Skip to main content
NCBI home page
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2021 Dec 1.
Published in final edited form as: J Neurovirol. 2020 Sep 22;26(6):945–951. doi: 10.1007/s13365-020-00907-3

Elevated serum substance P during simian varicella virus infection in rhesus macaques; implications for chronic inflammation and adverse cerebrovascular events

Andrew N Bubak 1, Vicki Traina-Dorge 2, Christina N Como 1, Brittany Feia 1, Catherine M Pearce 1, Laura Doyle-Meyers 2, Arpita Das 2, Jayme Looper 3, Ravi Mahalingam 1, Maria A Nagel 1,4
PMCID: PMC7718397  NIHMSID: NIHMS1631855  PMID: 32964407

Abstract

Varicella and zoster, produced by varicella zoster virus (VZV), are associated with an increased risk of stroke that may be due to persistent inflammation and hypercoagulability. Because substance P is associated with inflammation, hypercoagulability, and atherosclerotic plaque rupture that may contribute to increased stroke risk after VZV infection, we measured serum substance P in simian varicella virus-infected rhesus macaques. We found significantly increased and persistent serum substance P concentrations during varicella and zoster compared to pre-inoculation, supporting the hypothesis that VZV-induced increases in serum substance P may contribute to increased stroke risk associated with VZV infection.

Keywords: Varicella, Zoster, Stroke, Simian varicella virus, Substance P

Introduction

Varicella zoster virus (VZV) causes varicella during primary infection then establishes life-long latency in ganglionic neurons. Upon immunosuppression and/or age-related immunosenescence, virus can reactivate to produce herpes zoster. Multiple studies show a significantly increased risk of stroke weeks to months after varicella or zoster. Specifically, using electronic health records in the United Kingdom, Thomas and colleagues (2014) found a 4-fold increased risk of stroke in children during the first 6 months after chickenpox; another study found the median time between varicella and stroke to be 4 months (Science et al. 2014). Similar findings associating increased risk of stroke after varicella were seen in a systemic review and meta-analysis of 41 published reports that assessed the risk of stroke associated with VZV infection; furthermore, zoster was associated with a 1.5-fold increased stroke risk four weeks following rash onset, which resolved after 1 year (Forbes et al. 2018). Subgroup analyses suggested that post-zoster stroke risk was greater among ophthalmic zoster patients, younger individuals, and others who were not taking antivirals. Another study of VZV vasculopathy patients found that the average time from rash to stroke was 4 months (Nagel et al. 2009).

The mechanism(s) for increased stroke risk is not well-characterized. However, direct VZV infection and subsequent persistent arterial inflammation is a major contributor because multiple proinflammatory cytokines are produced in cerebrospinal fluid of VZV vasculopathy patients, as well as in VZV-infected arterial cells in culture. Furthermore, inflammatory cells are associated with vascular damage through release of soluble factors that contribute to myofibroblast accumulation in the lumen and death of vascular smooth muscle cells (Nagel et al, 2011, 2013, 2015; Jones et al. 2016, 2017). In addition, VZV infection may contribute to a hypercoagulable state by alterations in protein C and S (Nguyen et al. 1994; Siddiqi et al. 2012; Sardana et al. 2012; Sada et al. 2012; Menon and Goyal 2012; Sudhaker et al. 2014; Paul et al. 2016; reviewed in Nagel et al. 2020).

An important upstream mediator of cytokine production and inflammation that may play a role in VZV pathogenesis is substance P, a peptide that is released by neurons and inflammatory cells in response to noxious stimuli (e.g. severe inflammation, tissue damage). Substance P binding to its neurokinin-1 receptor (NK-1R) is considered an immediate defense, stress, repair and survival response (Vishwanath and Mukherjee 1996; Quinlan et al. 1998; Nessler et al. 2006; Mashaghi et al. 2016). Substance P is involved in vasodilation, smooth muscle cell contraction, inflammation, cell growth/proliferation/angiogenesis/migration, and initiates expression of most cytokines (Freidin et al. 1992; Rameshwar et al. 1992; Derocq et al. 1996; Palma and Manzini 1998; Garza et al. 2008). However, in chronic inflammatory diseases, dysregulation of substance P signaling (e.g., virus induced increases in substance P or inflammation–mediated increases in NK-1R expression), can induce excessive inflammation, perpetuating disease and tissue damage (reviewed in O’Connor et al. 2004). Importantly, elevated levels of substance P have been documented in serum of stroke patients correlating with heightened mortality (Lorente et al. 2016, 2020). Further studies on substance P show that it can produce a hypercoagulable state and cause rupture of atherosclerotic plaques (Jones et al. 2008; Azma et al. 2009; Bot et al. 2010).

