European journal of pain : EJP
-
Review
Nature or nurture in low back pain? Results of a systematic review of studies based on twin samples.
Twin studies are becoming popular to investigate risk factors for low back pain (LBP) because they consider the genetic factor and allow for more precise estimates of risks. We aimed to identify and summarize the results of studies based on twin samples investigating risk factors for LBP. The MEDLINE, CINAHL, LILACS, Web of Science and EMBASE databases were searched. ⋯ Co-morbidities such as asthma, diabetes and osteoarthritis were associated with LBP (pooled OR ranging from 1.6 to 4.2). The contribution of genetics to LBP appears to be dependent on the severity of the condition. Twin studies could be better used to explore possible causation paths between lifestyle factors, co-morbidities and LBP.
-
Diurnal variations in pain have been observed in experimental protocols, post-surgery states and pathological conditions. Chronotype is considered to have the most profound effect on diurnal variations, and in addition, previous studies suggest that evening types may be more vulnerable to pain than morning types. This study aimed to examine whether or not morning and evening chronotypes differ in terms of their daily levels and diurnal fluctuations of pain sensitivity. ⋯ The results showed that chronotype could be an important factor determining sensitivity to pain, regardless of time of day.
-
Persistent pain resulting from peripheral injury/inflammation is associated with altered sensitivity to cutaneous stimuli, which can manifest as hyperalgesia. The role of oxidant stress in the development, progression and maintenance of hyperalgesia is still not understood. Furthermore, there appears to be a relationship between c-Src kinase in the pain pathway and oxidative stress. ⋯ These results confirm that prooxidant-activated c-Src plays a role in initiating and maintaining hyperalgesia by regulating a stimulus-response coupling between the inflamed tissue and the DRG in the pain pathway. Our data also suggest that oxidant-induced dysregulation of c-Src/nuclear factor kappa B coupling may contribute to our understanding of the transition from acute to chronic dysfunctional pain state seen in many human diseases.
-
The angiotensin II (AngII) receptor subtype 2 (AT2 R) is expressed in sensory neurons and may play a role in nociception and neuronal regeneration. ⋯ AT2 R antagonists could be particularly useful in the treatment of chronic pain and hypersensitivity associated with abnormal nerve sprouting.