Bio

Bio


Dr. Parikh is cardiologist specializing in the care of patients with inherited cardiovascular diseases. She completed clinical cardiology fellowship at Stanford School of Medicine and her medical residency at the University of California, San Francisco. Funded by research grant from the NIH, she currently studies multiple causes of cardiomyopathy in the laboratory. She has a particular clinical and scientific interest in inherited arrhythmogenic cardiomyopathies, which are an increasingly recognized disease entity. Dr. Parikh is currently using patient cohort genetics, high throughput molecular biology and human induced pluripotent stem cell derived cardiomyocytes to study variant pathogenicity in this disease.

Clinical Focus


  • Cardiovascular Disease
  • Inherited Cardiomyopathies
  • Inherited Arrhythmia
  • Arrhythmogenic Cardiomyopathy

Academic Appointments


Honors & Awards


  • Ruth L. Kirschtein NRSA NIH Postdoctoral Fellowship Grant, National Institutes of Health (2/2016-2/2019)
  • Women in Cardiology Award for Trainee Excellence, American Heart Association (11/2016)
  • Excellence in Cardiology Fellowship Award, American College of Cardiology (05/2016)
  • Sarnoff Cardiovascular Research Foundation Fellowship, Sarnoff Cardiovascular Foundation (2009-2010)

Professional Education


  • Board Certification: Cardiovascular Disease, American Board of Internal Medicine (2017)
  • Fellowship:Stanford University School of Medicine - Office of Graduate Affairs - Postdoctoral Affairs (2017) CA
  • Board Certification: Internal Medicine, American Board of Internal Medicine (2014)
  • Residency:University of California San Francisco (2014) CA
  • Medical Education:Stanford University School of Medicine (2011) CA
  • Doctor of Medicine, Stanford University, MED-MD (2011)
  • Bachelor of Arts, Stanford University, HUMBI-BAH (2005)

Stanford Advisors


Research & Scholarship

Lab Affiliations


Publications

All Publications


  • Delivering Clinical Grade Sequencing and Genetic Test Interpretation for Cardiovascular Medicine. Circulation. Cardiovascular genetics Harper, A. R., Parikh, V. N., Goldfeder, R. L., Caleshu, C., Ashley, E. A. 2017; 10 (2)

    View details for DOI 10.1161/CIRCGENETICS.116.001221

    View details for PubMedID 28411191

  • Vascular stiffness mechanoactivates YAP/TAZ-dependent glutaminolysis to drive pulmonary hypertension JOURNAL OF CLINICAL INVESTIGATION Bertero, T., Oldham, W. M., Cottrill, K. A., Pisano, S., Vanderpool, R. R., Yu, Q., Zhao, J., Tai, Y., Tang, Y., Zhang, Y., Rehman, S., Sugahara, M., Qi, Z., Gorcsan, J., Vargas, S. O., Saggar, R., Saggar, R., Wallace, W. D., Ross, D. J., Haley, K. J., Waxman, A. B., Parikh, V. N., De Marco, T., Hsue, P. Y., Morris, A., Simon, M. A., Norris, K. A., Gaggioli, C., Loscalzo, J., Fessel, J., Chan, S. Y. 2016; 126 (9): 3313-3335

    Abstract

    Dysregulation of vascular stiffness and cellular metabolism occurs early in pulmonary hypertension (PH). However, the mechanisms by which biophysical properties of the vascular extracellular matrix (ECM) relate to metabolic processes important in PH remain undefined. In this work, we examined cultured pulmonary vascular cells and various types of PH-diseased lung tissue and determined that ECM stiffening resulted in mechanoactivation of the transcriptional coactivators YAP and TAZ (WWTR1). YAP/TAZ activation modulated metabolic enzymes, including glutaminase (GLS1), to coordinate glutaminolysis and glycolysis. Glutaminolysis, an anaplerotic pathway, replenished aspartate for anabolic biosynthesis, which was critical for sustaining proliferation and migration within stiff ECM. In vitro, GLS1 inhibition blocked aspartate production and reprogrammed cellular proliferation pathways, while application of aspartate restored proliferation. In the monocrotaline rat model of PH, pharmacologic modulation of pulmonary vascular stiffness and YAP-dependent mechanotransduction altered glutaminolysis, pulmonary vascular proliferation, and manifestations of PH. Additionally, pharmacologic targeting of GLS1 in this model ameliorated disease progression. Notably, evaluation of simian immunodeficiency virus-infected nonhuman primates and HIV-infected subjects revealed a correlation between YAP/TAZ-GLS activation and PH. These results indicate that ECM stiffening sustains vascular cell growth and migration through YAP/TAZ-dependent glutaminolysis and anaplerosis, and thereby link mechanical stimuli to dysregulated vascular metabolism. Furthermore, this study identifies potential metabolic drug targets for therapeutic development in PH.