We hypothesize that elevated levels of substance P in serum during VZV infection contributes, in part, to the increased stroke risk associated with varicella or zoster. Herein, we used a rhesus macaque (RM) model of VZV infection (simian varicella virus [SVV] infection in nonhuman primates) that recapitulates varicella, latency, and reactivation (zoster) seen in humans (Mahalingam et al. 2019). Serum substance P levels were measured pre-inoculation and at several days/weeks post-inoculation with SVV that spanned times when animals developed varicella, became latently infected, and during reactivation.

Materials and Methods

Non-human primates

Five SVV-seronegative rhesus macaques were housed in the Tulane National Primate Research Center (TNPRC) in Covington, LA. All procedures were performed in accordance with the US department of Agriculture Animal Welfare Act regulations, the Guide for the Care and Use of Laboratory Animals, and procedures were performed following appropriate guidelines and protocols approved by the Institutional Animal Care and Use Committee at the TNPRC.

SVV inoculation and establishment of latency

SVV inoculation, primary infection, and establishment of latency in the five rhesus macaques have been described earlier (Traina-Dorge et al. 2019). Briefly, five rhesus macaques (Table 1) were inoculated with 8–10×105 plaque-forming units (PFU) of SVV intrabronchially and were examined at key timepoints during acute infection; blood samples were obtained and analyzed at pre-inoculation and at 4, 9, 14, 30 days post-inoculation (dpi) and monthly thereafter until latency. All monkeys developed varicella between 4–9 dpi. Latency was established by eight months post inoculation as evidenced by the absence of SVV DNA in 2 consecutive weekly blood samples by PCR.

Table 1.

Rhesus macaques used in this study and corresponding sex, age, and weight

Animal Sex Age (years) Weight (kgs)
1 male 4.4 6.8
2 male 4.2 6.4
3 male 4.4 8.0
4 male 4.0 7.3
5 (reactivation control) male 3.9 5.4
Open in a new tab

Immunosuppression

Immunosuppressive treatments were performed as described previously (Traina-Dorge et al. 2015). Briefly, eight months after primary infection, when SVV was latent, all five macaques were transported by a van (3-h round trip) from the TNPRC in Covington, LA, to the School of Veterinary Medicine Radiation Oncology facility at Louisiana State University, Batton Rouge, LA. The four experimental monkeys were anesthetized, exposed to a single dose of 200-cGy total body X-irradiation, then treated daily with oral tacrolimus (Prograf; 500 μg; 80 μg/kg of body weight/day) and prednisone (5 mg, 2 mg/kg/day) until they were euthanized at the time of zoster rash. The reactivation control monkey was not irradiated or treated with drugs but was similarly transported with the experimental animals. All animals were monitored by weekly physical exams, with blood/serum samples were collected weekly until zoster developed (SVV reactivation).

DNA extraction from blood samples and real-time PCR

DNA was extracted from peripheral blood mononuclear cells (PBMCs) and analyzed by real-time qPCR using primers specific for SVV open reading frame (ORF) 61 as described previously (Messaoudi et al. 2009). Each sample was analyzed in triplicate and scored positive only if at least two of three PCRs were positive for SVV DNA.

Collection of biopsied skin samples

At the time any animal reactivated and demonstrated zoster rash, skin biopsy samples of representative lesions were collected. Animals were anesthetized using intramuscular administration of ketamine HCl (10 mg/kg) or telazol (tiletamine/zolazepam) (3–8 mg/kg) and a representative lesion of zoster rash was biopsied. The tissue specimens were fixed in Z-Fix (Zinc-Formalin:10% neutral buffered formalin with added zinc; Anatech, Battle Creek, Michigan) and paraffin embedded for immunohistochemical analysis.

