Does granulocyte-colony stimulating factor stimulate peripheral nerve regeneration? An experimental study on traumatic lesion of the sciatic nerve in rats

AIM OF THE STUDY

To analyse the therapeutic potential of granulocyte-colony stimulating factor (G-CSF) treatment using a rat model of traumatic sciatic nerve lesion.

CLINICAL RATIONALE FOR THE STUDY

G-CSF has proven strong neurotrophic properties in various models of ischaemic and traumatic brain injury. Fewer studies exist regarding the influence of G-CSF on posttraumatic peripheral nerve regeneration. Currently, the possibilities of pharmacological prevention or treatment of mechanical nerve injury are limited, and there is an urgent need to find new treatment strategies applicable in clinical situations.

MATERIAL AND METHODS

A controlled traumatic right sciatic nerve lesion was set using a waterjet device. Three treatment groups were created. In the first group, G-CSF was administered after sciatic nerve injury. The second group received G-CSF before and after trauma, while the third group was treated with glucose 5%-solution. Sciatic nerve function was assessed clinically and electrophysiologically at day 1, and after weeks 1, 2, 4 and 6. Additionally, α-motoneurons of the spinal cord and sciatic nerve fibres were counted at week 6.

RESULTS

Clinically, rats in both G-CSF groups improved faster compared to the control group. Additionally, animals treated with G-CSF had a significantly better improvement of motor potential amplitude and motor nerve conduction velocity at week 6 (p < 0.05). Histologically, G-CSF treatment resulted in a significantly higher number of α-motoneurons and small myelinated nerve fibres compared to placebo treatment (p < 0.05).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Under G-CSF treatment, the recovery of motor nerve conduction velocity and amplitude was enhanced. Further, signs of nerve regeneration and preservation of α-motoneurons were observed. These results indicate that G-CSF might accelerate and intensify the recovery of injured nerves. Thus, treatment with G-CSF may be beneficial for patients with peripheral nerve damage, and should be explored in further clinical studies.

The genomic and clinical landscape of fetal akinesia

PURPOSE

Fetal akinesia has multiple clinical subtypes with over 160 gene associations, but the genetic etiology is not yet completely understood.

METHODS

In this study, 51 patients from 47 unrelated families were analyzed using next-generation sequencing (NGS) techniques aiming to decipher the genomic landscape of fetal akinesia (FA).

RESULTS

We have identified likely pathogenic gene variants in 37 cases and report 41 novel variants. Additionally, we report putative pathogenic variants in eight cases including nine novel variants. Our work identified 14 novel disease-gene associations for fetal akinesia: ADSSL1, ASAH1, ASPM, ATP2B3, EARS2, FBLN1, PRG4, PRICKLE1, ROR2, SETBP1, SCN5A, SCN8A, and ZEB2. Furthermore, a sibling pair harbored a homozygous copy-number variant in TNNT1, an ultrarare congenital myopathy gene that has been linked to arthrogryposis via Gene Ontology analysis.

CONCLUSION

Our analysis indicates that genetic defects leading to primary skeletal muscle diseases might have been underdiagnosed, especially pathogenic variants in RYR1. We discuss three novel putative fetal akinesia genes: GCN1, IQSEC3 and RYR3. Of those, IQSEC3, and RYR3 had been proposed as neuromuscular disease-associated genes recently, and our findings endorse them as FA candidate genes. By combining NGS with deep clinical phenotyping, we achieved a 73% success rate of solved cases.

Murine genetic deficiency of neuronal nitric oxide synthase (nNOS(-/-) ) and interstitial cells of Cajal (W/W(v) ): Implications for achalasia?

