkers should be investigated further to explain the pathogenesis of dengue and to validate their prognostic utility.

Liver involvement in dengue: A systematic review

Liver involvement is an unusual yet frequently overlooked dengue complication. Pivotal for an efficient clinical management, the early diagnosis of dengue-associated liver involvement relies on an accurate description of its clinical and biological characteristics, its prognosis factors, its association with severe dengue and its clinical management. We conducted a systematic review by searching PubMed and Web of Science databases for original case reports, cohort and cross-sectional studies reporting the clinical and/or biological features of dengue-associated liver involvement. The study was registered in PROSPERO (CRD42021262657). Of the 2552 articles identified, 167 were included. Dengue-associated liver involvement was characterised by clinical features including abdominal pain, hepatomegaly, jaundice, nausea/vomiting, and an echogenic liver exhibiting hepatocellular necrosis and minimal inflammation. Elevated Aspartate Aminotransferase and Alanine Aminotransferase but also elevated bilirubin, Alkaline Phosphatase, gamma-glutamyl transferase, increased International Normalised Ratio, creatinine and creatine kinase, lower albumin and prolonged prothrombin and activated partial thromboplastin time were prevalent in dengue-associated liver involvement. Cardiovascular and haematological systems were frequently affected, translating in a strong association with severe dengue. Liver involvement was more common in males and older adults. It was associated with dengue virus serotype-2 and secondary infections. Early paracetamol intake increased the risk of liver involvement, which clinical management was mostly conservative. In conclusion, this systematic review demonstrates that early monitoring of transaminases, clinical assessment, and ultrasound examination allow an efficient diagnosis of dengue-associated liver involvement, enabling the early identification and management of severe dengue.

Glycolysis is reduced in dengue virus 2 infected liver cells

Infections with dengue virus (DENV) remain a worldwide public health problem. A number of bona fide cellular targets of DENV have been identified including liver cells. Despite the many lines of evidence confirming the involvement of hepatocytes during DENV infection, only a few studies have used proteomic analysis to understand the modulation of the cellular proteome occurring upon DENV infection. We utilized a 2D-gel electrophoresis analysis to identify proteins that were differentially regulated by DENV 2 infection of liver (Hep3B) cells at 12 h post infection (hpi) and at 48 hpi. The analysis identifies 4 proteins differentially expressed at 12 hpi, and 14 differentially regulated at 48 hpi. One candidate protein identified as downregulated at 48 hpi in the proteomic analysis (GAPDH) was validated in western blotting in Hep3B cells, and subsequently in induced pluripotent stem cell (iPSC) derived human hepatocytes. The reduced expression of GAPDH was coupled with an increase in NADH, and a significantly reduced NAD + /NADH ratio, strongly suggesting that glycolysis is down regulated in response to DENV 2 infection. Metformin, a well characterized drug used in the treatment of diabetes mellitus, is an inhibitor of hepatic gluconeogenesis was shown to reduce the level of DENV 2 infection and new virus production. Collectively these results show that although glycolysis is reduced, glucose is still required, possibly for use by the pentose phosphate pathway to generate nucleosides required for viral replication.

Dengue induced acute liver failure: A meta summary of case reports

BACKGROUND

Dengue fever is the most common cause of viral hemorrhagic fever, with more than 400 million cases being reported annually, worldwide. Even though hepatic involvement is common, acute liver failure (ALF) is a rare complication of dengue fever.

AIM

To analyze the demographic profile, symptomology, hospital course and outcomes of patients presenting with ALF secondary to dengue infection by reviewing the published case reports.

METHODS

A systematic search was performed from multiple databases including PubMed, Reference Citation Analysis, Science Direct, and Google Scholar. The search terms used were "dengue" OR "severe dengue" OR "dengue shock syndrome" OR "dengue haemorrhagic syndrome" OR "dengue fever" AND "acute liver failure" OR "hepatic failure" OR "liver injury". The inclusion criteria were: (1) Case reports or case series with individual patient details; (2) Reported acute liver failure secondary to dengue infection; and (3) Published in English language and on adult humans. The data were extracted for patient demographics, clinical symptomatology, clinical interventions, hospital and intensive care unit course, need for organ support and clinical outcomes.

RESULTS

Data from 19 case reports fulfilling the predefined inclusion criteria were included. The median age of patients was 38 years (inter quartile range: Q3-Q1 26.5 years) with a female preponderance (52.6%). The median days from diagnosis of dengue to development of ALF was 4.5 d. The increase in aspartate aminotransferase was higher than that in alanine aminotransferase (median 4625 U/L vs 3100 U/L). All the patients had one or more organ failure, with neurological failure present in 73.7% cases. 42.1% patients required vasopressor support and hepatic encephalopathy was the most reported complication in 13 (68.4%) cases. Most of the patients were managed conservatively and 2 patients were taken up for liver transplantation. Only 1 death was reported (5.3%).

CONCLUSION

Dengue infection may rarely lead to ALF. These patients may frequently require intensive care and organ support. Even though most of these patients may improve with supportive care, liver transplantation may be a therapeutic option in refractory cases.

Severe dengue in the intensive care unit

Dengue fever is considered the most prolific vector-borne disease in the world, with its transmission rate increasing more than eight times in the last two decades. While most cases present mild to moderate symptoms, 5% of patients can develop severe disease. Although the mechanisms are yet not fully comprehended, immune-mediated activation leading to excessive cytokine expression is suggested as a cause of the two main findings in critical patients: increased vascular permeability that may shock and thrombocytopenia, and coagulopathy that can induce hemorrhage. The risk factors of severe disease include previous infection by a different serotype, specific genotypes associated with more efficient replication, certain genetic polymorphisms, and comorbidities such as diabetes, obesity, and cardiovascular disease. The World Health Organization recommends careful monitoring and prompt hospitalization of patients with warning signs or propensity for severe disease to reduce mortality. This review aims to update the diagnosis and management of patients with severe dengue in the intensive care unit.