Substance P quantification

Substance P enzyme-linked immunosorbent assay (ELISA; Enzo Life Sciences Inc., Farmingdale, NY) was used to measure the concentration of substance P according to manufacturer’s instructions. Samples were thawed, stored on ice, and briefly centrifuged at 500 RPMs to avoid debris. All samples were run in duplicate and concentrations were determined using a standard curve and tested against quality controls. All samples fell within the upper- and lower-limits of detection as outlined by the manufacturer’s instructions. Values were calculated as a fold-change difference relative to pre-inoculation samples.

Immunohistochemistry

Sections of fixed skin samples were analyzed by immunohistochemical staining using polyclonal rabbit anti-SVV nucleocapsid antibodies (1:40,000 dilution) or normal rabbit serum as described previously (Mahalingam et al. 2010).

Statistical Analysis

A one-way ANOVA with a Dunnett’s test to correct for multiple comparisons was used to examine statistical differences in serum substance P levels at varying timepoints. Baseline substance P levels were established using pre-inoculation concentrations; changes at all other timepoints were relative to that timepoint. Alpha was set at 0.05. All statistical tests were performed in Prism 8 (GraphPad Software, LLC).

Results

Like VZV, SVV produced the characteristic varicella rash during primary infection in all five RMs inoculated with SVV (Fig. 1a, red arrows; torso). Four animals were immunosuppressed and all four reactivated and developed zoster (Fig. 1b, red arrows; right upper arm). The non-immunosuppressed monkey (reactivation control) spontaneously reactivated and developed zoster rash, confirmed by the detection of SVV antigen in the skin biopsy (Fig. 2), as has been (occasionally) observed in previous studies (Mahalingam et al. 2007; Traina-Dorge et al. 2015, 2019).

Fig. 1.

Fig. 1

Open in a new tab

Persistent elevations in serum substance P during primary SVV infection and reactivation. a Primary simian varicella virus (SVV) infection causes varicella (chickenpox; red arrows, torso). b Similar to VZV infection in humans, SVV reactivated to produce zoster (shingles; red arrows, right upper arm). c Higher levels of SVV DNA were detected in peripheral blood mononuclear cells (PBMCs) at 4- and 9-days post-inoculation (dpi). Minimal to no SVV DNA was detected in PBMCs during latency or reactivation despite the appearance of zoster at weeks 12 and 15 post-immunosuppression. Levels of substance P were significantly lower at 9 dpi, followed by a substantial and sustained increase through to latency (12 weeks after inoculation), before returning to baseline. A secondary spike in substance P was observed during onset of zoster (15 weeks post-immunosuppression). (*p < 0.05)

Fig. 2.

Fig. 2

Open in a new tab

Detection of SVV antigens in zoster rash in the reactivation control monkey. Five micron-sections of biopsied, paraformaldehyde-fixed, paraffin-embedded zoster rash (a and c) or normal skin (b and d) were analyzed by immunohistochemistry using rabbit anti-SVV antiserum (a and b) or normal rabbit serum (c and d). Inset in panel a shows the detection of SVV antigens in sweat glands in higher magnification. Magnification panels A-D:X100, inset X600.

Serum samples were longitudinally collected from all monkeys and SVV DNA and substance P levels were determined at multiple timepoints (pre-inoculation, primary infection, latency, and reactivation). SVV DNA in PBMCs was not detected at pre-inoculation but was detected during acute infection at 4, 9, and 14 dpi (Fig. 1c, red box plots). As previously observed (Mahalingam et al. 2007), only minimal quantities of SVV DNA were detected during reactivation despite the presence of zoster rash. During primary infection, we measured a substantial decrease in serum substance P levels at 9 dpi compared to pre-inoculation, followed by a significant and sustained increase at 14 dpi that continued after varicella resolution (12 weeks later) (Fig. 1c). Substance P levels returned to baseline by the time of immunosuppression; however, levels significantly increased prior to and during the appearance of zoster rash (weeks 12 and 14 post-immunosuppression, respectively) (Fig. 1c).

