Sensory Phenotyping Research Articles

Neuropathic pain phenotyping as a predictor of treatment response in painful diabetic neuropathy: Data from the randomized, double-blind, COMBO-DN study

Sensory profiles are heterogeneous in neuropathic pain disorders, and subgroups of patients respond differently to treatment. To further explore this, patients in the COMBO-DN study were prospectively assessed by the Neuropathic Pain Symptom Inventory (NPSI) at baseline, after initial 8-week therapy with either duloxetine or pregabalin, and after subsequent 8-week combination/high-dose therapy. Exploratory post hoc cluster analyses were performed to identify and characterize potential subgroups through their scores in the NPSI items. In patients not responding to initial 60mg/d duloxetine, adding 300mg/d pregabalin for combination treatment was particularly effective regarding the dimensions pressing pain and evoked pain, whereas maximizing the duloxetine dose to 120mg/d appeared more beneficial regarding paresthesia/dysesthesia. In contrast, adding 60mg/d duloxetine to 300mg/d pregabalin in case of nonresponse to initial pregabalin led to numerically higher decreases in all NPSI dimensions/items compared to maximizing the pregabalin dose to 600mg/d. Cluster analysis revealed 3 patient clusters (defined by baseline scores for the 10 NPSI sensory items) with different pain profiles, not only in terms of overall pain severity, but also across NPSI items. Mean Brief Pain Inventory average pain improved in all clusters during combination/high-dose therapy. However, in patients with severe pain, the treatment effect showed a trend in favor of high-dose monotherapy, whereas combination therapy appeared to be more beneficial in patients with moderate and mild pain (not significant). These complementary exploratory analyses further endorse the idea that sensory phenotyping might lead to a more stratified treatment and potentially to personalized pain therapy.

Subgrouping of patients with neuropathic pain according to pain-related sensory abnormalities: a first step to a stratified treatment approach

Patients with neuropathic pain present with various pain-related sensory abnormalities. These sensory features form different patterns or mosaics-the sensory profile-in individual patients. One hypothesis for the development of sensory profiles is that distinct pathophysiological mechanisms of pain generation produce specific sensory abnormalities. Several controlled trials of promising new drugs have produced negative results, but these findings could have been a result of heterogeneity in the patient population. Subgrouping patients on the basis of individual sensory profiles could reduce this heterogeneity and improve trial design. A statistical categorisation of patients with neuropathic pain showed that subgroups of patients with distinct sensory profiles who perceive their pain differently do exist across a range of neuropathic disorders, although some distinct disorder-specific profiles were also detected. Results of the first clinical trials to use the subgroup approach at baseline could show a superior effect of the study drugs in specific subgroups, rather than in the entire cohort of patients. WHERE NEXT?: A new classification of neuropathic pain should take into account subgroups of patients with different sensory profiles. Sensory phenotyping has the potential to improve clinical trial design by enriching the study population with potential treatment responders, and might lead to a stratified treatment approach and ultimately to personalised treatment.

Texture analysis in an apple progeny through instrumental, sensory and histological phenotyping

Phenotypic analysis of texture traits was performed in an apple progeny by three complementary approaches: two classical instrumental measurements (compression and penetrometry), sensory assessment and histological screening. The progeny was composed of 141 individuals harvested over 2 years. Sensory and instrumental texture were assessed at harvest and after 2 and 4 months of cold storage. Histological screening was performed by combining macro-vision of outer parenchyma sections and image analysis on fruits after 2 months storage. Harvest year was observed to have a major impact on texture phenotypes followed by storage and genetic factors. Principal component analysis of data from the instrumental texture evaluations showed that the two methods complemented each other in characterizing the texture of the apple progeny. Compression parameters correlated better than penetrometry variables with sensory descriptors related to crispness, firmness, and graininess. Cell size distribution differentiated individuals in the apple progeny. It correlated with instrumental texture analyses and with juiciness perception. All measured texture related traits showed that they were all under genetic control with high heritability values. Higher values were obtained for fruits after 2 months storage. These results provide ground for future search of new apple texture QTLs.