Photo of Josephine (Josephine) Mun-Yee Lok, MD

Josephine (Josephine) Mun-Yee Lok, MD

  • Physician, Assistant in Pediatrics, Pediatric Critical Care Medicine
  • Assistant Professor of Pediatrics, Harvard Medical School






Centers & Specialties

MassGeneral Hospital for Children

Clinical Interests
  • Airway management
  • Critical care
  • Simulation-based preparation for Pediatric Emergencies
  • Traumatic brain injury and concussion in children
Medical Education
  • MD, Albert Einstein College of Medicine
  • Residency, Beth Israel Deaconess Medical Center|Residency, Tufts Medical Center
  • Fellowship, The Johns Hopkins Hospital
Board Certifications
  • Pediatric Critical Care Medicine
Foreign Languages
  • Cantonese/Yue
  • Boston: Massachusetts General Hospital
Insurances Accepted
  • Aetna Health Inc.
  • Beech Street
  • Blue Cross Blue Shield - Blue Care 65
  • Blue Cross Blue Shield - Indemnity
  • Blue Cross Blue Shield - Managed Care
  • Blue Cross Blue Shield - Partners Plus
  • BMC HealthNet Mass Health MCO/ACO
  • Cigna (PAL #'s)
  • Commonwealth Care Alliance
  • Fallon Community HealthCare
  • Great-West Healthcare (formally One Health Plan)
  • Harvard Pilgrim Health Plan - ACD
  • Harvard Pilgrim Health Plan - PBO
  • Health Care Value Management (HCVM)
  • Humana/Choice Care PPO
  • MassHealth
  • Medicare
  • Medicare - ACD
  • Neighborhood Health Plan - ACD
  • Neighborhood Health Plan - PBO
  • OSW - Connecticut
  • OSW - Maine
  • OSW - New Hampshire
  • OSW - New York
  • OSW - Rhode Island
  • OSW - Vermont
  • Private Health Care Systems (PHCS)
  • Senior Whole Health
  • TriCare
  • Tufts Health Plan
  • Unicare
  • United Healthcare (non-HMO) - ACD
  • United Healthcare (non-HMO) - PBO
  • Well Sense Pediatrics

Note: This provider may accept more insurance plans than shown; please call the practice to find out if your plan is accepted.

Patient Age Group
Provider Gender


Josephine Lok is an pediatric critical care physician at MassGeneral for Children.  She attended Harvard-Radcliffe College in Cambridge, MA where she obtained a B.A. in Biology.  She obtained her medical degree from the Albert Einstein College of Medicine in Bronx, New York, and completed residency in Pediatrics at the Floating Hospital for Children/Tufts-New England Medical Center,  Boston, MA.  After completing residency, she practiced primary care Pediatrics at the Apopka Family Health Center in Florida as part of the National Health Service Corps, then went on to Pediatric Critical Care Medicine fellowship at Johns Hopkins Hospital. During the fellowship, she became interested in Neuroscience research and trained in the laboratory of Dr. Lee Martin.   After completing training in Pediatric Critical Care, she joined the Pediatric Critical Care faculty at Boston Medical Center for two years, then the Pediatric Critical Care division at  Mass General Hospital for Children, where she continues her clinical practice as well as research into the pathophysiology of brain injury.   She is also involved in resident education, and co-directs the PICU simulation-based team training program with weekly sessions involving the multidisciplinary team of nurses, pharmacists, physicians, and respiratory therapists.



Research & Publications

Research Summary

My  research focuses on the neurovascular responses, in particular as it relates to the pathological processes after brain trauma.  I am also interested in the actions of neuregulin-1, an endogenous growth factor, within the neurovascular unit.  NRG1 is known to be important in the function of neurons and glia, but its activity in endothelial cells is not  well defined.  My goals are to 1) determine the roles played by NRG1/erbB signaling in the biology of brain microvascular endothelial cells; and 2) to investigate the neuroprotective potential of NRG1 in brain injury due to trauma and hemorrhage.  Data from my experiments demonstrated that NRG1 has key functions in brain microvascular cells; in particular, NRG1 prevents endothelial hyper-permeability due to cytokine injury, a significant finding given the many pathological processes that stem from microvascular hyper-permeability during CNS and systemic illness. 


View my most recent publications at PubMed

View my most recent publications at PubMed:

News & Events

  • Not Taking a Breath for Granted: Mikey's Story at FAC Grand Rounds

    At 3 months old, Mikey was diagnosed with laryngomalacia. This made it hard for him to breathe. It also meant that he might need surgery and a tracheotomy. On April 11, his parents, Katie and Michael, shared their family’s experience at this year’s Grand Rounds, sponsored by the Family Advisory Council at MassGeneral Hospital for Children (MGHfC).

  • Research of Josephine Lok, MD

    The microvascular endothelium is instrumental in many processes in the brain, including oxygen delivery, barrier function, and response to inflammation. After brain trauma, microvasculature disturbances lead to increased permeability, vasoconstriction, and capillary occlusion, events which amplify the primary insult. An understanding of these endothelial responses to injury is important in the investigation of neuroprotective strategies during brain injury. This topic forms one major area of my research.


Pediatric Critical Care Unit
55 Fruit Street
Boston, MA 02114-2696
Phone: 617-724-4380
Fax: 617-724-4391

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