    View details for DOI 10.1172/JCI86387

    View details for Web of Science ID 000382513400015

    View details for PubMedID 27548520

    View details for PubMedCentralID PMC5004943

  • Early Outcomes After Extracardiac Conduit Fontan Operation Without Cardiopulmonary Bypass PEDIATRIC CARDIOLOGY McCammond, A. N., Kuo, K., Parikh, V. N., Abdullah, K., Balise, R., Hanley, F. L., Roth, S. J. 2012; 33 (7): 1078-1085

    Abstract

    Cardiopulmonary bypass is associated with a systemic inflammatory response. The authors hypothesized that avoiding cardiopulmonary bypass would lead to improved postoperative outcomes for patients undergoing the extracardiac Fontan operation, the final stage in surgical palliation of univentricular congenital heart defects. A review of the Children's Heart Center Database showed a total of 73 patients who underwent an initial Fontan operation at Lucile Packard Children's Hospital at Stanford between 1 November 2001 and 1 November 2006. These patients were divided into two groups: those who underwent cardiopulmonary bypass (n = 26) and those who avoided cardiopulmonary bypass (n = 47). Preoperative demographics, hemodynamics, and early postoperative outcomes were analyzed. The two groups had comparable preoperative demographic characteristics and hemodynamics except that the average weight of the off-bypass group was greater (17.9 ± 9.1 vs 14.2 ± 2.7 kg; P = 0.01). Intraoperatively, the off-bypass group trended toward a lower rate of Fontan fenestration (4.3 vs 19.2%; P = 0.09), had lower common atrial pressures (4.6 ± 1.4 vs 5.5 ± 1.5 mmHg; P = 0.05), and Fontan pressures (11.9 ± 2.1 vs 14.2 ± 2.4 mmHg; P ≤ 0.01), and required less blood product (59.1 ± 37.6 vs 91.9 ± 49.4 ml/kg; P ≤ 0.01). Postoperatively, there were no significant differences in hemodynamic parameters, postoperative colloid requirements, duration of mechanical ventilation, volume or duration of pleural drainage, or duration of cardiovascular intensive care unit or hospital stay. Avoiding cardiopulmonary bypass influenced intraoperative hemodynamics and the incidence of fenestration but did not have a significant impact on the early postoperative outcomes of children undergoing the Fontan procedure.

    View details for DOI 10.1007/s00246-012-0228-5

    View details for Web of Science ID 000308828200011

    View details for PubMedID 22349678

  • Physiological consequences of social descent: studies in Astatotilapia burtoni JOURNAL OF ENDOCRINOLOGY Parikh, V. N., Clement, T., Fernald, R. D. 2006; 190 (1): 183-190