Discussion

Herein, we hypothesize that elevated levels of substance P in serum during VZV infection contributes, in part, to the increased stroke risk associated with varicella or zoster (Science et al. 2014; Thomas et al. 2014; Forbes et al. 2018). We used a rhesus macaque model of SVV infection that recapitulates the VZV infection in humans (Mahalingam et al. 2019). We found that compared to pre-inoculation samples, serum substance P was significantly elevated during varicella and at least 12 weeks post-varicella and during zoster.

Substance P is secreted from neurons and immune cells in response to noxious stimuli (Mashaghi et al. 2016). In our studies, substance P may be secreted from sensory neurons which are infected during primary infection (Hokfelt et al. 1975; Mitchell et al. 2003), and from neurons where SVV exits latency and replicates during reactivation. Substance P may also be produced by infected immune cells, or bystander cells. The persistence of substance P up to 4 weeks after varicella rash may be due to residual replicating virus in sensory ganglia that continue to produce substance P. Alternatively, the virus-induced phenotypic alterations in immune cells resulting in substance P secretion may persist for several weeks. The persistence of substance P after zoster was not assessed in this study because animals were necropsied at the time of rash.

Several non-mutually exclusive possibilities exist that may explain how virus-induced elevations in substance P could potentially contribute to increased stroke risk after varicella and zoster. First, the increased substance P may produce a hypercoagulable state. Azma and colleagues (2009) added substance P to human whole blood ex vivo and found significant increases in clot formation by an oscillating-probe viscoelastometer; treatment with a NK-1R antagonist prevented this increase. Similarly, Jones and colleagues (2008) found that disrupting NK-1R signaling activity resulted in substantially reduced thrombosis formation, as well as increased bleeding time and diminished thrombosis in mice. Thus, the virus-induced elevations in substance P, as well as alterations in protein C and S (Nguyen et al. 1994; reviewed in Nagel et al. 2020), may lead to a hypercoagulable state, resulting in increased stroke risk during infection.

Second, substance P may contribute to atherosclerotic plaque rupture during zoster through the activation of mast cells. Bot and colleagues (2010) found that perivascular substance P administration at the site of an artery lesion significantly enhanced the number and activation status of adventitial mast cells and resulted in intraplaque hemorrhages in western-type diet fed mice. Co-treating with a NK-1R antagonist prevented these effects and did not occur in mast cell deficient mice indicating a critical role of mast cells in this process.

Finally, chronic and persistent inflammatory states are associated with the risk of adverse vascular events that positively correlate with severity of inflammation (Libby et al. 2002; Libby 2006; Dregan et al. 2014). The role of substance P in modulating persistent inflammatory states is well characterized based on studies showing increased substance P and NK-1R expression in affected tissues and the therapeutic benefit of NK-1R antagonists in such cases (reviewed in O’Conner et al. 2004). Previous studies have shown that substance P acts as a chemoattractant and induces secretion of almost all known cytokines from multiple immune cells (Freidin et al. 1992; Rameshwar et al. 1992; Derocq et al. 1996; Palma and Manzini 1998; O’Connor et al. 2004; Garza et al. 2008). Furthermore, substance P acts as a stimulator of natural killer activity and proliferation in lymphocytes, induces oxidative bursts and release of arachidonic acid metabolites in monocytes/macrophages, stimulates degranulation and increases adherence to epithelial cells in neutrophils, and stimulates activation and degranulation of eosinophils (reviewed in O’Connor et al. 2004). Precedence for virus-induced substance P leading to worse inflammation and disease is provided by a study on herpes simplex 1 (HSV-1) keratitis in mice; higher levels of substance P were associated with more severe eye disease as well as elevations in IL-6 and IFN-γ. Increases in infiltrating neutrophils and CD4 T-Cells were also noted (Twardy et al. 2011). Treatment with a NK-1R antagonists significantly reduced clinical severity in these mice (Twardy et al. 2011). Furthermore, the successful application of NK-1R antagonists to reduce inflammation in response to other infectious pathogens have been reported in Borrelia burgdorferi-infected rhesus macaques (Martinez et al. 2017) as well as in human immunodeficiency virus-infected humans (Tebas et al. 2015).

