Single Cell RNA-Sequence Analyses Reveal Uniquely Expressed Genes and Heterogeneous Immune Cell Involvement in the Rat Model of Intervertebral Disc Degeneration.

Intervertebral disc (IVD) degeneration is characterized by a loss of cellularity, and changes in cell-mediated activity that drives anatomic changes to IVD structure. In this study, we used single-cell RNA-sequencing analysis of degenerating tissues of the rat IVD following lumbar disc puncture. Two control, uninjured IVDs (L2-3, L3-4) and two degenerated, injured IVDs (L4-5, L5-6) from each animal were examined either at the two- or eight-week post-operative time points. The cells from these IVDs were extracted and transcriptionally profiled at the single-cell resolution. Unsupervised cluster analysis revealed the presence of four known cell types in both non-degenerative and degenerated IVDs based on previously established gene markers: IVD cells, endothelial cells, myeloid cells, and lymphoid cells. As a majority of cells were associated with the IVD cell cluster, sub-clustering was used to further identify the cell populations of the nucleus pulposus, inner and outer annulus fibrosus. The most notable difference between control and degenerated IVDs was the increase of myeloid and lymphoid cells in degenerated samples at two- and eight-weeks post-surgery. Differential gene expression analysis revealed multiple distinct cell types from the myeloid and lymphoid lineages, most notably macrophages and B lymphocytes, and demonstrated a high degree of immune specificity during degeneration. In addition to the heterogenous infiltrating immune cell populations in the degenerating IVD, the increased number of cells in the AF sub-cluster expressing Ngf and Ngfr, encoding for p75NTR, suggest that NGF signaling may be one of the key mediators of the IVD crosstalk between immune and neuronal cell populations. These findings provide the basis for future work to understand the involvement of select subsets of non-resident cells in IVD degeneration.

Bioactive in situ crosslinkable polymer-peptide hydrogel for cell delivery to the intervertebral disc in a rat model.

Degeneration of the intervertebral disc (IVD) is associated with significant biochemical and morphological changes that include a loss of disc height, decreased water content and decreased cellularity. Cell delivery has been widely explored as a strategy to supplement the nucleus pulposus (NP) region of the degenerated IVD in both pre-clinical and clinical trials, using progenitor or primary cell sources. We previously demonstrated an ability for a polymer-peptide hydrogel, serving as a culture substrate, to promote adult NP cells to undergo a shift from a degenerative fibroblast-like state to a juvenile-like NP phenotype. In the current study, we evaluate the ability for this peptide-functionalized hydrogel to serve as a bioactive system for cell delivery, retention and preservation of a biosynthetic phenotype for primary IVD cells delivered to the rat caudal disc in an anular puncture degeneration model. Our data suggest that encapsulation of adult degenerative human NP cells in a stiff formulation of the hydrogel functionalized with laminin-mimetic peptides IKVAV and AG73 can promote cell viability and increased biosynthetic activity for this population in 3D culture in vitro. Delivery of the peptide-functionalized biomaterial with primary rat cells to the degenerated IVD supported NP cell retention and NP-specific protein expression in vivo, and promoted improved disc height index (DHI) values and endplate organization compared to untreated degenerated controls. The results of this study suggest the physical cues of this peptide-functionalized hydrogel can serve as a supportive carrier for cell delivery to the IVD. STATEMENT OF SIGNIFICANCE: Cell delivery into the degenerative intervertebral disc has been widely explored as a strategy to supplement the nucleus pulposus. The current work seeks to employ a biomaterial functionalized with laminin-mimetic peptides as a cell delivery scaffold in order to improve cell retention rates within the intradiscal space, while providing the delivered cells with biomimetic cues in order to promote phenotypic expression and increase biosynthetic activity. The use of the in situ crosslinkable material integrated with the native IVD, presenting a system with adequate physical properties to support a degenerative disc.

Balint syndrome.

We report a patient who presented with complaints of blindness following stroke and was subsequently diagnosed to have Balint syndrome.

A comparative study of pregnancy outcomes and menstrual irregularities in northern Indian patients with systemic lupus erythematosus and rheumatoid arthritis.

Systemic lupus erythematosus (SLE) can affect the menstruation, fertility, and pregnancy outcomes of the affected subjects. There is very little data on this aspect of the disease in Indian patients. Our aim was to study the menstrual, fertility, and pregnancy outcomes in these patients in comparison with patients of rheumatoid arthritis (RA) and also to study the effect of cyclophosphamide therapy on menstrual cycles in patients with SLE. Four hundred and twenty patients of SLE (210) and RA (210) were interviewed using a standard questionnaire and available medical records used. After disease-onset, the chances of adverse pregnancy outcomes were significantly more in patients with SLE compared to RA [OR = 5.17 (2.13-12.52); p ≤ 0.001]. Compared to the National average in India, the average number of living children is lesser in patients with RA (2.39 ± 1.39, p = 0.002), but more so in patients with SLE (1.44 ± 1.35, p = 0.001). A younger age at diagnosis and cyclophosphamide therapy was found to be independently associated with menstrual irregularities after disease-onset. We conclude that pregnancy outcome in patients with SLE in India is worse in comparison to patients with RA. Average family size of patients with SLE and RA is less when compared to National average in India. Patients with SLE are more prone for menstrual irregularities, especially those who receive cyclophosphamide treatment.