Urinary NGF as A Biomarker for Acute Bacterial Cystitis
Condition: Urinary Tract Infection
MeSH terms: Urinary Tract Infections; Cystitis
Study type: Interventional

Summary: 
      This study will enroll 30 female patients with the first time urinary tract infection (UTI),
      30 female patients with recurrent UTI and 10 female without any prior history of UTI or
      urinary tract pathology will be invited to serve as the controls. Urine samples will be
      collected in the patients at baseline, 7 days after antibiotics treatment, and 2 weeks, 4
      weeks, 8 weeks, and 12 weeks. Urinalysis will be performed at each visit and urine culture
      will be performed at baseline and at the 2 weeks and 3 months visits. Urine samples at
      baseline and 3 months will be collected from the controls for comparison.
    

Detailed description: 
      Recurrent UTI is a very bothersome and a popular problem in the urogynecology clinical
      practice. According to the International Urogynecological Association (IUGA)/International
      Continence Society (ICS) joint report on the terminology for female pelvic floor dysfunction,
      recurrent UTI is defined as at least three symptomatic and medically diagnosed UTI in the
      previous 12 months. The previous UTI(s) should have resolved prior to a further UTI being
      diagnosed. Recurrent UTI is one of the most common diagnoses for female pelvic floor
      dysfunction.

      Patients with recurrent UTI might also have bladder irritative symptoms. Previous studies
      have revealed that patients with recurrent UTI have elevated urinary NGF, suggesting chronic
      inflammation is present in the bladder of these patients after resolution of UTI. The
      investigators preliminary results showed that chronic inflammation, urothelial cell apoptosis
      and impairment of barrier function of urothelial cells could be the underlying
      pathophysiology of recurrent UTI in women. Chronic inflammation might reside in the bladder
      wall after resolution of UTI, which might also cause urothelial dysfunction and defective
      barrier function and UTI will be easy to recur in these patients. This evidence provides a
      new focus for clinical management and future research of recurrent urinary tract infection.

      Based on these knowledge, the investigators hypothesized that chronic inflammation might
      reside in the bladder wall, which might also cause urothelial dysfunction and defective
      barrier function. UTI might be easy to recur in these patients with residual chronic bladder
      inflammation. If the investigators can determine complete resolution of the chronic
      inflammation after acute cystitis episode, it is possible to inhibit recurrent cystitis
      through treating the inflammation with anti-inflammatory agents.

      Nerve growth factor (NGF) is a small secreted protein which induces the differentiation and
      survival of particular target neurons. NGF has been implicated as a chemical mediator of
      pathology-induced changes in C-fiber afferent nerve excitability and reflex bladder activity.
      The levels of neurotrophic factors including NGF increase in the bladder after spinal cord
      injury (SCI) and increased levels of NGF have been detected in the lumbosacral spinal cord
      and dorsal root ganglion of rats after SCI. Chronic administration of NGF into the bladder of
      rats induces bladder hyperactivity and increases the firing frequency of dissociated bladder
      afferent neurons. Increased levels of urinary NGF have also been detected in BOO patients
      exhibiting overactive bladder (OAB) symptoms. Increased bladder tissue NGF was noted in
      patients with interstitial cystitis/painful bladder syndrome (IC/PBS). Recent research has
      focused on the urinary NGF levels in detecting OAB and IC/PBS in lower urinary tract
      dysfunction (LUTD). Evidences have shown that urinary proteins such as NGF and prostaglandin
      E2 levels increase in patients with OAB, sensory urgency and detrusor overactivity (DO).
      Patients with OAB-dry and OAB-wet have significantly higher urinary NGF levels compared to
      the control group and patients with increased bladder sensation. The urinary NGF levels
      increase physiologically with small scale in the normal subjects at urge to void but increase
      pathologically with large scale in OAB patients at small bladder volume and at urgency
      sensation. The urinary NGF levels decrease after antimuscarinic therapy and further decrease
      after detrusor botulinum toxin injections in refractory OAB. Put together, the urinary NGF
      levels seem to be a potential biomarker for diagnosis of OAB and the underlying chronic
      inflammation.

      Several urological diseases including bacterial cystitis, lower ureteral stone and urothelial
      cell carcinoma may develop storage symptoms mimicking OAB or IC/PBS. The urinary NGF levels
      are also elevated in these disorders. In the previous study the investigators found that UTI
      may increase NGF production in urine associated with urinary tract stones. Patients with
      resolution of UTI but also with persistent OAB may have high urinary NGF levels. These
      results provide evidence that urinary NGF is a product of inflammation in the urinary tract.
      Therefore, urinary NGF may be considered as a second-line product following urothelial damage
      or changes of urothelial environment that initiate the sensory nerve excitation and cause
      bladder hypersensitivity or DO. Measuring urinary NGF is a non-invasive tool to assess
      chronic inflammatory status and for longitudinal comparison of the treatment.