Overall, we show that during varicella and zoster in rhesus macaques, substance P levels are increased compared to pre-inoculation levels and remained elevated weeks following viral clearance. This persistent elevation supports the premise that substance P may contribute to the increased risk of stroke after virus infection by sustained induction of a hypercoagulable state, destabilization of pre-existing atherosclerotic plaques, and chronic inflammation. However, the current study is correlational, therefore, future studies need to assess hypercoagulability and persistent inflammation in association with SVV infection in rhesus macaques in vivo, as well as determine if blockade of substance P signaling (using NK-1R antagonists such as aprepitant or rolapitant) attenuates these effects. Determining the contributions of substance P to increased stroke risk after varicella and zoster may point to a role of treating with NK-1R antagonists in the short term to decrease cerebrovascular-associated risks.

Acknowledgments

Funding This study was funded by National Institutes of Health (NIH) NIA P01 AG032958; and NIH NINDS R01 NS093716. This work was also supported in part with federal funds from the National Center for Research Resources and the Office of Research Infrastructure Programs (ORIP) of the National Institutes of Health through grant number P51 RR00164 to the Tulane National Primate Research Center (V.T-D, A.D., L.D.-M.).

Footnotes

Conflict of interest The authors declare that there are no conflicts of interest.

Publisher's Disclaimer: This Author Accepted Manuscript is a PDF file of a an unedited peer-reviewed manuscript that has been accepted for publication but has not been copyedited or corrected. The official version of record that is published in the journal is kept up to date and so may therefore differ from this version.