    Abstract

    In many species, social interactions regulate reproductive capacity, although the exact mechanisms of such regulation are unclear. Since social stress is often related to reproductive regulation, we measured the physiological signatures of change in reproductive state as they relate to short-term stress and the stress hormone cortisol. We used an African cichlid fish, Astatotilapia burtoni, with two distinct, reversible male phenotypes: dominant (territorial, T) males that are larger, more brightly colored, more aggressive, and reproductively competent and non-dominant males (non-territorial, NT) that are smaller, camouflage colored, and have regressed gonads. Male status, and hence reproductive competence, depends on social experience in this system. Specifically, if a T male is placed among larger male fish, it quickly becomes NT in behavior and coloration, but complete regression of its reproductive axis takes ca. 3 weeks (White et al. 2002). Reproduction in all vertebrates is controlled by the hypothalamic-pituitary-gonadal axis in which the key signaling molecule from the brain to the pituitary is GnRH1. Here, we subjected T males to territory loss, a social manipulation which results in status descent. We measured the effects of this status change in levels of circulating cortisol and testosterone as well as mRNA levels of GnRH1 and GnRH receptor-1 (GnRH-R1) in the brain and pituitary, respectively. Following short-term social suppression (4 h), no change was observed in plasma cortisol level, GnRH1 mRNA expression, GnRH-R1 mRNA expression, or plasma testosterone level. However, following a somewhat longer social suppression (24 h), cortisol and GnRH1 mRNA levels were significantly increased, and testosterone levels were significantly decreased. These results suggest that in the short run, deposed T males essentially mount a neural 'defense' against loss of status.

    View details for DOI 10.1677/joe.1.06755

    View details for Web of Science ID 000239385600021

    View details for PubMedID 16837622

  • Androgen level and male social status in the African cichlid, Astatotilapia burtoni BEHAVIOURAL BRAIN RESEARCH Parikh, V. N., Clement, T. S., Fernald, R. D. 2006; 166 (2): 291-295

    Abstract

    In vertebrates, circulating androgen levels are regulated by the hypothalamic-pituitary-gonadal (HPG) axis through which the brain controls the gonads via the pituitary. Androgen levels ultimately depend on factors including season, temperature, social circumstance, age, and other variables related to reproductive capacity and opportunity. Previous studies with an African cichlid fish, Astatotilapia burtoni, suggested that changes in both testosterone and 11-ketotestosterone (11-KT), an androgen specific to teleost fish, depend on male social status. Here we characterize circulating plasma concentrations of testosterone and 11-KT in socially dominant (territorial) and socially subordinate (non-territorial) males. Territorial males have significantly higher circulating levels of both forms of androgen, which is another defining difference between dominant and subordinate males in this species. These results underscore how internal and external cues related to reproduction are integrated at the level of the HPG axis.

    View details for DOI 10.1016/j.bbr.2005.07.011

    View details for Web of Science ID 000234643600014

    View details for PubMedID 16143408

  • Behavioral coping strategies in a cichlid fish: the role of social status and acute stress response in direct and displaced aggression HORMONES AND BEHAVIOR Clement, T. S., Parikh, V., Schrumpf, M., Fernald, R. D. 2005; 47 (3): 336-342

    Abstract

    The African cichlid fish, Astatotilapia burtoni, has a complex social system with a sophisticated social hierarchy that offers unique opportunities to understand how social rank and its physiological substrates relate to behavioral strategies. In A. burtoni, a small fraction of the males are dominant (T, territorial), as distinguished by being large, brightly colored, reproductively active, and aggressively defending territories. In contrast, the majority of males are non-dominant (NT, non-territorial), being smaller, drably colored, sexually immature, and typically schooling with females. The social system is regulated by aggressive interactions between males and behavioral responses to aggression can be direct or displaced with respect to the animal that acts. To determine whether direct and displaced behaviors are differentially exhibited by T and NT males, individuals were shown a video presentation of a dominant male displaying aggressively. Analysis of aggressive acts toward the video display and displaced activity toward a tank mate revealed that T males exhibited more direct behavior (toward the video display), while NT males engaged in more displaced behavior (toward tank mates). Because similar experiments with primates suggest that shifts in behavioral strategies are linked to changes in the stress response (as measured by circulating cortisol levels), we measured cortisol levels of T and NT males following exposure to the aggressive stimulus. Although in some animals subordinate males are reported to have higher cortisol levels, here we show that in A. burtoni the endocrine response to specific situations can vary considerably even among animals of the same status. Interestingly, NT males with intermediate cortisol levels showed more directed behavior while NT males with both high and low cortisol levels showed more displaced. This suggests an optimal physiological stress response in NT males that predisposes them to challenge aggressors perhaps making it more likely for them to ascend in status.

    View details for DOI 10.1016/j.yhbeh.2004.11.014

    View details for Web of Science ID 000227326100013

    View details for PubMedID 15708763