BACKGROUND AND AIM

Nitric oxide (NO) is an important inhibitory mediator of esophageal function, and its lack leads to typical features of achalasia. In contrast, the role of intramuscular interstitial cells of Cajal (ICC-IM) and vasoactive intestinal peptide (VIP) in lower esophageal sphincter (LES) function is still controversial. Therefore, we examined the function and morphology of the LES in vivo in NO-deficient (nNOS(-/-) ), ICC-IM-deficient (W/W(v) )-, and wild-type (WT) mice.

METHODS

Esophageal manometry was performed with a micro-sized transducer catheter to quantify LES pressure, swallow evoked LES relaxation, and esophageal body motility. The LES morphology was examined by semiquantitative analysis of the immunoreactivity (reduction grade I-IV) of neuronal NOS (nNOS), ICC-IM, and VIP and their correlation with esophageal function.

RESULTS

nNOS(-/-) in comparison to WT mice showed a significantly higher LES mean resting pressure with an impaired swallow induced relaxation, whereas W/W(v) mice had a hypotensive LES with decreased relaxation. W/W(v) and nNOS(-/-) mice demonstrated differing degrees of tubular esophageal dysfunction. The reduced immunoreactivity of nNOS correlated with an increased LES pressure and decreased LES relaxation, respectively. Cajal-cell reduction correlated with impaired LES relaxation, whereas VIP reduction revealed no correlation with esophageal function.

CONCLUSIONS

The reduction of ICC-IM and nNOS can cause dysfunction of the LES and esophageal peristalsis, whereas VIP reduction seems to have no effect. ICC-IM and nNOS deficiency might be independent relevant causes of esophageal dysfunction similar to that seen in human achalasia.

Distribution of the hematopoietic growth factor G-CSF and its receptor in the adult human brain with specific reference to Alzheimer's disease

The granulocyte colony-stimulating factor (G-CSF), being a member of the hematopoietic growth factor family, is also critically involved in controlling proliferation and differentiation of neural stem cells. Treatment with G-CSF has been shown to result in substantial neuroprotective and neuroregenerative effects in various experimental models of acute and chronic diseases of the central nervous system. Although G-CSF has been tested in a clinical study for treatment of acute ischemic stroke, there is only fragmentary data on the distribution of this cytokine and its receptor in the human brain. Therefore, the present study was focused on the immunohistochemical analysis of the protein expression of G-CSF and its receptor (G-CSF R) in the adult human brain. Since G-CSF has been shown not only to exert neuroprotective effects in animal models of Alzheimer's disease (AD) but also to be a candidate for clinical treatment, we have also placed an emphasis on the regulation of these molecules in this neurodegenerative disease. One major finding is that both G-CSF and G-CSF R were ubiquitously but not uniformly expressed in neurons throughout the CNS. Protein expression of G-CSF and G-CSF R was not restricted to neurons but was also detectable in astrocytes, ependymal cells, and choroid plexus cells. However, the distribution of G-CSF and G-CSF R did not substantially differ between AD brains and control, even in the hippocampus, where early neurodegenerative changes typically occur.

How to treat tumefactive demyelinating disease?

Glioma-like inflammatory demyelinating lesions can be found in patients with pre-diagnosed multiple sclerosis, but they have also been described as an isolated disease entity. The initial diagnostic work-up usually includes a biopsy for histopathological analysis. However, even after unambiguous histopathologic classification, tumefactive lesions pose a therapeutic challenge. Until now, there have been no guidelines on how to treat patients with these rare and extreme lesion phenotypes. Here we report a patient with a relapsing unifocal tumefactive demyelinating lesion. The patient initially showed a good response to steroid treatment, with full clinical recovery. However, after relapse of the same lesion, recovery was incomplete. Although immunosuppression was initiated, the patient presented with subsequent further deterioration. Only maximal escalation of immunosuppression was able to stop the inflammatory activity. Due to the length of time of the step-wise escalation treatment however, the lengthy lesion activity led to irreversible tissue destruction and residual non-remitting disability. Early aggressive treatment with an induction therapy regimen might be more appropriate for these rare and often strongly disabling lesion subtypes.