Pain
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Microglia take on an altered morphology during chronic opioid treatment. This morphological change is broadly used to identify the activated microglial state associated with opioid side effects, including tolerance and opioid-induced hyperalgesia (OIH). Microglia display similar morphological responses in the spinal cord after peripheral nerve injury (PNI). ⋯ After PNI, we identify an early proliferative transcriptional event across models that precedes the upregulation of histological markers of microglial activation. However, we found no proliferative transcriptional response associated with opioid-induced microglial activation, consistent with histological data, indicating that the number of microglia remains stable during morphine treatment, whereas their morphological response differs from PNI models. Collectively, these results establish the diversity of pain-associated microglial transcriptomic responses and point towards the targeting of distinct insult-specific microglial responses to treat OIH, PNI, or other central nervous system pathologies.
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The co-occurrence of bruxism, temporomandibular disorders (TMDs), and headache is common in patients. However, there is conflicting evidence regarding whether this association is simply a result of their high prevalence or whether there are indeed causal relationships. This review provides an overview of the current state of research while taking into account the controversies surrounding research methods, particularly in definitions and diagnostic standards. ⋯ Treatment wise, it is important to differentiate all 3 conditions because treatment of one condition may have an effect on the other 2 without proving causality. For future research, it is crucial to establish greater consistency and applicability in diagnostic procedures and definitions. In addition, more experimental and clinical studies investigating the question of causality are needed.
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For decades, clinicians and researchers have observed bidirectional relationships between child development and the pain experience in childhood. Pain in childhood is an inherently developmental phenomenon, embedded in an iterative, time-dependent process that reflects individual biological, behavioral, social, psychological, and environmental characteristics that unfold across the early life span. Childhood pain can have wide ranging effects on brain development in ways that contribute-for better and worse-to social, emotional, and cognitive well-being in childhood and on into adulthood. ⋯ In this paper, pain will be considered as a determinant of development, and conversely development will be considered as a key determinant of a child's pain experience. We will discuss how intersectional identities (eg, gender, race, socioeconomic status) and associated social, structural, systemic, and physical environments influence the relationship between development and pain. Finally, we will identify what might be needed to think "developmentally" in ways that extend from the "bench side" in the lab to the "curb side" in the community, integrating a developmental perspective into research and clinical practice to achieve health accessibility and equity in pain care for all children across the developmental spectrum.