Dengue hemorrhagic fever: a growing global menace

Dengue virus is an arthropod-borne virus, transmitted by Aedes aegypti among humans. In this review, we discussed the epidemiology of dengue hemorrhagic fever (DHF) as well as the disease's natural history, cycles of transmission, clinical diagnosis, aetiology, prevention, therapy, and management. A systematic literature search was done by databases such as PubMed and Google Scholar using search terms, 'dengue fever', 'symptoms and causes of dengue fever', 'dengue virus transmission', and 'strategies to control dengue'. We reviewed relevant literature to identify hazards related to DHF and the most recent recommendations for its management and prevention. Clinical signs and symptoms of dengue infection range from mild dengue fever (DF) to potentially lethal conditions like DHF or dengue shock syndrome (DSS). Acute-onset high fever, muscle and joint pain, myalgia, a rash on the skin, hemorrhagic episodes, and circulatory shock are among the most common symptoms. An early diagnosis is vital to lower mortality. As dengue virus infections are self-limiting, but in tropical and subtropical areas, dengue infection has become a public health concern. Hence, developing and executing long-term control policies that can reduce the global burden of DHF is a major issue for public health specialists everywhere.

Updates in the Management of Dengue Shock Syndrome: A Comprehensive Review

Dengue is a very serious public health problem that can manifest a wide range of symptoms from asymptomatic to fatal conditions, such as dengue shock syndrome (DSS). It is a life-threatening mosquito-borne viral infection widely spread in tropical areas. Dengue virus transmission occurs from an infected Aedes mosquito to humans. Various factors are responsible for the occurrence of the disease, such as viral load, age of the host, immune status of the host, and genetic variability. Dengue infection occurs in three phases: febrile, critical, and recovery. The febrile phase lasts for seven days and manifests symptoms such as high-grade fever, headache, arthralgia, and backache, and in some cases, the upper respiratory tract and gastrointestinal tract are also involved. Severe dengue is characterized by endothelial dysfunction that causes vascular permeability and plasma leakage. The fundamental mechanisms of these immune pathologies are not yet known. Dengue manifests various complications such as dengue encephalopathy, encephalitis, stroke, ocular involvement, acute transverse myelitis, myalgia, and cerebellar syndrome, but the most commonly seen is liver involvement. Dengue is managed supportively because there are no proven curative treatments. The cornerstone of care during the critical period of dengue is prudent fluid resuscitation. The first fluid of preference is a crystalloid. Prophylactic transfusion of platelets is not advised. The occurrence of four antigenically different dengue virus serotypes, each able to elicit a cross-reactive and disease-enhancing antibody response against the other three serotypes, has made the creation of the dengue vaccine a difficult undertaking. The development of a dengue vaccine has faced significant challenges due to a lack of the best animal models and a variety of immunological conditions in people, particularly in endemic locations. Dengvaxia is a live attenuated vaccine, which was developed by Sanofi. It is made up of four chimeric vaccine viruses produced by Vero cells.

Liver immunopathogenesis in fatal cases of dengue in children: detection of viral antigen, cytokine profile and inflammatory mediators

Introduction

Dengue virus (DENV), the etiologic agent of dengue fever illness, represents a global public health concern, mainly in tropical and subtropical areas across the globe. It is well known that this acute viral disease can progress to severe hemorrhagic stages in some individuals, however, the immunopathogenic basis of the development of more severe forms by these patients is yet to be fully understood.

Objective

In this context, we investigated and characterized the histopathological features as well as the cytokine profile and cell subpopulations present in liver tissues from three fatal cases of DENV in children.

Methods

Hematoxylin and Eosin, Periodic Acid Schiff and Picro Sirius Red staining were utilized for the histopathological analysis. Immunohistochemistry assay was performed to characterize the inflammatory response and cell expression patterns.

Results

Vascular dysfunctions such as hemorrhage, vascular congestion and edema associated with a mononuclear infiltrate were observedin all three cases. Liver tissues exhibited increased presence of CD68+ and TCD8+ cells as well as high expression of MMP-9, TNF-a, RANTES, VEGFR-2 mediators. Viral replication was confirmed by the detection of NS3 protein.

Conclusion

Taken together, these results evidenced key factors that may be involved in the development of severe alterations in liver tissues of children in response to DENV infection.

Comparative Analysis of Human Hepatic Lesions in Dengue, Yellow Fever, and Chikungunya: Revisiting Histopathological Changes in the Light of Modern Knowledge of Cell Pathology

Arboviruses, such as yellow fever virus (YFV), dengue virus (DENV), and chikungunya virus (CHIKV), present wide global dissemination and a pathogenic profile developed in infected individuals, from non-specific clinical conditions to severe forms, characterised by the promotion of significant lesions in different organs of the harbourer, culminating in multiple organ dysfunction. An analytical cross-sectional study was carried out via the histopathological analysis of 70 samples of liver patients, collected between 2000 and 2017, with confirmed laboratory diagnoses, who died due to infection and complications due to yellow fever (YF), dengue fever (DF), and chikungunya fever (CF), to characterise, quantify, and compare the patterns of histopathological alterations in the liver between the samples. Of the histopathological findings in the human liver samples, there was a significant difference between the control and infection groups, with a predominance of alterations in the midzonal area of the three cases analysed. Hepatic involvement in cases of YF showed a greater intensity of histopathological changes. Among the alterations evaluated, cell swelling, microvesicular steatosis, and apoptosis were classified according to the degree of tissue damage from severe to very severe. Pathological abnormalities associated with YFV, DENV, and CHIKV infections showed a predominance of changes in the midzonal area. We also noted that, among the arboviruses studied, liver involvement in cases of YFV infection was more intense.

Aminotransferases in Relation to the Severity of Dengue: A Systematic Review

A systematic review was conducted to investigate the relationship between aminotransferases and the severity of dengue infection, which is a prevalent and significant infection in tropical and subtropical regions. Aminotransferases are enzymes that are often elevated in dengue due to the liver's physiological and immunological response to the infection. This review focused on analyzing various studies that examined the correlation between aminotransferase levels and the severity of dengue. Extensive literature searches were performed using ("dengue*" OR "dengue fever*" OR "dengue haemorrhagic fever*" OR "dengue shock syndrome*") AND ("alanine aminotransferase*" OR "aspartate aminotransferase*") on PubMed. The selected articles were thoroughly reviewed, encompassing epidemiology, pathogenesis, and clinical manifestations of dengue. The consistent findings across the studies indicated that aminotransferases can serve as predictive markers for dengue severity. Therefore, early assessment of liver enzyme levels is crucial in dengue cases, and elevated levels should be closely monitored to prevent adverse outcomes.

Concurrent Dengue-Malaria Infection: The Importance of Acute Febrile Illness in Endemic Zones

Context

Acute febrile disease (AFI) in endemic tropical areas is a frequent reason for consulting the emergency services. Infection by 2 or more etiological agents may modify clinical and laboratory parameters, making diagnosis and treatment a challenge.