References

  1. Azma T, Matsubara Y, Kinoshita H, Hidaka I, Shiraishi S, Nakao M, Kawamoto M, Yuge O, Hatano Y (2009) Prothrombotic roles of substance-P, neurokinin-1 receptors and leukocytes in the platelet-dependent clot formation in whole blood. J Thromb Thrombolysis 27:280–286. doi: 10.1007/s11239-008-0215-0 [DOI] [PubMed] [Google Scholar]
  2. Bot I, de Jager SC, Bot M, van Heiningen SH, de Groot P, Veldhuizen RW, van Berkel TJ, Jan H, Biessen EA (2010) The neuropeptide substance P mediates adventitial mast cell activation and induces intraplaque hemorrhage in advanced atherosclerosis. Circ Res 106:89–92. doi: 10.1161/circresaha.109.204875 [DOI] [PubMed] [Google Scholar]
  3. Derocq JM, Ségui M, Blazy C, Emonds-Alt X, Le Fur G, Brelière JC, Casellas P (1996) Effect of substance P on cytokine production by human astrocytic cells and blood mononuclear cells: characterization of novel tachykinin receptor antagonists. FEBS Lett 399:321–325. doi: 10.1016/s0014-5793(96)01346-4 [DOI] [PubMed] [Google Scholar]
  4. Dregan A, Charlton J, Chowienczyk P, Gulliford MC (2014) Chronic inflammatory disorders and risk of type 2 diabetes mellitus, coronary heart disease, and stroke: a population-based cohort study. Circulation 130:837–844. doi: 10.1161/circulationaha.114.09990 [DOI] [PubMed] [Google Scholar]
  5. Forbes HJ, Williamson E, Benjamin L, Breuer J, Brown MM, Langan SM, Minassian C, Smeeth L, Thomas SL, Warren-Gash C (2018) Association of herpesviruses and stroke: Systematic review and meta-analysis. PLoS One 13:e0206163. doi: 10.1371/journal.pone.0206163 [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Freidin M, Bennett MV, Kessler JA (1992) Cultured sympathetic neurons synthesize and release the cytokine interleukin 1 beta. Proc Natl Acad Sci U S A 89:10440–10443. doi: 10.1073/pnas.89.21.10440 [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Garza A, Weinstock J, Robinson P (2008) Absence of the SP/SP receptor circuitry in the SP precursor knockout mice or SP-receptor, neurokinin (NK1) knockout mice leads to an inhibited cytokine response in granulomas associated with murine Taenia crassiceps infection. J Parasitol 94:1253–1258. doi: 10.1645/GE-1481.1 [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Hokfelt T, Kellerth JO, Nilsson G, Pernow B (1975) Substance P: localization in the central nervous system and in some primary sensory neurons. Science 190:889–890. doi: 10.1126/science.242075 [DOI] [PubMed] [Google Scholar]
  9. Jones S, Tucker KL, Sage T, Kaiser WJ, Barrett NE, Lowry PJ, Zimmer A, Hunt SP, Emerson M, Gibbins JM (2008) Peripheral tachykinins and the neurokinin receptor NK1 are required for platelet thrombus formation. Blood 111:605–612. doi: 10.1182/blood-2007-07-103424 [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Jones D, Alvarez E, Selva S, Gilden D, Nagel MA (2016) Proinflammatory cytokines and matrix metalloproteinases in CSF of patients with VZV vasculopathy. Neurol. Neuroimmunol. Neuroinflamm. 3:e246; doi: 10.1212/NXI.0000000000000246 [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Jones D, Neff CP, Palmer BE, Stenmark K, Nagel MA (2017) Varicella zoster virus-infected cerebrovascular cells produce a proinflammatory environment. Neurol. Neuroimmunol. Neuroinflamm. 4:e382; doi: 10.1212/NXI.0000000000000382 [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Libby P (2006) Inflammation and cardiovascular disease mechanisms. Am J Clin Nutr 83:456S–460S. doi: 10.1093/ajcn/83.2.456S [DOI] [PubMed] [Google Scholar]
  13. Libby P, Ridker PM, Maseri A (2002) Inflammation and atherosclerosis. Circulation 105:1135–1143. doi: 10.1161/hc0902.104353 [DOI] [PubMed] [Google Scholar]
  14. Lorente L, Martín MM, Almeida T, Pérez-Cejas A, Ramos L, Argueso M, Riaño-Ruiz M, Solé-Violán J, Hernández M (2016) Serum levels of substance P and mortality in patients with a severe acute ischemic stroke. Int J Mol Sci 17:991. doi: 10.3390/ijms17060991 [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Lorente L, Martín MM, Pérez-Cejas A, González-Rivero AF, Argueso M, Ramos L, Solé-Violán J, Cáceres JJ, Jiménez A, García-Marín V (2020) High serum substance P levels and mortality after malignant middle cerebral artery infarction. J Crit Care 57:1–4. doi: 10.1016/j.jcrc.2020.01.022 [DOI] [PubMed] [Google Scholar]