      It is essential to know whether the urinary NGF levels can also increase at acute cystitis
      episode and the production has a relation with the associated storage symptoms in different
      stage after antibiotics treatment. This study is designed to measure the urinary NGF levels
      in patients with acute cystitis and different stages after antibiotics treatment. If the
      urinary NGF levels have association with the underlying inflammation in the bladder wall, the
      investigators might use it as a biomarker to determine the status of resolution of the
      inflammation and provide physicians to decide how long should the investigators treat
      patients with acute cystitis.

      Materials and Methods

      This study will enroll 30 female patients with the first time UTI and 30 female patients with
      recurrent UTI (at least two previous UTI episodes in the latest 12 months) but have a recent
      acute episode. Ten age-matched women (30 to 50 years old) without any prior history of UTI or
      urinary tract pathology will be invited to serve as the controls. Urine samples will be
      collected in the patients at baseline, 7 days after antibiotics treatment, and 2 weeks, 4
      weeks, 8 weeks, and 12 weeks after the UTI episode. Urinalysis will be performed at each
      visit and urine culture will be performed at baseline and at the 2 weeks and 3 months visits.
      Urine samples at baseline and 3 months will be collected from the controls for comparison.

      All patients should be proven to have UTI by detecting pyuria in urinalysis (WBC>10 per high
      power field) and had a positive urine culture result. In addition, a kidney, ureter, and
      bladder (KUB) film, and renal sonography will be performed to exclude to possibility of
      urolithiasis or other urinary tract pathology. The one-day voiding diary will be requested to
      record at each visit to determine the functional bladder capacity (FBC) and frequency
      episodes per day. Bladder symptoms will be recorded by Overactive Bladder Symptom Score
      (OABSS) and visual analog scale of pain (VAS). In addition, uroflowmetry, including maximum
      flow rate (Qmax), voided volume and postvoid residual volume (PVR) will also be measured at
      visit 2. Urine samples at baseline and each visit after treatment will be collected at a
      comfortably full bladder and sent for NGF measurements. Antibiotics (Cephalexin 500mg Q6H)
      for 1 to 2 weeks will be started at the baseline until the urinalysis proven negative and
      urine culture turned to be negative. Then antimicrobial agent (Baktar 800mg h.s.) or
      anti-inflammatory agent (Celecoxib 200mg QD) will be randomly prescribed for UTI prophylaxis
      for 3 months after complete resolution of acute cystitis. All patients will be followed-up
      for up to one year to monitor whether they have occurrence of recurrent UTI.

      All urine samples will be collected with a full bladder and natural voiding. Measurement of
      urinary NGF levels will be performed by the ELISA method. Urine samples are not diluted.
      Voided urine is put on ice immediately and centrifuged at 3000 g for 10 min at 4 ◦C. The
      supernatant is separated into aliquots in 1.5 mL tubes and preserved in a -80 ◦C freezer. At
      the same time, 3 mL of urine is taken to measure urinary creatinine levels. Urinary NGF
      concentration is determined using the Emax ImmunoAssay System (Promega, Madison, Wisconsin,
      USA) with a specific and highly sensitive ELISA kit, which has a minimum sensitivity of 7.8
      pg/mL. The amount of NGF in urine samples fall below the detection limits of NGF assay was
      extracted from an NGF standard curve. All samples will be run in triplicate, urinary NGF
      levels without a consistent value in three measures will be repeated and the values will be
      averaged. The total urinary NGF levels are further normalized by the concentration of urinary
      creatinine (NGF/Cr level). The NGF/Cr levels are compared among all subgroups.

      Statistical analyses will be performed by a paired t-test for paired data in consecutive time
      points. Mann-Whitney test will be used for non-parametric analysis between different
      subgroups. A P-value of less than 0.05 is considered significant.

      Expected Results

      The investigators hypothesized that patients with recurrent UTI may have persistently
      elevated urinary NGF levels compared with those with the first time UTI. The urinary NGF
      levels will remain elevated in patients who have persistent OAB symptoms after acute cystitis
      episode and might be persistently higher than the controls after 3 months. Patients treated
      with anti-inflammatory agent might have lower urinary NGF levels at 3 months visit compared
      to those taking antimicrobials. The incidence of recurrent UTI in the following one year
      might be more in the patients treating with antimicrobials than those treating with
      anti-inflammatory agents.
    

Intervention name(s): Baktar 800mg h.s.; Celecoxib 200mg QD
Intervention type(s): Drug; Drug
Intervention description(s): Antimicrobial agent (Baktar 800mg h.s.); Anti-inflammatory agent (Celecoxib 200mg QD)
Other intervention name(s): Antimicrobial agent; Anti-inflammatory agent
Intervention MeSH terms: Anti-Infective Agents; Celecoxib; Anti-Inflammatory Agents
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Urinary tract infection; Urothelium; Inflammation; Apoptosis