Case report

We report the case of a patient who came from Africa and consults in Colombia, with AFI with thrombocytopenia that was eventually diagnosed to have concurrent infection with Plasmodium falciparum malaria and dengue.

Conclusions

Dengue-malaria coinfection infection reports are scarce; it should be suspected in patients living or returning from areas where both diseases are endemic or during dengue outbreaks. This case serves as a reminder of this important condition that causes high morbidity and mortality if it is not early diagnosed and treated.

Liver transcriptomics reveals microRNA features of the host response in a mouse model of dengue virus infection

BACKGROUND

Organ dysfunction, especially liver injury, caused by dengue virus (DENV) infection has been associated with fatal cases in dengue patients around the world. However, the pathophysiological mechanisms of liver involvement in dengue remain unclear. There is accumulating evidence that miRNAs are playing an important role in regulating viral pathogenesis, and it can help in diagnostic and anti-viral therapies development.

METHODS

We collected liver tissues of DENV-infected for small RNA sequencing to identify significantly different express miRNAs during dengue virus infection, and the identified target genes of these miRNAs were annotated by biological function and pathway enrichment.

RESULTS

31 significantly altered miRNAs were identified, including 16 up-regulated and 15 down-regulated miRNAs. By performing a series of miRNA prediction and signaling pathway enrichment analyses, the down-regulated miRNAs of mmu-miR-484, mmu-miR-1247-5p and mmu-miR-6538 were identified to be the crucial miRNAs. Further analysis revealed that the inflammation and immune responses involving Hippo, PI3K-Akt, MAPK, Wnt, mTOR, TGF-beta, Tight junction, and Platelet activation were modulated collectively by these three key miRNAs during DENV infection. These pathways are considered to be closely associated with the pathogenic mechanism and treatment strategy of dengue patients.

CONCLUSION

The miRNAs identified by sequencing, especially miR-484 may be the potential therapeutic targets for liver involvement in dengue patients which involves the regulation of vascular permeability and expression of inflammatory cytokines.

Liver Function Derangement in Patients with Severe Fever and Thrombocytopenia Syndrome

BACKGROUND AND AIMS

Patients with severe fever with thrombocytopenia syndrome (SFTS) commonly show liver function impairment. This study aimed to characterize the liver function indices in SFTS patients and investigate their association with mortality.

METHODS

Clinical information and laboratory results of 459 laboratory-confirmed SFTS patients, including 78 deceased and 381 surviving patients, were retrospectively analyzed. To explore the infectivity of SFTS caused by novel Bunyavirus (SFTSV) in hepatocytes, Huh7 human hepatoma cells were infected with various concentrations of SFTSV in vitro.

RESULTS

The proportion of SFTS patients developing liver injury during hospitalization was 73.2% (336/459); the hepatocellular injury was the predominant type. The median time to occurrence of liver injury from disease onset was 8 d. Liver injury in the deceased group occurred earlier than that in the surviving group. Alanine aminotransferase (ALT) level between 2-5 times upper limit of normal (ULN) at 4-6 d and between 5-15 ULN at 7-12 d of disease course were independent predictors of mortality. Alkaline phosphatase (ALP) >2 ULN at 7-9 d and elevated ALP at 10-12 days after disease onset were risk factors for death. ALT and aspartate transaminase (AST) levels were correlated with lymphocyte count and platelet-to-lymphocyte ratio (PLR). Total bilirubin (TB), ALT, AST levels showed positive correlation with viral load. In the in vitro experiment, SFTSV infected and replicated inside Huh7 cells.

CONCLUSIONS

Liver injury is common in SFTS patients. ALT and ALP were independent predictors of SFTS-related mortality. Frequent monitoring and evaluation of liver function indices are needed for SFTS patients.

Defective Mitochondrial Quality Control during Dengue Infection Contributes to Disease Pathogenesis

Mitochondrial fitness is governed by mitochondrial quality control pathways comprising mitochondrial dynamics and mitochondrial-selective autophagy (mitophagy). Disruption of these processes has been implicated in many human diseases, including viral infections. Here, we report a comprehensive analysis of the effect of dengue infection on host mitochondrial homeostasis and its significance in dengue disease pathogenesis. Despite severe mitochondrial stress and injury, we observed that the pathways of mitochondrial quality control and mitochondrial biogenesis are paradoxically downregulated in dengue-infected human liver cells. This leads to the disruption of mitochondrial homeostasis and the onset of cellular injury and necrotic death in the infected cells. Interestingly, dengue promotes global autophagy but selectively disrupts mitochondrial-selective autophagy (mitophagy). Dengue downregulates the expression of PINK1 and Parkin, the two major proteins involved in tagging the damaged mitochondria for elimination through mitophagy. Mitophagy flux assays also suggest that Parkin-independent pathways of mitophagy are also inactive during dengue infection. Dengue infection also disrupts mitochondrial biogenesis by downregulating the master regulators PPARγ and PGC1α. Dengue-infected cells release mitochondrial damage-associated molecular patterns (mtDAMPs) such as mitochondrial DNA into the cytosol and extracellular milieu. Furthermore, the challenge of naive immune cells with culture supernatants from dengue-infected liver cells was sufficient to trigger proinflammatory signaling. In correlation with our in vitro observations, dengue patients have high levels of cell-free mitochondrial DNA in their blood in proportion to the degree of thrombocytopenia. Overall, our study shows how defective mitochondrial homeostasis in dengue-infected liver cells can drive dengue disease pathogenesis. IMPORTANCE Many viruses target host cell mitochondria to create a microenvironment conducive to viral dissemination. Dengue virus also exploits host cell mitochondria to facilitate its viral life cycle. Dengue infection of liver cells leads to severe mitochondrial injury and inhibition of proteins that regulate mitochondrial quality control and biogenesis, thereby disrupting mitochondrial homeostasis. A defect in mitochondrial quality control leads to the accumulation of damaged mitochondria and promotes cellular injury. This leads to the release of mitochondrial damage-associated molecular patterns (mt-DAMPs) into the cell cytoplasm and extracellular milieu. These mt-DAMPs activate the naive immune cells and trigger proinflammatory signaling, leading to the release of cytokines and chemokines, which may trigger systemic inflammation and contribute to dengue disease pathogenesis. In correlation with this, we observed high levels of cell-free mitochondrial DNA in dengue patient blood. This study provides insight into how the disruption of mitochondrial quality control in dengue-infected cells can trigger inflammation and drive dengue disease pathogenesis.

