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Vijay Ramakrishnan, MD

Associate Professor - Rhinology


​​Vijay Ramakrishnan, MD​, joined the University of Colorado Department of Otolaryngology in 2010 after completing fellowship training in advanced rhinology and skull base surgery at the University of Pennsylvania. He is a board-certified Otolaryngologist and Fellow of the American Rhinologic Society. He serves as Co-Director of the CU Skull Base Program, with clinical expertise including the treatment of nasal obstruction, chronic rhinosinusitis and nasal polyps, complex sino-orbital diseases, CSF leaks and skull base tumors. He has participated in clinical research in the realm of minimally invasive endoscopic and skull base approaches, and is currently involved in a multicenter study of surgical outcomes in chronic rhinosinusitis (CRS). His research program examines chemosensory detection in the airway with specific regard to the microbiome and mucosal inflammation, with active grants from the NIH and FAMRI. 

Our lab has been interested in the role of the microbiome in the chronic inflammatory state of CRS. In collaboration with the Frank Lab, we have shown healthy sinuses are not sterile and that clinical cultures are insufficient in enumeration of bacteria in disease.hauser fig.jpg

In fact, bacteria colonize the sinonasal mucosal surface in similar amounts in healthy sinuses when compared to sinuses in CRS subjects. Using modern bacterial DNA detection techniques, we have demonstrated that the local microbiome in CRS is compositionally different than that found in healthy subjects, even despite the underlying between-subject differences. Some common differences have been replicated by other labs, such as the preponderance for anaerobes in CRS, and the potential protective effect of certain healthy taxa. In a JACI 2015 article, we described sinonasal microbiome differences in CRS phenotypes, and ide
ntify Actinobacteria as predictive of surgical outcomes in refractory CRS cases. 


In different investigations, our lab also was one of the first to identify solitary chemosensory cells and taste transduction machinery in human sinonasal tissues. Research mentors at the Rocky Mountain Taste and Smell Center (Finger, Tizzano) described the function of such cells in rodents, and established a role for their function in detection of irritants in the airway surface liquid.  These cells are elongated in shape with a microvillar tuft on the apical projection, express sweet and bitter taste receptors on their surface, utilize canonical taste transduction machinery, and are frequently innervated in rodents. 
Subsequently, we documented the presence of such cells and taste transduction molecules in human sinonasal tissues using PCR and immunohistochemistry.


 

 

 Solitary chemosensory cells

 
​​​​​Credit: Eric Larson, PhD​​​​​​​​​

Interest in extraoral taste receptors, particularly bitter taste receptors, has exploded in the past few years. Their presence, whether on cilia or in specialized chemosensory cells, has been documented in many organ systems and they may serve a role in any number of physiologic functions. Our current research focuses on SCCs in the respiratory tract and their response to airway irritants. We utilize both mouse models and human tisues in a collaborative environment with other researchers in the RMTSC​.​

sketch fig.jpg 


plos one fig.jpg 

Dysbiosis in the CRS microbiome may seemingly serve as a biomarker or additional factor to endotype CRS subjects. However, we are currently interested in identifying functional roles for the microbiome in the health state, and potential causal mechanisms for induction or sustenance of chonic inflammation in CRS. This includes study of factors governing establishment of the airway microbiome, host-bacteria interactions at the airway surface, induction of inflammatory pathways, and resilience to perturbation. We have found age and cigarette smoke exposure to be factors in multivariate analysis of healthy subjects, and continue to explore mechanistic aspects of the microbiome in the airway.

  • Jennifer Kofonow, MS
  • Cathy Anderson, MS
  • Eric Larson, PhD
  • Jing-guo Chen, predoctoral student
  • Shivani Pathak, MD
  • Conner Massey, MD



​Division of Rhinology: Todd Kingdom, MD and Anne Getz, MD
CU Skull Base Program collaborators


   

  • Complete List of Published Work in MyBibliography:  

    http://www.ncbi.nlm.nih.gov/myncbi/browse/collection/44542048/?sort=date&direction=ascending

     

     Ramakrishnan VR, Hauser LJ, Feazel LM, Ir D, Robertson CE, Frank DN. Sinus microbiota varies among chronic rhinosinusitis phenotypes and predicts surgical outcome. J Allergy Clin Immunol 2015; 136(2):334-42.

     

    Ramakrishnan VR, Feazel LM, Gitomer SA, Ir D, Robertson CE, Frank DN. The microbiome of the middle meatus in healthy adults. PLoS ONE 2013; 8(12): e85507.

     

    Frank DN and Ramakrishnan VR. Impact of cigarette smoking on the middle meatus microbiome in health and chronic rhinosinusitis. Int Forum Allergy Rhinol 2015;5(11):981-9.

     

    Feazel L, Robertson C, Ramakrishnan VR, Frank DN. Staphylococcus aureus and microbiome diversity in chronic rhinosinusitis. Laryngoscope 2011; 122(2):467-72.

     

    Hauser LJ, Feazel LM, Ir D, Fang R, Wagner BD, Robertson CE, Frank DN, Ramakrishnan VR. Sinus culture poorly predicts resident microbiota. Int Forum

    Allergy Rhinol 2015;5(1):3-9.

     

    Barham HP, Cooper SE, Tizzano M, Kingdom TT, Finger TE, Kinnamon SC, Ramakrishnan VR. Solitary chemosensory cells and bitter taste receptor signaling in human sinonasal mucosa. Int Forum Allergy Rhinology 2013; 3(6):450-7.

     

    Sokoya M, Ramakrishnan VR, Frank DN, Rakhola J, Getz A, Kingdom TT, Kofonow JM, Nguyen Q, Janoff EN. Expression of Immunoglobulin D is Increased in Chronic Rhinosinusitis. Annals Allergy Asthma 2017;119(4):317-323.

     

    Mudd PA, Katial RK, Alam R, Hohensee S, Ramakrishnan V, Kingdom TT. Variations in expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase in nasal mucosa of aspirin-sensitive versus aspirin-tolerant patients with nasal polyposis. Ann Allergy Asthma Immunol 2011;107(4):353-9.

     

    Gitomer SA, Fountain CR, Kingdom TT, Getz AE, Sillau SH, Katial RK, Ramakrishnan VR. Clinical examination of tissue eosinophlia in patients with chronic rhinosinusitis and nasal polyposis. Otolaryngol Head Neck Surg 2016;155(1):173-8.