  16. Mahalingam R, Traina-Dorge V, Wellish M, Lorino R, Sanford R, Ribka EP, Alleman SJ, Brazeau E, Gilden DH (2007) SVV reactivation in Cynomologous monkeys. Virology 368:50–59. doi: 10.1016/j.virol.2007.06.025 [DOI] [PubMed] [Google Scholar]
  17. Mahalingam R, Traina-Dorge V, Wellish M, Deharo E, Singletary ML, Ribka EP, Sanford R, Gilden D (2010) Latent simian varicella virus reactivates in monkeys treated with tacrolimus with or without exposure to irradiation. J Neurovirol 16:342–354. doi: 10.3109/13550284.2010.513031 [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Mahalingam R, Gershon A, Gershon M, Cohen JI, Arvin A, Zerboni L, Zhu H, Gray W, Messaoudi I, Traina-Dorge V (2019) Current in vivo models of varicella-zoster virus neurotropism. Viruses 11:502. doi: 10.3390/v11060502 [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Martinez AN, Burmeister AR, Ramesh G, Doyle-Meyers L, Marriott I, Philipp MT (2017) Aprepitant limits in vivo neuroinflammatory responses in a rhesus model of Lyme neuroborreliosis. J Neuroinflammation 14:1–9. doi: 10.1186/s12974-017-0813-x [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Mashaghi A, Marmalidou A, Tehrani M, Grace PM, Pothoulakis C, Dana R (2016) Neuropeptide substance P and the immune response. Cell Mol Life Sci 73:4249–4264. doi: 10.1007/s00018-016-2293-z [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Menon B, Goyal R (2012) Cerebral venous thrombosis as a complication of chicken pox. Ann Trop Med Public Health 5:520–522. [Google Scholar]
  22. Messaoudi I, Barron A, Wellish M, Engelmann F, Legasse A, Planer S, Gilden D, Nikolich-Zugich J, Mahalingam R (2009) Simian varicella virus infection of rhesus macaques recapitulates essential features of varicella zoster virus infection in humans. PLoS Pathog 5:e1000657. doi: 10.1371/journal.ppat.1000657 [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Mitchell BM, Bloom DC, Cohrs RJ, Gilden DH, Kennedy PG (2003) Herpes simplex virus-1 and varicella-zoster virus latency in ganglia. J NeuroVirol 9:194–204. doi: 10.1080/13550280390194000 [DOI] [PubMed] [Google Scholar]
  24. Nagel MA, Gilden D, Shade T, Gao B, Cohrs RJ (2009) Rapid and sensitive detection of 68 unique VZV gene transcripts in five multiplex reverse transcription-polymerase chain reactions. J Virol Methods 157:62–68. doi: 10.1016/j.jviromet.2008.11.019 [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Nagel MA, Traktinskiy I, Azarkh Y, Kleinschmidt-DeMasters B, Hedley-Whyte T, Russman A, VanEgmond EM, Stenmark K, Frid M, Mahalingam R, Wellish M, Choe A, Cordery-Cotter R, Cohrs RJ, Gilden D (2011) Varicella zoster virus vasculopathy: Analysis of virus-infected arteries. Neurology 77:364–370. doi: 10.1212/WNL.0b013e3182267bfa [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Nagel MA, Traktinskiy I, Stenmark KR, Frid MG, Choe A, Gilden D (2013) Varicella zoster virus vasculopathy: Immune characteristics of virus-infected arteries. Neurology 80:62–68. doi: 10.1212/WNL.0b013e31827b1ab9 [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Nagel MA, Choe A, Rempel A, Wyborny A, Stenmark K, Gilden D (2015) Differential regulation of matrix metalloproteinases in varicella zoster virus-infected human brain vascular adventitial fibroblasts. J Neurol Sci 358:444–446. doi: 10.1016/j.jns.2015.09.349 [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Nagel MA, Niemeyer CS, Bubak AN (2020) Central nervous system infections produced by varicella zoster virus. Curr Opin Infect Dis 33:273–279. doi: 10.1097/QCO.0000000000000647 [DOI] [PubMed] [Google Scholar]
  29. Nessler S, Stadelmann C, Bittner A, Schlegel K, Gronen F, Brueck W, Hemmer B, Sommer N (2006) Suppression of autoimmune encephalomyelitis by a neurokinin-1 receptor antagonist—a putative role for substance P in CNS inflammation. J Neuroimmunol 179:1–8. doi: 10.1016/j.jneuroim.2006.06.026 [DOI] [PubMed] [Google Scholar]
  30. Nguyen P, Munzer M, Reynaud J, Richard O, Pouzol P, Francois P (1994) Varicella and thrombotic complications associated with transient protein C and protein S deficiencies in children. Eur J Pediatr 153:646–649. doi: 10.1007/BF02190684 [DOI] [PubMed] [Google Scholar]