Alpha-mangostin inhibits viral replication and suppresses nuclear factor kappa B (NF-κB)-mediated inflammation in dengue virus infection

Severe dengue virus (DENV) infection results from viral replication and dysregulated host immune response, which trigger massive cytokine production/cytokine storm. The result is severe vascular leakage, hemorrhagic diathesis, and organ dysfunction. Subsequent to previously proposing that an ideal drug for treatment of DENV infection should efficiently inhibit both virus production and cytokine storm, we discovered that α-mangostin (α-MG) from the pericarp of the mangosteen fruit could inhibit both DENV infection and cytokine/chemokine production. In this study, we investigated the molecular mechanisms underlying the antiviral and anti-inflammatory effects of α-MG. Time-of-drug-addition and time-of-drug-elimination studies suggested that α-MG inhibits the replication step of the DENV life cycle. α-MG inhibited polymerization activity of RNA-dependent RNA polymerase (RdRp) with IC50 values of 16.50 μM and significantly reduced viral RNA and protein syntheses, and virion production. Antiviral and cytokine/chemokine gene expression profiles of α-MG-treated DENV-2-infected cells were investigated by polymerase chain reaction array. α-MG suppressed the expression of 37 antiviral and cytokine/chemokine genes that relate to the NF-κB signaling pathway. Immunofluorescence and immunoblot analyses revealed that α-MG inhibits NF-κB nuclear translocation in DENV-2-infected cells in association with reduced RANTES, IP-10, TNF-α, and IL-6 production. These results suggest α-MG as a potential treatment for DENV infection.

Dengue Virus Replication Is Associated with Catecholamine Biosynthesis and Metabolism in Hepatocytes

Previously, the association between the catecholamine biosynthetic enzyme L-Dopa decarboxylase (DDC) and Dengue virus (DV) replication was demonstrated in liver cells and was found to be mediated at least by the interaction between DDC and phosphoinositide 3-kinase (PI3K). Here, we show that biogenic amines production and uptake impede DV replication in hepatocytes and monocytes, while the virus reduces catecholamine biosynthesis, metabolism, and transport. To examine how catecholamine biosynthesis/metabolism influences DV, first, we verified the role of DDC by altering DDC expression. DDC silencing enhanced virus replication, but not translation, attenuated the negative effect of DDC substrates on the virus and reduced the infection related cell death. Then, the role of the downstream steps of the catecholamine biosynthesis/metabolism was analyzed by chemical inhibition of the respective enzymes, application of their substrates and/or their products; moreover, reserpine, the inhibitor of the vesicular monoamine transporter 2 (VMAT2), was used to examine the role of uptake/storage of catecholamines on DV. Apart from the role of each enzyme/transporter, these studies revealed that the dopamine uptake, and not the dopamine-signaling, is responsible for the negative effect on DV. Accordingly, all treatments expected to enhance the accumulation of catecholamines in the cell cytosol suppressed DV replication. This was verified by the use of chemical inducers of catecholamine biosynthesis. Last, the cellular redox alterations due to catecholamine oxidation were not related with the inhibition of DV replication. In turn, DV apart from its negative impact on DDC, inhibits tyrosine hydroxylase, dopamine beta-hydroxylase, monoamine oxidase, and VMAT2 expression.

Liver function in dengue and its correlation with disease severity: a retrospective cross-sectional observational study in a tertiary care center in Coastal India

Introduction

dengue, the most important arthropod- borne disease is transmitted to humans by mosquitos of the Aedes family. Liver dysfunction in dengue varies from mild injury with elevation of transaminases to severe hepatocyte injury. The aim of our study was to assess the prevalence of hepatic dysfunction in patients with dengue and to correlate between the severity of the disease with the extent of hepatic dysfunction.

Methods

retrospective cross-sectional observational study including 120 patients with confirmed dengue serology admitted in Medicine Department of Father Muller Medical College during November 2018-December 2019. Patient demographics, presenting symptoms, clinical signs, laboratory parameters such as complete blood count, serum glutamic-oxaloacetic transaminase (SGOT), serum glutamic-pyruvic transaminase (SGPT), alkaline Phosphatase (ALP), total and direct bilirubin; serum albumin and globulin levels were collected. Patients were categorized based on the modified WHO classification of 2009 into dengue with or without the warning signs and severe dengue. Comparison of multiple means across disease severity was performed using One Way-ANOVA with post hoc analysis using least significant difference. Pearson's correlation coefficient test was used to calculate the correlation between transaminases and platelet count. P-value <0.05 and CI 95% were considered in all analyses.

Results

serum glutamic-oxaloacetic transaminase was elevated in 66.7%, 78.6% and 91.7% patients of dengue without warning signs, warning signs and severe dengue respectively. Serum glutamic-pyruvic transaminase was elevated in 42.4%, 52.4% and 91.7% patients of dengue without warning signs, warning signs and severe dengue respectively. Patients with elevated SGOT (93.8%) and SGPT (81.2%) had a higher incidence of bleeding manifestations. Hypoalbuminemia (50.8%) and A: G ratio reversal (27.3%) was significantly more in severe dengue (p<0.0001). Serum glutamic-oxaloacetic transaminase and serum glutamic-pyruvic transaminase levels negatively correlated with platelet count (p<0.0001).

Conclusion

liver involvement in the form of elevated transaminases was found in 74.2% dengue patients. Serum glutamic-oxaloacetic transaminase and serum glutamic-pyruvic transaminase level increases with increase in dengue severity which is indicated by fall in platelet count as they are negatively correlated with each other. Liver damage is one of the common complications of dengue and transaminitis, hypoalbuminemia and reversal of A: G ratio should be used as biochemical markers in dengue patients to detect and monitor hepatic dysfunction.

Immunocompetent Mice Infected by Two Lineages of Dengue Virus Type 2: Observations on the Pathology of the Lung, Heart and Skeletal Muscle

Dengue virus (DENV) infection by one of the four serotypes (DENV-1 to 4) may result in a wide spectrum of clinical manifestations, with unpredictable evolution and organ involvement. Due to its association with severe epidemics and clinical manifestations, DENV-2 has been substantially investigated. In fact, the first emergence of a new lineage of the DENV-2 Asian/American genotype in Brazil (Lineage II) in 2008 was associated with severe cases and increased mortality related to organ involvement. A major challenge for dengue pathogenesis studies has been a suitable animal model, but the use of immune-competent mice, although sometimes controversial, has proven to be useful, as histological observations in infected animals reveal tissue alterations consistent to those observed in dengue human cases. Here, we aimed to investigate the outcomes caused by two distinct lineages of the DENV-2 Asian/American genotype in the lung, heart and skeletal muscle tissues of infected BALB/c mice. Tissues were submitted to histopathology, immunohistochemistry, histomorphometry and transmission electron microscopy (TEM) analysis. The viral genome was detected in heart and skeletal muscle samples. The viral antigen was detected in cardiomyocytes and endothelial cells of heart tissue. Heart and lung tissue samples presented morphological alterations comparable to those seen in dengue human cases. Creatine kinase serum levels were higher in mice infected with both lineages of DENV-2. Additionally, statistically significant differences, concerning alveolar septa thickening and heart weight, were observed between BALB/c mice infected with both DENV-2 lineages, which was demonstrated to be an appropriate experimental model for dengue pathogenesis studies on lung, heart and skeletal muscle tissues.

Brazilian Dengue Virus Type 2-Associated Renal Involvement in a Murine Model: Outcomes after Infection by Two Lineages of the Asian/American Genotype

Dengue virus type 2 (DENV-2) is, traditionally, the most studied serotype due to its association with explosive outbreaks and severe cases. In Brazil, almost 20 years after the first introduction in the 1990s, a new lineage (Lineage II) of the DENV-2 Asian/American genotype emerged and caused an epidemic with severe cases and hospitalizations. Severe dengue includes multiple organ failure, and renal involvement can be potentially related to increased mortality. In order to better understand the role of DENV infection in renal injury, here we aimed to investigate the outcomes of infection with two distinct lineages of DENV-2 Asian/American genotype in the kidney of a murine model. BALB/c mice were infected with Lineages I and II and tissues were submitted to histopathology, immunohistochemistry, histomorphometry and ultrastructural analysis. Blood urea nitrogen (BUN) was detected in blood sample accessed by cardiac puncture. A tendency in kidney weight increase was observed in mice infected with both lineages, but urea levels, on average, were increased only in mice infected with Lineage II. The DENV antigen was detected in the tissue of mice infected with Lineage II and morphological changes were similar to those observed in human dengue cases. Furthermore, the parameters such as organ weight, urea levels and morphometric analysis, showed significant differences between the two lineages in the infected BALB/c, which was demonstrated to be a suitable experimental model for dengue pathophysiology studies in kidneys.

Transfusion-transmissible dengue infections

Dengue is an important global health problem and is endemic in many developing and developed countries. Transmission of dengue may occur in several ways and information on transfusion-transmitted dengue is limited. We conducted a literature search on transfusion-related dengue using the PubMed, Scopus, Embase and Google Scholar databases and have summarized the findings. A number of apparently healthy blood donors have been found to be infected with the dengue virus (DENV) and thus may transmit the virus onto recipients of this blood. It is not possible to identify and exclude such donors at the donor selection stage and thus reliable screening tests should be available in highly endemic areas to ensure a safe blood supply.

The atypical lymphocyte count: a novel predictive factor for severe thrombocytopenia related to dengue

BACKGROUND

Early identification of patients at risk of severe dengue disease (DD) is critical to guide its management. We evaluated whether the atypical lymphocyte count (ALC), generated from the Sysmex automated full blood count analyzer, is predictive of severe thrombocytopenia secondary to Dengue infection.

METHODS

We prospectively collected data on patients admitted with DD between December 2017 and October 2018. ALC data were extracted from the Sysmex XS500i analyzer from day 1 to day 7 of admission. Clinical data were obtained from patients' medical records.

RESULTS

We enrolled 256 patients with DD. A negative correlation between ALC on admission and platelet count on day 5 to day 7 (Spearmen's correlation; day 5:-0.485, day 6:-0.428 and day 7:-0.344) (p=0.001) was observed. Based on receiver operator characteristic curve analysis, we found that an ALC of >0.5x103/L had 90% sensitivity and 70% specificity for severe thrombocytopenia (platelet count <50x109/L) on day 5. The positive and negative predictive values were 74.4 and 91.2%, respectively (power 84.7).

CONCLUSIONS

We propose that ALC on admission may be a novel negative predictive factor for severe thrombocytopenia on day 5 to day 7 of DD. Further studies are required to validate our findings and evaluate whether ALC is predictive of other complications of DD.

Comparative analysis of liver involvement caused by two DENV-2 lineages using an immunocompetent murine model

Dengue (DEN) is the most prevalent arbovirus among humans, and four billion people live at risk of infection. The clinical manifestations of DEN are variable, and the disease may present subclinically or asymptomatically. A quarter of patients develop classical dengue (CD) or severe dengue (SD), which is potentially lethal and involves vascular permeability changes, severe hemorrhage and organ damage. The involvement of the liver is a fairly common feature in DEN, and alterations range from asymptomatic elevation of transaminases to acute liver failure. Since its introduction in Brazil in 1990, two strains of Dengue virus (DENV) serotype 2 (DENV-2) have been detected: Lineage I, which is responsible for an outbreak in 1991, and Lineage II, which caused an epidemic greater than the previous one and had a different epidemiological profile. To date, studies on different strains of the same serotype/genotype and their association with disease severity are scarce. In addition, one of the greatest challenges regarding the study of DEN pathogenesis and the development of drug and vaccine therapies is the absence of an animal model that reproduces the disease as it occurs in humans. The main goals of this study were to assess BALB/c mouse susceptibility experimentally infected by two distinct DENV-2 strains and characterize possible differences in the clinical signs and alterations induced in the liver resulting from those infections. Mice infected by the two DENV-2 lineages gained less weight than uninfected mice; however, their livers were slightly heavier. Increased AST and AST levels were observed in infected mice, and the number of platelets increased in the first 72 h of infection and subsequently decreased. Mice infected with both lineages presented leukocytosis but at different times of infection. The histopathological changes induced by both lineages were similar and comparable to the changes observed in DEN fatal cases. The viral genome was detected in two liver samples. The results demonstrate the susceptibility of BALB/c mice to both DENV-2 lineages and suggest that the changes induced by those strains are similar, although for some parameters, they are manifested at different times of infection.