  31. O’Connor TM, O’Connell J, O’Brien DI, Goode T, Bredin CP, Shanahan F (2004) The role of substance P in inflammatory disease. J Cell Physiol 201:167–180. doi: 10.1002/jcp.20061 [DOI] [PubMed] [Google Scholar]
  32. Palma C, Manzini S (1998) Substance P induces secretion of immunomodulatory cytokines by human astrocytoma cells. J Neuroimmunol 81:127–137. doi: 10.1016/s0165-5728(97)00167-7 [DOI] [PubMed] [Google Scholar]
  33. Paul G, Paul BS, Singh G (2016) Unseen face of varicella-zoster infection in adults. Indian J Crit Care Med 20:731–734. doi: 10.4103/0972-5229.195713 [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Quinlan KL, Song IS, Bunnett NW, Letran E, Steinhoff M, Harten B, Olerud JE, Armstrong CA, Wriht-Caughman S, Ansel JC (1998) Neuropeptide regulation of human dermal microvascular endothelial cell ICAM-1 expression and function. Am J Physiol 275:C1580–C1590. doi: 10.1152/ajpcell.1998.275.6.C1580 [DOI] [PubMed] [Google Scholar]
  35. Rameshwar P, Gascon P, Ganea D (1992) Immunoregulatory effects of neuropeptides. Stimulation of interleukin-2 production by substance P. J Neuroimmunol 37:65–74. doi: 10.1016/0165-5728(92)90156-f [DOI] [PubMed] [Google Scholar]
  36. Sada S, Kammineni A, Kaniikannan MA, Afshan J (2012) Cerebral sinus venous thrombosis: A rare complication of primary varicella virus. Neurol India 60:645–646. doi: 10.4103/0028-3886.105204 [DOI] [PubMed] [Google Scholar]
  37. Sardana V, Mittal LC, Meena SR, Sharma D, Khandelwal G (2014) Acute venous sinus thrombosis after chickenpox infection. J Assoc Physicians India 62:741–743. [PubMed] [Google Scholar]
  38. Science M, MacGregor D, Richardson SE, Mahant S, Tran D, Bitnun A (2014) Central nervous system complications of varicella-zoster virus. J Pediatr 165:779–785. doi: 10.1016/j.jpeds.2014,06.014 [DOI] [PubMed] [Google Scholar]
  39. Siddiqi SA, Nishat S, Kanwar D, AH F, Azeemuddin M, Wasay M (2012) Cerebral venous sinus thrombosis: Association with primary varicella zoster virus infection. J Stroke Cerebrovasc Dis 21:917.e1–4. doi: 10.1016/j.jstrokecerebrovasdis.2012.04.013 [DOI] [PubMed] [Google Scholar]
  40. Sudhaker B, Dnyaneshwar MP, Jaidip CR, Rao SM (2014) Cerebral venous sinus thrombosis (CVST) secondary to varicella induced hypercoagulable state in a adult. Intern Med Inside 2:1. doi: 10.7243/2052-6954-2-1 [DOI] [Google Scholar]
  41. Tebas P, Spitsin S, Barrett JS, Tuluc F, Elci O, Korelitz JJ, Wagner W, Winters A, Kim D, Catalano R, Evans DL (2015) Reduction of soluble CD163, substance P, programmed death 1 and inflammatory markers: phase 1B trial of aprepitant in HIV-1-infected adults. AIDS 29(8):931–9. doi: 10.1097/QAD.0000000000000638 [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Thomas SL, Minassian C, Ganesan V, Langan SM, Smeeth L (2014) Chickenpox and risk of stroke: a self-controlled case series analysis. Clin Infect Dis 58:61–68. doi: 10.1093/cid/cit659 [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Traina-Dorge V, Doyle-Meyers LA, Sanford R, Manfredo J, Blackmon A, Wellish M, James S, Alvarez X, Midkiff C, Palmer BE, Deharo E (2015) Simian varicella virus is present in macrophages, dendritic cells, and T cells in lymph nodes of rhesus macaques after experimental reactivation. J Virol 89:9817–9824. doi: 10.1128/JVI.01324-15 [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Traina-Dorge V, Mehta SK, Rooney B, Crucian B, Doyle-Meyers L, Das A, Coleman C, Nagel M, Mahalingam R (2019) Simian varicella virus DNA in saliva and buccal cells after experimental acute infection in rhesus macaques. Front Microbiol 10:1009. doi: 10.3389/fmicb.2019.01009 [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Twardy BS, Channappanavar R, Suvas S (2011) Substance P in the corneal stroma regulates the severity of herpetic stromal keratitis lesions. Invest Ophthalmol Vis Sci 52:8604–8613. doi: 10.1167/iovs.11-8089 [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Vishwanath R, Mukherjee R (1996) Substance P promotes lymphocyte-endothelial cell adhesion preferentially via LFA-1/ICAM-1 interactions. J Neuroimmunol 71:163–171. doi: 10.1016/s0165-5728(96)00143-9 [DOI] [PubMed] [Google Scholar]

RESOURCES