Dengue Infections and the Surgical Patient

Dengue infections are increasing globally and account for significant morbidity and mortality. Severe dengue results in microvascular changes and coagulopathy that may make surgical intervention risky and the overall surgical management challenging. We outline the potential surgical manifestations and complications following dengue infections and describe the clinical, pathogenetic, diagnostic, and treatment aspects of dengue and surgical patients. The main surgical presentations were acute cholecystitis, acute pancreatitis, acute appendicitis, splenic rupture, bowel perforation, gastrointestinal bleeding, and hematomas. Dengue may also mimic an acute abdomen without any true surgical complications. A majority were treated nonoperatively. Misdiagnosis and unnecessary surgical intervention resulted in poor outcomes. Better knowledge of the potential surgical complications would help in early diagnosis, treatment, and referral to specialized centers and thus improve outcomes. A high degree of suspicion of dengue fever is necessary when patients in a dengue-epidemic area present with acute abdomen or bleeding manifestations. In endemic areas, early dengue antigen testing and abdominal imaging before surgical intervention may help in the diagnoses. Multidisciplinary team involvement with case-by-case decision-making is needed for optimal care.

Gene Expression Signatures in AML-12 Hepatocyte Cells upon Dengue virus Infection and Acetaminophen Treatment

Dengue is an acute viral disease caused by Dengue virus (DENV) and is considered to be the most common arbovirus worldwide. The clinical characteristics of dengue may vary from asymptomatic to severe complications and severe organ impairment, particularly affecting the liver. Dengue treatment is palliative with acetaminophen (APAP), usually known as Paracetamol, being the most used drug aiming to relieve the mild symptoms of dengue. APAP is a safe and effective drug but, like dengue, can trigger the development of liver disorders. Given this scenario, it is necessary to investigate the effects of combining these two factors on hepatocyte homeostasis. Therefore, this study aimed to evaluate the molecular changes in hepatocytes resulting from the association between DENV infection and treatment with sub-toxic APAP concentrations. Using an in vitro experimental model of DENV-2 infected hepatocytes (AML-12 cells) treated with APAP, we evaluated the influence of the virus and drug association on the transcriptome of these hepatocytes by RNA sequencing (RNAseq). The virus-drug association was able to induce changes in the gene expression profile of AML-12 cells and here we highlight and explore these changes and its putative influence on biological processes for cellular homeostasis.

Crocetin Improves Dengue Virus-Induced Liver Injury

Dengue virus (DENV) infection is one of the most widespread mosquito-borne viral infections. Liver injury is commonly observed in severe DENV infection, and the present study aimed to examine the efficacy of crocetin treatment in an immunocompetent mouse model of DENV infection exhibiting liver injury. The efficacy of crocetin treatment in DENV-induced liver injury was assessed via both transaminase levels and histopathology analysis. A real-time polymerase chain reaction array was then used to describe the expression of 84 apoptosis-related genes. Using real-time RT-PCR and Western blot analysis, the gene expressions of host factors were investigated. Additionally, the effect of crocetin in NF-kB signaling during DENV infection was studied. We did not observe any significant reduction in virus production when DENV-infected mice were treated with crocetin. However, DENV-infected mice treated with crocetin showed reduced DENV-induced apoptosis. The real-time polymerase chain reaction array revealed pro-inflammatory cytokine expressions to be significantly reduced in the crocetin-treated DENV-infected mice. We also found that crocetin could effectively modulate antioxidant status in DENV-infected mice. Moreover, crocetin demonstrated the ability to reduce the nuclear translocation of NF-kB in DENV-infected mice. Our results suggest that crocetin treatment does not inhibit DENV replication in the liver of DENV-infected mice; however, we did find that crocetin improves host responses that reduce liver injury.

Triple positivity for nonstructural antigen 1, immunoglobulin M and immunoglobulin G is predictive of severe thrombocytopaenia related to dengue infection

BACKGROUND

The early identification of patients at risk of severe dengue infection (DI) is critical to guide clinical management. Non-structural antigen 1 (NS-1), immunoglobulin M (IgM) and immunoglobulin G (IgG) are used routinely for the diagnosis of DI.

OBJECTIVES

We sought to evaluate whether positivity for NS-1, IgM and IgG individually or together is predictive of severe complications of DI.

METHODS & MATERIALS

A prospective study was conducted among patients with DI admitted to our institution between 2014 and 2019. DI was diagnosed based on a positive NS1 or IgM. IgG was also tested on all the patients. Clinical data was obtained from electronic medical records at NH. Statistical analyses were performed using SPSS version 20.

RESULTS

We collected data on 3504 patients. Patients who were positive for NS1, IgM and IgG (triple positive: TP) were more likely to develop severe DI (63.8 %) in comparison to those who were only NS1 positive (single positive: SP) (3.0 %) and patients with positive NS1 and IgM (double positive: DP) (7.5 %). [p = 0.001]. Regression analysis confirmed that TP status on admission was predictive of severe complications. (p < 0.01). Receiver operator characteristic curve (ROC) analysis showed (AUC: 84.8; sensitivity = 90.7 and specificity = 83.2) that TP status on admission is predictive of thrombocytopenia on day 5. The predictive power of TP status was superior to that of NS1 and IgG positivity.

CONCLUSIONS

We propose that TP status on admission is a novel predictive factor for severe DI. Further studies are required to explore the biological basis for this finding.

Tryptophan Trimers and Tetramers Inhibit Dengue and Zika Virus Replication by Interfering with Viral Attachment Processes

Here, we report a class of tryptophan trimers and tetramers that inhibit (at low micromolar range) dengue and Zika virus infection in vitro These compounds (AL family) have three or four peripheral tryptophan moieties directly linked to a central scaffold through their amino groups; thus, their carboxylic acid groups are free and exposed to the periphery. Structure-activity relationship (SAR) studies demonstrated that the presence of extra phenyl rings with substituents other than COOH at the N1 or C2 position of the indole side chain is a requisite for the antiviral activity against both viruses. The molecules showed potent antiviral activity, with low cytotoxicity, when evaluated on different cell lines. Moreover, they were active against laboratory and clinical strains of all four serotypes of dengue virus as well as a selected group of Zika virus strains. Additional mechanistic studies performed with the two most potent compounds (AL439 and AL440) demonstrated an interaction with the viral envelope glycoprotein (domain III) of dengue 2 virus, preventing virus attachment to the host cell membrane. Since no antiviral agent is approved at the moment against these two flaviviruses, further pharmacokinetic studies with these molecules are needed for their development as future therapeutic/prophylactic drugs.

Trajectories of hepatic and coagulation dysfunctions related to a rapidly fatal outcome among hospitalized patients with dengue fever in Tainan, 2015

Background

Hepatic dysfunction and coagulopathy are common in acute dengue illness. We analyzed the trajectories of the above parameters in the survivors and fatal patients in the outbreak in Tainan, 2015.

Methods

A retrospective study was conducted using data from a tertiary hospital between January and December 2015. Multilevel modeling (MLM) was used to identify the changes in aminotransferase (AST), alanine aminotransferase (ALT), activated partial thromboplastin time (aPTT), and platelet counts from Day 0 to Day 7 of the onset of dengue infection. The machine-learning algorithm was used by purity measure assumption to calculate the accuracy of serum transaminases and coagulation variables to discriminate between the fatal and survival groups.

Results

There were 4,069 dengue patients, of which 0.9% died in one week after illness onset (i.e., early mortality). Case fatality rate was the highest for those aged ≥70 years. Both AST and ALT values of the fatal group were significantly higher than those of the survivor group from Day 3 (AST median, 624 U/L vs. 60 U/L, p < 0.001; ALT median, 116 U/L vs. 29 U/L, p = 0.01) of illness onset and peaked on Day 6 (AST median, 9805 U/L vs. 90 U/L, p < 0.001; ALT median, 1504 U/L vs. 49 U/L, p < 0.001). AST ≥ 203 U/L, ALT ≥ 55 U/L, AST²/ALT criteria ≥337.35, or AST/platelet count ratio index (APRI) ≥ 19.18 on Day 3 of dengue infection had a high true positive rate, 90%, 78%, 100%, or 100%, respectively, of early mortality. The platelet counts of the fatal group declined significantly than those of the survivor group since Day 3 of illness onset (median, 19 x10³/μl vs. 91 x10³/μl, p < 0.01), and aPTT values of the fatal group significantly prolonged longer since Day 5 (median, 68.7 seconds vs. 40.1 seconds, p < 0.001).

Conclusions

AST, ALT, and platelet counts should be monitored closely from Day 0 to Day 3 of dengue infection, and aPTT be followed up on Day 5 of infection to identify the individuals at risk for early mortality.

Dengue fever (DF) is currently one of the most severe public health problems. Clinical presentations of dengue are diverse and non-specific, often with unpredictable clinical progression and outcome. Hepatic dysfunction and abnormal coagulation factors are common in acute dengue illness, reflected by abnormal alanine aminotransferase (AST), aspartate aminotransferase (ALT), activated partial thromboplastin time (aPTT), and platelet counts. However, there is no information available about the monitoring frequency required, which could help identify those dengue patients who are likely to die, especially during epidemic outbreaks with limited healthcare resources. We examined all the laboratory-confirmed dengue patients who admitted to the major tertiary hospital in Tainan during the 2015 dengue outbreak, and the different trajectories of hepatic function and coagulation factors between survivors and rapidly fatal dengue patients were analyzed. Although there were no differences in AST, ALT, aPTT, and platelet counts between the survivor and fatal groups on the day DF symptoms first appeared, the differences increased from the early stages of infection and became more prominent during the early stages of the illness. The necessity of monitoring the AST, ALT, aPTT, and platelet count frequently during the febrile phase is emphasized by this study.

Emerging Role of l-Dopa Decarboxylase in Flaviviridae Virus Infections

l-dopa decarboxylase (DDC) that catalyzes the biosynthesis of bioactive amines, such as dopamine and serotonin, is expressed in the nervous system and peripheral tissues, including the liver, where its physiological role remains unknown. Recently, we reported a physical and functional interaction of DDC with the major signaling regulator phosphoinosite-3-kinase (PI3K). Here, we provide compelling evidence for the involvement of DDC in viral infections. Studying dengue (DENV) and hepatitis C (HCV) virus infection in hepatocytes and HCV replication in liver samples of infected patients, we observed a negative association between DDC and viral replication. Specifically, replication of both viruses reduced the levels of DDC mRNA and the ~120 kDa SDS-resistant DDC immunoreactive functional complex, concomitant with a PI3K-dependent accumulation of the ~50 kDa DDC monomer. Moreover, viral infection inhibited PI3K-DDC association, while DDC did not colocalize with viral replication sites. DDC overexpression suppressed DENV and HCV RNA replication, while DDC enzymatic inhibition enhanced viral replication and infectivity and affected DENV-induced cell death. Consistently, we observed an inverse correlation between DDC mRNA and HCV RNA levels in liver biopsies from chronically infected patients. These data reveal a novel relationship between DDC and Flaviviridae replication cycle and the role of PI3K in this process.

Zika Virus Induced More Severe Inflammatory Response Than Dengue Virus in Chicken Embryonic Livers

Dengue (DENV) and Zika virus (ZIKV) are important flaviviruses in tropical and subtropical regions, causing severe Dengue Hemorrhagic Fever (DHF)/Dengue Shock Syndrome (DSS) and microcephaly, respectively. The infection of both viruses during pregnancy were reported with adverse fetal outcomes. To investigate the effects of ZIKV and DENV infections on fetal development, we established an infection model in chicken embryos. Compared with DENV-2, the infection of ZIKV significantly retarded the development of chicken embryos. High viral loads of both DENV-2 and ZIKV was detected in brain, eye and heart 7 and 11 days post-infection, respectively. Interestingly, only ZIKV but not DENV-2 was detected in the liver. Even both of them induced apparent liver inflammation, ZIKV infection showed a more severe inflammatory response than DENV-2 infection based on the inflammation scores and the gene expression levels of IL-1β, TNF, IL-6, and TGFβ-2 in liver. Our results demonstrated that ZIKV induced more severe inflammatory response in chicken embryo liver compared to DENV-2, which might partially attribute to viral replication in liver cells. Clinicians should be aware of the potential liver injury associated with ZIKV infection in patients, especially in perinatal fetuses.

Drug repurposing of N-acetyl cysteine as antiviral against dengue virus infection

Liver injury is one of the hallmark features of severe dengue virus (DENV) infection since DENV can replicate in the liver and induce hepatocytes to undergo apoptosis. N-acetyl cysteine (NAC), which is a clinically-used drug for treating acetaminophen toxicity, was found to benefit patients with DENV-induced liver injury; however, its mechanism of action remains unclear. Accordingly, our aim was to repurpose NAC in the preclinical studies to investigate its mechanism of action. Time of addition experiments in HepG2 cells elucidated effectiveness of NAC to reduce infectious virion at pre-, during- and post infection. In DENV-infected mice, NAC improved DENV-associated clinical manifestations, including leucopenia and thrombocytopenia, and reduced liver injury and hepatocyte apoptosis. Interestingly, we discovered that NAC significantly reduced DENV production in HepG2 cells and in liver of DENV-infected mice by induction of antiviral responses via interferon signaling. NAC treatment in DENV-infected mice helped to maintain antioxidant enzymes and redox balance in the liver. Therefore, NAC reduces DENV production and oxidative damage to ameliorate DENV-induced liver injury. Taken together, these findings suggest the novel therapeutic potential of NAC in DENV-induced liver injury and recommend evaluating its efficacy and safety in humans with DENV-induced liver injury.

The Role of Tissue Oxygen Tension in Dengue Virus Replication

Low oxygen tension exerts a profound effect on the replication of several DNA and RNA viruses. In vitro propagation of Dengue virus (DENV) has been conventionally studied under atmospheric oxygen levels despite that in vivo, the tissue microenvironment is hypoxic. Here, we compared the efficiency of DENV replication in liver cells, monocytes, and epithelial cells under hypoxic and normoxic conditions, investigated the ability of DENV to induce a hypoxia response and metabolic reprogramming and determined the underlying molecular mechanism. In DENV-infected cells, hypoxia had no effect on virus entry and RNA translation, but enhanced RNA replication. Overexpression and silencing approaches as well as chemical inhibition and energy substrate exchanging experiments showed that hypoxia-mediated enhancement of DENV replication depends on the activation of the key metabolic regulators hypoxia-inducible factors 1α/2α (HIF-1α/2α) and the serine/threonine kinase AKT. Enhanced RNA replication correlates directly with an increase in anaerobic glycolysis producing elevated ATP levels. Additionally, DENV activates HIF and anaerobic glycolysis markers. Finally, reactive oxygen species were shown to contribute, at least in part through HIF, both to the hypoxia-mediated increase of DENV replication and to virus-induced hypoxic reprogramming. These suggest that DENV manipulates hypoxia response and oxygen-dependent metabolic reprogramming for efficient viral replication.

Femur-sparing pattern of abnormal fetal growth in pregnant women from New York City after maternal Zika virus infection

BACKGROUND

Zika virus is a mosquito-transmitted flavivirus, which can induce fetal brain injury and growth restriction following maternal infection during pregnancy. Prenatal diagnosis of Zika virus-associated fetal injury in the absence of microcephaly is challenging due to an incomplete understanding of how maternal Zika virus infection affects fetal growth and the use of different sonographic reference standards around the world. We hypothesized that skeletal growth is unaffected by Zika virus infection and that the femur length can represent an internal standard to detect growth deceleration of the fetal head and/or abdomen by ultrasound.

OBJECTIVE

We sought to determine if maternal Zika virus infection is associated with a femur-sparing pattern of intrauterine growth restriction through analysis of fetal biometric measures and/or body ratios using the 2014 International Fetal and Newborn Growth Consortium for the 21st Century Project and World Health Organization Fetal Growth Chart sonographic references.

STUDY DESIGN

Pregnant women diagnosed with a possible recent Zika virus infection at Columbia University Medical Center after traveling to an endemic area were retrospectively identified and included if a fetal ultrasound was performed. Data were collected regarding Zika virus testing, fetal biometry, pregnancy, and neonatal outcomes. The 2014 International Fetal and Newborn Growth Consortium for the 21st Century Project and World Health Organization Fetal Growth Chart sonographic standards were applied to obtain Z-scores and/or percentiles for fetal head circumference, abdominal circumference, and femur length specific for each gestational week. A novel 2014 International Fetal and Newborn Growth Consortium for the 21st Century Project standard was also developed to generate Z-scores for fetal body ratios with respect to femur length (head circumference:femur length, abdominal circumference:femur length). Data were then grouped within clinically relevant gestational age strata (<24, 24-27 6/7, 28-33 6/7, >34 weeks) to analyze time-dependent effects of Zika virus infection on fetal size. Statistical analysis was performed using Wilcoxon signed-rank test on paired data, comparing either abdominal circumference or head circumference to femur length.

RESULTS

A total of 56 pregnant women were included in the study with laboratory evidence of a confirmed or possible recent Zika virus infection. Based on the Centers for Disease Control and Prevention definition for microcephaly after congenital Zika virus exposure, microcephaly was diagnosed in 5% (3/56) by both the 2014 International Fetal and Newborn Growth Consortium for the 21st Century Project and World Health Organization Fetal Growth Chart standards (head circumference Z-score ≤-2 or ≤2.3%). Using 2014 International Fetal and Newborn Growth Consortium for the 21st Century Project, intrauterine fetal growth restriction was diagnosed in 18% of pregnancies (10/56; abdominal circumference Z-score ≤-1.3, <10%). Analysis of fetal size using the last ultrasound scan for all subjects revealed a significantly abnormal skewing of fetal biometrics with a smaller abdominal circumference vs femur length by either 2014 International Fetal and Newborn Growth Consortium for the 21st Century Project or World Health Organization Fetal Growth Chart (P < .001 for both). A difference in distribution of fetal abdominal circumference compared to femur length was first apparent in the 24-27 6/7 week strata (2014 International Fetal and Newborn Growth Consortium for the 21st Century Project, P = .002; World Health Organization Fetal Growth Chart, P = .001). A significantly smaller head circumference compared to femur length was also observed by 2014 International Fetal and Newborn Growth Consortium for the 21st Century Project as early as the 28-33 6/7 week strata (2014 International Fetal and Newborn Growth Consortium for the 21st Century Project, P = .007). Overall, a femur-sparing pattern of growth restriction was detected in 52% of pregnancies with either head circumference:femur length or abdominal circumference:femur length fetal body ratio <10th percentile (2014 International Fetal and Newborn Growth Consortium for the 21st Century Project Z-score ≤-1.3).

CONCLUSION

An unusual femur-sparing pattern of fetal growth restriction was detected in the majority of fetuses with congenital Zika virus exposure. Fetal body ratios may represent a more sensitive ultrasound biomarker to detect viral injury in nonmicrocephalic fetuses that could impart long-term risk for complications of congenital Zika virus infection.